In an implantable cardiac stimulation device including a pulse generator that delivers atrial and ventricular pacing stimulation pulses to a heart, each ventricular pacing pulse being delivered on demand an AV delay after at least an atrial pacing pulse, and the atrial pacing pulses being delivered an atrial escape interval after a natural or paced ventricular event, a system for treating a repetitive non-reentrant ventriculo-atrial synchronous (RNRVAS) cardiac rhythm, the system comprising:
- a sensing circuit that senses cardiac activity of the heart;
- a detector responsive to the sensing circuit that determines if a repetitive non-reentrant ventriculo-atrial synchronous rhythm is present;
- and
- a therapy control circuit that causes the pulse generator to deliver a secondary atrial pacing pulse following a primary atrial pacing pulse delivered at the end of an atrial escape interval responsive to the detector determining that a repetitive non-reentrant ventriculo-atrial synchronous rhythm is present.