Evaluation of left ventricular function and mitral regurgitation during left ventricular-based pacing in patients with heart failure

Background: Beneficial effects of left ventricular (LV)-based pacing on acu te hemodynamic parameters were reported in several series, but only a few s tudies examined the long-term effects of this new pacing procedure. Aims: T o assess long-term effects of permanent LV-based pacing on LV function and mitral regurgitation (MR) in patients with refractory congestive heart fail ure (CHF). Methods: A prospective evaluation of LV function and MR was perf ormed in 23 patients with severe but stable CHF and left bundle branch bloc k (mean QRS: 186 +/- 31 ms) by radionuclide and echocardiographic technique s at baseline and 6 months after implantation of a permanent LV-based (LV a lone: 13 patients; biventricular: 10 patients) pacemaker programmed either in a DDD mode (sinus rhythm, n = 14) or in a VVIR mode (atrial fibrillation ; n 9). Results: Compared to baseline, the 6 months follow-up visit demonst rated a significant increase in radionuclide derived LV ejection fraction f rom 23.3 +/- 7 to 26.2 +/- 7% (P < 0.01) and in echocardiographic LV fracti onal shortening from 13 +/- 4 to 16 +/- 6% (P < 0.05), without any change i n cardiac index, a significant decrease in LV end-diastolic diameter (from 73.2 +/- 6 to 71.2 +/- 7 mm; P < 0.05), end-systolic diameter (from 63.6 +/ - 6 to 60.2 +/- 8 mm; P < 0.05) and color Doppler MR jet area (from 11.5 +/ - 6 to 6.6 +/- 4 cm(1); P < 0.001). A comparison of patients with LV pacing alone and patients with biventricular pacing showed similar beneficial eff ects of pacing on MR severity in the two subgroups and a non-significant tr end for a better improvement of LV function during biventricular pacing. Co nclusion: Thus, in patients with severe CHF and left bundle branch block, p ermanent LV-based pacing may significantly improve LV systolic function and decrease MR. (C) 2001 European Society of Cardiology. All rights reserved.