The cardiac conduction system receives its blood supply from branches of the left anterior descending coronary artery and right coronary artery. A critical portion of the interventricular conduction system is supplied by the first septal branch of the left anterior descending artery. The bundle of His receives blood supply from both the left anterior descending artery and right coronary artery, with approximately 50% of the blood coming from the septal branch of the left anterior descending artery and atrioventricular nodal branch of the right coronary artery.

1. Blood supply to
cardiac conduction
system

2. Schematic diagram of blood supply to cardiac conduction system. The first septal branch of the left anterior
descending (LAD) coronary artery supplies a critical portion of the interventricular conduction system (red
oval). AV, atrioventricular; marginal a., marginal artery; PDA, posterior descending artery; RCA, right
coronary artery; SA, sinoatrial. Reproduced, with permission, from Harthorne JW, Pohost. GM, Electrical
therapy of cardiac dysrhythmias. In Levine, HJ (ed) Clinical Cardiovascular Physiology, New York, Grune
and Stratton: 1976. pp. 853–882

3. Blood Supply to Bundle of Branches
LBBB RBBB
Anterosuperior fascicle Posteromedial fascicle
 Both LAD and RCA
 50% By septal
branch of LAD and
AV node branch of
RCA
 Other 50% by only
LAD
 50% Only by the AV
nodal branch of
RCA(Kugel’s artery)
 Other 50% by AV nodal
branches of RCA
 Septal branches of LAD
Both LAD and RCA
50% By septal branch
of LAD and AV node
branch of RCA
Other 50% by only
LAD

4. Simplification is the finest art