Sick sinus syndrome in a patient with single coronary artery anomaly.

Single coronary artery anomaly is very rare. The reported manifestations include angina pectoris and congestive heart failure. Here we describe a case of single coronary artery anomaly presenting as sick sinus syndrome, which has no literature precedence. A 47-year-old woman had complained of intermittent dizziness for years. A Holter electrocardiogram showed sinus bradycardia and junctional or ventricular rhythm with a maximal ventricular pause of up to 3.2 seconds. Electrophysiologic study revealed prolonged corrected sinus nodal recovery time. Coronary angiography showed that the left anterior descending artery had a long course with a side branch originating from the proximal part and coursing anteriorly to the territory of the proximal portion of the right coronary artery. The sinus node is usually supplied by the sinoatrial branch via the right coronary artery. Aortography showed that the right coronary artery ostium was absent. A permanent pacemaker was implanted and the patient was discharged in good condition. The present case suggests that coronary artery anomaly may lead to compromised blood supply to the sinus node, and hence sick sinus syndrome.