[Dynamic cardiomyoplasty: current status and future perspective].

Abstract

Dynamic Cardiomyoplasty is a new approach to manage patients with heart failure. The phase I study shows that the muscle stimulator and electrodes function as designed and that the operation is done without any impairment of the patient's motor function. The results of the phase II study has been made public. The hemodynamic effects on patients with dilated cardiomyoplasty have been reported to be excellent. The assisting mechanism of dynamic cardiomyoplasty is based on the conformational change of the wrapped muscle with the ability to restore its optimal length and tension. In the chronic postoperative stage, the muscle seems to form a layer outside the epicardium. This change is important for the myocardinal sparing and girdling effects which are related to the wall stress of the heart. The hypothesis that the wrapped muscle becomes another layer of the heart can explain these effects. Increasing the wall thickness of the left ventricle reduces the wall stress (myocardinal sparing effect) according to Laplace's law. Even if the wrapped muscle is not transformed or stimulated (adynamic cardiomyoplasty), the wall stress is reduced after conformation, and the dilatation of the heart may be protected (girdling effect). The systolic augmentation is shown as the increase of cardiac output, ejection fraction, and blood velocity of the ascending aorta and ejection time. The dynamic cardiomyoplasty might effect the remodelling of the impaired heart and delay its progressive dilatation. When the efficacy of dynamic cardiomyoplasty is proven by the phase III study, which has been going on in the centers of North and South Americas, it will be useful as a bridge to heart transplantation, or as one of the surgical treatment modalities for advanced heart failure.