Notes on Murmurs

Overview

• Murmurs are sounds produced due to turbulence in blood flow.
• Focus on three types: Diastolic, Systolic, and Continuous murmurs.

Mitral Stenosis

Definition

• Mitral Stenosis: Narrowing of the mitral valve orifice, normal area: 4-6 cm².
• Severe Mitral Stenosis: Mitral valve area < 1.5 cm².

Hemodynamics

• Obstruction leads to:
  • Reduced blood flow into the left ventricle.
  • Turbulence and noise due to narrow valve.

Murmur Characteristics

• Opening Snap: Occurs when the mitral valve opens, loud in mitral stenosis due to high pressure.
• Murmur Type: Mid-Diastolic Murmur (MDM begins after the opening snap).
• Configuration:
  • Begins from opening snap.
  • Peaks in mid-diastole.
  • Pre-systolic Accentuation: Small spike due to atrial systole.

Importance of Atrial Systole

• Pre-systolic accentuation disappears in Atrial Fibrillation (no atrial contraction).
• Severity determined by the length of the murmur (longer murmur indicates severe stenosis).

Management of Severe Mitral Stenosis

• Percutaneous Mitral Balloon Valvotomy (PMBV): Treatment of choice.
• Contraindications for PMBV:
  1. Calcified mitral valve.
  2. Severe mitral stenosis with mitral regurgitation (MR worsens).
  3. Left atrial appendage thrombus (risk of emboli).

Diastolic Murmurs

Types

1. Early Diastolic Murmur:

   • Graham Steel Murmur: Mild pulmonic regurgitation due to pulmonary artery hypertension.
   • Aortic Regurgitation (mild): Also presents as early diastolic.

2. Mid-Diastolic Murmur:

   • Austin-Flint Murmur: Severe aortic regurgitation.
   • Mitral Stenosis MDM with pre-systolic accentuation.

3. Late Diastolic Murmur:

   • Kerry-Coombs Murmur: Associated with rheumatic fever.

4. Flow Murmur: Occurs in Atrial Septal Defect (ASD) due to increased flow across the tricuspid valve; not a shunt murmur.

Systolic Murmurs

Types

1. Ejection Systolic Murmur:

   • Conditions include aortic stenosis, pulmonic stenosis, and hypertrophic obstructive cardiomyopathy.

2. Pansystolic Murmur:

   • Seen in mitral regurgitation and tricuspid regurgitation.

3. Late Systolic Murmur:

   • Associated with mitral valve prolapse (MVP).

Mitral Valve Prolapse (MVP)

• Mechanism: Damage to papillary muscles leads to displacement of valve leaflets.
• Auscultation:
  • Mid-systolic clicks (due to stretching of chordae tendineae).
  • In later stages: Late systolic murmur from mitral regurgitation.

Continuous Murmurs

• Coarctation of Aorta: Peak at S2, heard in both systole and diastole.
• Other Causes:
  1. Patent Ductus Arteriosus (PDA).
  2. Peripheral pulmonic stenosis.
  3. Venous hum (physiological in pregnancy).
  4. Sinus of Valsalva rupture.

Dynamics of Murmurs

• Intensities Change:
  • Decreased Intensity: Valsava maneuver, standing, or amyl nitrite.
  • Increased Intensity: Sit-ups or handgrip (except in HOCM and MVP).
  • HOCM: Murmur becomes softer.
  • MVP: Murmur duration increases (mid-systolic click occurs earlier or later).

Summary Table of Murmurs

• Diastolic Murmurs:
  • Early: Graham Steel, Aortic Regurgitation.
  • Mid: Austin Flint (Severe Aortic Regurgitation), Mitral Stenosis.
  • Late: Kerry-Coombs (Rheumatic).
• Continuous Murmurs:
  • Coarctation of Aorta, PDA, Peripheral Pulmonic Stenosis.
• Systolic Murmurs:
  • Ejection: Aortic Stenosis, Pulmonic Stenosis, HOCM.
  • Pansystolic: MR, TR.
  • Late: MVP.

---

Note: This lecture covered key topics regarding murmurs, their classifications, and clinical significance.