Coronary sinus rhythm in anomalous systemic venous connection.

YSTEMIC venous anomalies, such as persistent left superior vena cava and absent inferior vena cava, are not so rare in various congenital heart diseases.1) Preoperative identification of these anomalous systemic venous connections is clinically important, because their presence necessitates modified technique for venous cannulation of cardiopulmonary bypass. In cases of persistent left superior vena cava, usually entering the right atrium via the coronary sinus, coronary sinus rhythm was occasionally shown in routine electrocardiograms, resulting from persistent pacemaker of the left horn of the sinus venosus.2) In addition, typical coronary sinus rhythm was frequently found in patients with absent inferior vena cava in our experience. The detailed description of these observations is the purpose of this report.