Devices, systems, and methods for using magnetic neuromodulation for the treatment of reduced cardiac output in humans, and related methods.

Abstract

A device for non-invasive medical intervention for users with reduced cardiac output is provided. The medical device includes at least one electrical coil and a power control circuit configuration. The power control circuit configuration is configured to provide an electrical output supplied to at least one electrical coil at a selected voltage and frequency to drive a current through at least one electrical coil to generate a time-varying magnetic field having a frequency and intensity that triggers a response that activates skeletal muscle to increase venous return of blood and lymphatic return of interstitial fluid in order to improve the user's resting cardiac output.

Description

[Technical Field]

[0001] Background of the Invention 1. Field of Invention The present invention generally relates to medical interventions for improving resting cardiac output in humans. Specifically, at least one embodiment relates to a device that generates a time-varying magnetic field to modulate neural activity in order to trigger a response that increases blood return to the heart from the lower part of the body. [Background technology]

[0002] 2. Explanation of related technologies While sedentary activity is associated with a reduced level of cardiac output in all individuals, this reduction can be particularly pronounced in older adults, whose cardiac output can generally drop to a level that does not allow them to maintain normal blood pressure (a condition known as "postural hypotension"), and can generate significant acute health problems. More importantly, sustained low cardiac output has been shown to result in reduced blood flow to all tissues of the body, leading to reduced metabolic activity in all tissues, and thus an increased risk of cardiac events, increased risk of dementia, and increased overall mortality.

[0003] The preferred intervention to increase cardiac output is increased physical activity. Exercise increases cardiac output in response to the demands of muscle activity and, as a direct result, to blood pressure and blood flow throughout the body. Increased blood flow allows for an increased metabolic rate of tissues throughout the body through enhanced delivery of both oxygen and nutrients. However, a large segment of modern society exhibits sedentary lifestyles that result in decreased cardiac output and associated complications. These complications may include, among others, an increased risk of cardiovascular disease, diabetes, osteoporosis, and reduced lifespan. The U.S. Public Health Service has determined that, for adults, a minimum level of 30 minutes of moderate activity per day is sufficient to overcome the negative effects of sedentary behavior.

[0004] The challenge in implementing exercise strategies as a preventative health measure is that most Americans are unable or unwilling to follow exercise recommendations without strict supervision. Numerous factors explain this hesitation, including the following: many people don't like sweating; many find it difficult to fit exercise prescriptions into their daily routines; and many older adults worry about falling and getting injured. Specifically, walking outdoors during the winter months in the northern United States or the summer months in the southern United States is not realistically feasible for many older adults. While exercise equipment can be used at home, such equipment can be expensive and take up a lot of space in a home or apartment. In addition, many people are hesitant to operate exercise equipment or worry about repetitive joint injuries associated with the continuous use of such equipment.

[0005] The heart muscle can circulate a sufficient amount of blood throughout the body (approximately 5-7 liters / minute for a young, healthy adult) when a person is in a supine position (e.g., lying down). However, when a person is in an upright position (sitting or standing), cardiac output decreases if there is insufficient residual pressure in the venous system to return blood from the lower body to the heart (a vertical distance of 1-1.5 meters) and adequate venous return is not present. While venous pressure in a supine position is usually only about 20 mmHg, when a person is upright, pressure exceeding 100 mmHg is required to pump blood from the feet back to the heart against gravity. Therefore, proper circulation critically depends on a process called "skeletal muscle pumping" to move and return blood to the heart in an upright person. While all muscles play a certain role in pumping blood during physical activity (i.e., breathing and exercise), the soleus muscle is the dominant muscle during skeletal muscle pumping when an individual is sitting or standing still. These are specialized deep postural muscles located within the lower limbs, responsible for returning over 70% of the blood from the lower body to the heart when an individual is resting in an upright position. The soleus muscle is commonly called our "second heart" because of this crucial role in ensuring venous return.

[0006] Without adequate secondary cardiac activity, gravity causes both blood and interstitial fluid (fluid that seeps from capillaries into surrounding tissues) to accumulate in the lower body (the part of the body below the heart) whenever a person is sitting or standing still. Inadequate secondary cardiac activity can lead to complications through three different mechanisms. The first is a complication that arises directly from fluid accumulation in the lower extremities. Commonly observed symptoms of excessive lower extremity fluid accumulation include swollen ankles / feet / legs, lower extremity joint pain, nocturnal leg cramps, varicose veins (leading to venous deficiency and deep vein thrombosis), sleep apnea, and osteoporosis.

[0007] Secondly, fluid retention in the lower extremities and the resulting reduced fluid return to the heart lead to a reduced resting cardiac output. This reduced resting cardiac output, in turn, results in decreased blood flow to all tissues of the body, limiting the flow of oxygen and nutrients and thus leading to decreased metabolic activity within the tissues. Common symptoms of low cardiac output due to excess fluid retention include chronic coldness of the hands and feet, peripheral neuropathy, chronic fatigue, delayed wound healing, digestive problems, and uncontrollable weight, all resulting from reduced resting metabolic activity. In fact, these signs and symptoms are well-established indicators of secondary cardiac failure in individuals who do not have a diagnosis of heart failure.

[0008] A third category of complications arising from inadequate secondary cardiac activity is the progression of chronic hypotension (orthostatic hypotension). This condition occurs when vasoconstriction is insufficient to compensate for the decrease in cardiac output and is most common in the elderly. A resting diastolic blood pressure (DBP) in the range of 80–90 mmHg is associated with the lowest all-cause mortality rate. Moreover, the patent applicant's own study of the distribution of resting diastolic blood pressure among a sample of elderly (55–90 years) men and women found that more than 75% of elderly individuals had a resting diastolic blood pressure of less than 80 mmHg. In this study, resting diastolic blood pressure was obtained after individuals had been sitting for at least 10 minutes.

[0009] Low diastolic blood pressure levels are also linked to low cognitive ability. For example, using an FDA-approved cognitive assessment system, a cognitive ability score below 75 is considered to be within the range of mild cognitive impairment, while a score below 50 indicates moderate or severe cognitive impairment. A study of cognitive ability in relation to resting diastolic blood pressure in a selected group (individuals over 60 years of age) identified a significant correlation between low cognitive ability and low diastolic blood pressure levels (p=0.004). This study found that in subjects in this group, the mean cognitive ability score was below 75 for diastolic blood pressure values ​​below 80 mmHg.

[0010] While gravity affects blood circulation in all animals, blood flow in humans is particularly affected by gravity for three reasons. Firstly, we are relatively tall animals and maintain an upright posture for most of the day. Secondly, our skin is very flexible. While other tall animals exist (e.g., giraffes, ostriches, horses), the skin on the legs of these upright animals is very taut and does not expand easily. As a result, fluid cannot be substantially stored in the lower limbs of their bodies. Thirdly, in humans, the heart is positioned high in the body so that most of the blood in the human body is below the level of the heart, whereas in most animals, more than 70% of the blood in the body is normally held above the heart.

[0011] For these reasons, humans needed to evolve means to protect themselves from gravity in relation to our blood supply. Specifically, humans needed a means to pump blood from the lower body back to the heart when we are upright. The soleus muscle evolved to perform this task. The soleus muscle in humans became a specialized muscle containing multiple venous torsos capable of holding a large volume of blood and interstitial fluid. When the soleus muscle contracts, sufficient pressure (over 200 mmHg) is generated within the muscle to drive these isolated fluids back to the heart (blood is returned via blood vessels, and interstitial fluid via the lymphatic system).

[0012] Several studies demonstrate the effect of soleus muscle activity when an individual transitions from a mobile (walking) state to a standing (sitting) position. For example, even in healthy individuals, cardiac output during sitting can decrease by up to 25-30% in the first 5-10 minutes as fluid (blood and interstitial fluid) accumulates in the lower extremities. The subsequent increase in cardiac output usually occurs when the soleus muscle is then activated and begins to pump the accumulated fluid back to the heart, enabling the maintenance of normal resting cardiac output (blood flow at approximately 4-6 l / min).

[0013] Conversely, individuals with inadequate soleus muscle activity experience persistent fluid retention when seated or standing, resulting in a continuous decline in cardiac output throughout the diastolic period. For example, in a sample of 25 women aged 45–85 years, cardiac output (resting cardiac output) was measured while seated. Persistent retention was reflected in a decline in cardiac output that lasted for more than 90 minutes after individuals assumed a seated position. The cardiac index is cardiac output (cardiac output divided by body surface area) adjusted for body size, and allows for averaging of cardiac output data across a group of individuals. The mean decline in cardiac output in this test group was over 35% during the 90-minute test period. Longer-term studies have shown that seated individuals can retain fluid for more than 4 hours, and cardiac output continues to decline throughout the entire period.

[0014] The soleus muscle is a postural muscle and is primarily activated during specific postural activities. For example, it is necessary during prolonged standing activities (the rocking motion of a person standing without support is due to the periodic contraction of the soleus). Whenever the soleus contracts, the standing individual is pulled backward, and simultaneously, blood and interstitial fluid are pumped back to the heart. When the soleus relaxes, the individual begins to lean forward. Therefore, the soleus, through slow and periodic contractions, helps maintain an upright posture, and also acts like the cardiac muscle in ensuring that the circulatory system can function effectively when people are upright.

[0015] While the soleus muscle is used to maintain an upright posture, its primary evolutionary postural role is thought to be maintaining balance during squatting. This is because, when our knees are bent, the gastrocnemius muscle (a large medullary muscle in the back of the calf) cannot generate significant contractile force, so the only way to extend the leg (i.e., plantarflex) is to use the soleus muscle. Squatting is a natural resting posture for humans, and prolonged squatting activity during the day is how our ancestors maintained the soleus muscle. Many cultures still utilize squatting as a common resting posture. However, with the development of inexpensive, mass-produced chairs, sitting has become the most common resting posture for most people in the developed world. This shift in behavior has contributed to a decrease in the use of the soleus muscle in adults in modern society.

