[Role of echo-doppler in programming of sequential pacemakers. Evaluation of optimal atrioventricular delay in patients with normal or hypertrophic left ventricle].

2D-echocardiography, together with simultaneous measurement of systolic blood pressure and pulsed doppler examination of the transmitral flow were used to assess the left ventricular (LV) systolic and diastolic function during sequential pacing at 4 different atrioventricular (AV) intervals (50, 100, 150, 200 msec), and VVI pacing under the same rate of 90 beats/min in 13 patients (pts), mean age 61.25 +/- 8.26 years with DDD pacemakers implanted for complete AV block. The pts were divided into 2 groups: group I was comprised of 7 subjects showing no clinical abnormalities and normal echocardiograms, and group II of 6 hypertensive subjects with LV hypertrophy and normal systolic function on echocardiography. There was no change in LV diastolic dimension, but a depression in LV systolic function and contractility were shown by the conversion from DDD to VVI pacing in all pts, particularly in group II VVI pacing caused mitral regurgitation with LV filling pattern changing from beat to beat. By changing the AV interval during DDD pacing, the LV filling pattern was modified in all pts. Systolic performance showed little change in group I, whereas in group II more evident modifications were seen. An optimal AV delay, defined as the delay with maximal stroke volume, was identified in all subjects as being 100 and 150 ms in group I and group II respectively. Echo-doppler can thus provide useful information in choosing the mode of pacing and in programming optimal AV delay. In contrast to normal ventricles the systolic performance in hypertrophic ventricles is highly influenced by variation in the AV delay.(ABSTRACT TRUNCATED AT 250 WORDS)