Guideline Recommendations for Evaluation and Management of Innocent (Haemic) Murmurs

Definition and Typical Characteristics

Innocent (haemic) murmurs are midsystolic, crescendo‑decrescendo sounds of grade ≤ 2, heard best along the left sternal border, without radiation to the neck or back and without any associated abnormal cardiac findings. [American College of Cardiology] 1, 5, 6, 7
These murmurs arise from increased blood‑flow velocity through normal cardiac structures and are commonly observed in high‑output states such as anemia, pregnancy, thyrotoxicosis, or arteriovenous fistula. [American College of Cardiology] 4

A grade 2 or softer midsystolic murmur identified as innocent by an experienced observer does not require echocardiography; clinical reassurance alone is sufficient. [American College of Cardiology] 1, 2, 3
This recommendation applies especially to:
Routine ECG and chest radiography are not recommended in the evaluation of an innocent murmur. [American College of Cardiology] 6, 7, 8

Murmur type – diastolic, continuous (excluding venous hums and mammary souffles), holosystolic, late‑systolic, or any midsystolic murmur graded ≥ 3. [American College of Cardiology] 1, 2, 3, 8
Associated signs – presence of ejection clicks or radiation of the murmur to the neck or back. [American College of Cardiology] 1, 2, 3, 8
Clinical symptoms – heart‑failure signs, myocardial ischemia or infarction, syncope, thromboembolism, infective endocarditis, or any other evidence of structural heart disease. [American College of Cardiology] 1, 2, 3, 8

Increased murmur intensity with the Valsalva maneuver (suggests hypertrophic cardiomyopathy or mitral‑valve prolapse). [American College of Cardiology] 9
Murmur becomes louder when the patient stands and softer when squatting. [American College of Cardiology] 9
Intensification during sustained hand‑grip or transient arterial occlusion (suggests mitral regurgitation or ventricular‑septal defect). [American College of Cardiology] 9

Murmurs accompanied by other abnormal cardiac physical findings (e.g., widely split S2, abnormal systolic ejection sounds). [American College of Cardiology] 1, 3, 8
Abnormal ECG findings such as ventricular hypertrophy, prior infarction, or arrhythmias. [American College of Cardiology] 1, 6, 3, 7, 8
Abnormal chest‑X‑ray (e.g., chamber enlargement, pulmonary congestion, cardiac calcification). [American College of Cardiology] 1, 6, 3, 7, 8
Symptoms that are likely non‑cardiac but where a cardiac basis cannot be excluded. [American College of Cardiology] 1, 2, 3, 8

Provide reassurance that no structural heart disease is present. [American College of Cardiology] 1, 2, 5
No specific treatment is required beyond addressing the underlying high‑output condition (e.g., treating anemia). [American College of Cardiology] 4
Routine follow‑up echocardiography is unnecessary unless the clinical status changes. [American College of Cardiology] 1, 2, 5
No activity restrictions are imposed. [American College of Cardiology] 1, 2

Unnecessary echocardiography in asymptomatic younger patients with short grade 1–2 midsystolic murmurs and normal examinations adds cost without clinical benefit. [American College of Cardiology] 1, 2, 5, 7
Trace or mild valvular regurgitation detected by Doppler ultrasound is a common physiological finding in healthy individuals and should not be misinterpreted as pathologic valve disease. [American College of Cardiology] 9
The basic cardiovascular examination remains the most appropriate screening tool; reliance on echocardiography alone should be avoided. [American College of Cardiology] 9