112 results about "Ventricular contraction" patented technology

A catheter based system for treating mitral valve regurgitation includes a restraining device having a flexible member, a plurality of movable anchor members attached to the outer surface of the flexible member, and an adjustment filament attached to the ends of the flexible member. One embodiment of the invention includes a method for attaching a flexible restraining device to the annulus of a mitral valve, and adjusting the length of the adjustment filament attached to the flexible member of the restraining device, thereby reshaping the mitral valve annulus so that the anterior and posterior leaflets of the mitral valve close during ventricular contraction.

Excessive dilation of the annulus of a mitral valve may lead to regurgitation of blood during ventricular contraction. This regurgitation may lead to a reduction in cardiac output. Disclosed are systems and methods relating to an implant configured for reshaping a mitral valve. The implant comprises a plurality of struts with anchors for tissue engagement. The implant is compressible to a first, reduced diameter for transluminal navigation and delivery to the left atrium of a heart. The implant may then expand to a second, enlarged diameter to embed its anchors to the tissue surrounding and/or including the mitral valve. The implant may then contract to a third, intermediate diameter, pulling the tissue radially inwardly, thereby reducing the mitral valve and lessening any of the associated symptoms including mitral regurgitation.

An abnormally rapid ventricular cardiac rate that results from atrial fibrillation can be reduced by stimulating a vagal nerve of the heart. An apparatus for such stimulation includes a power transmitter that emits a radio frequency signal. A stimulator, implanted in a blood vessel adjacent the vagal nerve, has a pair of electrodes and an electrical circuit thereon. The electrical circuit receives the radio frequency signal and derives an electrical voltage from the energy of that signal. The electrical voltage is applied in the form of pulses to the pair of electrodes, thereby stimulating the vagal nerve. The pattern of that stimulating pulses can be varied in response to characteristics of the atrial fibrillation or the ventricular contractions.

The patterns of contraction and relaxation of the heart before and during left ventricular or biventricular pacing are analyzed and displayed in real time mode to assist physicians to screen patients for cardiac resynchronization therapy, to set the optimal A-V or right ventricle to left ventricle interval delay, and to select the site(s) of pacing that result in optimal cardiac performance. The system includes an accelerometer sensor; a programmable pace maker, a computer data analysis module, and may also include a 2D and 3D visual graphic display of analytic results, i.e. a Ventricular Contraction Map. A feedback network provides direction for optimal pacing leads placement. The method includes selecting a location to place the leads of a cardiac pacing device, collecting seismocardiographic (SCG) data corresponding to heart motion during paced beats of a patient's heart, determining hemodynamic and electrophysiological parameters based on the SCG data, repeating the preceding steps for another lead placement location, and selecting a lead placement location that provides the best cardiac performance by comparing the calculated hemodynamic and electrophysiological parameters for each different lead placement location.

A system for treating mitral valve regurgitation includes a tensioning device having a flexible annuloplasty ring, a plurality of anchoring members and a tensioning filament attached to the flexible ring. One embodiment of the invention includes a method for attaching a flexible annuloplasty ring to the annulus of a mitral valve, and adjusting the lengths of segments of the tension filament attached to the flexible ring in order to exert force vectors on the annulus, thereby reshaping the mitral valve annulus so that the anterior and posterior leaflets of the mitral valve close completely during ventricular contraction.

The present invention provides one medicine composition for treating coronary heat disease ventricular premature beat based on the Chinese medicine theory of benefiting vital energy, nourishing Yin, promoting blood circulation, dredging meridian, clearing away heat-evil in the pericardium and tranquilizing. The medicine composition has 12 kinds of Chinese medicinal materials including ginseng, ophiopogon root, dogwood, red sage, common jujube seed, etc. The pharmacological test shows that the composite medicine capsule has obvious effect of preventing mouse's arrhythmia caused by CaCl2 and decreasing the sustained time of rat's arrhythmia caused by aconitine.

This document discusses, among other things, systems, devices, and methods measure an impedance and, in response, adjust an atrioventricular (AV) delay or other cardiac resynchronization therapy (CRT) parameter that synchronizes left and right ventricular contractions. A first example uses parameterizes a first ventricular volume against a second ventricular volume during a cardiac cycle, using a loop area to create a synchronization fraction (SF). The CRT parameter is adjusted in closed-loop fashion to increase the SF. A second example measures a septal-freewall phase difference (PD), and adjusts a CRT parameter to decrease the PD. A third example measures a peak-to-peak volume or maximum rate of change in ventricular volume, and adjusts a CRT parameter to increase the peak-to-peak volume or maximum rate of change in the ventricular volume.

A system for treating mitral valve regurgitation includes a tensioning device having a plurality of helical anchors and a tensioning filament. One embodiment of the invention includes a method for attaching a tensioning device to the annulus of a mitral valve in a trans-leaflet configuration, and applying a tension force to the tension filament in order to exert force vectors on the annulus, thereby reshaping the mitral valve annulus so that the coaption of the anterior and posterior leaflets of the mitral is improved during ventricular contraction.

