16th February 2024

Cardiac blood supply

The blood supply to the heart is by the left and right coronary arteries. The left coronary artery comes off the left coronary cusp, while the right coronary artery comes off the right coronary cusp above the aortic valve. The left coronary artery starts as the left main stem and then divides into the left anterior descending (LAD) and left circumflex artery. The LAD lies within the anterior interventricular groove and travels towards the apex of the heart. The left marginal artery travels along the coronary sulcus towards the posterior heart surface. 

The right coronary artery travels along the coronary sulcus, with the right marginal artery branching off the artery. The right coronary artery continues as the posterior interventricular artery within the posterior interventricular groove. 

The distribution of the arteries’ blood supply in a typical right-dominant system is as follows:

• Right coronary artery – Right atrium, SA node, AV node
• Right marginal artery – Lateral right ventricular wall. 
• Right interventricular artery – Inferior aspect of the heart
• LAD – Anterior interventricular septum and anterior left ventricular wall
• Left circumflex artery – Lateral left ventricular wall 

Venous return from the heart is through the coronary sinus into the right atrium. The main tributaries for the coronary sinus include the great cardiac, small, middle, and posterior cardiac veins.

Image Source: Wikimedia Commons (2013). 2014ab Coronary Blood Vessels, Licensed under a creative commons licence. Available for free at: https://upload.wikimedia.org/wikipedia/commons/7/7c/2014ab_Coronary_Blood_Vessels.jpg (Accessed: 9 January 2024).