EARLY EFFECTS OF RIGHT LATISSIMUS-DORSI CARDIOMYOPLASTY ON LEFT-VENTRICULAR FUNCTION

Background. We hypothesized that left ventricular function could be im proved with cardiomyoplasty using the right latissimus dorsi. Methods and Results. Five dogs underwent cardiomyoplasty using the right latis simus dorsi. Left ventricular volume and pressure were measured using sonomicrometry and a micromanometer catheter, respectively. Pressure v olume loops were recorded with the muscle stimulated at 1:2 and with t ransient caval occlusion. During stimulated beats, there were signific ant increases in stroke work (13.90+/-4.49 vs 9.78+/-3.81 g/m, P<.01), preload recruitable stroke work (0.766+/-0.110 vs 0.594+/-0.207 g . m -1 . m-3, P<.05), and stroke volume (15+/-4 vs 10+/-3 mL, P<.05) when compared with unstimulated beats. There were no changes in diastolic f illing. This operation was done in 11 patients, with no operative deat hs. Six weeks after surgery, resting left ventricular ejection fractio n (LVEF) increased from 25+/-1.6% to 35+/-3% (P<.05), and left ventric ular end-diastolic volume (LVEDV) decreased from 365+/-18 to 307+/-24 mL, (P<.05). Nine patients were alive at 6 months. Preoperative and 6- month LVEF and LVEDV for those 9 patients were 26+/-2% and 29+/-2% (P= NS) and 316+/-23 and 261+/-22 mL (P<.05), respectively. Conclusions. L ong-term studies are needed to determine if these changes will improve patient survival.