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 st udy the authors used color Doppler echocardiography to evaluate the ef fect of different AV delays on left ventricular diastolic function (LV DF) and on the incidence bf diastolic mitral regurgitation. In 26 pati ents with DD PM, the following parameters were evaluated during five d ifferent 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 si ck sinus syndrome (n: 10, 38%). Mean age of patients was fifty-two (ni neteen to sixty-three) and 13 (50%) of them were women. Correlation wa s sought between AV delay and investigated parameters. The correlation coefficients of AV delay and E wave, A wave, IVRT, DT, LVDd, LVDs, an d EF were -0.137, 0.243, 0.541, 0.031, 0.210, 0.241, and -0.184 respec tively. 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 sys tolic function did not correlate with AV delay. Second, DMR was observ ed in all patients when the AV delay was prolonged more than 150 msec.