NEW TECHNIQUE MEASURES DECREASED TRANSMURAL MYOCARDIAL PRESSURE IN CARDIOMYOPLASTY

Background. We introduce the use of a fluid-filled balloon, interposed between myocardium and latissimus dorsi (LD), as a new technique to m easure transmural myocardial pressure in an acute goat model of dynami c cardiomyoplasty. Methods. A half-ellipsoidal balloon, composed of po lychloryl vinyl layers, was sutured to the atrioventricular groove in 5 goats, thereby completely enveloping both ventricles. Left LD dynami c cardiomyoplasty was then performed, anchoring the LD to the felt sew ing skirt of the balloon so that the LD completely covered the balloon . Left ventricular pressure and balloon pressure were measured with th e stimulator in the 1:2 mode as balloon volume was varied. Results. Av erage transmural myocardial pressure, defined as left ventricular pres sure minus balloon pressure, decreased from 34.4 mm Hg to 15.6 mm Hg d uring stimulator-on beats (p < 0.05). Conclusion. These results suppor t the conclusion that dynamic cardiomyoplasty unloads the left ventric le by decreasing wall stress. Furthermore, transmural myocardial press ure decreased more when balloon volume was increased, implying that th e LD sarcomere length has an effect on wall stress. A balloon may ther efore allow optimization of LD sarcomere length and thus assisted card iac performance.