The influence of different AV delays on left ventricular diastolic functions and on incidence of diastolic mitral regurgitation.

In patients with a DDD pacemaker (PM), programming of atrioventricular (AV) delay can influence ventricular filling and function. In this study the authors used color Doppler echocardiography to evaluate the effect of different AV delays on left ventricular diastolic function (LVDF) and on the incidence bf diastolic mitral regurgitation. In 26 patients with DD PM, the following parameters were evaluated during five different AV delays; by echocardiography: (1) mitral E wave amplitude (by pulsed Doppler), (2) mitral A wave amplitude (by pulsed Doppler), (3) isovolumetric relaxation time (IVRT), (4) deceleration time (DT); (5) LV diastolic dimension (LVDd), (6) LV systolic dimension (LVDs), (7) ejection fraction (EF), and (8) diastolic mitral regurgitation (DMR). Patients had been paced for symptomatic AV block (n: 16, 62%) and sick sinus syndrome (n: 10, 38%). Mean age of patients was fifty-two (nineteen to sixty-three) and 13 (50%) of them were women. Correlation was sought between AV delay and investigated parameters. The correlation coefficients of AV delay and E wave, A wave, IVRT, DT, LVDd, LVDs, and EF were -0.137, 0.243, 0.541, 0.031, 0.210, 0.241, and -0.184 respectively. DMR was detected in all cases when AV delay was increased more than 150 msec. In conclusion, a slight correlation was found between AV delay and IVRT (r: 0.541). Other parameters of LV diastolic and systolic function did not correlate with AV delay. Second, DMR was observed in all patients when the AV delay was prolonged more than 150 msec.