[0016] Generally, while children and young people squat normally throughout the day, most adults living in the modern world no longer utilize their soleus muscles sufficiently during the day to maintain their health. As a result, during sitting, most older adults experience extensive fluid retention in the lower body, leading to a wide range of the aforementioned complications. Complications indicating soleus muscle dysfunction include lower limb complications such as foot and ankle swelling, varicose veins, deep vessel thrombosis, peripheral neuropathy, chronic cold extremities, and nocturnal leg cramps. In addition, insufficient blood return to the heart limits cardiac output, thus reducing the body's resting metabolic rate, making it difficult to maintain a normal weight, leading to the progression of chronic fatigue syndrome and delayed wound healing. Finally, a corresponding decrease in cerebral blood flow is associated with the progression of cognitive impairment, Alzheimer's disease, Parkinson's disease, macular degeneration, hearing loss, and attention deficit disorder. A physician who discovers a patient has any of the above conditions without a diagnosis of heart failure will recognize that the individual is likely to develop secondary heart failure and may conduct additional tests to confirm this.

[0017] Several studies have shown that 40%–50% of older adults have one or more of the above complications severe enough to significantly reduce their quality of life. Because soleus muscle dysfunction is a highly age-dependent condition, the vast majority of older adults are unable to maintain normal levels of cardiac output while standing (sitting or standing still). One classic study (Katori (1979)) showed that the standard cardiac output found in an 80-year-old standing upright is typically less than two-thirds that of a 20-year-old. This study of cardiac output in a group of 20–80-year-old individuals in a semi-sitting position found that cardiac output peaked at nearly 8 l / min in younger individuals and declined to less than 5 l / min by age 80. This 40% decline in cardiac output with age is further exacerbated by the effects of orthostatic stress during prolonged sitting or standing, which can reduce cardiac output by another 30–50%.

[0018] Conventional methods employ mechanical stimulation of the soleus muscle postural reflex arc to promote recovery from secondary heart failure. Meissner's corpuscles, located on the plantar surface of the foot, are a type of mechanoreceptor capable of detecting skin displacement on the foot. Skin displacement (vertical or horizontal) on the anterior plantar surface stimulates Meissner's corpuscles, triggering a reflex response and causing contraction of the soleus muscle. Conversely, activation of Meissner's corpuscles in the heel region of the foot relaxes the soleus muscle.

[0019] Like all mechanoreceptors, Meissner's corpuscles are activated by specific mechanical stimuli applied at a selected frequency, triggering the soleus postural reflex arc and subsequently leading to activation of the soleus muscle. However, while mechanical stimulation strategies for activating the soleus muscle have been shown to be effective interventions for soleus muscle retraining, this method actually has numerous limitations that negatively impact its usefulness. For example, suitable mechanical devices for use in activating the soleus muscle are relatively large and heavy devices containing significant moving parts. In addition, the mechanical sensation of stimulation on the foot can be unpleasant for some people. Furthermore, the mechanical nature of these devices also makes them relatively noisy, limiting their usefulness in quiet environments or in situations where multiple devices would be used simultaneously.

[0020] The use of electrical nerve stimulation devices applied to the human body is also known. However, any electrical nerve stimulation requires the placement of electrodes in contact with the skin to guide a sufficient current into the tissue to modify nerve activity. As a result, any electrical nerve stimulation intervention in the foot requires the patient to first remove their shoes and socks / stockings in order to effectively apply the electrical stimulation. This requirement is very inconvenient for many people, especially the elderly. Furthermore, sustained electrical stimulation can lead to rapid nerve inactivation due to repeated depolarization of the same nerve segment. Direct electrical nerve simulation also increases the risk of inappropriately high levels of exposure to the device's electrical output in the event of circuit failure, as well as the risk of stimulating currents interacting with other biomedical devices the patient may have in their body (e.g., pacemakers, defibrillators, bone growth stimulators).

[0021] The use of magnetic nerve stimulation devices applied to the human body is also known. This is a much more recent area of ​​research than electrical nerve stimulation. According to the current consensus of the scientific / engineering community, time-varying magnetic fields must be induced into the target tissue to produce an electric field in the range of 5–25 V / m or more in order to obtain consistent nerve excitation. Achieving this type of stimulation typically requires a time-varying magnetic flux in the range of 15–50 Tesla / second that is sustained for a period of at least 300 microseconds. These flux pulses are typically applied at a rate of 1–1000 Hz, so that each stimulation generates a refractory period after which the nerve cannot be re-excited. As a result, conventional techniques developed to achieve magnetic nerve stimulation are designed to generate relatively large magnetic flux densities for short periods at low stimulation rates.

[0022] However, typical magnetic nerve stimulation devices described to date have many of the same limitations as mechanical devices used to stimulate mechanoreceptors on the heel of the foot: namely, they are large, expensive, and high-power devices that are not useful for low cost, ease of use, or portability. In addition, the high voltages and currents utilized in these devices raise many safety concerns that can significantly increase the time and expense required to obtain regulatory approval to bring the device to market. The IEEE Standards Committee has established and published standard specifications for safety levels regarding human exposure to magnetic fields. This standard specification document is titled "IEEE Standards for Safety Levels with Respect to Human Exposure to Electric, Magnetic, and Electromagnetic Fields, 0Hz to 300GHz". These standard specifications identify the magnetic flux density levels at which a person can be safely exposed. Regarding magnetic field exposure at frequencies above 3KHz, these new exposure guidelines limit hand and foot exposure (of an individual who is exposed knowingly within a restricted environment) to a magnetic flux density of less than 353 millitesla RMS (494 millitesla peak). However, head and torso exposure is limited to 0.615 millitesla RMS (0.87 millitesla peak) within a restricted environment. These limitations regarding magnetic flux density represent common knowledge among those skilled in the art. The limits also reflect the understanding of those skilled in the art. Magnetic field exposure at frequencies above 3KHz with a magnetic flux density of less than 0.87 millitesla peak has no significant effect on human physiology. Summary of the Invention Problems to be Solved by the Invention

[0023] Summary of the Invention Therefore, there is a need to provide patients with the ability to improve or restore the ability to enhance venous and lymphatic blood return to the heart in an adult sitting or standing still to normalize cardiac output by activating the soleus muscle, as well as a number of symptoms associated with both lower limb fluid retention and low cardiac output and orthostatic hypotension. Means for Solving the Problems

[0024] Embodiments of the present invention provide alternative methods for improving cardiac reflux to reduce complications of fluid retention, improving blood flow to all tissues of the body, and producing increased levels of metabolic activity in tissues without exercise. While achieving the foregoing objectives, these embodiments reduce or eliminate risks and other objections that people have with traditional exercise prescriptions and / or traditional nerve and muscle stimulation techniques.

[0025] The present applicants have discovered that plantar nerve behavior can be effectively modulated by a low-intensity time-varying magnetic field in a manner that activates the soleus muscle reflex arc. Time-varying magnetic fields easily penetrate not only living tissues but also all non-magnetic artificial materials. As a result, in various embodiments, time-varying magnetic fields are utilized to directly modulate plantar nerve activity. These techniques are effective even when an individual is wearing shoes and socks. In addition, embodiments also provide magnetic fields that reach deep into tissues as needed, for example, such that effective intervention is available from the upper part of the foot or one side of the foot in some embodiments. Further, various embodiments effectively activate the soleus muscle reflex arc by using a time-varying magnetic field while bypassing Meissner's corpuscles and other skin surface receptors so as to cause no annoying sensations felt by the user.

[0026] The applicant has also discovered that a treatment activating the soleus muscle via a time-varying magnetic field applied to the plantar region of the foot at an intensity below which it is understood to provide nerve excitation can be employed to successfully increase resting cardiac output. Accordingly, according to several embodiments, the treatments described herein modulate intrinsic nerve activity to effectively treat patients with reduced cardiac output. Furthermore, according to various embodiments described herein, successful treatment is provided by the application of a magnetic field at a magnetic flux density below the safe exposure level established in the relevant industrial standards. This highlights the importance of the applicant's discovery, as it informs those otherwise skilled in the art that the standards state that "the magnetic flux densities of the magnetic fields included in these treatment protocols are negligible when applied to human subjects."

[0027] According to various embodiments, several systems, devices, and methods focus on directly modulating the plantar nerve located deep within the tissue while minimizing the intensity of magnetic field exposure. The patent applicant has identified the optimal exposure site or area for the stimulus treated for the most effective activation of the soleus muscle reflex arc by using a time-varying magnetic field. Various embodiments also optimize the magnetic field frequency, magnetic field intensity, magnetic field orientation, and duty cycle for the application of the magnetic field used in magnetic neuromodulation for soleus muscle activation.

[0028] According to one embodiment, a device is provided for a non-invasive medical intervention of a user by reducing cardiac output. In various embodiments, the medical device includes at least one electrical coil and a power control circuit configuration. The power control circuit configuration is configured to provide an electrical output supplied to at least one electrical coil at a selected voltage and frequency to drive a current through at least one electrical coil to generate a time-varying magnetic field having a frequency and intensity that triggers a response that activates skeletal muscle to increase venous return of blood and lymphatic return of interstitial fluid in order to improve the user's cardiac output.

[0029] According to several embodiments, the frequency of the time-varying magnetic field includes a range of 2 to 16 kHz, and the magnetic flux density of the time-varying magnetic field includes a range of 2 to 8 Gauss peaks (0.2 to 0.8 millitesla). According to another embodiment, the device generates a time-varying magnetic field for a period of 50 to 90 seconds at a duty cycle of 30% to 50%.

[0030] According to several embodiments, the device is employed in a method for treating a medical condition in a human subject, the method comprising positioning at least one electrical coil adjacent to a treatment area of ​​the human subject, the treatment area including a target nerve, oriented the at least one electrical coil so that the time-varying magnetic field generated by the at least one electrical coil is localized perpendicular to the target nerve, and operating the device to generate a time-varying magnetic field at a frequency and intensity that triggers a response that activates skeletal muscle in order to improve the resting cardiac output of the human subject by increasing venous return of blood and lymphatic return of interstitial fluid.

