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Sinoatrial (SA) Node

A Cath Lab Anatomy & Hemodynamics term on the RCIS exam blueprint, defined for cath lab and EP clinicians.

Supplied by the SA nodal artery, which arises from the RCA in roughly 68% of cases, the left circumflex in roughly 22%, and the left main/LCA proper in roughly 3%; a duplicated SA nodal artery occurs in only about 4% of hearts. Note: many board-review sources simplify this to RCA ~60% and LCx ~40%, so recognise both framings — the RCA is the dominant supply either way.

Origin of the sinoatrial nodal artery by percentage: right coronary artery about 68 percent, left circumflex about 22 percent, left main or left coronary artery about 3 percent, with a duplicated SA nodal artery in about 4 percent of hearts.
Which artery feeds the SA node — and both framings you will see on exam sources.

Domain: Cath Lab Anatomy & Hemodynamics · Blueprint: RCIS exam guide

Related RCIS terms

Atrioventricular (AV) Node Bundle Branches Left Anterior Descending (LAD) Artery Left Circumflex (LCX) Artery Left Main Coronary Artery (LMCA)

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Written and reviewed by John-Philip (JP) Maarschalk, BSN, RN, CNML — a nurse manager who runs operations for the cardiac cath lab, electrophysiology, and interventional service lines at an academic health system in North Carolina. He hires and develops the staff who sit for these exams. More about JP and how this content is made →
Cardiac Codex is an independent study tool published by MdoubleA LLC, not affiliated with or endorsed by CCI or any certifying body. This glossary entry is exam-preparation information, not medical advice or a substitute for clinical judgment. Always verify current clinical practice against primary sources and institutional protocol.