Could a Test Predict the Risk of SIDS?
July 26, 2000 -- Although few things are more devastating to a family than losing a baby to sudden infant death syndrome (SIDS), experts still don't know exactly what causes the syndrome or how to prevent it. But some Italian researchers may have discovered another clue to unraveling the mystery: Some cases of SIDS, they say, may be linked to a heart rhythm problem called long-QT syndrome.
One reason this finding is important is that long-QT syndrome -- an abnormality in the heart's rhythm that usually runs in families -- can be detected by an electrocardiogram (also called EKG or ECG). Researcher Peter J. Schwartz, MD, of the University of Pavia in Italy, says he would like to see all babies screened for the heart problem, but other experts raise questions about the expense and feasibility of such widespread testing.
Nonetheless, "this is an important finding, and it adds information to what we already know about SIDS," Jeffrey Towbin, MD, tells WebMD. He says he hopes the discovery will help doctors learn more about the causes of SIDS, and ultimately prevent deaths from this mysterious disorder. Towbin is a professor of pediatric cardiology and molecular and human genetics at Baylor College of Medicine in Houston.
In a case study, published in the latest issue of TheNew England Journal of Medicine, Schwartz and colleagues report that an infant who experienced a near-SIDS episode was diagnosed with this heart problem.
The 7-week-old baby had been healthy before he was found blue, without a heartbeat, and not breathing. He was rushed to the emergency room, where doctors revived him. Once his heart began beating normally, they discovered that he had long-QT syndrome, as well as a genetic abnormality also found in people with this condition. The baby was put on medication, and five years later, his heart rhythm has improved and he has not had any further episodes.
This report is a follow-up to an earlier, 19-year study of more than 34,000 infants, in which the same researchers found in 1998 that infants who had long-QT syndrome were more likely to die from SIDS.
The 7-week-old's case helps to validate the previous work, Schwartz believes. "Maybe 25 to 30% of SIDS cases may be related to this," he says, "And what is important is that it is preventable." Schwartz is chairman of the department of cardiology at Policlinico San Matteo Istituto di Ricovero e Cura a Carattene Scientifico and the University of Pavia.
The findings have stirred debate among pediatricians and SIDS experts about whether screening all infants for the heart problem is feasible or even necessary, whether it will help reduce SIDS deaths, and whether the research evidence linking long QT with SIDS is convincing enough.