When should a systolic murmur be worked up?

When to Work Up a Systolic Murmur

Systolic murmurs should be worked up with echocardiography when they are grade 3 or greater in intensity, when they are holosystolic or late systolic in timing, when they are accompanied by symptoms, or when dynamic auscultation suggests specific cardiac pathology. 1

Immediate Indications for Echocardiography

• All diastolic or continuous murmurs (except for cervical venous hum or mammary souffle during pregnancy) require echocardiographic evaluation regardless of intensity 1
• Holosystolic or late systolic murmurs at the apex or left sternal edge require echocardiography 1
• Midsystolic murmurs of grade 3 or greater intensity require echocardiography 1, 2
• Any systolic murmur accompanied by symptoms (syncope, angina, heart failure, thromboembolism) requires echocardiography 1

Dynamic Auscultation Findings Requiring Workup

• Murmurs that increase in intensity during the Valsalva maneuver, become louder when standing, and decrease when squatting (suggesting hypertrophic cardiomyopathy or mitral valve prolapse) 1
• Murmurs that increase during transient arterial occlusion or sustained handgrip exercise 1
• Murmurs that do not increase in intensity after a premature ventricular contraction or after a long R-R interval in atrial fibrillation (suggesting mitral regurgitation or ventricular septal defect) 1

When Echocardiography is Indicated for Grade 1-2 Midsystolic Murmurs

Despite being low-grade, echocardiography is indicated in patients with grade 1-2 midsystolic murmurs when:

• Symptoms of infective endocarditis are present 1
• Thromboembolism has occurred 1
• Heart failure symptoms are present 1
• Myocardial ischemia/infarction is suspected 1, 3
• Syncope has occurred 1
• Abnormal physical findings are present (widely split second heart sounds, systolic ejection sounds) 1
• ECG or chest X-ray abnormalities are present (ventricular hypertrophy, atrial enlargement, etc.) 1

Characteristics of Innocent Murmurs Not Requiring Workup

In asymptomatic adults, systolic murmurs with the following characteristics are typically innocent and do not require further workup:

• Grade 1-2 intensity at the left sternal border 1, 2
• Systolic ejection pattern (crescendo-decrescendo) 1, 4
• Normal intensity and splitting of the second heart sound 1, 2
• No other abnormal sounds or murmurs 1, 2
• No evidence of ventricular hypertrophy or dilatation 1, 2
• No increase in intensity with Valsalva maneuver or standing 1, 2
• Normal ECG and chest X-ray (if obtained) 1

Pitfalls and Caveats

• The ability of cardiac examination alone to determine the exact cause of a systolic murmur is limited, especially when multiple lesions are present 5, 6
• Trivial or physiological valvular regurgitation may be detected by echocardiography in many normal patients who have no heart murmur at all 1
• In older patients with systemic hypertension, grade 1-2 midsystolic murmurs may be related to sclerotic aortic valve leaflets or flow into tortuous, noncompliant great vessels 1
• The severity of aortic stenosis may be misjudged clinically when left ventricular function is severely diminished 5, 3
• Murmur intensity does not always correlate with the severity of the underlying condition - a loud systolic murmur does not necessarily indicate serious heart disease 7, 4