Abstract
The patient presented with complete atrioventricular block and dyspnea. They had a primary cardiac tumor originating in the coronary sinus, a rare site of origin. It filled the sinus and involved the right atrium. The patient might have presented with complete atrioventricular block due to tumor invasion and respiratory distress due to elevated LVEDP as the tumor filled the coronary sinus. As for anesthesia management, in addition to the usual management, we observed CS obstruction and also considered myocardial protection methods. It is important to anticipate the risks and develop an appropriate anesthetic plan accordingly.