What is the evaluation and management of an ejection murmur?

Evaluation and Management of Ejection Murmurs

Ejection murmurs require careful evaluation with echocardiography for all patients with concerning features, while asymptomatic patients with grade 1-2 midsystolic murmurs and normal cardiac examination do not require further testing. 1

Characteristics of Ejection Murmurs

Ejection murmurs (also called midsystolic murmurs) have specific characteristics:

• Crescendo-decrescendo (diamond-shaped) configuration
• Begin shortly after S1 when ventricular pressure opens the semilunar valve
• Occur when blood is ejected across the aortic or pulmonic outflow tracts
• Intensity increases as ejection increases and diminishes as ejection declines 2

Common Causes

Ejection murmurs may be:

• Innocent/Physiologic: Common in children and young adults, originating from aortic or pulmonic outflow tracts
• Pathologic: Due to structural abnormalities

Causes include:

• Increased flow rate (pregnancy, thyrotoxicosis, anemia, arteriovenous fistula)
• Ejection into a dilated vessel
• Increased sound transmission through thin chest walls
• Valvular, supravalvular, or subvalvular obstruction (stenosis)
• Sometimes functional mitral or tricuspid regurgitation 2

Evaluation Algorithm

Step 1: Risk Stratification

Determine if further evaluation is needed based on:

1. Low Risk (No further testing required):

   • Grade 1-2 midsystolic murmur
   • Normal cardiac examination
   • Asymptomatic patient 1

2. High Risk (Requires further evaluation):

   • Diastolic, continuous, holosystolic, or late systolic murmurs
   • Grade 3 or louder midsystolic murmurs
   • Abnormal associated findings
   • Symptoms (heart failure, infective endocarditis, thromboembolism, myocardial ischemia, syncope) 1

Step 2: Physical Examination Techniques

Use dynamic auscultation to help determine the origin and significance:

• Respiration: Right-sided murmurs increase with inspiration; left-sided murmurs are louder during expiration
• Valsalva maneuver: Most murmurs decrease in intensity, except HCM (becomes louder) and MVP (becomes longer/louder)
• Exercise: Murmurs across normal or obstructed valves become louder
• Positional changes: Most murmurs diminish with standing; with squatting, most become louder 2

Step 3: Diagnostic Testing

For high-risk patients:

• Echocardiography with color flow and spectral Doppler: Provides definitive diagnosis of valve morphology, function, chamber size, wall thickness, and ventricular function 1
• Cardiac catheterization: Rarely needed for initial evaluation; useful when discrepancy exists between echocardiographic and clinical findings 1

Management Approach

Management depends on the underlying cause:

For Innocent Murmurs

• Reassurance
• No specific intervention needed
• No activity restrictions

For Pathologic Murmurs

Treatment is directed at the underlying condition:

1. For stenotic lesions:

   • Mild to moderate: Endocarditis prophylaxis if indicated, regular monitoring with echocardiography, risk factor management
   • Severe symptomatic: Surgical valve replacement/repair, transcatheter interventions when appropriate 1

2. For regurgitant lesions:

   • Mild to moderate: Periodic echocardiographic monitoring, medical therapy if ventricular dilation occurs
   • Severe: Surgical valve repair/replacement when symptomatic or when ventricular function deteriorates 1

3. For flow murmurs due to anemia or high-output states:

   • Treat the underlying cause (e.g., iron supplementation for anemia)
   • Address contributing factors (e.g., thyroid disorders) 1

Referral Criteria

Refer to a cardiologist when:

• Diastolic or continuous murmurs
• Holosystolic or late systolic murmurs
• Grade 3 or louder midsystolic murmurs
• Murmurs with abnormal associated findings
• Cardiac symptoms
• Uncertain diagnosis 1

Common Pitfalls

1. Overreliance on ECG/chest X-ray: These tests rarely assist in diagnosis and may lead to false reassurance 1

2. Misclassification of murmur timing: Proper identification of systolic ejection versus holosystolic murmurs is critical for determining pathology 2

3. Failure to use dynamic auscultation: Changes in murmur intensity with maneuvers provide important diagnostic clues 2

4. Missing associated findings: Careful assessment for fixed splitting of S2, ejection sounds, or abnormal heart sounds is essential 2

5. Assuming all ejection murmurs are innocent: Grade 3 or louder murmurs often require echocardiography to distinguish benign from pathologic causes 1