Electrocardiogram Blip Signals Heart Trouble
June 24 -- TUESDAY, June 23 (HealthDay News) -- A slight abnormality in an electrocardiogram (EKG), until now thought to be insignificant, can be a warning sign of future cardiac problems and an increased risk of early death, a new study indicates.
Lengthening of what is called the PR interval, the right-hand portion of the jagged blip that records electrical activity as the heart contracts and expands, was associated with a doubled risk of developing the abnormal heartbeat called atrial fibrillation, three times the risk of needing a pacemaker, and one-and-a-half times the risk of early death, according to a report in the June 24 issue of the Journal of the American Medical Association.
"Historically, this has been viewed as benign," said study senior author Dr. Thomas Wang, associate director of heart failure and heart transplantation at Massachusetts General Hospital. "The main message of this paper is that there is an association between this EKG finding and future risk of heart rhythm abnormalities and death."
The PR interval records the time that the electrical activity of the heart moves across the atria, the two upper chambers of the heart that receive blood flowing from the body, into the ventricles, the lower blood-pumping chambers. EKG activity is recorded in thousandths of seconds, and a PR interval is said to be prolonged if it is greater than 200 milliseconds. Such a prolonged PR interval is generally seen in healthy adults, middle-aged and older, with the incidence increasing with age.
Analysis of EKGs of 7,500 participants in the Framingham Heart Study found a prolonged PR interval in 124 of them, and the increased risk was detected in a long-term follow-up.
"It is not known exactly why it happens," Wang said. "It could be scarring and other abnormalities in the electrical system of the heart."
When the abnormality is detected on an EKG, "there is no need to be panicked," Wang said. "But physicians should follow these patients more closely. There is no evidence that such patients should be treated differently, but future studies may show otherwise."