This document discusses, among other things, systems, devices, and methods measure an impedance and, in response, adjust an atrioventricular (AV) delay or other cardiac resynchronization therapy (CRT) parameter that synchronizes left and right ventricular contractions. A first example uses parameterizes a first ventricular volume against a second ventricular volume during a cardiac cycle, using a loop area to create a synchronization fraction (SF). The CRT parameter is adjusted in closed-loop fashion to increase the SF. A second example measures a septal-freewall phase difference (PD), and adjusts a CRT parameter to decrease the PD. A third example measures a peak-to-peak volume or maximum rate of change in ventricular volume, and adjusts a CRT parameter to increase the peak-to-peak volume or maximum rate of change in the ventricular volume.

An implantable cardioverter/defibrillator includes a tachycardia detection system that detects one-to-one (1:1) tachycardia, which is a tachycardia with a one-to-one relationship between atrial and ventricular contractions. When the 1:1 tachycardia is detected, the system discriminates ventricular tachycardia (VT) from supraventricular tachycardia (SVT) based on analysis of a cardiac time interval. Examples of the cardiac time interval include an atrioventricular interval (AVI) and a ventriculoatrial interval (VAI). A template time interval is created during a known normal sinus rhythm. The system measures a tachycardia time interval after detecting the 1:1 tachycardia, and indicates a VT detection if the tachycardia time interval differs from the template time interval by at least a predetermined percentage of the template time interval.

A system including an implantable medical device (IMD). The IMD includes a ventricular contraction sensing circuit that provides a sensed ventricular contraction signal, a timer circuit that provides a ventricular time interval between ventricular contractions, and a controller circuit coupled to the timer circuit, the controller circuit determines the ventricular contraction rate using the ventricular time interval. The controller circuit further includes a tachyarrhythmia detection module that declares tachyarrhythmia, in response to detecting a sudden rate increase, without comparing a ventricular rate or time interval to a respective tachyarrhythmia detection rate or time interval threshold.

A method for assessing cardiac function using an ultrasound imaging catheter system includes positioning an ultrasound catheter so the ultrasound transducer can image a ventricle, obtaining images of the ventricle at two or more times within the cardiac cycle, recognizing an edge of the endocardium, measuring dimensions of the ventricle, calculating a volume or area of the ventricle at the two or more points in the cardiac cycle, and calculating the ejection fraction based upon the difference in volume or area at the two or more times in the cardiac cycle. The method can be used to determine a location for an intervention, such as placement of a pacemaker pacing lead, and may be performed before and after an intervention to assess the impact of the treatment on cardiac function.

Herein provided are methods for optimizing the atrio-ventricular (A-V) delay for efficacious delivery of cardiac resynchronization therapy. The A-V delay is set such that pacing-induced left ventricular contraction occurs following completion of left atrial (LA) contraction. This maximizes left ventricular filling (preload) which theoretically results in optimal LV contraction via the Frank-Starling mechanism. In CRT devices, the programmed A-V delay starts with detection of electrical activity in the right atrium (RA). Thus, a major component of the A-V delay is the time required for inter-atrial conduction time (IACT) from the RA to the LA. This IACT can be measured during implantation as the time from the atrial lead stimulation artifact to local electrograms in a coronary sinus (CS) catheter. Assuming that the beginning of LA contraction closely corresponds with the beginning of LA electrical activity, the optimal AV delay should be related to the time between the start of RA electrical activity and the start of LA electrical activity plus the duration of LA atrial contraction. Thus the inventors hypothesized that during atrial pacing the IACT measured at implantation correlated with the echocardiographically defined optimal paced AV delay (PAV).

The present invention demonstrates that continuous hemodynamic monitoring can be used to identify the optimal AV-delay in a pacemaker-treated patient with end stage heart failure. The AV-delay determines the timing of late diastolic filling in relation to the onset of ventricular contraction and the duration of diastolic filling. An optimal tuning of the AV-delay improves left ventricular filling pressures in patients with a DDD-programmed pacemaker and is particularly important in the presence of a compromised left ventricular function. It has been discovered that using the lowest ePAD pressure, an indirect parameter of the left ventricular end-diastolic pressure, as an indicator for the optimal AV interval. Importantly, measurements of the ePAD revealed the same optimal AV-delay as echocardiographic assessment of left ventricular diastolic filling by standard echocardiographic methods. Importantly, the HR determined as optimal during the acute hemodynamic test did not turn out to be optimal during daily living activities.

A medical device monitors a patient to predict worsening heart failure. An input circuit of the medical device receives a pressure signal representative of a pressure sensed within a ventricle of the patient's heart as a function of time. A processor derives from the pressure signal a ventricular pressure index for a ventricular contraction based upon pressures in the ventricle. The processor then provides an output based upon the ventricular pressure index.

The invention discloses a sinus heart rate turbulence trend detection method based on piecewise linearization. The piecewise linearization is adopted for specifically analyzing whether the variation trend of sinus heart rate accelerates first and then decelerates after premature ventricular contractions or not. The method includes the steps: (1) electrocardiosignal preprocessing; (2) self-learning process for first 10 seconds; (3) HRT (heart rate turbulence) sample collection; (4) piecewise trend analysis; and (5) turbulence trend representation based on a cloud model. The variation trend of the sinus heart rate at the RR interval is detected by means of piecewise linearization, and the turbulence trend is further represented by natural language through the cloud model. By the aid of an MATLAB (matrix laboratory) simulation tool, signals in an MIT-BIH heart beat irregularity database are selected for verification, and the variation trend of the sinus heart rate after single-time ventricular premature beat can be detected correctly. In addition, using the exponential smoothing method to predicate QRS complex occurrence positions to facilitate detection of QRS complex, and using a template for judging sinus heart beat is simple to implement and suitable for real-time treatment.

A method and apparatus for treatment of hypertension and heart failure by increasing secretion of endogenous atrial hormones by pacing of the heart. Pacing is done during the ventricular refractory period resulting in premature atrial contraction that does not result in ventricular contraction. Pacing results in the atrial wall stress, peripheral vasodilation, ANP secretion. Concomitant reduction of the heart rate is monitored and controlled as needed with backup pacing.

The invention provides a premature ventricular contraction identification method and system. The method includes the steps that electrocardiogram signals are received; the electrocardiogram signals are preprocessed; the preprocessed electrocardiogram signals are classified through several classification models to obtain several original probability values; fusion decision-making is conducted on the original probability values based on a preset fusion decision-making rule to obtain a comprehensive probability value after fusion decision-making, and whether the preprocessed electrocardiogram signals are electrocardiogram signals indicating premature ventricular contraction or to-be-determined electrocardiogram signals indicating premature ventricular contraction is identified according to the comprehensive probability value; if the preprocessed electrocardiogram signals are to-be-determined electrocardiogram signals indicating premature ventricular contraction, extraction is conducted, and identification is conducted again according to the characteristic parameters of the preprocessed electrocardiogram signals. By means of the premature ventricular contraction identification method and system, higher PVC identification sensitivity, better PVC identification performance and higher PVC identification accuracy can be achieved.

Techniques are provided for overdrive pacing the ventricles using a pacemaker wherein an increase in an overdrive pacing rate is performed primarily to achieve a high degree of rate smoothing. The ventricles are paced at an overdrive pacing rate selected to permit the detection of the least some intrinsic ventricular pulses and then the overdrive pacing rate is dynamically adjusted based on the detected intrinsic ventricular pulses. In one example, an increase in the ventricular overdrive rate is performed only in response to detection of at least two intrinsic ventricular beats within a predetermined search period. If at least two intrinsic ventricular beats are not detected within the search period, the overdrive pacing rate is decreased. Various techniques are also provided for determining when to activate ventricular overdrive pacing depending, in part, on the capabilities of the particular pacemaker, the current mode of operation, the density of premature ventricular contractions, the degree of heart rate stability, and the presence of atrial fibrillation. Adaptive techniques for automatically adjusting ventricular overdrive pacing control parameters are also described.

A dual-chamber cardiac pacemaker comprising an atrial detection unit which is adapted to detect electrical signals in the atrium of a heart as atrial sense events, a ventricular detection unit which is adapted to detect electrical signals of a ventricle of the heart as ventricular sense events, a stimulation unit which is adapted at least to trigger the delivery of electrical pulses to the ventricle as ventricular stimulation events, and a control unit which is connected to the atrial and the ventricular detection units and the stimulation unit and adapted to control triggering of the delivery of pulses in dependence on the atrial detection unit and the ventricular detection unit in such a way that pulse delivery to the ventricle is triggered after the expiry of an AV time after detection of an atrial sense or stimulation event if prior to expiry of the AV time no ventricular sense event is detected by the ventricular detection unit, wherein the control unit is further adapted to divide ventricular sense events into at least two categories of which a first category concerns ventricular sense events to be associated with natural stimulus conduction from the atrium to the ventricle while a second category concerns ventricular sense events to be associated with ventricular extrasystoles or premature ventricular contractions (PVC) and control of the cardiac pacemaker is differentiated in accordance with whether a ventricular sense event is or is not associated with the first category, characterized in that for the control of triggering of pulse delivery an AV monitoring interval is provided in such a way that the AV monitoring interval is triggered by each atrial sense event which is outside an atrial refractory time, wherein the cardiac pacemaker is adapted to associate ventricular events occurring within the AV monitoring interval to the first category.