Arterial supply to sinuatrial and atrioventricular nodes: Imaging with multidetector CT

Purpose: To retrospectively evaluate the depiction of anatomic characteristics of the arterial supply to the sinuatrial node (SAN) and the atrioventricular node (AVN) with 64-section computed tomography (CT). Materials and Methods: The institutional review board approved this HIPAA-compliant study; informed consent was not required. Anatomic origin, number, course, and variants of the arteries to the SAN and AVN were examined with coronary multidetector CT in 102 patients (55 men, 47 women; mean age, 57 years ± 13 [standard deviation]). Known accessory blood supplies to the AVN, including left and right Kugel anastomotic arteries, were investigated. Possible extension of the first septal perforating artery to the AVN was evaluated. Univariate and bivariate statistical data were reported. Means ± standard deviations, 95% confidence intervals, and percentages were calculated. Results; A single sinuatrial nodal artery originated from the proximal 40 mm of the right coronary artery (RCA) in 67 and from the proximal 35 mm of the left circumflex (LCX) artery in 28 patients. A dual blood supply to the SAN was seen in six patients. The sinuatrial nodal artery was not visualized in one patient. An S-shaped variant was seen in 18% of left sinuatrial nodal arteries and invariably traveled posteriorly in the sulcus between the left superior pulmonary vein and left atrial appendage. The sinuatrial nodal artery approached the nodal tissue by one of three routes - retrocaval (47.5%), precaval (42.6%), or pericaval (9.9%). The AVN was supplied by the RCA in 89 patients, the LCX artery in 11 patients, and by both arteries in two patients. Two left and six right Kugel anastomotic arteries were detected as supplying the AVN area. The first septal perforating artery had no detectable connection to the AVN. Conclusion: The arterial blood supply to the SAN and the AVN is variable and can be imaged with multidectector CT.