The arterial blood supply of the conducting system in normal human hearts

Area of Science:

• Cardiovascular Anatomy
• Cardiac Electrophysiology
• Surgical Anatomy

Background:

• The conducting system of the heart is vulnerable during cardiac surgery.
• Understanding the arterial supply to the cardiac conduction system is vital for surgical safety.
• The precise arterial sources for the sinu-atrial (SA) node, atrioventricular (AV) node, and bundle branches require detailed definition.

Purpose of the Study:

• To anatomically characterize the principal arterial sources supplying the SA and AV nodes.
• To clarify the morphology of the tendon of Todaro in relation to the AV node.
• To delineate the arterial supply to the atrioventricular bundle branches and their divisions.

Main Methods:

• Gross anatomical dissection of 30 human hearts.
• Histological examination of four hearts to confirm conducting system anatomy.
• Detailed mapping of arterial origins supplying the SA node, AV node, and bundle branches.

Main Results:

• The SA node received supply from the right coronary artery (73%), left coronary artery (3%), or both (23%).
• The AV node was supplied by the right coronary artery (80%), left coronary artery (10%), or both (10%).
• The AV bundle branch originated from the left coronary artery (73%) more frequently than the right (10%) or both (17%). The moderator band (right bundle) was primarily supplied by left coronary artery branches.

Conclusions:

• The right coronary artery is the predominant source for the SA and AV nodes.
• The left coronary artery is the main supplier of the AV bundle branches.
• Precise knowledge of these arterial distributions is essential for minimizing injury during cardiac surgical procedures.