Mitral Regurgitation Overview and Introduction

Definition

• Mitral regurgitation involves the backward leakage of blood through the mitral valve each time the left ventricle contracts.
• Can cause significant hemodynamic instability, especially in acute cases, requiring urgent medical treatment.

Heart Valve Anatomy and Auscultation

• Heart Valves and Auscultation Locations:
  • Aortic Valve: Best heard in the right second intercostal space, parasternal.
  • Pulmonary Valve: Best heard in the left second intercostal space, parasternal.
  • Tricuspid Valve: Best heard in the left fourth intercostal space, parasternal.
  • Mitral Valve: Best heard in the left fifth intercostal space, midclavicular line.
• Valve Structure:
  • Pulmonary, tricuspid, aortic valves have three leaflets.
  • Mitral valve has two leaflets, also known as the bicuspid valve.

Cardiac Cycle and Mitral Regurgitation

• Normal Function:
  • During diastole, mitral and tricuspid valves open for ventricular filling.
  • During systole, blood is ejected as the ventricles contract.
• Mitral Regurgitation Effect:
  • Mitral valve fails to close properly.
  • Blood is ejected back into the left atrium, potentially affecting the pulmonary system, leading to edema and increased vascular pressure.

Complications

• Pulmonary edema, congestive heart failure, cor pulmonale.
• Atrial fibrillation is common, characterized by absent P waves and irregular rhythms.

Types and Symptoms

• Acute Mitral Regurgitation: Aggressive onset; symptoms include fatigue, diaphoresis, palpitations, dyspnea on exertion, and edema.
• Chronic Mitral Regurgitation: May be asymptomatic until severe.

Examination and Murmur Characteristics

• Examination:
  • Listen at the left fifth intercostal space, midclavicular, near the heart apex.
• Heart Sounds:
  • S1 and S2 correlate with the closure of atrioventricular and aortic/pulmonary valves respectively.
  • Systole is between S1 and S2; diastole is between S2 and S1.
• Murmur:
  • Heard during systole, described as a flat continuous or pansystolic murmur.
  • Radiates to the left axilla.
  • Diminished S1 sounds.

Investigations

• ECG: May show atrial fibrillation.
• Echocardiogram: Gold standard for assessing valvular disease.

Causes of Mitral Regurgitation

• Mitral valve prolapse, rheumatic heart disease, endocarditis, valve calcification, myocardial infarction affecting chordae tendineae or papillary muscles, cardiomyopathy.

Management

• Preoperative: Diuretics to reduce edema.
• Surgical Options:
  • Valve repair or replacement (mechanical or bioprosthetic).
  • Valvuloplasty using a balloon to dilate the valve.
  • Annuloplasty to support the mitral valve.
  • Intra-aortic balloon counterpulsation as a temporary solution.