When should a patient with a murmur be referred to cardiology?

When to Refer a Patient with a Murmur to Cardiology

Patients with heart murmurs should be referred to cardiology when they have diastolic or continuous murmurs, holosystolic or late systolic murmurs, grade 3 or louder midsystolic murmurs, murmurs with abnormal associated findings, or when the patient has cardiac symptoms. 1, 2

Murmur Characteristics Requiring Referral

Immediate Referral Required

• Diastolic murmurs: Virtually always pathological and require further evaluation 1, 2
• Continuous murmurs: Unless clearly identified as venous hum or mammary souffle during pregnancy 1, 2
• Holosystolic or pansystolic murmurs: Indicate flow between chambers with widely different pressures 1
• Late systolic murmurs: Often due to mitral valve prolapse or papillary muscle dysfunction 1
• Systolic murmurs with specific dynamic changes:
  • Murmurs that increase with Valsalva maneuver or standing (suggests hypertrophic cardiomyopathy or mitral valve prolapse) 1
  • Murmurs that increase during transient arterial occlusion or sustained handgrip 1
  • Murmurs that do not increase after premature ventricular contraction or long R-R interval in atrial fibrillation 1

Referral Based on Intensity and Associated Findings

• Grade 3 or louder midsystolic murmurs: Require echocardiographic evaluation 1, 2
• Murmurs with ejection clicks: Suggest valve abnormalities such as bicuspid aortic valve 1, 2
• Murmurs that radiate to the neck or back: May indicate significant aortic or mitral pathology 2

Patient Symptoms and Signs Requiring Referral

Symptoms

• Heart failure (dyspnea, orthopnea, edema) 1, 2
• Chest pain or angina suggesting myocardial ischemia 1, 2
• Syncope or presyncope 1, 2
• History of thromboembolism 2
• Exercise intolerance 2

Physical Examination Findings

• Signs of infective endocarditis (fever, petechiae, Osler's nodes, Janeway lesions) 1, 2
• Abnormal second heart sound (fixed splitting, soft/absent A2, reversed splitting) 1
• Evidence of ventricular hypertrophy or dilatation 1
• Peripheral signs of cardiac disease (poor perfusion, clubbing) 2

Patients with Grade 1-2 Midsystolic Murmurs

For patients with grade 1-2 midsystolic murmurs, referral is not necessary if:

• Patient is asymptomatic 1
• Cardiac examination is otherwise normal 1
• No other physical findings associated with cardiac disease 1

However, even with grade 1-2 midsystolic murmurs, referral is indicated if:

• Patient has symptoms or signs consistent with infective endocarditis, thromboembolism, heart failure, myocardial ischemia, or syncope 1
• Abnormal ECG or chest X-ray findings 2
• Widely split second heart sounds or systolic ejection sounds 1

Special Considerations

Innocent Murmurs

Characteristics of innocent murmurs in asymptomatic adults include:

• Grade 1-2 intensity at left sternal border 1
• Systolic ejection pattern 1
• Normal intensity and splitting of second heart sound 1
• No other abnormal sounds or murmurs 1
• No evidence of ventricular hypertrophy or dilatation 1

Common Pitfalls to Avoid

• Overreliance on ECG/chest X-ray: These rarely assist in diagnosis and may lead to false reassurance 2
• Missing aortic regurgitation: Often presents with a systolic rather than the classical diastolic murmur when evaluated by non-cardiologists 3
• Underestimating murmur significance: A seemingly benign systolic murmur may be associated with significant valvular disease, particularly when multiple lesions are present 4
• Failure to recognize combined valve lesions: In one study, 35% of patients with organic heart disease had more than one abnormality 4

Conclusion

The decision to refer a patient with a heart murmur to cardiology should be based on the characteristics of the murmur, associated physical findings, and patient symptoms. While many grade 1-2 midsystolic murmurs in asymptomatic patients are innocent, any diastolic or continuous murmur, holosystolic or late systolic murmur, or grade 3 or louder murmur warrants cardiology referral and echocardiographic evaluation to determine the underlying cardiac pathology and guide appropriate management.