[Left ventricular stroke volume in individuals with dual chamber pacemaker (DDD). Effect of atrioventricular delay]

Programming of atrioventricular delay in patients with dual chamber pacemaker is very important for left ventricular filling and has a consequence for its stroke volume. The aim of this study was to evaluate the influence of atrioventricular delay for left ventricular stroke volume during pacing at two different rates. The study was performed in 36 patients with DDD pacemaker aged from 30 to 81 years, mean 56.1 +/- 14.6. Using Doppler echocardiography we have assessed left ventricular stroke volume during two pacing rates (70 and 100 ppm) with four atrioventricular delays (100, 150, 200 and 250 ms). We have found statistically significant difference between stroke volume with various atrioventricular delays. During pacing rate of 70 ppm the maximal difference was 19% and 15% during 100 ppm. Comparing both pacing rates the distributions of hemodynamically optimal atrioventricular delays was also significantly different. The best atrioventricular delay from the hemodynamic point of view was 36 ms longer during 70 ppm of pacing rate than during 100 ppm (p = 0.0009). The most often optimal delay at 70 ppm was 190-200 ms, and the rarest optimal delay was 90-100 ms; during 100 ppm pacing respectively: 140-150 ms and 240-250 ms. We have observed considerable personal variability in the hemodynamic response for atrioventricular delay changing as well as in the hemodynamically optimal values of this parameter during both pacing rates.

1. Atrioventricular delay programming has significant influence on left ventricular stroke volume. 2. Programming of atrioventricular delay should be performed individually in every patient because of personal variability of optimal values of this parameter.(ABSTRACT TRUNCATED AT 250 WORDS)