A prosthetic myocardium: hemodynamic advantages.

When a large left ventricular aneurysm or infarct is excised, a frequent complication is inability of the left ventricle to regain adequate performance. Reduction in ventricular volume and impairment of myocardial contractility, either of which can diminish cardiac output to levels incompatible with life, are probably the main factors that lead to left ventricular failure after such surgery. A prototype prosthetic myocardium, designed to mimic the actions of the left ventricular myocardium, offers a direct means of restoring both ventricular volume and contractility after excision of a large portion of the left ventricle. In dog experiments 17 +/- 1.1% (AV +/- SE) of the left ventricle was infarcted and excised under cardiopulmonary bypass. The prosthetic myocardium was implanted and activated, and changes in hemodynamic parameters produced by the assist device were studied. "On" to "off" changes in 11 dogs in congestive failure averaged over the course of the experiment were as follows: m-AoP was increased 19 +/- 1.7% (Mean +/- SE): LV Syst. Press. was increased 24 +/- 1.7%; SV was increased 34 +/- 3.2%, LVEDP and m-LAP were reduced 43 +/- 2.4% and 22 +/- 1.4% respectively; and LVSW incrdased 88 +/- 8.8%. With these hemodynamic benefits this prototype represents an encouraging step toward the development of a device for orthotopic replacement of damaged myocardium.