(25)
In our study; the programming to asynchronous ventricular pacing (VVI mode) at rate of 100 b/min in group III demonstrated a further reduction of both global and regional LV LSS when compared to both groups (P value <0.05).
Dual chamber pacing during AS-VP mode maintains physiological A-V synchrony. This is important as atrial contribution to ventricular filling is extremely valuable as result of LV diastolic and systolic pacing induced dysfunction. Loss of A-V synchrony during VVI mode has a deleterious impact on ventricular filling and may even lead to occasional simultaneous atrioventricular contractions which can lead to pacemaker syndrome. A sub-study of the Mode Selection Trial (MOST) showed that pacing of RV was strongly associated with heart failure, hospitalization and atrial fibrillation in both “physiologic pacing” (dual-chamber pacing: n = 707) and ventricular pacing (single-chamber ventricular pacing: n = 632). They observed that ventricular pacing > 40% in DDD group and >80% in VVI group was closely related to heart failure and hospitalization.