Lecture on Aortic Stenosis

Overview

• Aortic Stenosis: Characterized by obstruction of the left ventricular outflow, leading to decreased cardiac output.
• Typically asymptomatic if mild to moderate but requires monitoring.

Heart Valve Auscultation Areas

• Aortic Valve: Right second intercostal space, parasternal.
• Pulmonary Valve: Left second intercostal space, parasternal.
• Tricuspid Valve: Left fourth intercostal, parasternal.
• Mitral Valve: Left fifth intercostal space, midclavicular.

Valve Leaflet Composition

• Pulmonary Valve: 3 leaflets.
• Mitral Valve: 2 leaflets (bicuspid).
• Tricuspid Valve: 3 leaflets.
• Aortic Valve: 3 leaflets.

Cardiac Cycle

• When the aortic and pulmonary valves are open, tricuspid and mitral valves are closed.
• Stenotic valve leads to inefficient blood pumping.

Signs and Symptoms of Aortic Stenosis

• Cardinal Symptoms:
  • Dizziness or syncope on exertion.
  • Dyspnea on exertion.
  • Exertional angina.
• Examination Findings:
  • Slow and weak carotid pulse.
  • Reduced intensity of the second heart sound (S2).

Normal Heart Sounds

• S1: AV valves close, blood in ventricles.
• S2: Aortic and pulmonary valves close.

Murmurs in Aortic Stenosis

• Systolic Click Crescendo-Decrescendo Murmur:
  • Begins at S1, aortic valve opens, turbulence increases then decreases, followed by valve closure.
  • Murmur can radiate to the carotids.

Etiology of Aortic Stenosis

• Congenital Abnormality: Bicuspid aortic valve.
• Calcification: Age-related stiffening.
• Rheumatic Valvular Heart Disease: Scar tissue formation.

Investigations

• ECG: May show left ventricular hypertrophy.
• Cardiac Catheterization: Through femoral or radial artery to visualize aortic valve.
• Transthoracic Echocardiogram: Gold standard for valvular heart diseases.

Management

• Valve Replacement:
  • Mechanical or bioprosthetic.
  • Mechanical preferred for younger patients (longer lasting).
• Other Procedures:
  • Balloon valvuloplasty.
  • Transcatheter valve replacement.

Post-Surgical Considerations

• Use of anticoagulants and antibiotics may be necessary for infection risk management.
• Balloon valvuloplasty may precede other interventions.