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Abstract

An implantable cardiac stimulator including and accelerometer utilizes heart sound measurements to optimize the AV delay. One or more of the amplitude of the heart sound, the pre-ejection interval or the ejection interval is derived from the measurements and examined at various values of AV delay. The optimal AV delay is selected that corresponds to the highest cardiac function such as contractility, cardiac output and stroke volume. The stimulation device determines when the patient is at rest and the accelerometer provides a signal that corresponds to the audible component of a vibration produced as a result of ventricular contraction, blood movement toward the atrium, and the opening and closing of valves. The AV delay is adjusted within a range of values and the cardiac parameters are determined multiple times for each AV delay value. The average value of the cardiac parameter is examined to determine the optimal AV delay value.

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First Claim