Which heart murmurs are considered pathological?

Pathological Heart Murmurs

Diastolic murmurs are virtually always pathological and require further cardiac evaluation, as are holosystolic murmurs and continuous murmurs. 1, 2

Classification of Pathological Murmurs

Timing-Based Classification

Pathological Systolic Murmurs

• Holosystolic (pansystolic) murmurs

  • Begin with S1 and continue throughout systole until S2
  • Maintain relatively constant intensity throughout systole
  • Indicate blood flow between chambers with widely different pressures 2
  • Almost always pathological, typically associated with:
    • Mitral regurgitation (MR) - best heard at apex, radiates to axilla
    • Tricuspid regurgitation (TR) - best heard at left lower sternal border, increases with inspiration
    • Ventricular septal defect (VSD)

• Late systolic murmurs

  • Associated with mitral valve prolapse (MVP) and papillary muscle dysfunction 1
  • Often accompanied by a mid-systolic click

• Early systolic murmurs

  • Associated with acute MR or TR without pulmonary hypertension 1

Pathological Diastolic Murmurs

• Early diastolic murmurs

  • High-pitched, decrescendo murmurs beginning with or shortly after S2
  • Associated with aortic regurgitation (AR) or pulmonic regurgitation with pulmonary hypertension 1

• Middiastolic murmurs

  • Occur during early ventricular filling
  • Associated with mitral or tricuspid stenosis
  • May also occur with severe regurgitation of these valves 1

• Presystolic murmurs

  • Begin during ventricular filling following atrial contraction
  • Usually due to mitral or tricuspid stenosis
  • May also be caused by atrial myxoma 1

Continuous Murmurs

• Begin in systole, peak near S2, and continue into diastole
• Arise from high-to-low pressure shunts
• Almost always pathological 1

Red Flags for Pathological Murmurs

Characteristics Suggesting Pathology

• Grade 3/6 or higher intensity 3
• Harsh quality
• Abnormal S2
• Diastolic timing (virtually always pathological) 1, 4
• Holosystolic timing 2
• Maximal intensity at upper left sternal border
• Presence of a systolic click
• Increased intensity with standing 1, 2

Associated Findings Suggesting Pathology

• Symptoms of syncope, angina, or heart failure 1
• Abnormal ECG or chest X-ray
• Abnormal pulses (e.g., parvus et tardus in aortic stenosis)
• Signs of heart failure (e.g., bibasilar pulmonary rales) 1

Dynamic Auscultation to Identify Pathological Murmurs

Dynamic maneuvers can help differentiate pathological from innocent murmurs:

Maneuver	Pathological Response
Valsalva	Hypertrophic cardiomyopathy (HCM) murmurs become louder; MVP murmurs become longer/louder [1,2]
Standing	HCM and MVP murmurs become louder; most other murmurs diminish [1,2]
Squatting	HCM and MVP murmurs soften; most other murmurs become louder [1,2]
Handgrip	Increases murmurs of MR, VSD, and AR [1,2]
Post-PVC	Murmurs of aortic/pulmonic stenosis increase; MR murmurs may not change or diminish [1]

Common Pathological Murmurs and Their Characteristics

1. Aortic Stenosis

   • Midsystolic, crescendo-decrescendo murmur
   • Best heard at right upper sternal border
   • Often radiates to carotids
   • Delayed carotid upstroke (parvus et tardus) in severe cases
   • Increases with post-PVC beat 1, 5

2. Mitral Regurgitation

   • Holosystolic murmur
   • Best heard at apex
   • Radiates to axilla
   • Increases with handgrip
   • Associated with broad apical murmur pattern 1, 2, 5

3. Tricuspid Regurgitation

   • Holosystolic murmur
   • Best heard at left lower sternal border
   • Increases with inspiration
   • May be early systolic when occurring without pulmonary hypertension 1, 2

4. Aortic Regurgitation

   • Early diastolic, high-pitched, decrescendo murmur
   • Best heard at left sternal border
   • Patient leaning forward, end-expiration
   • May present with a systolic murmur in some cases 6

5. Mitral Stenosis

   • Middiastolic or presystolic rumbling murmur
   • Best heard at apex with bell of stethoscope
   • Often preceded by an opening snap 1

Clinical Approach

1. Identify timing of the murmur in relation to heart sounds
2. Determine configuration and duration
3. Note location, radiation, and intensity
4. Apply dynamic maneuvers to further characterize
5. Assess for associated symptoms and signs

Echocardiography is recommended for definitive diagnosis of any potentially pathological murmur, particularly all diastolic and holosystolic murmurs. 1, 2

Common Pitfalls

• Mistaking aortic regurgitation for a systolic murmur (occurs in up to 86% of moderate AR cases) 6
• Failing to recognize that innocent murmurs are typically grade 1-2/6, midsystolic, and without radiation 4
• Not appreciating that classic physical findings may be absent in many patients with significant cardiac lesions 5
• Overlooking that neonatal heart murmurs are more likely to represent structural heart disease and warrant echocardiographic evaluation 3