Abstract: An implantable cardiac stimulation device provides biventricular pacing and pacemaker mediated tachycardia (PMT) detection. The device includes a pulse generator that provides right ventricular and left ventricular pacing pulse pairs to a right ventricle and left ventricle of a heart in a biventricular pacing mode. A sensing circuit senses activations of an atrium of the heart and a pacemaker mediated tachycardia detector times a plurality of V-P intervals from first issued pacing pulses of each pacing pulse pair to sensed activations of the atrium. A limit circuit of the PMT detector sets V-P interval limits response to the plurality of timed V-P intervals and a compare circuit determines if a last timed V-P interval is within the V-P interval limits. The timed V-P intervals are preferably recorded in a histogram format.