Static left latissimus dorsi cardiomyoplasty: effect on left ventricular function.

When the latissimus dorsi is used for ventricular augmentation in cardiomyoplasty, a delay of several weeks occurs before the muscle revascularizes, adheres to the heart, and is transformed to fatigue-resistant status. This study analyzes the effect of static (unstimulated) cardiomyoplasty on left ventricular function. Four mongrel dogs underwent staged left latissimus dorsi cardiomyoplasty. Left ventricular pressure was measured with a micromanometer catheter. Left ventricular volume was measured by sonomicrometry. Cardiac output, heart rate, preload recruitable stroke work, maximum elastance, left ventricular end-diastolic volume, left ventricular end-diastolic pressure, stroke work, and the diastolic relaxation constant were measured before and immediately after cardiomyoplasty with the myoplasty static. Results, expressed as mean +/- standard error of the mean, showed no significant differences in indexes of systolic function (stroke work, 1017 +/- 223 gm.cm to 984 +/- 403 gm.cm; preload recruitable stroke work, 110 +/- 13 gm.cm/cm3 to 115 +/- 19.8 gm.cm/cm3; maximum elastance, 10.38 +/- 5.6 mm Hg/ml to 13.59 +/- 6.5 mm Hg/ml; cardiac output 4.51 +/- 0.43 L/min to 4.21 +/- 0.34 L/min) or diastolic function (left ventricular end-diastolic volume, 21 +/- 5.2 ml to 20 +/- 5.3 ml; left ventricular end-diastolic pressure, 13 +/- 3.5 mm Hg to 15 +/- 3 mm Hg; diastolic relaxation constant 42.8 +/- 5.2 msec to 42.5 +/- 4.5 msec). Heart rate also remained unchanged (131 +/- 8.9 beats/min to 140 +/- 9.8 beats/min). The static (unstimulated) left latissimus dorsi cardioplasty can be done with little effect on left ventricular systolic or diastolic function in the normal canine heart.