AED may effectively detect heart rhythm disturbances in children

DALLAS, May 22 – An automated external defibrillator (AED) – an electronic device that recognizes and restores normal heartbeat rhythm through electric shock – is as accurate in recognizing rhythm abnormalities in children as in adults, according to a report in today’s Circulation: Journal of the American Heart Association.

“The AED that was studied proved to be very accurate despite the fact that it was originally designed to evaluate adult heart rhythms,” says senior author Dianne L. Atkins, M.D., associate professor of pediatrics at the University of Iowa College of Medicine in Iowa City. “Even though young children have a much higher heart rate and very different kinds of rhythms, the device still performed well.”

The study did not address the more complicated issues related to the delivery of appropriate levels of shock to correct children’s rhythm disturbances that require treatment.

AEDs have been used for more than 20 years to treat adults in cardiac arrest. The devices are programmed to evaluate a heart rhythm and deliver an electric shock when certain life-threatening arrhythmias are detected.

Although the Food and Drug Administration approved marketing of modified electrode AED pads for use in children earlier this month, the American Heart Association does not currently recommend the use of AEDs for children under age 8 or lighter than 55 pounds due to insufficient information about the safety and accuracy of AEDs in interpreting pediatric rhythms. In addition, there is concern that the large energy shocks they deliver could be harmful to small children.

Researchers in Iowa City, Seattle, Boston, and San Diego conducted a study to determine if a specific AED model could recognize normal and abnormal heart rhythms in children. They created a database of recordings of actual children’s heart rhythms and digitized previous unusual electrocardiogram (ECG) readings from children ages 12 and younger. Some of the evaluations used AEDs that had been modified to monitor heart rhythm directly in children at risk for arrhythmias but not to deliver shocks. Researchers analyzed whether the AED studied could determine if a shock was needed.

The AEDs in the study correctly identified all heart rhythms that did not require treatment in children ages 12 and younger – demonstrating high specificity. In addition, the device identified 96 percent of abnormal rhythms (ventricular tachycardia or fibrillation) that would have qualified for treatment with brief electric shocks – demonstrating high sensitivity. No shocks were delivered from devices used in this study; manual defibrillators were available if needed.

A total of 696 five-second rhythm readings were obtained from 191 children ages 1 day to 12 years. Seventy-three percent of the children had heart disease and 63 percent of those had congenital heart disorders and 10 percent had cardiomyopathy, or diseased heart muscle. Pediatric heart specialists evaluated each of the readings and classified the recordings according to the need for delivery of a shock to correct the disturbance.

“We are very excited to see good research studies addressing the potential use of AEDs in children,” says Vinay Nadkarni, M.D., chairman of the American Heart Association’s Committee on Emergency Cardiovascular Care (ECC). “AED use is becoming widespread, and our Pediatric Resuscitation Subcommittee will evaluate and make recommendations on AED use in young children as soon as our science reviewers determine that the evidence demonstrates that they are both safe and accurate for use in this age group.

“This study begins to answer the very important basic questions that confront our EMS providers in the field, and sets the stage for additional studies that will allow the American Heart Association to make thoughtful and evidence-based recommendations on AED use in infants and young children.”

Other researchers involved in the study included Frank Cecchin, M.D., Brian W. Duncan, M.D., Flavian M. Lupinetti, M.D., and Geoffrey L. Rosenthal, M.D., Ph.D., of the University of Washington; Charles I. Berul, M.D., of Harvard Medical School in Boston; James C. Perry, M.D., and A. Andrew Zimmerman, M.D., of Children’s Hospital and Medical Center in San Diego; and Dawn B. Jorgenson, Ph.D., David Snyder, Thomas D. Lyster, and Brett Cross of Agilent Technologies.

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