Increased coronary artery blood flow with aortomyoplasty in chronic heart failure

Background. We hypothesized that diastolic counterpulsation using aortomyoplasty will increase coronary blood flow. Methods. In dogs (n = 6, 20 to 25 kg), the left latissimus dorsi muscle was isolated, wrapped around the descending thoracic aorta, and conditioned by chronic electrical stimulation. Heart failure was induced by rapid ventricular pacing. In a terminal study, left ventricular and aortic pressures, and blood flow in the left anterior descending coronary artery and descending aorta were measured. The endocardial-viability ratio was calculated. Results. Aortomyoplasty increased mean diastolic aortic pressure (70 ± 5 to 75 ± 5 mm Hg, p < 0.05) and reduced peak left ventricular pressure (86 ± 4 to 84 ± 4 mm Hg, p < 0.05), leading to a 16% increase in endocardial-viability ratio (1.29 ± 0.05 to 1.49 ± 0.05, p < 0.05). Coronary blood flow was increased by 15% (8.2 ± 1.5 to 9.4 ± 1.6 mL/min, p < 0.05). During muscle contraction, 2.7 ± 0.5 mL was ejected from the wrapped aortic segment. Conclusions. These data demonstrate that aortomyoplasty provides successful diastolic counterpulsation after muscle conditioning and heart failure.