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Lack of Influence of Atrioventricular Delay on Stroke Volume at Rest in Patients with Complete Atrioventricular Block and Dual Chamber Pacing

Dual chamber pacing (DDD) maintains atrioventricular (AV) sequence; AV delay program mobility modifies the relationship between atrial and ventricular contraction. To evaluate the hemodynamic effects of such a modification, ten patients with a DDD unit for complete AV block were studied by time‐motion (M‐mode) and Doppler echocardiography during inhibited ventricular pacing (VVI), atrial‐triggered ventricular pacing (VDDJ and atrioventricular sequential pacing (DVI) at different AV delay (90, 140, 390, 240 msec). A significant improvement in stroke volume (SV) (15%–20%, P < 0.05) was seen during DDD versus VVI pacing; no changes, however, were observed in the same patient with different AV delay or during DVI versus VDD pacing. These data suggest that programming of AV delay does not affect systolic performance at rest; longer diastolic filling times recorded during DDD pacing with “short” AV delay (90–340 msec) do not seem to be a hemodynamically relevant epiphenomenon of PM programming.