What is the management approach for patients presenting with heart murmurs?

Management of Heart Murmurs

The management of heart murmurs is determined primarily by murmur characteristics and clinical context, with echocardiography reserved for specific high-risk features rather than all murmurs. 1

Immediate Echocardiography Required (Class I Indications)

Perform echocardiography immediately for any of the following murmur types, regardless of symptoms: 1

• Diastolic murmurs (always pathologic) 1, 2
• Continuous murmurs 1, 2
• Holosystolic murmurs 1, 2
• Late systolic murmurs 1, 2
• Murmurs with ejection clicks 1
• Murmurs radiating to neck or back 1
• Grade 3 or louder midsystolic murmurs in asymptomatic patients 1

Perform echocardiography for any murmur accompanied by: 1

• Heart failure symptoms or signs 1, 2
• Myocardial ischemia or infarction 1, 2
• Syncope 1, 2
• Thromboembolism 1, 2
• Signs of infective endocarditis 1, 2
• Other clinical evidence of structural heart disease 1

Consider Echocardiography (Class IIa Indications)

Echocardiography is reasonable when: 1

• Murmur is associated with other abnormal cardiac physical findings (widely split S2, abnormal heart sounds) 1, 2
• Abnormal ECG findings present (ventricular hypertrophy, atrial enlargement, prior infarction, conduction abnormalities) 1
• Abnormal chest X-ray (chamber enlargement, abnormal pulmonary vasculature, cardiac calcification) 1
• Symptoms are likely noncardiac but cardiac basis cannot be excluded by standard evaluation 1

Echocardiography NOT Recommended (Class III)

Do not perform echocardiography for: 1

• Grade 2 or softer midsystolic murmurs identified as innocent or functional by an experienced clinician 1
• Asymptomatic young patients with grade 1-2 midsystolic murmurs at left sternal border with normal physical findings 1

This recommendation is based on cost-effectiveness, as echocardiography adds little value in this low-risk population and may detect trivial physiologic regurgitation that exists in many normal individuals. 1

Characteristics of Innocent Murmurs (No Workup Needed)

An innocent murmur diagnosis requires ALL of the following: 2, 3

• Grade 1-2 intensity at left sternal border 2, 3
• Systolic ejection pattern (crescendo-decrescendo) 2, 3
• Normal intensity and splitting of second heart sound 2, 3
• No other abnormal cardiac sounds 2, 3
• No increase with Valsalva maneuver or standing 2, 3
• Normal ECG and chest X-ray (if obtained) 1, 3
• Asymptomatic patient 1

Dynamic Auscultation Findings Requiring Workup

Perform echocardiography if murmur demonstrates: 2, 3

• Increases with Valsalva or standing (suggests hypertrophic cardiomyopathy or mitral valve prolapse) 2, 3
• Increases with handgrip or transient arterial occlusion (suggests mitral regurgitation) 2, 3
• Does not increase after premature ventricular contraction or long R-R interval in atrial fibrillation (suggests mitral regurgitation or ventricular septal defect) 2, 3

Additional Diagnostic Testing

ECG and Chest X-Ray

Do not routinely obtain ECG and chest X-ray for asymptomatic patients with isolated grade 1-2 midsystolic murmurs at left sternal border, particularly in younger patients. 1

Obtain ECG and chest X-ray when: 1

• Murmur characteristics suggest pathology 1
• Patient is symptomatic 1
• Physical examination reveals other abnormalities 1

If ECG or chest X-ray shows abnormalities (ventricular hypertrophy, atrial enlargement, chamber enlargement), proceed to echocardiography. 1

Cardiac Catheterization

Cardiac catheterization is not necessary for most patients with cardiac murmurs and normal or diagnostic echocardiograms. 1

Consider cardiac catheterization when: 1

• Discrepancy exists between echocardiographic and clinical findings 1
• Hemodynamic assessment of specific valve lesions is needed 1
• Coronary angiography is indicated 1

Exercise Testing

Exercise testing is valuable in patients with valvular heart disease whose symptoms are difficult to assess, and can be safely performed even in asymptomatic patients with severe aortic stenosis. 1, 2

Special Clinical Scenarios

Murmurs in Anemic Patients

Anemia commonly causes functional systolic ejection murmurs (grade 1-2, left sternal border) due to increased cardiac output and blood flow velocity. 2

Management approach: 2

• Treat the underlying anemia first 2
• Reassess murmur after anemia correction 2
• If murmur persists after anemia treatment, proceed to echocardiography as it suggests underlying structural disease 2

When to Consider TSH Testing

TSH testing is not routinely indicated for cardiac murmur evaluation but should be considered when: 4

• Clinical features suggest thyroid dysfunction (tachycardia, tremor, weight changes, heat/cold intolerance) 4
• New-onset atrial fibrillation, particularly in older adults 4
• Risk factors for thyroid disease with cardiovascular symptoms 4

Critical Pitfalls to Avoid

Beware that clinical examination has limitations: 5

• Sensitivity for detecting intraventricular pressure gradients is only 18% 5
• Aortic regurgitation is missed in 79% of cases by clinical exam alone 5
• Combined aortic and mitral valve disease is correctly identified in only 55% 5
• Mitral valve prolapse is correctly identified in only 55% 5
• Severe aortic stenosis may be underestimated when left ventricular ejection fraction is severely reduced 5

Doppler echocardiography detects trivial physiologic regurgitation in many normal individuals, particularly through tricuspid and pulmonic valves, which should not be misinterpreted as pathology. 1

In older patients with hypertension, grade 1-2 midsystolic murmurs may result from sclerotic aortic valve leaflets or flow into tortuous vessels rather than significant stenosis. 1, 3

Advanced Imaging When Transthoracic Echo Inadequate

When transthoracic echocardiography is inadequate, consider: 1

• Transesophageal echocardiography 1
• Cardiac magnetic resonance 1
• Cardiac catheterization 1

The choice depends on specific clinical circumstances and the information needed for better characterization of the valvular lesion. 1