[0031] According to several other embodiments, the device is employed in a method for treating a medical condition in a human subject, the method comprising applying a time-varying magnetic field to a treatment area positioned within the foot of a human subject, and selecting the frequency of the time-varying magnetic field, the magnetic flux density of the time-varying magnetic field, the duration of application of the time-varying magnetic field, and the duty cycle of application of the time-varying magnetic field to trigger a response that activates the soleus muscle to increase venous and lymphatic blood return and improve the resting cardiac output of the human subject.

[0032] In another embodiment, a method is provided for improving cardiac output, comprising employing a device comprising at least one electrical coil. In various embodiments, the method comprises positioning at least one electrical coil adjacent to a treatment area of ​​a user, wherein the treatment area includes a target nerve; oriented the at least one electrical coil so that a time-varying magnetic field generated by the at least one electrical coil is localized perpendicular to the target nerve; and operating the device to generate a time-varying magnetic field at a frequency and intensity to trigger a response that activates skeletal muscle to improve the user's cardiac output by increasing venous blood return and interstitial fluid lymphatic return.

[0033] In another embodiment, this method of improving cardiac output is included in methods of treating undesirable medical conditions, which are selected from the group consisting of heart failure, resistant hypertension, cognitive impairment, delayed wound healing, macular degeneration, age-related hearing loss, osteoporosis, and sleep apnea.

[0034] In yet another embodiment, this method of improving cardiac output is employed in a method of increasing cerebral blood flow.

[0035] In yet another embodiment, this method of improving cardiac output is employed in a method of normalizing blood pressure in patients diagnosed with chronic hypotension.

[0036] In another embodiment, a method is provided for improving cardiac output using a device comprising at least one electrical coil. In various embodiments, the method includes positioning at least one electrical coil adjacent to the surface of a user's treatment area, the treatment area including a target nerve; oriented the at least one electrical coil so that the time-varying magnetic field generated by the at least one electrical coil is localized perpendicular to the target nerve; and operating the device to generate a time-varying magnetic field with a frequency in the range of 2 to 16 kHz and a magnetic flux density of 2 to 8 Gauss peaks to trigger a response that activates skeletal muscle to improve the user's cardiac output by increasing venous return of blood and lymphatic return of interstitial fluid. In another embodiment, the method includes generating a time-varying magnetic field for a period of 50 to 90 seconds at a duty cycle of 30% to 50%.

[0037] In yet another embodiment, a method is provided for treating an individual with an undesirable medical condition at least partially resulting from reduced cardiac output. According to some embodiments, the method includes applying a time-varying magnetic field to a treatment area positioned within the individual's foot, and selecting the frequency of the time-varying magnetic field, the magnetic flux density of the time-varying magnetic field, the duration of application of the time-varying magnetic field, and the duty cycle of application of the time-varying magnetic field to trigger a response that activates the soleus muscle to improve the user's cardiac output by increasing venous and lymphatic blood return.

[0038] Unless otherwise expressly stated herein, the term “cardiac output” means resting cardiac output. A person skilled in the art will recognize, based on the disclosures provided herein, that cardiac output values ​​and related values ​​(such as cardiac output and cardiac output indices recorded during periods of inactivity by the subject (e.g., resting standing, sitting, or lying down)) relate to resting cardiac output even if such periods immediately follow periods of physical activity by the subject. A person skilled in the art will also recognize, based on the disclosures provided herein, that any of the aforementioned values ​​recorded during periods of exercise or other activities performed by the subject, such as walking, toe raises, or step-ups, do not constitute resting cardiac output.

[0039] As used herein, the term “user” refers to a subject receiving treatment in the form of a time-varying magnetic field. Therefore, those skilled in the art will recognize, based on the disclosures provided herein, that the user is the patient, while the device employed to provide treatment may be operated by another person. Furthermore, the embodiments shown and described herein enable direct self-treatment by a patient by using a device for delivering a time-varying magnetic field to a patient's treatment area, office, or medical facility in the home, without the assistance of a medical professional or any other individual.

[0040] Brief explanation of the drawing The attached drawings are not intended to be drawn to actual size. In the attached drawings, identical or nearly identical parts shown in various drawings are represented by similar reference numerals. For clarity purposes, not all parts can be labeled in every drawing. [Brief explanation of the drawing]

[0041] [Figure 1] This shows a plot of cardiac output versus time including the period during which a magnetic field is applied to the subject's feet, according to one embodiment. [Figure 2] This shows a plot of vascular resistance versus time including the period during which a magnetic field is applied to the subject's foot according to one embodiment. [Figure 3] A bar graph is shown illustrating the change in the gradient of vascular resistance resulting from the application of a magnetic field to the subject's foot at a selected frequency according to one embodiment. [Figure 4] This figure shows a plot of the change in cardiac output index versus the peak magnetic flux density of the magnetic field applied to the subject's feet according to one embodiment. [Figure 5] This shows the location of nerves within the human foot, as viewed from the sole. [Figure 6] This shows a plot of changes in cardiac output in another embodiment versus the peak magnetic flux density of the magnetic field applied to the subject's feet. [Figure 7]This figure shows a plot of the change in cardiac output index versus the duty cycle of the magnetic field applied to the subject's feet according to one embodiment. [Figure 8] This figure shows a plot of changes in cardiac output in one embodiment versus the on-time of magnetic field application to the subject's feet. [Figure 9] This shows a plot of cardiac output indices for a seated individual with and without a magnetic field applied to the subject's feet according to one embodiment. [Figure 10] This shows a plot of cardiac output of a resting, standing individual subject with and without a magnetic field applied to their feet according to one embodiment. [Figure 11] The electrical circuit configuration included in a device employed to generate a magnetic field for application to a subject's foot according to one embodiment is shown. [Figure 12] This shows a top view of a device configured to generate a magnetic field for application to a subject's foot according to one embodiment. [Figure 13] A cross-sectional view of the apparatus shown in Figure 12 according to one embodiment is shown. [Figure 14] Figure 12 shows the device adopted by a user according to one embodiment. [Modes for carrying out the invention]

[0042] Detailed explanation The present invention is not limited in its applications to the details of the construction and arrangement of components described in the following specification or shown in the accompanying drawings. The present invention is capable of carrying out other embodiments and can be carried out or performed in a variety of ways. Furthermore, the language and terminology used herein are for illustrative purposes only and should not be considered limiting. The use of “includes,” “has,” “contains,” “involves,” and variations thereof means that additional items are included as well as the items listed below and their equivalents.

[0043] The applicant has designed, constructed, and tested various embodiments of a device for delivering a control magnetic field to the plantar nerve. This testing has enabled the development of a therapeutic device that provides magnetic nerve modulation for highly effective treatment of reduced cardiac output in human patients. Furthermore, the testing described herein has provided the applicant with previously unknown insights into the optimal magnetic field orientation, frequency, intensity, duty cycle, and treatment duration that influence the improvement of soleus muscle activity that can be sustained during the treatment period in which the device is actively employed by the patient.

[0044] Referring to Figure 1, a plot 100 of "cardiac output index" versus "time including the period during which the magnetic field is applied to the subject's feet" according to one embodiment is shown. Figure 1 shows the X-axis for time (minutes) and the cardiac output index (milliliters / m³). 2 The Y-axis includes ). Plot 100 shows a typical response to neuromodulation of the plantar nerve provided by an electromagnetic therapy device. The horizontal dashed line represents the value of cardiac output indices that are expected to decrease after the transition from standing to sitting in healthy individuals of the same age who are not exposed to fluid retention in the lower extremities. A decrease in cardiac output indices of approximately 20% is expected for these healthy individuals.

[0045] Here, the subject is a 68-year-old sitting individual with known soleus muscle dysfunction. Data points are cardiac output index measurements recorded from the time the subject remained seated up to 70 minutes into the study. A thick vertical line positioned at the 30-minute mark represents the time when the magnetic field was applied. The plot demonstrates that the subject experienced a significant and steady decline in cardiac output index while seated. The data show approximately a 50% decrease in cardiac output index measurements during the initial 30-minute period prior to the application of the time-varying magnetic field to the treatment area.

[0046] At the 30-minute mark, a time-varying magnetic field is applied to the treatment area (i.e., the central region of the anterior plantar surface of the subject's feet, both the right and left). In this example, a high-frequency, low-flux-density magnetic field is applied to the treatment area. Specifically, a sinusoidal magnetic field is provided at 4 kHz and a peak value of 0.8 mT. According to this embodiment, a 33% duty cycle is employed during treatment. The subject experiences an immediate increase in cardiac output upon initial application of treatment. This is followed by a steady increase over the next 40 minutes, resulting in an approximately 45% increase in the cardiac output index. This returns the subject's cardiac output to the level expected to be experienced by a healthy person while seated.

[0047] In addition to increased venous return, activation of the soleus muscle also works to remove interstitial fluid from the lower extremities, thereby reducing tissue pressure within the lower extremities. The combined effect of increased venous return and removal of interstitial fluid from the lower extremities results in a decrease in vascular resistance. This leads to a significant improvement in blood flow to the lower body. Referring here to Figure 2, a plot of vascular resistance versus time is shown in one embodiment in which a time-varying magnetic field is applied to the feet of a subject. Figure 2 shows the x-axis for time (minutes) and vascular resistance (mmHg / milliliter / m²). 2The Y-axis includes ) and includes measured systolic resistance (represented by square points) and measured diastolic resistance (represented by circular points). Here, vascular resistance is calculated as blood pressure (BP) divided by the cardiac output index. The data points are values ​​of each type of vascular resistance recorded from the time the subject has been seated up to 120 minutes. Again, the thick vertical line positioned at the 60-minute mark represents "the time when treatment begins using a sinusoidal magnetic field and a 0.8 mT peak value provided at 4 kHz". Again, the embodiment shown is for a magnetic field with a 33% duty cycle employed during treatment. The plot includes curve fits for each change in pre-treatment change in systolic resistance (upper of the two leftmost sloped lines) and pre-treatment change in diastolic resistance (lower of the two leftmost sloped lines). The plots also include curve fits for changes in systolic resistance during treatment (the upper of the two rightmost sloped lines) and changes in diastolic resistance during treatment (the lower of the two rightmost sloped lines). Each of these represents the rate of change and the direction of that change in the respective measurement.

