Inter-beat changes in left ventricular function with cardiomyoplasty as measured using MUGA scanning

Abstract

Dynamic cardiomyoplasty is a new surgical technique that uses electrically stimulated skeletal muscle to partially replace or reinforce the heart muscle in the treatment of advanced heart failure. Clinical experience with cardiomyoplasty is limited, which has precluded definitive conclusions about its value. We have studied the effect of cardiomyoplasty on the heart muscle when the skeletal muscle was being stimulated to coincide with alternate natural beats. The left ventricular function was assessed using radionuclide angiography during the beat immediately following skeletal muscle stimulation and during the beat immediately before stimulation. When the supported beat is compared with the unsupported beat, the results demonstrate that cardiomyoplasty improves the global and regional ejection fraction. The regurgitation index remains unchanged. The systolic peak emptying rate improves but the diastolic peak filling rate worsens. This latter finding provides additional information regarding the diastolic function of the heart following cardiomyoplasty, which is presently not well understood.