Adynamic Cardiomyoplasty: Effect on Cardiac Efficiency and Contractile Reserve in Dogs with Adriamycin-Induced Cardiomyopathy

The girdling effect of the skeletal muscle wrap seems to be the primary mechanism of action of cardiomyoplasty. It is associated with a myocardial sparing effect. Myocardial sparing effect has been shown with an active muscle wrap or an active muscle wrap acutely turned "OFF". The purpose of the study was to evaluate the effect of a passive skeletal muscle wrap on cardiac energetics parameters and contractile reserve in a canine model of cardiomyopathy. Six dogs with adriamycin-induced cardiomyopathy were studied. Three dogs underwent right latissimus dorsi adynamic cardiomyoplasty and 3 served as controls. Cardiac and coronary sinus catheterizations were performed at 0 and 6 weeks. A dobutamine stress test was performed at 6 weeks. Myocardial oxygen consumption was not reduced in the cardiomyoplasty group (139.20+/-86.90 Joules/min) compared to the control group (95.10+/-12.60 Joules/min, P = 0.27) at 6 weeks. Mechanical cardiac efficiency was increased in the cardiomyoplasty group (33.15+/-4.40%) compared to the control group (24.50+/-2.70%, P = 0.049) at 6 weeks. Left ventricular end diastolic diameter index was reduced in the cardiomyoplasty group (38.00+/-1.70 mm/m2) compared to the control group (46.30+/-1.55 mm/m2, P = 0.049) at 6 weeks. Indices of diastolic function -dp/dt, and tau were not significantly affected by adynamic cardiomyoplasty. Max dp/dt was increasing more in the cardiomyoplasty group than in the control group (P = 0.07) during dobutamine stress test. Mechanical cardiac efficiency was better preserved by the adynamic cardiomyoplasty. Myocardial contractile reserve might be better preserved with cardiomyoplasty.