[0048] Plot 200 shows a representative effect of magnetic field exposure to the plantar nerve on vascular resistance. During sitting, blood and interstitial fluid retention leads to both a decrease in venous return to the heart (decreased cardiac output) due to increased tissue pressure and compression of the lower limb capillaries (vasoconstriction), resulting in a decrease in cardiac output and an increase in blood pressure. This is reflected in the rapid increase in vascular resistance during sitting. For example, the slopes of systolic and diastolic resistance, respectively, in the two leftmost curve fits reflect the total increase in these values ​​during the first 60 minutes of sitting. The decrease in vascular resistance begins when the application of a sinusoidal magnetic field to the treatment area starts at the 60-minute mark. This is a result of activation of the soleus muscle, which improves venous return to the heart along with the removal of interstitial fluid from the lower limb tissues. The total decrease is indicated by the negative values ​​of the slopes of systolic and diastolic resistance, respectively, shown in Plot 200.

[0049] The applicant has found that "the therapeutic effect can be improved by selecting a sinusoidal frequency of a time-varying magnetic field, which is found to cause the vascular resistance to decrease most rapidly over the control test period, as this also provides the most substantial increase in cardiac output and a decrease in fluid retention over time." Referring here to Figure 3, a bar graph 300 showing the change in the gradient of vascular resistance resulting from the application of a magnetic field to the subject's foot at a selected frequency is shown according to one embodiment. Figure 3 shows the X-axis of frequency (KHz) and the change in the gradient of vascular resistance (millimeters Hg / ml / m²). 2 The Y-axis includes ( / min). Bar graph 300 includes the slope values ​​of systolic vascular resistance, indicated by the use of dark-shaded bars, and the slope values ​​of diastolic resistance, indicated by the use of gray-shaded bars. Here again, vascular resistance is calculated as blood pressure (either systolic or diastolic) divided by the cardiac output index.

[0050] The evaluation shown in Figure 3 is for a size of approximately 16 cm at 2 kHz, 4 kHz, 8 kHz, and 16 kHz, respectively. 2 This includes determining vascular resistance when a subject is treated with a time-varying sinusoidal magnetic field applied to an area within the anterior plantar surface. Slope values ​​showing both the rate of change in systolic and diastolic vascular resistance at a control frequency of 0 kHz are also shown in plot 300. These results indicate that treatment of the plantar nerve with the application of a high-frequency time-varying magnetic field reduces vascular resistance. This contrasts with the control, shown by the two leftmost bars, which each show an increase in both systolic and diastolic vascular resistance.

[0051] These results also indicate that the most effective frequency range for treatment with local magnetic exposure to plantar nerve endings is within the range of 2 kHz to 8 kHz, with the optimal frequency being approximately 4 kHz. For example, the rate of reduction in both systolic and diastolic vascular resistance is more than twice as high with treatment using a 4 kHz sinusoidal field compared to when either a 2 kHz or 8 kHz sinusoidal field is used for treatment. The applicant found that "these effects are observed in both increased cardiac output, reflecting increased venous return from the lower extremities to the heart, and corresponding decreases in blood pressure and tissue pressure resulting from increased interstitial fluid return from the lower extremities."

[0052] Contrary to the prior understanding of those skilled in the art, the applicant evaluated the therapeutic effect of a time-varying magnetic field with a sinusoidal frequency greater than 3 kHz at a magnetic flux density of less than 0.87 millitesla peak. That is, the applicant evaluated the treatment at magnetic flux density values ​​that are considered by those skilled in the art to lack any usefulness. In particular, the applicant evaluated several embodiments of the treatment using magnetic fields that are generally understood by those skilled in the art to be unable to affect neural activity in the brain. These same embodiments also include treatment of a subject's feet using a magnetic field 1000 × lower than the level that the relevant standardization body (i.e., IEEE) considers to be able to affect neural activity in the limbs. However, the applicant evaluated various embodiments to determine whether a magnetic flux density well below the 0.87 mT peak (i.e., 8.7 Gauss peak) would be able to achieve effective soleus muscle activation. In addition, as described herein, the applicant evaluated the effects of magnetic field orientation, duty cycle, and on-time duration on the therapeutic effect.

[0053] For example, the patent applicant employed various orientations of the electromagnet relative to the treatment area to determine the effect of changing the magnetic field orientation on soleus muscle activation. Referring here to Figure 4, a plot of cardiac output index versus peak magnetic flux density 400 in one embodiment in which the magnetic field is oriented perpendicular to the surface on which the subject's feet are placed is shown. Figure 4 shows the X-axis of peak magnetic flux density (Gauss) and cardiac output index (milliliters / m³). 2The Y-axis includes the ) metric. The cardiac output index is used to normalize the results determined for cardiac output across subjects of varying body sizes.

[0054] For this trial, the treatment area of ​​the magnetic neuromodulation device was increased. In the initial trial according to this embodiment, the magnetic neuromodulation device employed a 10 cm diameter multilayer air-core coil by using 90 windings of #20 magnet wire, resulting in a 1 cm thick coil with an inductance of 1500 microhenries. These coils were driven at 4 kHz with a current sufficient to generate magnetic flux densities in the range of 0–8 Gaussian peaks. Each foot of the study subject was positioned on the coil so that only the frontal half of the foot (anterior plantar surface) was over the coil windings. In this position, the magnetic flux penetrated the foot vertically. A standardized test protocol with 30 minutes of neuromodulation applied to both feet while cardiac output was monitored, following 30 minutes of sitting, was used. This provided subjects with exposure of the anterior plantar surface to vertically oriented magnetic flux across a range of magnetic flux densities.

[0055] Figure 4 shows the variability effect of 4kHz sinusoidal magnetic neuromodulation of the plantar nerve to achieve soleus muscle activation by changing the magnetic flux density of the applied magnetic field. For each value of magnetic flux density, the range of values ​​of change in cardiac output index was recorded. For each of these values ​​of magnetic flux density, plot 400 includes a vertical line representing the standard deviation and a single data point representing the recorded mean. Plot 400 shows that the maximum effect is observed at approximately 3 Gauss (0.3 mT peak) based on polynomial curve fitting. However, the applicant found that the overall effect was relatively low. For example, this test result for the estimated maximum effect of this vertically oriented magnetic field on cardiac output was approximately 0.1 ml / m². 2 It is per minute.

[0056] In addition, this evaluation demonstrates that increasing the magnetic nerve modulation intensity at low magnetic flux densities is associated with increased effectiveness, while at the highest magnetic flux densities tested in this series (6 Gauss peaks), the effect decreases. This results in a distinct peak effect occurring near 3 Gauss peaks. Based on these results, the patent applicant identifies that a nonlinear response occurs from the exposure of parts of the foot beyond the anterior plantar region exposed to high magnetic flux densities (e.g., occurring with increasing magnetic flux density of the applied magnetic field). That is, parts of the midfoot and / or heel regions of the plantar surface become exposed to high magnetic flux densities that can be sufficiently significant to modulate nerve fibers originating from the posterior region of the foot. This is counterproductive to the therapeutic goal, as activation of plantar nerve fibers in the anterior region of the foot triggers the reflex arc leading to soleus muscle contraction, while activation of plantar nerve fibers in the posterior region of the foot leads to soleus muscle relaxation.

[0057] Referring to Figure 5, the diagram of foot 500 shows the location of nerves within foot 500 as viewed from below. Foot 500 includes the longitudinal axis N as shown in Figure 5. The nerves of the foot include the tibial nerve, lateral plantar nerve, medial plantar nerve, and in the anterior region of foot 500, the common plantar digital nerve and proper plantar digital nerve. Figure 5 also shows the nerves to the abductor digiti minimi muscle. As shown in Figure 5, the pathways of each plantar nerve generally extend longitudinally within foot 500.

[0058] The relationship between the direction of the magnetic field and the direction of the induced electric field is well known. That is, the electric field induced by a magnetic field is generated perpendicular to the direction of the magnetic field. The patent applicant adopted this relationship to construct a device for delivering treatment to the plantar nerve with a time-varying magnetic field in a desired direction when the treatment is applied to the treatment area of ​​a subject.

[0059] That is, a magnetic field guided vertically through the foot from bottom to top will induce a horizontal annular current within the foot, with minimum amplitude at the center of the foot and maximum amplitude at the lateral and medial edges of the foot. As shown in Figure 5, the plantar nerve has branches that run along the outside of the foot (specifically, branches leading to the first and fifth toes), so these segments are within the area of ​​foot 500 (where the induced electric field may affect their behavior). The branches of the plantar nerve run longitudinally downward through the center of the anterior plantar surface, but will be minimally affected by any induced electric field generated by a magnetic field oriented perpendicular to the heel of the foot.

[0060] The applicant has applied a physical understanding of foot physiology related to magnetic fields to construct embodiments that optimize the results from neuromodulation of the plantar nerve. In particular, the embodiments described herein apply a magnetic field tangential to the plantar surface and directed from the medial to the lateral side of the foot to generate an induced electric field oriented linearly from the toe to the heel. That is, the embodiments described herein deliver treatment with a magnetic field oriented to generate an induced electric field in line with most of the branches of the plantar nerve at the front of the foot.

[0061] According to one embodiment, the two-coil device utilizes two adjacent elliptical coils measuring 10 cm on the long axis and 5 cm on the short axis. Each coil, wound with 75 windings of #22 magnet wire, produces a coil of 750 microhenries. When connected in series in the opposite manner (so that the magnetic flux of each coil is in the opposite direction to the magnetic flux of the adjacent coil in the device), the magnetic flux in the foot placed on the coils is primarily horizontal, maximizing the intensity of the induced electric field along the long axis of the foot (particularly along the branches of the plantar nerve running down along the long axis of the foot).

