Variation in the inter diastolic potentials interval leading to a variation in the inter PVC interval.

Intracardiac electrogram at successful ablation site. The bipolar electrogram on the ablation catheter (MAPd) exhibits sharp diastolic potentials (arrow head) after the T wave of the surface ECG in sinus rhythm, becoming pre-QRS during the PVCs. The variation of the interval between consecutive diastolic potentials is accompanied by a variation in the interval between the consecutive PVCs.