Standing Auscultation Excludes Pathologic Murmurs in Kids

Diana Swift

November 13, 2017

Heart murmur that resolves when a child moves from a supine to a standing position can reliably rule out pathologic heart murmurs in pediatric patients, a study found. Implementing this low-cost clinical assessment could avoid unnecessary cardiologist referrals and anxiety in parents and children, the researchers write.

Bruno Lefort, MD, from Gatien de Clocheville Children's Hospital, Tours University Hospital Center, France, and colleagues published their findings online November 13 in Annals of Family Medicine.

Among 100 study children (51%) who had a murmur while lying supine that completely disappeared when they stood up, only 2 proved to have a pathologic murmur caused by a cardiac abnormality.

"The complete disappearance of an isolated heart murmur on standing in otherwise healthy children aged 2 to 18 years without a family history is a valuable clinical test to exclude a pathologic cardiac murmur and avoid referral to a cardiologist," the authors explain. They caution that a larger study is required to confirm the dependability of this tool and to compare its reproducibility among both pediatric cardiologists and primary care physicians.

Heart murmur affects an estimated 65% to 80% of school children, the authors note, and distinguishing between innocent (ie, physiologic) heart murmurs and their pathologic (ie, organic) counterparts can be challenging in routine practice, often prompting costly but unnecessary further tests.

The study included 194 consecutive patients referred to pediatric cardiologists in France during 2014 to 2015. Clinicians auscultated patients' heart sounds in both supine and standing positions, and patients then underwent echocardiography. Children with heart murmurs were on average 6 to 7 years of age, and a majority were boys.

The study identified 30 (15%) children with pathologic heart murmurs as determined by echocardiographic abnormalities. Pathologic murmurs persisted on standing in 93% of patients and decreased in intensity in 43% (P < .001), while physiologic murmurs persisted on standing in 40% and decreased in intensity in 80% (P < .001).

The most common abnormality identified was atrial septal defect (n = 9), followed by sonographically important mitral regurgitation (n = 7), ventricular septal defect (n = 5), and aortic valve stenosis (n = 3).

The complete disappearance of the murmur in the standing position excluded pathologic heart disease, with a high positive predictive value of 98% (95% confidence interval [CI], 93% - 100%) and a specificity of 93% (95% CI, 78% - 99%). Sensitivity was considerably lower at 60% (95% CI, 52% - 67%).

The researchers note that innocent murmurs stem from normal blood flow through the heart and large blood vessels, and their disappearance upon switching position from supine to standing results from decreased venous return, left ventricular chamber size, and stroke volume.

In 2014, Medscape Medical News reported on appropriate-use criteria issued by the American College of Cardiology in partnership with the American Academy of Pediatrics and other specialty groups, recommending that echocardiography be reserved for patients with a family history of heart disease, cardiac symptoms, or abnormal clinical findings.

Nevertheless, the authors cite a 2016 study that found more than 40% of children at two hospital centers underwent echocardiography for innocent murmurs, suggesting that practice had not caught up with use guidelines.

Dr Lefort and coauthors say their findings support the need for a basic clinical tool to help primary care physicians rule out underlying cardiac disease in children with heart murmurs.

The authors have disclosed no relevant financial relationships.

Ann Fam Med. Published online November 13, 2017. Abstract

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