Common ECG finding may indicate serious cardiac problems

Jun 23, 2009

A common electrocardiogram (ECG) finding that has largely been considered insignificant may actually signal an increased risk of atrial fibrillation (a chronic heart rhythm disturbance), the future need for a permanent pacemaker and an increased risk for premature death. In their report in the June 24 Journal of the American Medical Association, researchers from Massachusetts General Hospital (MGH) and Boston University School of Medicine describe results of the first large-scale study looking at the significance of a prolonged PR interval in a general population.

"Lengthening of the PR interval is commonly seen on routine electrocardiograms, more often in older patients, and has been considered a relatively harmless finding," says Susan Cheng, MD, a cardiology fellow at MGH and Brigham and Women's Hospital who is lead author of the JAMA paper. "But our results indicate that PR interval prolongation is not as benign as previously thought."

A common diagnostic test available in most physicians' offices, the records the heart's electrical activity and translates it into waveforms that reflect how the contraction signal moves through the . A prolonged PR interval represents a delay in the time it takes for the signal to move across the atria at the top of the , which receive blood flowing in from the veins, into the ventricles at the bottom of the heart, which pump blood out into the arteries. Although a prolonged PR interval can signify conduction problems related to serious conditions such as a heart attack, a prolonged PR interval is most commonly seen in generally healthy, middle-aged to older adults and has been thought to reflect normal age-related changes. But previous investigations of the impact of PR prolongation were limited to younger, healthy participants, such as members of the military.

The current study analyzed data from more than 7,500 participants in the Framingham Heart Study, followed for more than three decades. Although only 124 of those participants showed a prolonged PR interval on the electrocardiogram taken when they entered the study, PR prolongation proved to be a significant risk factor. A PR interval of less than 200 milliseconds is considered normal, and participants whose interval was longer than 200 milliseconds had twice the overall risk of developing , three times the risk of needing a pacemaker and almost one and a half times the risk of early death. Further prolongation of the PR interval led to even greater risk.

"We do not yet know why a subtle finding such as a prolonged PR interval is associated with such serious adverse outcomes, but it may be a marker for progressive problems with the heart's electrical conduction system," says Thomas Wang, MD, of the MGH Heart Center, the study's senior author. "We need to learn more about how a prolonged PR interval is linked to these serious events and what should be done to prevent them. Right now, clinicians might consider that their patients with PR prolongation may be at increased risk of these problems and follow their electrocardiograms more closely." Wang is an assistant professor of Medicine at Harvard Medical School.

Source: Massachusetts General Hospital (news : web)

Explore further: Ebola has killed 61 in Guinea since January

add to favorites email to friend print save as pdf

Related Stories

ER/PR negative tumors associated with insurance status

Nov 18, 2008

African-American women are at a higher risk for ER/PR negative breast cancer. A new study, to be presented at the American Association for Cancer Research's Seventh Annual International Conference on Frontiers in Cancer Prevention ...

Researchers say ECG standards should be revised for elderly

Mar 14, 2008

Researchers at Mayo Clinic suggest that the established “normal” ranges for evaluating electrocardiograms for persons over 80 years old should be “revisited.” The recommendation comes in a study published today in ...

Abnormal EKG can predict death in stroke patients

Mar 20, 2009

People who suffer an ischemic stroke and also have an abnormality in the heart's electrical cycle are at a higher risk of death within 90 days than people who do not have abnormal electrical activity at the time of emergency ...

Recommended for you

Two expats die of MERS in Saudi commercial hub

21 hours ago

Two foreigners died of MERS in the Saudi city of Jeddah, the health ministry said Saturday, as fears rise over the spreading respiratory virus in the kingdom's commercial hub.

UAE reports 12 new cases of MERS

21 hours ago

Health authorities in the United Arab Emirates have announced 12 new cases of infection by the MERS coronavirus, but insisted the patients would be cured within two weeks.

Filipino tests negative for Middle East virus

Apr 19, 2014

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

User comments : 0

More news stories

Cancer stem cells linked to drug resistance

Most drugs used to treat lung, breast and pancreatic cancers also promote drug-resistance and ultimately spur tumor growth. Researchers at the University of California, San Diego School of Medicine have discovered ...

Poll: Big Bang a big question for most Americans

Few Americans question that smoking causes cancer. But they have more skepticism than confidence in global warming, the age of the Earth and evolution and have the most trouble believing a Big Bang created the universe 13.8 ...

Making graphene in your kitchen

Graphene has been touted as a wonder material—the world's thinnest substance, but super-strong. Now scientists say it is so easy to make you could produce some in your kitchen.