(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.