Canine latissimus dorsi cardio-double myoplasty: acute feasibility study.

Cardio-double myoplasty was performed in eight mongrel dogs. Both latissimus dorsi muscles were dissected from the chest wall and wrapped around the heart. They were then stimulated using an R wave synchronous stimulator. Hemodynamic measurements were obtained, first with the stimulator off and then with stimulator activated. After measuring hemodynamic effects in a normal heart, acute heart failure was induced by the infusion of propranolol (5 mg/kg). Hemodynamic data were then obtained in the same fashion. In a normal heart state, cardio-double myoplasty increased the cardiac output 9.9% ± 2.24 (p < 0.005), the left ventricular pressure 18.7% ± 3.53 (p < 0.001), the pulmonary artery pressure 72.2% ± 25.4 (p < 0. 01), and the stroke volume 13.4% ± 5.73 (p < 0.05). In a failing heart, the cardiac output increased 21.6% ± 3.34 (p < 0.005), the left ventricular pressure increased 20.8% ± 3.34 (p < 0.005), the pulmonary artery pressure increased 87.2% ± 39.9 (p < 0.05), and the stroke volume increased 46.9% ± 22.9 (p < 0.05). The left ventricular end-diastolic pressure decreased slightly and the central venous pressure did not change in either the normal state or during cardiac failure. Cardlo-double myopiasty resulted in a significant circulatory augmentation particularly in the setting of cardiac failure.