Highest-yield system. ACS, HF, arrhythmias, valvular disease.
SA node is the pacemaker; the AV node is the gatekeeper that delays conduction so the atria empty first.
RCA supplies the SA node in ~60% — inferior MI → watch for bradyarrhythmias & AV block.
“APT M” — All Physicians Take Money — Aortic → Pulmonic → Tricuspid → Mitral auscultation sites.
Beck’s triad = hypotension + JVD + muffled heart sounds → cardiac tamponade (a clinical emergency).