Heart Chambers and Valves: Anatomy, Blood Flow, and Clinical Correlates

The heart is a four-chambered pump organized into two serial circuits: systemic (left heart) and pulmonary (right heart). Understanding chamber roles and valvular function is fundamental to cardiovascular physiology and pathology.

Chambers & Blood Flow

Chamber	Receives	Via	Pumps To	Via
Right atrium	Deoxygenated systemic venous blood	Superior/inferior vena cava, coronary sinus	Right ventricle	Tricuspid valve
Right ventricle	Blood from RA	Tricuspid valve	Pulmonary artery	Pulmonic valve
Left atrium	Oxygenated pulmonary venous blood	4 pulmonary veins	Left ventricle	Mitral valve
Left ventricle	Blood from LA	Mitral valve	Aorta (systemic circulation)	Aortic valve

Valves: Structure & Function

• Atrioventricular (AV) valves: Tricuspid (3 leaflets), Mitral (2 leaflets)—prevent backflow into atria during ventricular systole
• Semilunar valves: Pulmonic, Aortic (3 cusps each)—prevent backflow into ventricles during diastole
• Apparatus: Leaflets/cusps, annulus, chordae tendineae (AV valves), papillary muscles

Key Supporting Structures

• Interventricular septum: Muscular (inferior) + membranous (superior); separates ventricles
• Interatrial septum: Fossa ovalis (remnant of foramen ovale)
• Coronary arteries: RCA, LAD, LCx—perfuse myocardium (diastole-dependent)
• Coronary veins → Coronary sinus → RA
• Myocardium: Contractile muscle; thickest in LV
• Endocardium: Endothelial lining
• Pericardium: Fibrous (outer) + serous (parietal/visceral) layers; <50 mL fluid

Clinical Correlates

• Valvular stenosis/regurgitation → volume/pressure overload → chamber remodeling
• Septal defects (ASD, VSD) → shunting direction depends on pressure gradients
• Coronary occlusion → ischemic cascade in supplied territory
• LV hypertrophy: Hypertension, AS, HCM; RV hypertrophy: PH, PS, chronic lung disease

This integrated anatomy underpins echocardiography, cardiac catheterization, surgical planning, and hemodynamic management.