Background: This study was designed to compare the rotation of the left ventricular (LV) apex and base, LV synchrony between LV apical and basal rotation, and LV twist, changing from intrinsic atrioventricular conduction to right ventricular apical (RVA) pacing.
Methods: Thirty consecutive patients with sick sinus syndrome who had undergone DDD pacemaker implantation were studied. Changing from intrinsic atrioventricular conduction to RVA pacing, the acute effect on echocardiographic parameters, including LV rotation and twist and LV apical-basal rotation delay, was assessed.
Results: During RVA pacing, values of peak rotation in the LV apex and base and LV twist were significantly lower than during intrinsic atrioventricular conduction (P=.007, P=.003, and P<.0001, respectively). Apical-basal rotation delay during RVA pacing was significantly longer than during intrinsic atrioventricular conduction (P=.02).
Conclusions: RVA pacing decreases apical and basal LV rotation and induces LV apical-basal rotation delay, resulting in impairment of LV twist.