Electrostimulated Cardiomyoplasty: From Experimental to Clinical Studies

Abstract

Cardiomyoplasty is a method for managing patients with dilated cardiomyopathy. We evaluated the means of carbon fiber electrode stimulation of the nerve to the latissimus dorsi muscle (LDM) in dogs to increase skeletal muscle contractility. Histochemical examination of biopsies of muscle electrically conditioned by a single pulse stimulator via the thoracodorsal nerve demonstrated transformation of muscle into fatigue resistant slow fibers without damage to muscle or nerve tissue. Canine experiments confirmed that carbon fibers are one of the best electrodes for chronic LDM stimulation. Between 1988 and 1992, we operated on ten patients, New York Heart Association (NYHA) Class III (4 patients) and Class IV (6 patients), with a mean left ventricular ejection fraction (LVEF) of 23%. The indications for cardiomyoplasty were idiopathic (7 patients) and ischemic (3 patients) cardiomyopathy refractory to maximum medical therapy. The operative procedure was performed via median sternotomy (5 patients) and left thoracotomy (5 patients). There was one operative mortality and two additional deaths during the late follow-up period. The mean postoperative LVEF increased to 27%. Functional class, quality-of-life, and ventricular performance were improved after cardiomyoplasty. Two of the surviving patients are in NYHA Class I, four in Class II, and one in Class III.

Dynamic Cardiomyoplasty: A New Summing Up

“…Improvement of left ventricular systolic function has been consistently reported in the clinical studies comparing data obtained before and 6 months after the procedure (2,9–17). Further evidence of the direct influence of skeletal muscle flap contraction on left ventricular performance has been demonstrated comparing the results obtained under stimulated and nonstimulated beats (18) or with the myostimulator turned on and off (19–23).…”

“…The analysis of left ventricular ejection fraction data obtained up to 5 years of follow‐up in some of the largest clinical series demonstrates that dynamic cardiomyoplasty benefits may be maintained at long‐term, especially when the muscle flap is stimulated to contract in synchronism with every other cardiac beat (11,14,17,34–36). The São Paulo Heart Institute study showed that ejection fraction tended to decrease at late follow‐up and return to preoperative levels at 5 years, but this fact occurred associated with an overstimulation of the latissimus dorsi muscle grafts (What does overstimulation mean?).…”