Dual-chamber committed mode pacing.

The proliferation of dual-chamber pacemakers has resulted in several different modalities of DVI pacing. A distinction is made between "committed" and "non-committed" modes, and the differences are presented. In addition, a new hybrid mode has been developed which has been termed "semi-committed" and is currently being introduced. The semi-committed mode divides the AV interval into an early non-physiologic interval and a later "physiologic" interval which enables inhibition of ventricular output following a sensed ventricular event.