Medtronic, Inc.

Robert S Kieval

Michael F Hess

Kenneth M Riff

Tommy Dean Bennett

Orhan Soykan

Stephanie Michele Fitts

Tom D Bettett

An implantable medical device determines activity levels and Heart Rate and from a combination of these produces a value for a heart rate activity coefficient (HRAC). This value has significant diagnostic and patient tracking value. Methods and apparatus for determining this HRAC value are described. This enables physician review of patient cardiac status. Additional physiologic data can be recorded along with the HRAC data if desired, and this too, as well as the HRAC data alone, may be reported out from the implanted device to a medical communications system for alarm purposes, titrating drugs/therapies or other monitoring tasks. Further, substitutes for heart rate measurements and activity measurements are described which can be used to augment or substitute for heart rate measurements and activity measurements. These substitutes should represent cardiovascular or cardiac responsiveness to substitute for heart rate in the HRAC signal; and should represent cardiac demand to substitute for activity in the HRAC signal.

Implantable medical device for tracking patient cardiac status

An implantable medical device for treatment of cardiovascular disorders by stimulating a selective nerve, the device including an implantable pulse generator, an implantable electrode body and a reservoir. The electrode body includes an electrode electrically connected to the pulse generator. Further, the electrode body is configured to sustain long-term contact between the electrode and the nerve. The reservoir maintains a nerve stimulating drug, such as a veratrum alkaloid, and defines a delivery surface through which the drug is released from the reservoir. Finally, the reservoir is operatively associated with the electrode body to deliver the nerve stimulating drug directly to the nerve. During use, the electrode and the delivered drug stimulate the nerve to effect control over the cardiovascular system of the patient.

Drug delivery neural stimulation device for treatment of cardiovascular disorders

A system and method for stimulating the baroreflex arc based on levels of indicators from the body includes a pacemaker for bradycardia support pacing should the indicators show the need for support pacing. Other indicators and a process take advantage of an assumed relationship between peripheral vascular resistance and pulmonary resistance to determine the level of nerve stimulation required. This level is adjusted or optimized based on its interaction with heart activity and changes in the other indicators. These other indicators are readily available to the implanted device and allow for a process to make an estimate of pulmonary vascular resistance, from which SVR is also estimated. The value determined for SVR is the primary value used to determine the level of nerve stimulation absent indicators for the need to provide bradicardia pacing. The pacemaker can be rate responsive, as can the process for determining the level of nerve stimulation to be delivered. Several different lead configurations are described.

Baroreflex modulation with carotid sinus nerve stimulation for the

An anodal stimulation method and apparatus for the prevention or treatment of tachyarrhythmias using anodal stimulation (AS) energy for effecting hyperpolarization of myocardial cells of a heart chamber to enhance the relaxation thereof in the diastolic phase and to enhance cardiac function, reverse or inhibit cell activation, and thereby treat or prevent tachyarrhythmias. In a preemptive mode with a recognizable ventricular rhythm, the AS pulse is optimally timed to be delivered in an AS delivery interval following an AS delay interval timed from a preceding ventricular depolarization to effect maximal cardiac relaxation and suppress aberrant electrical activity. In a reactive mode responsive to a detected tachyarrhythmia requiring delivery of an anti-tachyarrhythmia therapy, e.g. a cardioversion shock therapy, the AS pulse is delivered during charging of high voltage output capacitors providing the cardioversion shock energy. The sub-threshold AS pulse or train of pulses is increased in energy (amplitude) and/or decreased in energy to and from a peak energy level gradually rather than abruptly. The AS pulses are delivered through a plurality of discrete AS electrodes distributed about the heart chamber or through or large surface area epicardial patch or endocardial AS electrodes.

