Studies of Contractile Force in Man

Forty-five patients undergoing open-heart surgery for acquired aortic valve disease were studied with measurements of left ventricular contractile force. The data presented clearly indicate that coronary perfusion afforded, on the average, better protection to left ventricular contractility as recorded by a strain-gage arch than did hypothermia. This was particularly true in the usual case, which required an hour or longer of aortic occlusion. Patients who required 40 minutes or less of aortic occlusion demonstrated approximately identical decreases in contractile force with hypothermia or coronary perfusion. Bilateral coronary perfusion did not usually afford much additional left ventricular protection as compared to unilateral left coronary perfusion. In a small number of patients with significant coronary arterial occlusion, bilateral coronary perfusion appeared to give better left ventricular protection.