摘要:
A system and method for detecting and classifying cardiac arrhythmias based on cardiac pressure signals or the combination of cardiac electrical and cardiac pressure signals. A cardiac electrogram signal is sensed to derive a cardiac rate from which an arrhythmia detection is made when the cardiac rate meets arrhythmia detection criteria. An intracardiac pressure signal is sensed to derive an indicator of tachycardia based on an analysis of the pressure signal in either the time domain or frequency domain. The detected arrhythmia is classified as tachycardia or fibrillation based on the tachycardia indicator wherein the tachycardia indicator is compared to tachycardia detection criteria and the arrhythmia is classified as tachycardia if tachycardia detection criteria are met and the arrhythmia is classified as fibrillation if the tachycardia detection criteria are not met.
摘要:
A method and apparatus is provided for determining whether a current atrial-ventricular (AV) delay during cardiac pacing is appropriate for proper mechanical coupling of the atrium and ventricle. If proper mechanical coupling is determined to not exist, an additional atrial contraction is induced within the same ventricular cycle to maintain atrial-ventricular mechanical coupling.
摘要:
A method and apparatus is provided for determining whether a current atrial-ventricular (AV) delay during cardiac pacing is appropriate for proper mechanical coupling of the atrium and ventricle. If proper mechanical coupling is determined to not exist, an additional atrial contraction is induced within the same ventricular cycle to maintain atrial-ventricular mechanical coupling.
摘要:
An implantable medical device (IMD) having a therapy circuit for delivering atrial pacing and a control circuit for detecting a return to sinus rhythm. The control circuit determines the duration of an atrial arrhythmia preceding the return to sinus rhythm, and controls the therapy circuit to deliver transient atrial pacing based on the atrial arrhythmia duration.
摘要:
Methods and systems for treating patients with diastolic heart failure (DHF) are disclosed which include slowing a patient's heart rate below its intrinsic rate, and controlling the rate using cardiac pacing therapy to improve LV filling and cardiac output. In certain embodiments, a pacing treatment rate may be determined by adjusting an adaptive rate by an amount determined by evaluating one or more patient parameters.
摘要:
Control of defibrillation therapy delivered by implantable medical devices (IMDs) using hemodynamic sensor feedback is disclosed. The hemodynamic sensor feedback allows for increased control over application of atrial defibrillation therapy. Specifically, the therapy is delivered when a fibrillation episode results in a discrete loss of hemodynamic function. Defibrillation therapy is thus withheld for hemodynamically benign arrhythmias.
摘要:
A method of evaluating ventricular performance of a heart employing sensors to measure a ventricular dimension signal and deriving indices of ventricular performance therefrom. Premature Shortening (PS) and Isovolumic Lengthening (IL) comprise two indices of ventricular performance determined from analysis of the left ventricular dimension signal during the transition from ventricular filling to ventricular ejection. Measured values of PS and IL are compared to other measured values or reference values to determine if ventricular performance has improved (or worsened). In some embodiments, the dimension sensors may comprise piezoelectric sonomicrometer crystals that operate as ultrasound transmitters and receivers. The sensors may be mounted in relation to a ventricle of the heart either temporarily or permanently, and may be configured either separately from or integrally with cardiac pacing leads.
摘要:
An implantable medical device and associated method deliver a therapy to an autonomic nerve. The therapy delivery includes delivering therapeutic low frequency (LF) electrical stimulation pulses to the autonomic nerve and delivering a high frequency electrical signal to the autonomic nerve during the LF frequency stimulation pulse delivery. The high frequency stimulation signal blocks activation of autonomic nerve fibers innervating a non-targeted tissue during the therapeutic LF stimulation pulse delivery.
摘要:
Implantable pulse generators (IPGs) are adapted to deliver stimulation to refractory myocardial tissue. An IPG nominally delivers one to six monophasic stimulation pulses. Because monophasic stimulation tends to accumulate polarization, a programmable blanking period of between about 20 milliseconds (ms) and about 300 ms is implemented (subsequent to delivery of the last pulse in a RPS pulse train) to allow recovery from polarization. The stimulation pulse width is about 0.03 ms to about 1.6 ms and voltage amplitude of 0.5 volts to 8 volts at about 50 Hz. The amplitude of electrical current of the stimulation pulses is less than or equal to approximately 50 milliamps. The pulses are delivered to multiple sites within a cardiac chamber and device performance and/or diagnostic information can be stored within a memory structure and reviewed to confirm delivery of a desired therapy regimen.
摘要:
A method of controlling pulmonary capillary pressure is disclosed which includes increasing the output of a first ventricle (V1) (e.g., a left ventricle) relative to second ventricle (e.g., right ventricle) by increasing the magnitude of a post extrasystolic potentiation (PESP) therapy effect in the first ventricle relative to the magnitude of a PESP therapy effect produced in the second ventricle. In certain embodiments of the invention, this may be accomplished by adjusting the extra-stimulus interval (ESI) in either or both of the left ventricle and the right ventricle, for example.