Purpose: To assess the hemodynamic and pathologic effects of the right coronary artery occlusion in anesthetized dogs submitted to pericardiotomy.
Methods: Ten mongrel dogs were anesthetized with pentobarbital and submitted to a right thoracotomy, pericardiotomy and ligation of the right coronary artery. The pericardium was kept opened throughout the entire experiment. The circulatory pressures and the cardiac output were determined twice before and three times after the right coronary artery ligation. The hearts were then excised, barium was injected in the coronary arteries and radiographs were taken to confirm the artery occlusion. Three dogs were kept alive to later pathologic examination of the hearts.
Results: The observation of the radiographs showed proximal occlusion of the right coronary artery and absence of the right ventricle free wall vascularization. There was ischemic necrosis of about three quarters of this area, whereas the septum was normal. The cardiac index and the systemic mean arterial decreased 14% without significant variation of the central venous and the pulmonary artery pressures, although marked right ventricular dilation was observed.
Conclusion: The proximal right coronary artery ligation in the dog determines ischemia and infarction of the right ventricular free wall, without affecting the interventricular septum. There are few hemodynamic consequences with open pericardium and at rest.