Home › Academic Library › HAP-03
[HAP-03] Cardiovascular Anatomy, Cardiac Conduction, Action Potentials & Haemodynamics
HAP-03 • 1. Anatomy & PhysiologyLearning Objectives
Trace the cardiac conduction system (SA node → AV node → Bundle of His → Purkinje fibres) and correlate ECG waves (P, PR, QRS, QT, T) with Vaughan Williams antiarrhythmic classes.; Compare Phase 0–4 of the fast-response ventricular myocyte action potential vs the slow-response SA/AV nodal pacemaker action potential.; Calculate Cardiac Output (CO = HR × SV), Mean Arterial Pressure (MAP = DBP + 1/3 PP = CO × SVR), and Frank–Starling preload/afterload dynamics.
Chapter Overview & Core Explanation
The heart is a dual four-chamber muscular pump driven by its own natural pacemaker (the SA node). Blood pressure is the product of how much blood the heart pumps per minute (Cardiac Output) and how narrow the peripheral arteries are (Systemic Vascular Resistance).
Key Exam & Clinical Takeaways
- Phase 0 depolarization in ventricular muscle is driven by fast Na+ channels, whereas Phase 0 in the SA and AV nodes is driven by slow L-type Ca2+ channels.
- Never co-administer IV [3.29] Verapamil or [3.30] Diltiazem with a β-blocker ([3.11] Metoprolol) closely, as additive AV nodal depression can precipitate complete heart block or asystole.