Surgical ventricular restoration improves mechanical intraventricular dyssynchrony in ischemic cardiomyopathy.

ABSTRACT

BACKGROUND: In ischemic cardiomyopathy, dyssynchrony of left ventricular (LV) mechanical contraction produces adverse hemodynamic consequences. This study tests the capacity of geometric rebuilding by surgical ventricular restoration (SVR) to restore a more synchronous contractile pattern after a mechanical, rather than electrical, intervention. METHODS AND RESULTS: A prospective study of the global and regional components of dyssynchrony was conducted in 30 patients (58+/-8 years of age) undergoing SVR at the Cardiothoracic Center of Monaco. The protocol used simultaneous measurements of ventricular volumes and pressure to construct pressure/volume (P/V) and pressure/length (P/L) loops. Angiograms were done before and after SVR to study a 600-ms cycle during atrial pacing at 100 bpm. Mean QRS duration was similar, at 100+/-17 ms preoperatively and 114+/-28 ms postoperatively (NS). Preoperative LV contraction was highly asynchronous, because P/V loops showed abnormal isometric phases with a right shifting. Endocardial time motion was either early or delayed at the end-systolic phase so that P/L loops were markedly abnormal in size, shape, and orientation. Postoperatively, SVR resulted in leftward shifting of P/V loops and increased area; endocardial time motion and P/L loops almost normalized to allow a better contribution of single regions to global ejection. The hemodynamic consequences of SVR were improved ejection fraction (30+/-13% to 45+/-12%; P=0.001); reduced end-diastolic and end-systolic volume index (202+/-76 to 122+/-48 and 144+/-69 to 69+/-40 mL/m(2); P=0.001); more rapid peak filling rate (1.75+/-0.7 to 2.32+/-0.7 EDV/s; P=0.0001); peak ejection rate (1.7+/-0.7 to 2.6+/-0.9 Sv/s; P=0.0002), and mechanical efficiency (0.56+/-0.15 to 0.65+/-0.18; P=0.04). CONCLUSIONS: SVR produces a mechanical intraventricular resynchronization that improves LV performance.