[0062] Referring to Figure 6, a plot of cardiac output index versus peak magnetic flux density change 600 is shown in one embodiment where the magnetic field is oriented horizontally with respect to the surface on which the subject's feet are placed. That is, perpendicular to the longitudinal axis N of the feet 500, as shown in Figure 5, for example. Figure 6 shows the X-axis of peak magnetic flux density (Gauss) and cardiac output index (milliliters / m³).2 The Y-axis of the graph is included. Here again, the cardiac output index is used to normalize the results judged for cardiac output across subjects of varying body sizes. Figure 6 shows the variability effect of 4kHz sinusoidal magnetic neuromodulation of the plantar nerve to achieve soleus muscle activation by changing the magnetic flux density of the applied magnetic field, using one embodiment having a two-coil arrangement to deliver tangential magnetic field exposure to the foot. For each value of magnetic flux density tested, the range of values ​​of change in the cardiac output index was recorded.

[0063] In this embodiment, for each of these values ​​of magnetic flux density tested, plot 600 includes a vertical line representing the standard deviation and a single data point representing the mean value recorded at the selected magnetic flux density. The polynomial fitting of the data is 0.25 ml / m² / min. 2 At the ultra-high level, it indicates a peak response centered around 5 Gauss. This is more than twice the response observed with the perpendicular magnetic field configuration shown and explained, for example, with reference to Figure 4.

[0064] These experimental results demonstrate the dominance of a magnetic field oriented inward and laterally relative to the surface on which the feet are positioned, compared to results from vertical field orientation. In particular, horizontal field orientation delivers a 2 × larger change in cardiac output compared to vertical field orientation. Also, the peak effective magnetic flux density is more pronounced with horizontal field orientation. According to these embodiments, the application of a 4 kHz sinusoidal magnetic field produces a maximum response in cardiac output achieved at a magnetic flux density close to 5 Gauss peak (0.5 mT peak). In addition, the maximum effective magnetic flux density is below the exposure standard limit of 353 mTRMS (494 mT peak) for human limbs, and even stricter at the 0.87 mT peak standard limit for the head and torso. This confirms that these embodiments are inherently safe as they operate well below the IEEE exposure standards for any part of the body (including IEEE exposure standards applicable to either the head or torso), and recognize that the IEEE standards include a substantial safety factor. The reference here to the safe exposure levels established in this industrial standard also highlights the importance of the patent applicant's discovery, as this standard will separately inform those skilled in the art that "the magnetic flux density of the magnetic field involved in this treatment process is negligible when applied to a human subject." That is, the IEEE standard will inform those skilled in the art that the application of a magnetic field at this flux density will not result in, and does not need to result in, any medical intervention.

[0065] The nature of soleus muscle action also necessitated the applicant's evaluation of the duty cycle to which the treatment is applied. In particular, the function of the soleus muscle as a secondary heart in the body involves actions in both the contraction phase, when blood and lymph are pumped from the venous trunk within the muscle back to the heart, and the relaxation phase, when muscle fibers recover from fatigue and the venous trunk within the muscle is refilled with blood. The applicant recognized that continuous muscle activation is ineffective as a stimulation strategy. For example, continuous activation of the soleus muscle results in progressively fatigued muscle cells. In addition, the venous trunk does not have the opportunity to refill if the treatment results in continuous muscle activation. Conversely, slight activation of the soleus muscle repeated over long rest intervals also cannot have a significant long-term effect on venous return to the heart. Therefore, the applicant evaluated various embodiments to identify the optimal muscle activation time that is accompanied by an optimal muscle relaxation time. That is, the applicant evaluated various embodiments to identify the optimal duty cycle for soleus muscle activation.

[0066] The patent applicant has applied various treatments in various embodiments to isolate the optimal duty cycle. These include not only using a 2-minute stimulation "on" period and varying periods of magnetic field "off" time to achieve 20%, 33%, 50%, and 66% duty cycles, but also investigating the effects of continuous muscle activation (a 100% duty cycle refers to the stimulation being constantly on). Here, the term "on" refers to the portion of the treatment period in which the magnetic field is active / on. The "on" portion of the treatment period is followed by a period in which the magnetic field is turned off. The patent applicant notes that the "duration" of any treatment session determines the number of treatment periods. For example, if a 30-minute treatment period is used with a 2-minute "on" time and a 3-minute "off" time per treatment period, this results in a total of six 5-minute treatment periods.

[0067] Referring now to FIG. 7, a plot 700 is provided showing the effect of changes in the duty cycle of a neuromodulation treatment related to cardiac output according to one embodiment. FIG. 7 includes an X-axis of log duty cycle (%) and a Y-axis of change in cardiac output index (ml / m 2 / min). Again, the cardiac output index is used to normalize the results judged regarding cardiac output across subjects of various body sizes. FIG. 7 shows the varying effect of 4Khz sinusoidal magnetic neuromodulation of the plantar nerve to achieve soleus muscle activation by changes in the duty cycle of an applied magnetic field using one embodiment that delivers a tangential magnetic field exposure to the foot. At each value of the duty cycle tested, the range of values of the change in cardiac output index was recorded. At each of the values of the log duty cycle tested in this embodiment, plot 700 includes a vertical line representing the standard deviation recorded at the selected duty cycle and a single data point representing the mean value.

[0068] FIG. 7 shows the cardiac hemodynamic response to variations in the duty cycle of a neuromodulation intervention during a fixed 2-minute neuromodulation period. According to these embodiments, the 20% duty cycle is associated with an 8-minute "relaxation" period during a 10-minute treatment period. The 20% duty cycle is represented by the leftmost value plotted in FIG. 7. Continuous stimulation reflects a state of 100% duty cycle with no "relaxation" period. The 100% duty cycle is represented by the rightmost value plotted in FIG. 7.

[0069] The applicant found that, as expected, continuous application of neuromodulation intervention (100% duty cycle) resulted in very low effectiveness for the reasons described above. According to the embodiment shown in Figure 7, the effect of the stimulus applied by using a 100% duty cycle is statistically negligible. According to the embodiment shown, this is consistent with the expectation that "if no time is allowed for the soleus muscle to be refilled with blood and interstitial fluid, the minimum amount of fluid that can be pumped out during the soleus muscle contraction phase will be collected within the muscle." In addition, the lack of a relaxation period eliminates the opportunity for muscle fiber recovery, leading to the accumulation of fatigue.

[0070] The patent applicant also found that treatment processes involving very long “pauses” (or “off” periods) (e.g., 20% duty cycles) also had low efficacy. This is consistent with the expectation that further waiting time would be unproductive once the soleus muscle venous trunk is filled. Accordingly, the effect of magnetic neuromodulation demonstrated a peak effect between 20% and 100% duty cycles when the neuromodulation period was maintained at 2 minutes. Clinical experiments conducted by the patent applicant found that “the maximum level of effect is observed by using a modulation pattern of approximately 2 minutes of “on” followed by approximately 3 minutes of “pause” (i.e., relaxation). According to the embodiment shown in Figure 7, a Gaussian curve fit to the data indicates that the optimal duty cycle is centered at approximately 40%.

[0071] The applicant conducted additional studies with varying on-times other than 2 minutes to evaluate the effect of the length of the "on" period of treatment by using neuromodulation to activate the soleus muscle. For example, the applicant conducted these additional studies to find out whether 2 minutes (120 seconds) could be too short a period to achieve a full contraction, or alternatively, whether it could be 2 minutes (120 seconds) much longer than the time it takes for the soleus muscle to complete contraction. Referring here to Figure 8, a plot 800 is provided showing the effect of varying on-time of neuromodulation treatment on cardiac output according to one embodiment. Figure 8 shows the on-time (seconds) on the X-axis and the change in the cardiac output index (ml / m³). 2 The Y-axis includes ( / min). Here again, the cardiac output index is used to normalize the results judged for cardiac output across subjects of varying body sizes. Figure 8 shows the results of tests performed at 30, 60, 120, and 180 seconds of neuromodulation, each while maintaining a 1-minute rest period for all stimulation states. For each of these values ​​of on-time, plot 800 includes a vertical line representing the standard deviation and a single data point representing the mean value recorded at the selected on-time.

[0072] Plot 800, shown in Figure 8, provides a polynomial fitting of the data. This indicates that neuromodulation periods in the range of 50–90 seconds are superior for soleus muscle activation, with an optimal time of approximately 70 seconds. While identifying the optimal on time, the patent applicant also found that the results of this study indicate that "the peak response is not as large as observed in Figure 7." This suggests that the 1-minute "relaxation" time used in this study is insufficient to allow for complete muscle refilling, and that larger responses are likely to be accompanied by longer relaxation times (specifically, relaxation times aligned with a 40% duty cycle).

[0073] Additional research conducted by the present patent applicant indicates that "the optimal neuromodulation period for activating the soleus muscle is in the range of 50–90 seconds with approximately 40% duty cycle." This appears to provide adequate time for both muscle venous torso refilling and recovery from fatigue. According to one embodiment, a 70-second neuromodulation period with approximately 100 seconds of relaxation time is suitable as the optimally designed neuromodulation pattern for the plantar nerve.

[0074] As will be further explained below, the applicant also evaluated the effects of various coil configurations, coil orientations, and coil quantities to improve the performance and ease of use of the neuromodulation treatment device for activating the soleus muscle for the treatment of reduced cardiac output. Referring here to Figure 9, plot 900 shows a summary graph of the results of plantar nerve neuromodulation in terms of its effect on cardiac output as determined by cardiac output indices in a seated individual. Plot 900 also reflects the results using one embodiment of the treatment device shown and described herein with reference to Figures 11 and 12. Furthermore, these results also reflect the results when the subject was treated while wearing their own shoes and the treatment device was operated to deliver a magnetic flux of 5 Gauss peaks (at 1 cm above the treatment surface) at 4 kHz by using a 50% duty cycle signal with a 1 minute neuromodulation period.

