30 results about "VENTRICULAR RHYTHMS" patented technology

A system (10) for achieving a desired cardiac rate and cardiac rhythm in response to atrial fibrillation in a heart includes an atrial fibrillation (AF) detector (40) for detecting AF. The system also includes an atrioventricular node vagal stimulator (AVN-VS) (30) for stimulating vagal nerves associated with an atrioventricular (AV) node of the heart. The system further includes an on-demand pace maker (40) for providing ventricular pacing stimulation to the heart. A control unit (20) is operatively connected with the AF detection device, the AVN-VS device, and the on-demand pacing device. The control unit is responsive to AF detection by the AF detector to cause the AVN-VS to stimulate the vagal nerves to help reduce the ventricular rate of the heart. The control unit is further responsive to AF detection by the AF detector to cause the on-demand pace maker to help regulate the ventricular rate of the heart.

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 method and system for operating a cardiac rhythm management device which employs pacing therapy to regularize the ventricular rhythm. Such ventricular rate regularization may be employed with conventional bradycardia pacing, ventricular resynchronization therapy, or anti-tachyarrhythmia therapy.

An active implantable medical device, in particular a defibrillator/cardioverter, with a sophisticated discrimination of atrial fibrillations. This device is able to deliver therapy for defibrillation, cardioversion, and/or ventricular and/or atrial antitachycardiac pacing stimulation; sense the ventricular and atrial activity; identify a suspicion of and confirm the presence of episodes of tachycardia in the activity thus sensed; analyze the stability of detected RR intervals and the stability of the associated PR intervals; and, in the event of a detection of stable RR intervals and unstable PR intervals, discriminate between atrial fibrillation with fast ventricular rhythm and atrial fibrillation with ventricular tachycardia, and to control delivery of a differentiated therapy according to one case or the other. A bi-tachycardia discrimination also can be made.

A cardiac rhythm management device which employs pacing therapy to regularize the ventricular rhythm. Such ventricular rate regularization may be employed within bradycardia pacemakers, ventricular resynchronization devices, or implantable cardioverter/defibrillators.

A system (10) for achieving a desired cardiac rate and cardiac rhythm in response to atrial fibrillation in a heart includes an atrial fibrillation (AF) detector (40) for detecting AF. The system also includes an atrioventricular node vagal stimulator (AVN-VS) (30) for stimulating vagal nerves associated with an atrioventricular (AV) node of the heart. The system further includes an on-demand pace maker (40) for providing ventricular pacing stimulation to the heart. A control unit (20) is operatively connected with the AF detection device, the AVN-VS device, and the on-demand pacing device. The control unit is responsive to AF detection by the AF detector to cause the AVN-VS to stimulate the vagal nerves to help reduce the ventricular rate of the heart. The control unit is further responsive to AF detection by the AF detector to cause the on-demand pace maker to help regulate the ventricular rate of the heart.

A device is connected to electrode leads which performs intracardiac impedance measurements, conducts a transient pacing protocol, analyses the impedance measurements, and generates an LV lead position quality factor. The transient pacing protocol includes a repeated change (“transitions”) between ventricular intrinsic rhythm and biventricular paced rhythm and may also include a variation of the atrioventricular delay (AVD) and/or the interventricular delay (VVD). The quality factor expresses the degree to which hemodynamic properties have improved due to BiV stimulation for the current LV lead position compared to intrinsic ventricular rhythm.

An implantable cardiac stimulator includes a cardioversion/defibrillation unit connected to at least one electrode pair for generation and delivery of cardioversion or defibrillation shocks; an atrial sensing unit detecting atrial contraction, and outputting an atrial sensing signal indicating a atrial event when an atrial contraction is detected; a ventricular sensing unit detecting ventricular contraction, and outputting a ventricular sensing signal when a ventricular contraction is detected; a tachycardia detection unit connected to the atrial and ventricular sensing units and detecting a tachycardia, and classifying it as a ventricular tachycardia (VT) or as a supraventricular tachycardia (SVT); and a treatment control unit designed to trigger at least one atrial cardioversion shock when a ventricular rhythm detected by the ventricular sensing unit is faster than a programmed frequency limit, and the tachycardia detection unit classifies an SVT as an atrial fibrillation (AFib).

An implantable medical device (IMD) identifies suspected non-lethal ventricular arrhythmia, and takes one or more actions in response to the identification to avoid or delay delivery of a defibrillation or cardioversion shock. The IMD employs number of intervals to detect (NID) thresholds for detection of ventricular arrhythmias. When a NID threshold is met, the IMD determines whether the ventricular rhythm is a suspected non-lethal rhythm despite satisfying a NID threshold. In some embodiments, the IMD increases the NID threshold, i.e., extends the time for detection, in response to identifying a rhythm as a suspected non-lethal rhythm, and monitors subsequent ventricular beats to determine if the increased NID threshold is met before detecting a ventricular arrhythmia and delivering therapy. The IMD can determine whether a rhythm is a suspected non-lethal arrhythmia by, for example, comparing the median ventricular cycle length (VCL) to the median atrial cycle length (ACL).

