ABSTRACT
Introduction: The sinuatrial (SA) node is known as natural pacemaker of the heart. SA node is supplied by the sinuatrial (SA) nodal artery is an atrial branch. Ischemia of SA nodal artery due to injury or during surgical intervention leads arrhythmia. Origin of sinuatrial (SA) nodal artery is variable; most commonly arise from right coronary artery. It may arise from the circumflex branch of the Left circumflex artery (LCA). In some cases it may originate from the trunk of left coronary artery, aorta or left bronchial artery. SA node may be supplied by single SA nodal artery or may have dual and triple arterial supply. Methods: This study was conducted on 25 cadavers from the dissection laboratory with an age range of 50 – 70 years. The cadavers were embalmed through carotid arterial perfusion of formaldehyde solution, spirit, water and glycerine and preserved in a weak formalin solution before dissection. Dissection method was employed for this study. Result and Observation: Single SA nodal artery found in 22/25 hearts (88%) and dual supply found in 3/25 hearts (12%). The SA nodal artery originated from proximal segment of right coronary artery (RCA) in 16/25 hearts (64%), from proximal segment of circumflex branch (LCX) of left coronary artery (LCA) in 6/25 hearts (24%). The Mean+SD of diameter of SAN artery from right coronary artery was 1.7+0.42mm. The Mean+SD of diameter of SAN artery from circumflex branch of left coronary artery was 1.29+0.30mm. The termination types were 1) precaval found in 44% (11/25), 2) retrocaval in 52% (13/25) and 3) pericaval found in 4%(1/25) of all SA nodal arteries.Conclusion: To be aware of the origin and course of SAN artery may provide a safe approach to interventional cardiologist and cardiac surgeon during cardiac interventions. Cardiac surgeons especially should be careful because compensation.