Featured Research

from universities, journals, and other organizations

Common ECG Finding, Formerly Considered Insignificant, May Indicate Serious Cardiac Problems

Date:
June 24, 2009
Source:
Massachusetts General Hospital
Summary:
A common electrocardiogram finding that has largely been considered insignificant may actually signal an increased risk of atrial fibrillation, the future need for a permanent pacemaker and an increased risk for premature death.

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.

Related Articles


"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 electrocardiogram records the heart's electrical activity and translates it into waveforms that reflect how the contraction signal moves through the heart muscle. 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 heart, 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 atrial fibrillation, 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.

Co-authors of the JAMA report are Elizabeth McCabe, MS, and Christopher Newton-Cheh, MD, MPH, MGH Cardiology; Michelle Keyes, PhD, Martin Larson, ScD, Daniel Levy, MD, Emelia Benjamin, MD, ScM, and Ramachandran Vasan, MD, Boston University School of Medicine. The Framingham Heart Study is supported jointly by the National Heart, Lung and Blood Institute and Boston University.


Story Source:

The above story is based on materials provided by Massachusetts General Hospital. Note: Materials may be edited for content and length.


Journal Reference:

  1. Susan Cheng, MD; Michelle J. Keyes, PhD; Martin G. Larson, ScD; Elizabeth L. McCabe, MS; Christopher Newton-Cheh, MD, MPH; Daniel Levy, MD; Emelia J. Benjamin, MD, ScM; Ramachandran S. Vasan, MD; Thomas J. Wang, MD. Long-term Outcomes in Individuals With Prolonged PR Interval or First-Degree Atrioventricular Block. JAMA, 2009;301(24):2571-2577 [link]

Cite This Page:

Massachusetts General Hospital. "Common ECG Finding, Formerly Considered Insignificant, May Indicate Serious Cardiac Problems." ScienceDaily. ScienceDaily, 24 June 2009. <www.sciencedaily.com/releases/2009/06/090623163654.htm>.
Massachusetts General Hospital. (2009, June 24). Common ECG Finding, Formerly Considered Insignificant, May Indicate Serious Cardiac Problems. ScienceDaily. Retrieved December 18, 2014 from www.sciencedaily.com/releases/2009/06/090623163654.htm
Massachusetts General Hospital. "Common ECG Finding, Formerly Considered Insignificant, May Indicate Serious Cardiac Problems." ScienceDaily. www.sciencedaily.com/releases/2009/06/090623163654.htm (accessed December 18, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Thursday, December 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Kids Die While Under Protective Services

Kids Die While Under Protective Services

AP (Dec. 18, 2014) As part of a six-month investigation of child maltreatment deaths, the AP found that hundreds of deaths from horrific abuse and neglect could have been prevented. AP's Haven Daley reports. (Dec. 18) Video provided by AP
Powered by NewsLook.com
UN: Up to One Million Facing Hunger in Ebola-Hit Countries

UN: Up to One Million Facing Hunger in Ebola-Hit Countries

AFP (Dec. 17, 2014) Border closures, quarantines and crop losses in West African nations battling the Ebola virus could lead to as many as one million people going hungry, UN food agencies said on Wednesday. Duration: 00:52 Video provided by AFP
Powered by NewsLook.com
When You Lose Weight, This Is Where The Fat Goes

When You Lose Weight, This Is Where The Fat Goes

Newsy (Dec. 17, 2014) Can fat disappear into thin air? New research finds that during weight loss, over 80 percent of a person's fat molecules escape through the lungs. Video provided by Newsy
Powered by NewsLook.com
Why Your Boss Should Let You Sleep In

Why Your Boss Should Let You Sleep In

Newsy (Dec. 17, 2014) According to research out of the University of Pennsylvania, waking up for work is the biggest factor that causes Americans to lose sleep. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins