Adjustable model of chronic left ventricular dysfunction.

BACKGROUND

As an adjunct to the development of skeletal muscle-powered left ventricular assist devices, an adjustable model of chronic left ventricular failure was developed.

METHODS

Implantation of a left ventricular balloon to induce heart failure was accomplished via left thoracotomy. Upon recovery, left ventricular failure was simulated by manipulation of left ventricular balloon volume to chronically raise left atrial pressure.

RESULTS

Left atrial pressure increased from a baseline of 9.3 +/- 0.7 mm Hg to 18.5 +/- 1.2 mm Hg, 20.2 +/- 1.8 mm Hg, and 26.0 +/- 1.2 mm Hg by the 2nd, 6th, and 10th postoperative week, respectively. Cardiac index declined from a baseline of 4.4 +/- 0.3 L x min(-1) x m(-2), reaching stability by the 8th postoperative week at 3.0 +/- 0.4 L x min(-1) x m(-2). Stroke volume index declined from 1.12 +/- 0.1 mL x kg(-1) x beat(-1) to 0.60 +/- 0.1 mL x kg(-1) x beat(-1) by the 10th postoperative week. Mean survival was 75 +/- 7 days. Causes of death included left ventricular failure, thromboembolism, and euthanasia.

CONCLUSIONS

This method of simulating chronic left ventricular dysfunction proved to be stable and adjustable and has been useful in the development of ventricular assist systems.