Single coronary artery anomaly is very rare. The reported manifestations in
clude 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 interm
ittent dizziness for years. A Holter electrocardiogram showed sinus bradyca
rdia 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 anter
ior 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 b
y the sinoatrial branch via the right coronary artery. Aortography showed t
hat the right coronary artery ostium was absent. A permanent pacemaker was
implantated and the patient was discharged in good condition. The present c
ase suggests that coronary artery anomaly may lead to compromised blood sup
ply to the sinus node, and hence sick sinus syndrome.