PERICARDIUM-LINED SKELETAL-MUSCLE VENTRICLES IN CIRCULATION UP TO 589DAYS

Skeletal muscle ventricles (SMVs) were constructed from the latissimus dorsi muscle in 15 beagles. The animals were divided into two groups based on modifications in the SMV construction: group I consisted of 5 animals and group n of 10 animals. After a 3-week vascular delay and 6 to 8 weeks of 2-Hz electrical conditioning, the SMVs were connected to the thoracic aorta. In group I, counterpulsation at 33 Hz resulted in an initial 24.4% augmentation of the mean diastolic pressure, a 27. 1% decrease in the presystolic pressure, and a 15.9% increase in the e ndocardial viability ratio. In group II, the mean diastolic pressure r ose by 24.7%, the presystolic pressure decreased by 14.3%, and the end ocardial viability ratio increased by 24.5%. During propranolol-induce d heart failure, the percentage increase in the mean diastolic pressur e was improved (12.9% before propranolol infusion versus 27.6% during propranolol infusion), as was the percentage increase in the endocardi al viability ratio (11.2% versus 28.7%). Under low cardiac output cond itions, SMV contraction resulted in small but statistically significan t increases in the total cardiac output (4.3% at 33 Hz, 7.6% at 85 Hz) . One animal in group I survived for 589 days with a functioning SMV b efore progressive dilation of the SMV (impending rupture) developed. D elayed rupture of the SMV sewing ring anastomosis occurred in 2 dogs. Five animals in group II are all alive, with functioning SMVs in the c irculation for 377 to 464 days. No animals in group II had rupture of their SMV or showed evidence of thrombus formation.