Patent ID: 6952609

Claim:
An implantable cardiac stimulating device adapted for use with a first electrode adapted to be positioned in an atrium of a heart and with a second electrode adapted to be positioned in a ventricle of the heart, said cardiac stimulating device comprising: an atrial pulse generator adapted for connection to said first electrode for emitting atrial stimulating pulses; an atrial sensor adapted for connection to said first electrode for sensing events in the atrium; a ventricular pulse generator adapted for connection to said second electrode for emitting ventricular stimulating pulses; a ventricular sensor adapted for connection to said second electrode for sensing events in the ventricle; said ventricular sensor including an evoked response detector for detecting an evoked response of the ventricle to a ventricular stimulating pulse delivered to the ventricle; said ventricular pulse generator delivering a back-up pulse to the ventricle if said evoked response detector does not detect any evoked response to a delivered ventricular stimulating pulse; a control unit connected to said atrial pulse generator and to said ventricular pulse generator for, in response to events sensed in the atrium by said atrial sensor, operating said atrial pulse generator in a first manner wherein no atrial stimulating pulse is emitted, and operating said atrial pulse generator in a second manner wherein atrial stimulating pulses are generated; and said control unit operating said ventricular pulse generator to prevent delivery of said back-up pulse at least during a first heart cycle from a point in time when said control unit changes said atrial pulse generator from operation in said first manner to operation in said second manner.