1. Anatomy, Perfusion & Conduction

• Layers & Chambers: Heart layers: endocardium, myocardium, epicardium. Pericardium contains 10-15 mL of fluid. LV is 2-3x thicker than RV to pump into systemic circulation.
• Coronary Flow: Perfusion occurs primarily during diastole. LCA (branches into LAD, circumflex) supplies LV/LA/septum. RCA supplies RA/RV/posterior LV. In 90% of people, RCA supplies the AV node/bundle of His; blockages cause conduction defects.
• Electrical System: SA Node → AV Node → Bundle of His → Bundle Branches → Purkinje fibers (impulse in 0.12s).
  • P wave: Atrial depolarization.
  • QRS: Ventric ...