Cardiac arrhythmia management by application of adnodal stimulation for

An implantable system providing cardiac anodal stimulation (AS) as a system for effecting hyperpolarization of myocardial cells of a heart chamber to enhance the relaxation thereof in the diastolic phase and to thereby enhance cardiac function. The AS system is optimally timed to be delivered in an AS delivery interval following an AS delay interval timed from a preceding ventricular depolarization or pacing pulse to effect maximal cardiac relaxation. The sub-threshold AS pulse or train of pulses is increased in energy (amplitude) and/or decreased in energy to and from a peak energy level gradually rather than abruptly. The AS characteristics are optimized in an initialization process that determines the AS characteristics that provide the optimum blood pressure parameters and thereafter continually or from time to time in a confirmation process. Confirmation of the AS characteristics is determined by measuring one or more blood pressure parameter in the right atrium or ventricle reflecting the blood pressure in the heart chamber subjected to the AS pulses and comparing the measured blood pressure parameter to the corresponding optimum blood pressure parameter determined in the initialization process. The initialization process is repeated if the comparison shows a deterioration in cardiac function response to the AS. The AS pulse waveforms are preferrably delivered through a plurality of discrete AS electrodes distributed about the heart chamber or through or large surface area epicardial patch or endocardial AS electrodes.

System for providing hyperpolarization of cardiac to enhance cardiac

A dual chamber pacemaker is provided having capability for adjusting the AV escape interval so as to optimize the timing of delivered ventricular pace pulses for therapy of patients with cardiomyopathy. The pacemaker system continually monitors to determine when a delivered pace pulse results in a fusion beat, and periodically adjusts the AV escape interval in accordance with the percentage or rate of incidence of such fusion beats. In one specific embodiment, the pacing system determines the percentage of delivered ventricular pace pulses which are followed by fusion beats over a predetermined number of intervals, and decrements AV escape interval when such percentage is not below a predetermined minimum. The pacing system also periodically increments AV escape interval when the rate of fusion beats is acceptable, thereby providing a closed loop system for maintaining the AV interval at an optimally long value consistent with maximizing full capture by delivered ventricular pace pulses. In another embodiment, the V--V escape interval of a non-tracking mode pacemaker is controlled to optimize pre-excitation of the ventricle.

Dual chamber pacing system and method with continual adjustment of the

In a dual chamber cardiac pacemaker, a method and apparatus for determining an atrioventricular (AV) delay interval to maintain optimal left heart AV mechanical synchrony and function. When the intrinsic or paced atrial heart rate is stable, test AV delay intervals are selected and delivered as right ventricular absolute blood pressures (RVP) are measured at the opening of the pulmonary valve. The opening of the pulmonary valve is determined by the peak rate of change in the RVP (dP/dt) following depolarization of the right ventricle. The test AV delay interval providing the lowest amplitude RVP at the peak dP/dt, indicating the lowest pulmonary blood pressure, is selected as the optimal AV delay. The system may be fully contained in an implanted pacemaker system including a right ventricular absolute blood pressure sensor and automatically invoked to determine the optimum AV delay for the prevailing atrial heart rate at any time, or may be invoked at a predetermined time of day or may be invoked by a programmed-in command. The system may also be employed on a temporary basis in conjunction with an implanted dual chamber pacemaker and an external pacemaker programmer with a temporary absolute blood pressure sensor to provide the blood pressure signals.

Method and apparatus for optimizing pacemaker AV delay

An acoustic sensor is located in association with a patient's heart to detect abnormal heart sounds and a processor isolates abnormal heart sounds therefrom. The characteristics of these heart sounds are monitored while adjustments are made to the timing of pacing pulses to achieve a better heart function through pacing therapy. Particular adaption to cardiomyopathy is shown.

Method and apparatus to optimize pacing based on intensity of acoustic

A dual chamber pacemaker and a method of employing the pacemaker to accomplish atrial synchronized ventricular pacing with complete ventricular capture by control of the A-V escape intervals of the pacer. The maximum A-V escape interval effective to accomplish complete ventricular capture is determined and compared to intrinsic A-V conduction time to derive an offset interval. The offset interval is subtracted from the initially measured conduction time to select initial A-V escape interval durations and is subtracted from A-V conduction times measured after implant of the pacemaker to automatically adjust A-V escape interval durations of the pacemaker to maintain complete ventricular capture.

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Golden Valley, MN, United States of America

Robert S Kieval