Heart Murmurs with Normal Echocardiography
Yes, it is possible to have a heart murmur with a normal echocardiogram and no valve abnormalities. This occurs in a significant proportion of patients referred for evaluation of heart murmurs.
Types of Murmurs That May Have Normal Echocardiograms
- Innocent or Functional Murmurs: These are common, especially in children and young adults, and represent normal blood flow through structurally normal hearts 1
- Flow Murmurs: Occur in high-output states such as:
- Anemia
- Pregnancy
- Hyperthyroidism
- Fever
- Exercise
Evidence Supporting Normal Echocardiograms with Murmurs
Research shows that less than 50% of patients referred for echocardiography with a diagnosis of "murmur" actually have valvular abnormalities 2. In one study examining 3,460 echocardiogram reports for murmur evaluation, only 48.6% revealed valvular abnormalities 2.
Clinical Characteristics of Innocent Murmurs
Innocent murmurs typically have the following characteristics 1:
- Grade 1 to 2 intensity at the left sternal border
- Systolic ejection pattern
- Normal intensity and splitting of the second heart sound
- No other abnormal sounds or murmurs
- No evidence of ventricular hypertrophy or dilatation
- No increased intensity with Valsalva maneuver or with standing from a squatting position
Doppler Ultrasound Sensitivity
It's important to note that Doppler ultrasound is extremely sensitive and may detect:
- Trace or mild valvular regurgitation through structurally normal tricuspid and pulmonic valves in a large percentage of young, healthy subjects 1
- Trace or mild regurgitation through normal left-sided valves (particularly the mitral valve) in a variable but lower percentage of patients 1
These minimal findings are often physiological variants and not pathological.
When Echocardiography Is Not Recommended
According to ACC/AHA guidelines, echocardiography is specifically not recommended for:
- Patients with grade 2 or softer midsystolic murmurs identified as innocent or functional by an experienced observer 1
When to Pursue Further Evaluation
Despite a normal echocardiogram, further evaluation may be warranted if:
- The murmur is associated with symptoms (heart failure, syncope, exercise intolerance)
- The murmur has concerning characteristics (diastolic, continuous, holosystolic)
- There are other abnormal physical findings
- The ECG or chest X-ray is abnormal
Clinical Implications
The finding that many murmurs are associated with normal echocardiograms has important implications:
- Reduces unnecessary anxiety for patients
- Decreases healthcare costs by avoiding unnecessary testing
- Emphasizes the importance of skilled cardiac auscultation
Pitfalls to Avoid
- Over-reliance on echocardiography: Not all murmurs require echocardiographic evaluation, particularly those with classic innocent characteristics 1, 3
- Under-evaluation of concerning murmurs: Diastolic, continuous, or late systolic murmurs should always be evaluated with echocardiography 1, 3
- Misinterpreting physiologic regurgitation: Trace regurgitation on color Doppler may be a normal finding and not indicative of valve disease 1
In conclusion, the presence of a heart murmur does not always indicate structural heart disease, and many patients with murmurs will have completely normal echocardiograms without valve abnormalities.