The "stone heart" syndrome.

Abstract

Two types of myocardial failure have been encountered in patients undergoing open-heart surgery with ischemic cardiac arrest and nonblood prime while maintaining the patient at normothermic levels: [ 1) in which the left ventricle is flaccid and nonresponsive to inotropic drugs and (2) a tetanic contracture or myocardial rigidity which we have called “stone heart.” From July, 1966, through June, 1971,4,732 patients underwent total cardiopulmonary bypass with the use of this technique at the Texas Heart Institute, and 51 died in the operating room from acute myocardial insufficiency. Among these, 13 patients developed stone heart during or immediately after bypass. Exhaustive attempts to resuscitate these hearts by using pharmacological and physical means were uniformly unsuccessful. Before operation all patients had evidence of advanced left ventricular hypertrophy and myocardial conduction disturbance. Patients with concentric hypertrophy and high pressure gradients across a stenotic aortic valve were most prone to develop this complication. Microscopic study of the myocardium revealed only hypertrophy and usually diffuse fibrosis. Since September, 1971, all patients having left ventricular hypertrophy caused by aortic and/or mitral valve disease have been cooled to 30” C. before the ascending aorta was cross-clamped. lschemic arrest was used, and while the aorta was cross-clamped, body temperature was raised to 34” C. No instance of stone heart has occurred when hypothermia was utilized in a consecutive series of 266 patients undergoing aortic valve replacement in whom an incidence of 0,8 percent would have been expected if normothermic anoxic arrest had been used. We believe that the mechanism causing this myocardial complication is prevented by the hypothermic technique.