The Journal of thoracic and cardiovascular surgery
-
J. Thorac. Cardiovasc. Surg. · May 1988
Enhancement of crystalloid cardioplegic protection against global normothermic ischemia by superoxide dismutase plus catalase but not diltiazem in the isolated, working rat heart.
Oxygen-derived free radicals and intracellular calcium overload have been implicated as mediators of myocardial ischemia/reperfusion injury. We hypothesized that free radical scavengers or calcium channel blockers could enhance the protection afforded the isolated, working rat heart by crystalloid cardioplegia against this type of injury at 37 degrees C. Hearts from 42 male rats in seven groups (n = 6) were studied in an isolated, working heart preparation measuring aortic flow (ml/min/gm dry wt), peak systolic pressure (mm Hg), coronary artery flow (ml/min/gm dry wt), and calculated coronary vascular resistance (dyne.sec.cm-5/gm dry wt). ⋯ We conclude that the addition of superoxide dismutase and catalase but not diltiazem to St. Thomas' Hospital cardioplegic solution can significantly enhance myocardial protection against normothermic ischemia/reperfusion injury. This implicates oxygen-derived free radicals as mediators of this type of injury.
-
J. Thorac. Cardiovasc. Surg. · Apr 1988
Right atrial isolation: a new surgical treatment for supraventricular tachycardia. II. Hemodynamic effects.
Surgical isolation of the body of the right atrium presents a unique hemodynamic situation in which the synchronous right atrial contraction (kick) is lost but the synchronous left atrial contraction is preserved. The hemodynamic effects of this procedure were evaluated by pacing at selected atrial sites postoperatively to simulate (1) sinus rhythm with a synchronous right atrial kick, (2) sinus rhythm without a synchronous right atrial kick, (3) right atrial tachycardia propagated to the entire heart (propagated right atrial tachycardia), and (4) right atrial tachycardia confined to the isolated right atrium with sinus rhythm in the rest of the heart (confined right atrial tachycardia). ⋯ Moreover, cardiac hemodynamic performance remained within normal limits for up to 14 weeks. Thus the right atrial isolation procedure does not adversely affect cardiac hemodynamics despite the loss of synchronous right atrial contraction during sinus rhythm, and the procedure prevents hemodynamic deterioration during right atrial tachycardia.
-
J. Thorac. Cardiovasc. Surg. · Apr 1988
Right atrial isolation: a new surgical treatment for supraventricular tachycardia. I. Surgical technique and electrophysiologic effects.
This study describes the surgical technique and electrophysiologic effects of isolating the right atrium while preserving normal function and continuity of the sinoatrial node with the remainder of the heart. Thirteen adult mongrel dogs underwent normothermic cardiopulmonary bypass. A posterorlateral right atriotomy was performed that encircled the upper right atrium but excluded the atrial pacemaker complex. ⋯ Moreover, the simulated tachycardia did not affect normal sinus rhythm or normal atrioventricular conduction. It is concluded that isolation of the right atrium with preservation of normal sinoatrial node function and continuity is feasible. This technique offers an alternative to the current surgical approaches for management of refractory supraventricular tachycardias that arise in the right atrium.
-
J. Thorac. Cardiovasc. Surg. · Feb 1988
Management of penetrating lung injuries in civilian practice.
Recent reports of military thoracic injuries have advocated early thoracotomy and aggressive management of pulmonary injuries with resection as opposed to the more conservative and traditional treatment with chest tube thoracostomy. A retrospective study was therefore performed to determine the incidence of thoracotomy and lung resection in civilian injuries and to evaluate the effectiveness of treatment of these injuries. Between 1973 and 1985, in a series of 1,168 patients, there were 384 gunshot wounds and 784 stab wounds to the thorax. ⋯ Mortality for all thoracic injuries was 2.3%: for those treated with chest tube alone, 0.7%; for pulmonary hilar injuries, 30%; for pulmonary parenchymal injuries, 8.6%; and for injuries necessitating lung resection, 28%. Most civilian lung injuries can be treated by tube thoracostomy alone. Although relatively few patients with primary pulmonary injury require thoracotomy, those that do are at significant risk and may require lung resection to control bleeding or hemoptysis or to remove destroyed or devitalized lung tissue.
-
J. Thorac. Cardiovasc. Surg. · Feb 1988
Comparative StudyInadequate myocardial protection with cold cardioplegic arrest during repair of tetralogy of Fallot.
Postoperative low cardiac output is the most common cause of death in patients undergoing elective repair of tetralogy of Fallot. The incidence is much higher than in elective adult bypass operations for coronary artery disease. To explain this difference, we investigated 16 children having elective repair of tetralogy (mean age 6.3 years). ⋯ Microscopic study revealed focal myocyte necrosis in tetralogy of Fallot. Our findings, which demonstrate inadequate myocardial protection of patients with tetralogy during repair, with depression of adenosine triphosphate and increased lactate during ischemia and reperfusion, suggest a defect in oxidative metabolism. The drop in adenosine triphosphate after reperfusion in the patients with tetralogy implicates reperfusion injury as a mechanism of myocardial damage.