Heart murmurs recorded by a sensor based electronic stethoscope and e-mailed for remote assessment. (Original Article).

Background: Heart murmurs are common in children, and they are often referred to a specialist for examination. A clinically innocent murmur does not need further investigation. The referral area of the University Hospital is large and sparsely populated. A new service for remote auscultation (telemedicine) of heart murmurs in children was established where heart sounds and short texts were sent as an attachment to e-mails.

Aim: To assess the clinical quality of this method.

Methods: Heart sounds from 47 patients with no murmur (n = 7), with innocent murmurs (n = 20), or with pathological murmurs (n = 20) were recorded using a sensor based stethoscope and e-mailed to a remote computer. The sounds were repeated, giving 100 cases that were randomly distributed on a compact disc. Four cardiologists assessed and categorised the cases as having "no murmur", "innocent murmur", or "pathological murmur", recorded the assessment time per case, their degree of certainty, and whether they recommended referral.

Results: On average, 2.1 minutes were spent on each case. The mean sensitivity and specificity were 89.7% and 98.2% respectively, and the inter-observer and intro-observer variabilities were low (kappa 0.81 and 0.87), respectively. A total of 93.4% of cases with a pathological murmur and 12.6% of cases with an innocent murmur were recommended for referral.

Conclusion: Telemedical referral of patients with heart murmurs for remote assessment by a cardiologist is safe and saves time. Skilled auscultation is adequate to detect patients with innocent murmurs.

**********

Heart murmurs are common in children, and may be heard through infancy to adolescence. Most are innocent--that is, not associated with anatomical or physiological abnormalities. It has been estimated that up to 80% of schoolchildren may have heart murmurs under certain circumstances, but less than 1% have confirmed organic heart disease, the majority being diagnosed during infancy. (1-3)

Evaluation of a heart murmur represents one of the most common reasons for referral to a paediatric cardiologist. (4) Studies have shown that following clinical examination by a paediatric cardiologist, the diagnosis of a murmur as innocent or pathological, is correct with a specificity of 95% and a sensitivity of 96%. (5 6) Further procedures, such as chest radiography, electrocardiography, and echocardiography, are thus unlikely to alter a clinical diagnosis of an innocent murmur made by a paediatric cardiologist, based on auscultation. (7) Parents and referring physicians often expect a number of investigations to alleviate their concern, or to confirm or refute their suspicions. (4 8 9) In some circumstances there may even be a financial incentive for the cardiologist to perform echocardiography. Expensive investigations are therefore sometimes performed without any evident medical reason. (10 11)

The University Hospital in Tromso is a teaching hospital in north Norway. The coverage area of the hospital is sparsely populated with vast distances and a severe climate. Most of the doctors recruited to the small rural communities are young and inexperienced in assessing heart murmurs in children. During the period between January 1999 and December 2000, 103 children with heart murmurs were referred to the outpatient clinic at the University Hospital, and the waiting time averaged 60 days. It was found that 99 (96%) of these children had an innocent murmur, in most cases diagnosed by clinical examination only. We therefore suggested that utilising telemedicine by referring the children's heart sounds as sound files in an e-mail attachment, instead of referring the children, had the potential to eliminate waiting time, travel, and reduce cost associated with the assessment of cardiac murmurs in children in our area. Before introducing this method as a routine, we wanted to evaluate its clinical quality. Our hypothesis was that this could be safely performed both technically and clinically. To explore whether a heart murmur could be assessed accurately, we conducted simulated telemedicine consultations. The results of this evaluation are described.

SUBJECTS AND METHODS

A mix of normal heart sounds (from subjects with no murmur or an innocent murmur) and sounds from patients with cardiac lesions (with pathological murmurs) were recorded at the University Hospital of Tromso. Up to five sounds from different locations in each patient were recorded separately by a sensor based electronic stethoscope …