Overview
This lecture covers valvular heart disease (VHD), focusing on common left-sided valve disorders, their causes, complications, clinical presentation (including murmurs), diagnostic approach, and treatment strategies.
Types of Valvular Heart Disease
- Most commonly tested VHDs: mitral stenosis, mitral regurgitation, aortic stenosis, and aortic regurgitation.
- Right-sided valve disorders (e.g., tricuspid regurgitation) are less common but associated with IV drug use.
Pathophysiology and Causes
- Mitral Stenosis: Impaired blood flow from left atrium to left ventricle, mainly due to rheumatic fever.
- Mitral Regurgitation: Blood flows back from left ventricle to left atrium, often from left ventricular dilation (heart failure, dilated cardiomyopathy), mitral valve damage (endocarditis, connective tissue disease, mitral valve prolapse).
- Aortic Stenosis: Obstructed blood outflow from left ventricle to aorta, caused by bicuspid aortic valve (<70 yrs) or calcific degeneration (>70 yrs).
- Aortic Regurgitation: Blood returns from aorta to left ventricle, often due to aortic dilation (aneurysm), endocarditis, or aortic dissection.
Complications and Clinical Features
- Mitral Stenosis: Leads to pulmonary edema, left atrial dilation, increased risk of atrial fibrillation, and thromboembolism (e.g., stroke).
- Mitral Regurgitation: Causes pulmonary edema and, if acute, cardiogenic shock; chronic cases may compensate.
- Aortic Stenosis: Presents with syncope, angina, dyspnea ("SAD"), weak/delayed carotid pulse (pulsus parvus et tardus), may cause left ventricular hypertrophy.
- Aortic Regurgitation: Causes wide/bounding pulse (water hammer pulse), pulmonary edema, and risk of acute cardiogenic shock if sudden.
Rheumatic Fever and Jones Criteria
- Rheumatic fever, mainly after group A strep throat, often damages the mitral > aortic valve.
- Diagnosed with ≥2 major Jones criteria (joints, heart, nodules, erythema marginatum, chorea) or 1 major + 2 minor criteria, plus evidence of prior strep infection.
Murmur Evaluation and Diagnosis
- Systolic murmurs: aortic stenosis (carotid radiation), mitral regurgitation (apex to axilla).
- Diastolic murmurs: aortic regurgitation (decrescendo), mitral stenosis (opening snap, rumble at apex).
- Murmurs change with maneuvers; echocardiogram is first-line diagnostic test.
Management and Treatment
- Manage heart failure symptoms first.
- Surgical/interventional options: TAVR/SAVR for aortic stenosis, valve repair/replacement for regurgitation, balloon valvuloplasty for severe mitral stenosis.
- Acute severe regurgitation requires urgent surgery.
- Warfarin anticoagulation for mechanical valves (INR 2.5–3.5) and valvular atrial fibrillation; Penicillin G for rheumatic heart disease.
- Monitor for prosthetic valve complications (paravalvular or transvalvular leaks).
Key Terms & Definitions
- Valvular Heart Disease (VHD) — Abnormalities of heart valves leading to stenosis (narrowing) or regurgitation (backflow).
- Stenosis — Obstruction to forward blood flow through a valve.
- Regurgitation — Backward leakage of blood through a valve.
- Atrial Fibrillation (Afib) — Irregular atrial rhythm, often caused by atrial dilation.
- Pulmonary Edema — Fluid accumulation in lungs due to high hydrostatic pressures.
- Cardiogenic Shock — Critically low cardiac output and hypotension from severe pump failure.
- Water Hammer Pulse — Bounding arterial pulse with rapid rise and fall, seen in aortic regurgitation.
- Pulsus Parvus et Tardus — Weak, delayed carotid pulse, classic for aortic stenosis.
- Jones Criteria — Major/minor criteria for diagnosing rheumatic fever.
Action Items / Next Steps
- Review auscultation techniques and murmur characteristics.
- Practice identifying VHDs on echocardiograms.
- Study the Jones criteria and management algorithms for VHD.
- Prepare for questions on complications, especially embolic events and heart failure management.