[0075] Plot 900 shows the X-axis as time (minutes) and the cardiac output index (ml / m³). 2 The Y-axis includes the y-axis. In Figure 9, the measurement time period is 10 to 40 minutes following the start time when the subject is seated. A set of measurement results taken for control (i.e., data recorded without neuromodulation applied to the subject) are shown as square data points representing the result values. Circular data points represent the result values ​​when neuromodulation therapy is applied to stimulate the soleus muscle. Linear curve fits representing the rate of change in cardiac output are represented by straight lines associated with each set of data in several sets of data.

[0076] The control data points in Figure 9 show a continuous decline in cardiac output metrics during sitting periods without neuromodulation. This is generally represented by the negative slope of the curve fit for these data points. The overall decline in cardiac output is close to 20% during the 30-minute measurement window for the subjects evaluated in this study. Conversely, when neuromodulation is applied, these same subjects experience an increase in cardiac output metrics during the 30-minute measurement window. This is typically represented by the positive slope of the curve fit for these data points. These results demonstrate that neuromodulation, as described herein, prevents fluid retention. This is evidenced by the increase in cardiac output over time, consistent with enhanced venous return to the heart. These results are provided in combination with the recovery of fluid retention, as shown and described previously with reference to Figures 2 and 3.

[0077] Figure 10 shows plot 1000, which provides a summary graph of the results of plantar nerve neuromodulation in terms of its effect on cardiac output, as determined by cardiac output and heart rate of a resting standing individual, following a period of moderate-intensity exercise (in this case, a total of 20 toe raises). Plot 1000 also reflects the results obtained by using one embodiment of the treatment device shown and described herein with reference to Figures 11 and 12, where the subject was treated while wearing his own shoes, and the treatment device was operated to deliver a magnetic flux of 5 Gauss peaks at 4 kHz (at 1 cm above the treatment surface) by using a 50% duty cycle signal with a 1 minute neuromodulation period. Plot 1000 includes time (minutes) on the X axis and cardiac output (liters / min) on the Y axis. In Figure 10, the measurement time period is 0 to 30 minutes following the start time when the subject completed his moderate-intensity exercise. Here again, a set of measurements taken for control (i.e., data recorded without neuromodulation being applied to the patient) is shown as square data points representing the result values. Plot 1000 employs circular data points to represent the result values ​​when neuromodulation therapy is applied to stimulate the soleus muscle. Curve fits representing the rate of change in cardiac output are represented by straight lines associated with each set of several sets of data. Normal resting cardiac output is approximately 4 liters / min and is represented by a dashed horizontal line.

[0078] The control data points in Figure 10 show an immediate and rapid decrease in cardiac output within the first 2-3 minutes of resting standing following a period of moderate activity without neuromodulation. Subsequently, cardiac output continues to steadily decrease for the remainder of the 30-minute period, represented by plot 1000. This is generally represented by the negative slope of the curve fit for these data points. More specifically, the study protocol showed that resting (supine resting) cardiac output was approximately 4-5 liters / min. Twenty toe raises appear to increase cardiac output by only about 50%, to approximately 6 liters / min. The activity-dependent changes in cardiac output demonstrate that the cardiovascular system is healthy and that increased venous return can increase the subject's heart output; that is, the subject does not suffer from heart failure. When activity is stopped and the subject remains in a resting standing position, cardiac output appears to decrease to approximately 3.5 liters / min. In the absence of any plantar nerve dysfunction, cardiac output decreases by a further 15% over the remainder of the 30-minute period. This is generally represented by the negative slope of the curve fit associated with the plot of control data points.

[0079] Conversely, the fact that plantar nerve modulation applied during resting standing keeps cardiac output constant at approximately 3.5 liters / min for the next 30 minutes suggests that soleus muscle activation helps maintain cardiac output during relatively sedentary activities, not only in standing but also in sitting. This is generally represented by a slight positive slope in the curve fit of these data points. These results demonstrate that magnetic neuromodulation therapy applied to the plantar nerve to activate the soleus muscle helps maintain cardiac output over time. Consequently, magnetic neuromodulation of the plantar nerve is effective in preventing fluid retention when an individual is in a resting standing position. Therefore, in various embodiments, treatment protocols applying magnetic neuromodulation of the plantar nerve offer opportunities for individuals performing standing tasks. This may be particularly effective for individuals who must stand for extended periods.

[0080] Referring here to Figure 11, a circuit diagram of a circuit configuration 1100 included within the device to provide a medical intervention for a user with reduced cardiac output is shown according to one embodiment. In various embodiments, the medical device includes a circuit configuration 1100 that generates a time-varying magnetic field having a frequency and intensity that triggers a response that activates skeletal muscle to improve the user's cardiac output by increasing venous blood return and interstitial fluid lymphatic return. In some embodiments, the medical device is designed to provide a treatment to the plantar region of the subject's foot to trigger a response that activates the soleus muscle, thereby increasing venous blood return and interstitial fluid lymphatic return and improving the user's cardiac output.

[0081] According to the shown embodiments, the circuit configuration 1100 includes a power supply 1140, a timing circuit 1142, a waveform generator 1144, and an amplifier 1146. In various embodiments, the circuit configuration 1100 also includes a capacitor 1148, a first set of inductors 1150, and a second set of inductors 1152. According to the shown embodiments, power for the circuit configuration is supplied by connecting to a commonly available AC power source (e.g., 120 volts, 60 Hz AC power in the United States and 230 volts, 50 Hz AC power in Europe). Furthermore, in the shown embodiments, the input AC voltage is reduced to 24 volts DC by the power supply 1140. However, various output voltages may be adopted depending on the embodiment. According to other embodiments, connection to an external AC power source is not required. Instead, in these embodiments, the device includes a battery power source, and the circuit configuration 1100 includes a power conversion circuit configuration for utilizing DC power supplied by the battery power source or an integrated DC generator.

[0082] In the shown embodiment, the output of the power supply 1140 is supplied to the timing circuit 1142, the waveform generator 1144, and the amplifier 1146, respectively. The output of the timing circuit 1142 is connected to the input of the waveform generator 1144. The output of the waveform generator 1144 is connected to the input of the amplifier 1146. According to the shown embodiment, a capacitor 1148 is connected between the output of the amplifier 1146 and ground. Each of the first plurality of inductors 1150 and the second plurality of inductors 1152 is also connected between the output of the amplifier 1146 and ground.

[0083] According to the demonstrated embodiments, the first plurality of inductors 1150 includes six inductors connected in series between the output of the amplifier 1146 and ground. Similarly, the second plurality of inductors 1152 includes six inductors connected in series between the output of the amplifier 1146 and ground. Each inductor contained within the plurality of inductors 1150 and 1152 is indicated by a corresponding marking indicating the polarity of the inductor. The inductors within each of the plurality of inductors 1150 and 1152 are wired in series with alternating north-south magnetic field orientations. According to some embodiments, the device is a medical device configured to apply treatment to both feet simultaneously. In these embodiments, the first plurality of inductors 1150 is positioned within the device to deliver a time-varying magnetic field to a first foot (e.g., the left foot) of the subject, while the second plurality of inductors 1152 is positioned within the device to deliver a time-varying magnetic field to a second foot (e.g., the right foot) of the subject.

[0084] The demonstrated embodiment includes a total of 12 inductors, but various amounts of inductors may be employed and placed in various combinations depending on the embodiment, provided that "the inductors are physically positioned and oriented to deliver a time-varying magnetic field to a selective treatment area of ​​neuromodulation of selected peripheral nerves in order to trigger a response that activates skeletal muscle, thereby increasing venous blood return and interstitial fluid lymphatic return and improving the user's cardiac output." The applicant has found that the location, amount, and orientation of the inductors in the device can be adjusted to provide a more effective treatment depending on several considerations, as will be described in more detail below. In summary, the amount of inductors employed is determined at least in part by the physical dimensions of the inductors, the size of the treatment area, and the distance separating the treatment areas, where the treatment is applied to multiple treatment areas simultaneously by a single device.

[0085] In various embodiments, the capacitance value of capacitor 1148 and the inductance values ​​of inductors 1150 and 1152 are selected to provide a resonant circuit 1154 at a selected frequency. The output of amplifier 1146 is connected to a resonant circuit 1154 formed by a combination of capacitor 1148, a first plurality of inductors 1150, and a second plurality of inductors 1152. According to the shown embodiment, all combinations of 12 inductors, each having an inductance of 420 microhenries, are employed. The plurality of inductors 1150 and 1152 are each connected in parallel with capacitor 1148 having a capacitance of 1.36 microfarads. These values ​​provide a resonant circuit 1154 having a resonant frequency of 3980 Hz or approximately 4 kHz. Thus, these values ​​are selected to provide treatment at a frequency that has been found to provide the maximum reduction in vascular resistance, as shown and described with reference to Figures 2 and 3. In other embodiments, the resonant circuit 1154 may be constructed and configured to provide different resonant frequencies (for example, to provide the device with output frequencies of a time-varying magnetic field at different frequencies tuned to a specific treatment process).

[0086] During operation, circuit configuration 1100 receives external AC power at its input to power supply 1140. Power supply 1140 provides a 24-volt DC output supplied to timing circuit configuration 1142. Timing circuit configuration 1142 operates within a single treatment period by switching on and off to satisfy the duty cycle requirements of the treatment process. When the timing circuit configuration is on, a trigger signal is delivered to the input of waveform generator 1146. Waveform generator 1146 operates to provide a sinusoidal output supplied to amplifier 1144, which provides current to drive the resonant circuit 1154. When driven in this manner, each inductor contained within the multiple inductors 1150 and 1152 generates a time-varying magnetic field at a desired frequency (4 kHz in this case). When the inductors are correctly positioned relative to the treatment area, this time-varying magnetic field triggers a response that activates skeletal muscle to improve the user's cardiac output by increasing venous blood return and interstitial fluid lymphatic return. When the timing circuit configuration is off, no output is supplied to amplifier 1144. During this portion of the treatment period, no time-varying magnetic field is generated by the circuit configuration 1100. As described herein, a single treatment period comprises a combination of one or more on-periods and one or more off-periods to provide a combination of duty cycle and rest period lengths tailored to deliver optimized treatment. That is, the treatment is intended to improve cardiac output most effectively.

