Abstract
The efficacy of the latissimus dorsi muscle (LDM) cardiomyoplasty was evaluated experimentally in eight mongrel dogs. Using the anesthetized open-chest dogs, the electrically pre-conditioned LDM was sutured around the entire ventricle, and was stimulated synchronously by the pulse train stimulator. (synchronization ratio 2:1). The pulmonary artery pressure and the left ventricular pressuve were measured, and the left ventricular volume was also estimated continuously with a multi-electrode volume-conductance catheter. Emax was determined from multiple pressure volume loops obtained during a brief preload reduction by balloon occlusion of inferior vena cava. When the LDM was stimulated synchronously, the pulmonary pressure demenstrated a systolic augmentation, and the left ventricular stroke volume and ejection fraction improved significantly. The pressure volume loops of the left ventricle shifted to the left, and an increase in Emax was clearly observed. These results showed that the contractility of the left ventricle was improved by the synchronous contraction of the LDM wrapped around both ventricles.
