Anatomical aspects of the arterial blood supply to the sinoatrial and atrioventricular nodes of the human heart.

Classic anatomical dissection of 150 hearts from adults aged 18 - 80 years was performed. The sinoatrial (SA) node artery was most frequently a large atrial branch of the right coronary artery (63%), arising at a mean distance of 1.2 cm (range 0.2 - 2.2 cm) from its beginning, with a mean external diameter of 1.7 mm (range 1 - 3 mm). In 37% of cases the SA node artery was a branch of the left coronary artery or one of its branches, with an initial mean external diameter of 2.2 mm (range 2 - 3 mm). The origin of the SA node artery was not related to coronary arterial dominance. The atrioventricular (AV) node artery was the first and longest inferior septal perforating branch of the right (90%) or left (10%) coronary artery, arising from the U- or V-shaped segment of the corresponding artery at the level of the crux cordis. Mean external diameter was 2 mm (range 1 - 3.5 mm). The origin of the AV node artery was dependent on coronary arterial dominance. Identification of the anatomical variants of the arterial blood supply to the SA and AV nodes may help in overcoming potential difficulties in treating arrhythmias and in mitral valve surgery.