Power output of pericardium-lined skeletal muscle ventricles, left ventricular apex to aorta configuration: up to eight months in circulation.

OBJECTIVE

The purpose of this experiment was to evaluate the potential for a skeletal muscle ventricle connected to the circulation between the left ventricle and the aorta to provide effective, long-term cardiac assist.

METHODS

Skeletal muscle ventricles were constructed from the latissimus muscle in 10 dogs. After conditioning, the skeletal muscle ventricles were connected to the left ventricle and the aorta with 2 valved conduits. The skeletal muscle ventricle was programmed to contract during diastole.

RESULTS

At time of implantation, skeletal muscle ventricles stimulated at 33 Hz and in a 1:2 ratio with the heart significantly decreased left ventricular work by 56% (P <.01) and at 50 Hz by 65% (P <.01). At a 1:2 ratio, the power output of the skeletal muscle ventricles was 59% of left ventricular power output at 33 Hz (P <. 01) and 93% at 50 Hz (P <.01). Animals survived 7, 11, 16, 17, 72, 99, 115, 214, and 249 days. Three deaths were directly related to the skeletal muscle ventricle. One animal is alive at 228 days. In the animal that survived 249 days, skeletal muscle ventricle power output at 8 months with a 33 Hz stimulation frequency and a 1:2 contraction ratio was 57% of left ventricular power output and 82% at 50 Hz. At a 1:1 ratio, skeletal muscle ventricle power output was 97% and 173% of the left ventricle at 33 and 50 Hz, respectively.

CONCLUSIONS

Left ventricular assist with a skeletal muscle ventricle connected between the left ventricle and the aorta is the most hemodynamically effective configuration we have tested and can maintain significant power output up to 8 months.