Abnormal Heart Rhythm Linked to SIDS
Nov. 8, 1999 (Atlanta) -- Sudden Infant Death Syndrome: it's a parent's worst nightmare, and for good reason. Commonly known as SIDS or 'crib death,' the syndrome is the leading cause of death during the first year of an infant's life, striking one in every 1,000 infants. Still, its cause has remained a mystery to scientists. Now, following a 20-year study of more than 34,000 newborns, Italian researchers think they have found the answer: a heart rhythm disorder called long QT syndrome that is evident at birth.
The finding raises an important question: what if parents could find out if their newborn was predisposed to the affliction? An answer may be forthcoming.
Long QT syndrome is a poorly understood and not well recognized disorder that has been linked to the sudden death of both children and adults. The simplest way to test for the disease is an electrocardiogram (ECG), but it can commonly miss this transient abnormality. A more sophisticated and expensive test is a blood analysis for the genetic mutations known to be associated with Long QT syndrome, but this test is not widely available.
In this study, researchers set out to explain why infants die of SIDS. Their assumption was that if enough infants were followed for a long enough period time, they may come across an infant with a near-death incident due to SIDS, allowing scientists to test the heart rhythms of the infant immediately.
The researchers' assumptions proved correct. A two-month-old infant whose parents found him with no pulse was rushed to the hospital. An ECG showed abnormal heart rhythms, yet when the parents were later tested, their ECG readings were normal.
Genetic testing of the infant revealed a gene mutation that is known to cause long QT syndrome. The boy is now a three-year-old and has had no further related problems. He has been prescribed a beta-blocker, a medication proven to keep the heart rhythm normal. He must take the medication for the remainder of his life. "Had this infant not been resuscitated, it would have clearly been labeled as a typical case of SIDS, a diagnosis further supported by the normal ECG of both parents," the researchers write.