Image Number 4 for United States Patent #5549652.
An improved implantable cardiac stimulating device that performs cardiac wall motion-based automatic capture verification system is provided. Pacing pulses of varying energy content are administered to a patient's heart, and the response of the patient's heart is sensed by a cardiac wall motion sensor. The cardiac wall motion sensor provides a signal which is analyzed to determine the patient's capture threshold, defined as the minimum amount of electrical stimulation required to evoke a cardiac contraction. The device then sets the amount of electrical stimulation at a level safely above the measured capture threshold. Capture verification may be performed at predetermined time intervals, on demand, or upon the occurrence of a significant cardiac event. Capture verification can also be performed on every pacing pulse delivered by the implantable cardiac stimulating device.