WINSTON-SALEM, N.C., Jan. 19 (UPI) -- Absent other associated symptoms, people with a slower than normal heartbeat are not at increased risk for developing cardiovascular disease, researchers found in a new study.
A slow heartbeat, called bradycardia, defined as fewer than 50 beats per minute -- between 10 and 50 fewer beats than normal for an adult -- can cause light-headedness, shortness of breath, fainting or chest pain.
"For a large majority of people with a heart rate in the 40s or 50s who have no symptoms, the prognosis is very good," said Dr. Ajay Dharod, a professor of internal medicine at Wake Forest Baptist Hospital, in a press release. "Our results should be reassuring for those diagnosed with asymptomatic bradycardia."
Researchers conducting the study, which is published in JAMA Internal Medicine, analyzed data on 6,733 people collected as part of the Multi-Ethnic Study of Atherosclerosis from 2000 to 2002, who were followed for 10 years after enrolling in the study. All the participants were between the ages of 45 and 84 and did not have a diagnosis of cardiovascular disease when they joined the original study.
The researchers reported people with an average heart rate lower than 50 beats per minute were not associated with cardiovascular disease, and the mortality risk among people not taking heart rate modifying drugs was about the same for people whose heart rates were either below 50 or above 80.
Among the 902 participants taking heart rate modifying drugs, the risk for cardiovascular disease was no higher than those not on the drugs, however the risk for death was increased, researchers said.
"Bradycardia may be problematic in people who are taking medications that also slow their heart rate," Dharod said. "Further research is needed to determine whether this association is causally linked to heart rate or to the use of these drugs."