The invention relates to stephanine and its pharmaceutically acceptable salt and an application of a solvate for preparing an antiarrhythmic medicine, which belongs to the technical field of medicine. A structural formula of stephanine is shown as a formula (I); the researches on chloroform-induced mice arrhythmia show that stephanine can resist chloroform-induced ventricular fibrillation, preliminary determination is confirmed that the stephanine has antiarrhythmic effect; then barium chloride-induced rat ventricular rhythm test, aconitine intravenous injection-induced rat cardiac rhythm test and rat myocardial ischemia and ischemia reperfusion arrhythmia test are carried out, so that stephanine has good antiarrhythmic effect, and provides a good base for preparing various antiarrhythmic medicines next time.

An active implantable medical device of the multisite defibrillator/cardioverter type having a sophisticated management of ventricular tachycardias. This device delivers a one of a defibrillation and/or cardioversion and/or ventricular antitachycardia pacing (“ATP”) stimulation therapy mode, as desired and known in the art. The device senses the cardiac activity and detects in the sensed activity a disorder of the ventricular rhythm that is distinct from a ventricular fibrillation condition. The device also includes delivery of biventricular stimulation, connected to at least two ventricular sites, right and left, which is triggered on the detection of the aforesaid disorder of the ventricular rhythm prior to delivering the conventional ATP or shock therapy mode.

An implantable medical device system and method are provided for synchronizing atrial cardioversion shocks to the ventricular rhythm using an adjustable atrial cardioversion/defibrillation ventricular refractory period. Upon determining a need for an atrial shock therapy, the method determines if the ventricular rate meets synchronization criteria based on an upper ventricular refractory period limit. If synchronization criteria are not met, the refractory period is automatically adjusted in stepwise decrements until the synchronization criteria are met, or until a lower refractory period limit is exceeded. If synchronization criteria are met, an atrial shock is synchronized to the next ventricular depolarization occurring outside the current refractory period. If the lower refractory period limit is exceeded, the atrial therapy is aborted.

An implantable medical device is provided for detecting transportless ventricular rhythm of a heart lacking atrial transport and comprises a housing, sensors configured to be located proximate to a heart, a sensing module to sense cardiac signals representative of a rhythm originating from the heart and a rhythm detection module. The rhythm detection module determines a change in AV association and identifies a potential ventricular complex with loss of atrial transport (VCLAT) based on the change in AV association.

An implantable cardiac system that includes an implantable cardiac pacemaker or leadless pacemaker (iLP) and a second device such as a subcutaneous implantable cardioverter-defibrillator (S-ICD). The pacemaker includes an R-spike amplifier that amplifies stimulated ventricle excitations or R-waves to increase R-wave to T-wave signal to noise ratio and to improve indirect detection of ventricular rhythm classification by the S-ICD. The S-ICD includes an electrode line for defibrillation, a sensing unit and a stimulation detection unit. The S-ICD records a subcutaneous electrocardiogram between shock electrode poles and provides potentially life-saving therapy based thereon. The system significantly increases the specificity and sensitivity of an S-ICD in combination with an implanted cardiac pacemaker or iLP having an R-spike amplifier.

The invention provides a cardiac pace making system which comprises a perception module, a pace making module and a control module. Under a normal atrioventricular conduction condition, the control module controls the cardiac pace making system to work in a first mode and detect whether atrioventricular block occurs; various atrioventricular block events can be judged accurately by sensing and comparing PR (punctum remotum) intervals and ventricular event missing; when the atrioventricular block occurs, the control module controls the cardiac pace making system to work in a second mode; and acardiac pacemaker can timely work in an appropriate mode and provide an appropriate AV (atrioventricular) time sequence and a ventricular rhythm.

A heart stimulator for enhancing cardiac performance of a patient suffering from ventricular rhythms that tend to overdrive the patient's atrial rhythm, has sensing circuitry that detects atrial events and ventricular events, and an atrial stimulator that generates and supplies stimulation pulses to the atrium. A timer generates a detection window having a predetermined duration for the ventricular sensing, the detection window starting upon detection of an intrinsic or stimulated atrial event. If an R-wave is sensed from the ventricle during the detection window, a control unit determines that a focus, that pre-depolarizes the ventricles, exists, and the control unit operates the atrial stimulator to increase the atrial stimulation rate for a predetermined number of consecutive heart cycles.