Echocardiographic evaluation of the effect of biventricular pacing : the InSync Italian Registry

Biventricular pacing has been recently proposed as a new therapy to improve haemodynamics in patients with dilated cardiomyopathy. The aim of this report is to analyse the echocardiographic data obtained in the patients enrolled in the InSync Italian Registry in order to explain the effects of biventricular pacing on interventricular delay and on left and right ventricular function. Furthermore, a subgroup of 23 patients in the InSync Italian Registry were studied more accurately by echocardiography to obtain more significant data. After a mean follow-up period of 9.3 +/- 5.1 months the following changes in performance parameters were observed: a significant increase of cardiac output (3.6 +/- 1.21 . min(-1) vs 4.2 +/- 1.61 . min(-1), P<0.02), ejection fraction (32 +/- 8% vs 38 +/- 7%, P<0.0005), left ventricular filling time as a percentage of RR interval (38 +/- 14 vs 43 +/- 9, P<0.02), and a significant decrease of left ventricular electromechanical delay (149 +/- 34 ms vs 111 +/- 32 ms, P<0.002), right ventricular electromechanical delay (119 +/- 20 ms vs 95 +/- 22 ms, P<0.001), interventricular delay (38 +/- 26 ms vs 20 +/- 13 ms, P<0.01), left ventricular myocardial performance index (1.19 +/- 0.67 vs 0.78 +/- 0.48, P<0.009), and right ventricular myocardial performance index (1.35 +/- 0.76 vs 0.81 +/- 0.39, P<0.04). Data derived from the InSync Italian Registry indicate persistent haemodynamic benefit from biventricular stimulation in the population studied as a result of significant improvement in cardiac output, ejection fraction and both left and right myocardial performance indexes, and a significant reduction of the interventricular delay. (Eur Heart J Supplements 2000; 2 (Suppl J): J23-J30) (C) 2000 The European Society of Cardiology.