[0087] According to one embodiment, the circuit configuration 1100 includes 12 inductors and operates at a peak drive voltage of 70V and 0.74 amperes, resulting in a power consumption of 1.15W when "on". According to the shown embodiment, the circuit configuration operates with an average power consumption of 0.58W for 50% duty cycle operation. As is evident here and as discovered by the present patent applicant, in other multi-coil embodiments, the circuit configuration provides low power consumption when "on" and minimum power when "off". Furthermore, embodiments of the circuit configuration 1100 shown and described herein include a resonant circuit that helps to significantly reduce power consumption. However, a resonant circuit is not necessary, and therefore some embodiments may include circuit configurations that do not include a resonant circuit.

[0088] Referring here to Figure 12, the device 1200 provides medical care by generating a time-varying magnetic field having a frequency and intensity that triggers a response that activates the soleus muscle to improve the user's cardiac output by increasing venous return of blood and lymphatic return of interstitial fluid. According to the shown embodiment, the device 1200 includes a first plurality of inductors 1250, a second plurality of inductors 1252, a housing 1256 including an inner surface 1257, and a handle 1258. Furthermore, in some embodiments, the device 1200 includes a circuit configuration 1100 having a connection to an external power supply (partially shown here by inductors 1250 and 1252 shown as phantoms within the housing 1256). The inner surface 1257 includes one or more hollow cavities in which elements of the circuit 1100 shown and described with reference to Figure 11 can be located. If an integrated battery power supply is used, the battery may be located within the inner surface 1257. In the shown embodiment, the device 1200 includes a first plurality of inductors 1250 positioned within the left half of the inner surface 1257 and a second plurality of inductors 1252 positioned within the right half of the inner surface 1257. In this embodiment, each of both the first plurality of inductors 1250 and the second plurality of inductors 1252 each contained a total of six inductors. Each of the inductors included a coil 1260 of magnetic wire surrounding an air core 1262.

[0089] The applicant has found that the physical arrangement of inductors within the apparatus 1200 is important for delivering the most effective treatment. In particular, the applicant has found that the inductors contained within the plurality of inductors 1250, 1252 should be arranged in a linear array having alternating north and south poles to deliver the desired time-varying (sine) magnetic field. Accordingly, the inductors contained within the first plurality of inductors 1250 are positioned within the inner surface 1257 in a first linear array having inductors having alternating north and south poles. Similarly, the inductors contained within the second plurality of inductors 1252 are positioned within the inner surface 1257 in a second linear array having inductors having alternating north and south poles. This arrangement positions the inductors within two separate arrays such that the polarity of each of the plurality of electric coils is opposite to the polarity of the electric coil contained within the plurality of electric coils positioned adjacent to each coil within the inner surface of the housing. Furthermore, the two linear arrays are arranged within a cavity 1257 such that the leftmost array, which includes a first set of inductors 1250, is positioned for treatment applied to the anterior plantar region of the subject's left foot, while the rightmost array, which includes a second set of inductors 1252, is positioned for treatment applied to the anterior plantar region of the subject's right foot.

[0090] According to various embodiments, each of the inductors 1250 and 1252 is an air-core coil constructed with 65 windings of #24 magnetic wire to provide an inductance of 420 microhenries, respectively. Coils having various electrical properties or composed of various materials (e.g., iron-core coils) can also be employed in various embodiments, such that their combinations form a resonant circuit having a desired resonant frequency for treatment to reduce power consumption. In the shown embodiment, this construction provides an inductor that is 2.5 cm wide and 8.5 cm long. Coils having various dimensions can also be employed in various embodiments, provided that they are sized and positioned within the housing 1256 to deliver a time-varying sinusoidal magnetic field to a sufficiently large proportion of the treatment area (here, the anterior sole region of the subject's foot). However, the applicant has found that relatively narrow inductors, such as those provided in the shown embodiment, ensure that "at least two coils will cover the individual whenever they place their foot, even with respect to very narrow feet." This, in turn, ensures that a large portion of the anterior sole surface will be exposed to the horizontal magnetic field regardless of the precise location of the subject's foot on the treatment surface of the device.

[0091] Figure 13 shows a cross-sectional view of the device 1200 of Figure 12. This figure shows the housing 1256, which includes an inner surface 1257, an upper surface 1264, a bottom surface 1265, a near end 1266, and a far end 1267. This figure also provides a cross-sectional view of the elements of the coil 1260. The far end 1267 also includes a raised region 1268. According to the shown embodiment, a first region of the upper surface 1264, positioned above many of the upper surfaces including the one closest to the near end 1266, is sized and configured to accommodate the anterior sole region of the foot. A second region of the upper surface 1264, closer to the far end 1267, is sized and configured to accommodate, for example, the toes on the raised region 1268.

[0092] Generally, the form factor of the device 1200 is configured to provide a portable therapeutic device that simultaneously delivers sinusoidal time-varying magnetic fields tangentially to the heels of both of a patient's feet. Figure 12 includes a reference to the width A and depth B of the device 1200. According to one embodiment, the device 1200 has dimensions A of 53.1 centimeters (21 inches) and dimensions B of 32.9 centimeters (13 inches). A handle 1258 is positioned at the far end 1267 of the device 1200. A flat bottom surface 1265 allows the device 1200 to be placed on a flat surface such as a floor. In this orientation, a seated user can place their left foot on the area of ​​the top surface 1264 positioned directly over the first plurality of inductors 1250, and their right foot on the second plurality of inductors 1252. The applicant has found that the comfort of the subject's feet can be significantly improved by slightly angling the therapeutic surface upward. For clarification, this is reflected in the 10-degree angle between the top surface 1264 and the bottom surface 1265, as shown in Figure 13. Furthermore, the applicant's clinical trials have found that effective treatment can be provided to barefoot subjects, subjects with socked feet, or subjects wearing shoes. Figure 10 shows one such example. The applicant has recognized that the non-contact nature of magnetic field-based treatment offers greater flexibility in this respect than conventional electrical stimulation devices. In particular, the time-varying magnetic field delivered by the embodiments described herein penetrates all non-magnetic materials. Thus, the treatment device may be configured for use with one or more garments (including shoes) positioned between the treatment surface of the treatment device (e.g., top surface 1264) and the subject's skin near the treatment area of ​​the subject.

[0093] Referring here to Figure 14, a subject 1400 is shown using the device 1200 while seated in a desk chair with his shoes on. Here, the exterior of the housing 1256, including the top surface 1264, is shown. Subject 1400 has placed the heel of his shoe within the area of ​​the ball of his foot on the top surface. In one embodiment of the device shown and described with reference to Figures 11-13, subject 1400 may initiate treatment by turning on the circuit using an on / off switch (not shown) accessible from the exterior of the housing 1256. Alternatively, the device may include a sensing system to detect the presence of a foot and turn on automatically.

[0094] The embodiments shown and described herein include a treatment surface of the device (e.g., the upper surface 1264 of the device 1200) positioned adjacent to the treatment surface of a subject (e.g., the heel of the foot, particularly the ball of the foot), but other relative positions may be employed in other embodiments. According to some embodiments, the treatment device is configured such that the treatment area of ​​a subject is positioned between one or more inductors, where the inductors are included in a circuit configuration that is generally operated with reference to Figure 11 included herein. For example, if the treatment area is the anterior plantar region of the subject's foot, the treatment device may be configured such that the subject's foot is positioned between two elements including inductors. According to these embodiments, the foot is “sandwiched” between inductors positioned on either side of the foot for the application of a magnetic field to provide neuromodulation of the plantar nerve.

[0095] The applicant has also discovered that the treatments described in the various embodiments herein can be applied to the plantar region of each foot independently of the other foot. That is, an effective treatment protocol may apply a time-varying magnetic field to the treatment area on the first foot of the subject during a first period in which the other foot of the subject is not being treated. During a second period following the first period, the time-varying magnetic field is applied to the treatment area on the second foot of the subject. Such a method may be used with, for example, a smaller and more portable treatment device that is sized so that only one foot can be placed on the treatment surface of the device. The applicant has also recognized that this method also triggers a response that activates skeletal muscle to improve the user's cardiac output by increasing venous blood return and interstitial fluid lymphatic return.

[0096] The embodiments shown and described herein include multiple inductors, but according to some embodiments, only a single inductor is employed to provide neuromodulation to a subject by applying a magnetic field. According to these embodiments, the inductor is sized and positioned to provide appropriate physical dimensions to deliver a time-varying magnetic field to the patient's treatment area to trigger a response that activates skeletal muscle, thereby increasing venous blood return and interstitial lymphatic return and improving the user's cardiac output.

[0097] Reduced cardiac output is known to contribute to a wide variety of associated conditions, including, but not limited to, heart failure, drug-resistant hypertension, cognitive impairment, delayed wound healing, varicose veins, deep vein thrombosis, macular degeneration, age-related hearing loss, osteoporosis, and sleep apnea. Each of these conditions is an indicator that a subject is suffering from reduced cardiac output. Accordingly, the applicant evaluated various treatments by using the apparatus and methods described herein to determine their effects in treating these conditions. In general, the applicant found that treatment should be performed for at least 1 hour / day to improve soleus muscle performance during periods outside of treatment sessions. It was found that faster rejuvenation of the soleus muscle occurred with 2-3 hours of treatment daily. The applicant's study of subjects with osteoporosis found that 2.5 hours / day was sufficient to halt or reverse bone loss over a year. Cognitive aging studies by the present patent applicant have shown that 1-2 hours per day is sufficient to restore cognitive impairment within 6 months. Furthermore, the applicant has found that the ability of the therapeutics described herein to reduce vascular resistance (see, for example, Figures 2 and 3 and their related descriptions) presents an opportunity to apply time-varying magnetic fields to the plantar region to lower blood pressure in hypertensive patients in a non-pharmacological manner.

