Thorax 5 - Vascularization of the heart [Coronary arteries, cardiac veins]

Coronary Vascularization Basics
📌 The heart muscle is supplied by an important arterial network consisting of the right and left coronary arteries and their branches.
💔 Vascular disorders, such as heart failure, angina, and myocardial infarction (necrosis of the heart muscle), are very frequent pathologies.
⚙️ The coronary system originates above the aortic valve cusps (Right and Left semilunar valves) in the aortic sinuses (Sinus of Valsalva).

Coronary Artery Distribution Patterns
⚖️ The nodal distribution (balanced supply) occurs in about 30% of individuals, defining distinct territories for each artery.
📈 Variations exist, with right dominance occurring in about 60% of cases and left dominance in about 10% of cases, where one artery supplies a larger area.

Right Coronary Artery (RCA) Territory
⬇️ The RCA arises above the right semilunar cusp and travels in the anterior coronary sulcus, ending in the posterior diaphragm surface.
❤️ The RCA supplies the anterior face of the right ventricle, the right atrium, and the posterior third of the interventricular septum (IVS).
⚡️ The RCA typically supplies the sinoatrial node (SAN) and the atrioventricular node (AVN), crucial for cardiac automaticity and conduction.

Left Coronary Artery (LCA) Territory
➦ The LCA arises above the left semilunar cusp and quickly divides into the circumflex artery and the anterior interventricular artery (LAD).
🫀 The LCA generally supplies the left ventricle (anterior, left, and inferior faces), the left atrium, and the left auricle.
🩸 The Anterior Interventricular Artery (LAD) supplies 5 to 6 perforating branches responsible for vascularizing the anterior two-thirds of the IVS.

Coronary Vein Return and Physiology
🗄️ Venous return from the heart is primarily drained by the coronary sinus, which empties into the right atrium near the inferior vena cava opening.
🔄 The Great Cardiac Vein, Middle Cardiac Vein, and Small Cardiac Vein drain into the coronary sinus.
⏱️ A physiological peculiarity is that coronary blood flow occurs primarily during diastole (relaxation), as the contracting muscle compresses the coronary arteries during systole.

Key Points & Insights
➡️ Coronary artery diseases (like stenosis due to atherosclerosis) can cause angina pectoris (chest cramps due to hypoxia) or myocardial infarction if occlusion is complete.
➡️ The closure of the aortic valve during diastole creates the pressure necessary for blood to flow into the coronary arteries from the aorta.
➡️ Anomalies in coronary perfusion, especially involving the RCA-supplied SAN, are the underlying cause of many cardiac rhythm disorders.

📸 Video summarized with SummaryTube.com on Feb 21, 2026, 22:32 UTC