Initial evaluation of heart murmurs: are laboratory tests necessary?

Area of Science:

• Pediatric Cardiology
• Diagnostic Imaging
• Clinical Evaluation

Background:

• Heart murmurs are common reasons for pediatric cardiology referrals.
• Electrocardiograms (ECGs) and echocardiograms are frequently used in murmur evaluation.
• The diagnostic utility of these tests in initial assessments needs clarification.

Purpose of the Study:

• To determine the utility of electrocardiograms and echocardiograms in the initial assessment of heart murmurs in children and adolescents.
• To compare clinical diagnosis with post-test diagnoses.
• To evaluate the accuracy of clinical examination by a pediatric cardiologist.

Main Methods:

• Prospective study of 161 pediatric patients (1 month to 17 years) with heart murmurs.
• Clinical diagnosis by a pediatric cardiologist was compared with diagnoses after ECG and echocardiography (2D, M-mode, Doppler, color-Doppler).
• Patients were classified as "innocent murmur," "pathologic murmur," or "possible pathologic murmur" based on clinical diagnosis.

Main Results:

• ECG did not change any diagnoses.
• Echocardiography altered the diagnosis in a small percentage of cases (2/109 innocent murmurs changed to pathologic; 3/46 pathologic murmurs changed to innocent; 3/6 possible pathologic murmurs changed to innocent).
• Clinical examination demonstrated high accuracy: sensitivity 96%, specificity 95%, PPV 88%, NPV 98%.

Conclusions:

• Clinical examination by an experienced pediatric cardiologist is highly accurate for assessing pediatric heart murmurs.
• Electrocardiograms are unlikely to reveal unsuspected heart disease but can aid in specific diagnoses when pathology is present.
• Echocardiography is unnecessary for pediatric patients with clinically diagnosed innocent heart murmurs.