[0098] Clinical research by the patent applicant found that soleus muscle recovery generally requires approximately three months with one hour of treatment per day, but a continuous treatment process should be employed to prevent the soleus muscle atrophy that would occur over time if treatment were discontinued. This method provides a continuous improvement in cardiac output in subjects treated for low resting cardiac output, which can not only address specific medical conditions but also improve the subjects' quality of life.

[0099] While the embodiments described above refer to magnetic nerve modulation within the foot, the apparatus, systems, and methods shown and described herein may be employed in various embodiments relating to other elements of human anatomy.

[0100] Since several aspects of at least one embodiment of the present invention have been described in this manner, it should be understood that various changes, modifications, and improvements will readily come to mind for those skilled in the art. Such changes, modifications, and improvements are intended to be part of the present disclosure and to fall within the spirit and scope of the invention. Accordingly, the description and drawings set forth herein are for illustrative purposes only.

Claims

1. A device configured for non-invasive medical intervention for a user with reduced cardiac output, wherein the medical device is At least one electric coil, and Apparatus comprising a power control circuit configuration configured to provide an electrical output supplied to the at least one electrical coil at a selected voltage and frequency to drive a current through the at least one electrical coil in order to generate a time-varying magnetic field having a frequency and intensity that triggers a response that activates skeletal muscle in order to increase venous return of blood and lymphatic return of interstitial fluid in order to improve the resting cardiac output of the user.

2. The frequency of the aforementioned time-varying magnetic field includes the range of 2 to 16 kHz. The apparatus according to claim 1, wherein the magnetic flux density of the time-varying magnetic field includes a range of 2 to 8 Gauss peaks.

3. The apparatus according to claim 2, wherein the frequency of the time-varying magnetic field is a selectable frequency from the range of 2 to 16 kHz, and the selectable frequency is chosen such that the non-invasive medical intervention at the selectable frequency results in both stopping fluid accumulation in the user and eliminating existing fluid accumulation in the user.

4. The apparatus according to claim 3, wherein the selected frequency of the time-varying magnetic field is substantially equal to 4 kHz.

5. The apparatus according to claim 1, further comprising a timing circuit configuration configured to control the output of the power control circuit configuration in order to generate the time-varying magnetic field with a duty cycle of 30% to 50%.

6. The apparatus according to claim 5, wherein the duty cycle of the time-varying magnetic field is substantially equal to 40%.

7. The apparatus according to claim 5, wherein the timing circuit configuration is configured to control the output of the power control circuit configuration in order to periodically generate the time-varying magnetic field during a period of 50 to 90 seconds.

8. The apparatus according to claim 7, wherein the aforementioned period is substantially equal to 70 seconds.

9. The apparatus according to claim 1, further comprising a housing having an inner surface configured to accommodate at least one electric coil, and an outer surface configured to be placed toward a user's treatment area having the treatment area positioned in a predetermined orientation relative to the outer surface.

10. The aforementioned at least one electric coil includes a plurality of electric coils, The apparatus according to claim 9, wherein the polarity of each of the plurality of electrical coils is opposite to the polarity of the electrical coil included in the plurality of electrical coils that is positioned adjacent to each of the coils within the inner surface of the housing.

11. The treatment area of ​​the user includes at least one nerve that is targeted for modulation via the application of the time-varying magnetic field to the treatment area, and the at least one nerve has a longitudinal axis. The apparatus according to claim 10, wherein the plurality of electric coils are oriented within the inner surface of the housing such that the time-varying magnetic field is oriented perpendicular to the longitudinal axis by the treatment area which is positioned in the predetermined orientation.

12. The treatment area of ​​the user is included in the user's feet. The target group of nerves includes the plantar nerve. The apparatus according to claim 10, wherein the time-varying magnetic field is oriented perpendicular to the plantar nerve by the user's foot, which is positioned with respect to the outer surface in the predetermined orientation.

13. The apparatus according to claim 12, wherein the nerves of the target set include plantar nerves located within the anterior region of the user's foot, anterior to the heel of the user's foot, where the treatment area is located.

14. The treatment area of ​​the user is included within the user's foot. The target group of nerves includes the plantar nerve, The apparatus according to claim 10, wherein the time-varying magnetic field has an medial transverse orientation within the anterior region of the foot to expose the plantar nerve, due to the user's foot positioned in the predetermined orientation relative to the outer surface.

15. An apparatus according to any one of claims 1 to 8 for use in a method for treating a medical condition of a human subject, wherein the method is: Positioning the at least one electrical coil adjacent to the treatment area of ​​the human subject, wherein the treatment area includes a target nerve, Orienting the at least one electrical coil such that the time-varying magnetic field generated by the at least one electrical coil is localized in a direction perpendicular to the target nerve, and An apparatus comprising operating the apparatus to generate a time-varying magnetic field at a frequency and intensity that triggers a response that activates the skeletal muscle, in order to improve the resting cardiac output of the human subject by increasing the venous return of blood and the lymphatic return of interstitial fluid.

16. An apparatus according to any one of claims 1 to 8 for use in a method for treating a medical condition of a human subject, wherein the method is: Applying the time-varying magnetic field to a treatment area positioned within the foot of the human subject, and An apparatus comprising selecting the frequency of the time-varying magnetic field, the magnetic flux density of the time-varying magnetic field, the duration of application of the time-varying magnetic field, and the duty cycle of application of the time-varying magnetic field to trigger a response that activates the soleus muscle in order to increase venous return and lymphatic return of blood, thereby improving the resting cardiac output of the human subject.

17. A method for improving cardiac output using a device comprising at least one electrical coil, wherein the method is: Positioning the at least one electrical coil adjacent to the user's treatment area, wherein the treatment area includes a target nerve, Orienting the at least one electrical coil such that the time-varying magnetic field generated by the at least one electrical coil is localized perpendicular to the target nerve, and A method comprising operating the apparatus to generate the time-varying magnetic field at a frequency and intensity to trigger a response that activates skeletal muscle in order to increase venous return of blood and lymphatic return of interstitial fluid in order to improve the resting cardiac output of the user.

18. The method according to claim 17, further comprising selecting a frequency value of the time-varying magnetic field from within the range of 2 to 16 kHz, wherein the frequency value is selected such that treatment at the selected frequency results in both stopping fluid accumulation in the user and eliminating existing fluid accumulation in the user.

19. To generate the time-varying magnetic field having a frequency in the range of 2 to 16 kHz, and The method according to claim 17, further comprising generating the time-varying magnetic field having a magnetic flux density of 2 to 8 Gauss peaks.

20. The method according to claim 17, further comprising generating the time-varying magnetic field with a duty cycle of 30% to 50%.

21. The method according to claim 17, further comprising periodically generating the time-varying magnetic field over a period of 50 to 90 seconds.

22. The method according to claim 17, wherein the positioning action includes positioning the at least one electrical coil adjacent to the surface of the skin adjacent to the treatment area.

23. A method for improving cardiac output using a device comprising at least one electrical coil, wherein the method is: a) Positioning the at least one electrical coil adjacent to the surface of the user's treatment area, wherein the treatment area includes a target nerve. b) Orienting the at least one electrical coil such that the time-varying magnetic field generated by the at least one electrical coil is localized perpendicular to the target nerve, and c) A method comprising operating the apparatus to generate the time-varying magnetic field at a frequency in the range of 2 to 16 kHz and a magnetic flux density of 2 to 8 Gauss peaks in order to trigger a response that activates skeletal muscle in order to increase venous return of blood and lymphatic return of interstitial fluid to improve the user's resting cardiac output.

24. The method according to claim 23, further comprising generating the time-varying magnetic field for a period of 50 to 90 seconds in a 30% to 50% duty cycle.

25. A method for treating an individual with a medical condition at least partially resulting from reduced cardiac output, the method being: Applying a time-varying magnetic field to a treatment area located within the individual's foot, and A method comprising selecting the frequency of the time-varying magnetic field, the magnetic flux density of the time-varying magnetic field, the duration of application of the time-varying magnetic field, and the duty cycle of application of the time-varying magnetic field to trigger a response that activates the soleus muscle in order to increase venous return and lymphatic return of blood, thereby improving the user's resting cardiac output.

26. The plantar nerve located within the individual's foot is targeted for the application of the time-varying magnetic field, and the method further, Positioning at least one electric coil adjacent to the surface of the individual's foot, and The method according to claim 25, comprising orienting the at least one electric coil to generate the time-varying magnetic field in a direction perpendicular to the plantar nerve.

27. The method according to claim 26, wherein the cardiac output index for a resting subject returns to the value experienced by an individual without reduced cardiac output.

28. The method according to claim 26, further comprising applying the time-varying magnetic field for a selective duty cycle of at least one hour per day.

29. The method according to claim 28, wherein the subject suffers from any of the following conditions: heart failure, drug-resistant hypertension, cognitive impairment, delayed wound healing, varicose veins, deep vascular thrombosis, macular degeneration, age-related hearing loss, osteoporosis, and sleep apnea, and the method further comprises improving the said condition.

30. The method according to claim 29, wherein the medical condition is cognitive impairment, and the method comprises improving the cognitive abilities of the subject following the application of the time-varying magnetic field for one to two hours per day in a selective duty cycle for six consecutive months.

31. The method according to claim 29, wherein the medical condition is osteoporosis, and the method comprises cessating bone loss in the subject following the application of the time-varying magnetic field for at least two hours per day in a selective duty cycle for up to 12 consecutive months.

32. A method for increasing cerebral blood flow by the method of claim 25.

33. A method for normalizing blood pressure in a patient diagnosed with chronic hypotension by the method described in claim 25.

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