Having a slow heart rate, a condition called bradycardia, does not increase a person's risk for cardiovascular disease, according to researchers from the Wake Forest Baptist Medical Center.
People with bradycardia have heartbeats of less than 50 per minute, which is lower than the normal 60 to 100 beats per minute at rest. Although bradycardia can cause shortness of breath, chest pain or sometimes fainting because of the heart not being able to pump enough oxygen, no research has presented evidence that it can lead to the development of cardiovascular disease.
"For a large majority of people with a heart rate in the 40s or 50s who have no symptoms, the prognosis is very good," study author Dr. Ajay Dharod said in a press release. "Our results should be reassuring for those diagnosed with asymptomatic bradycardia."
However, the scenario changes when people with bradycardia take heart rate modifying drugs like calcium channel blockers and beta blockers, the researchers said.
The researchers analyzed data from 6,733 men and women aged 45 to 84 who participated in the Multi-Ethnic Study of Atherosclerosis (MESA). The participants did not have cardiovascular disease at the start of the study, but some of them were taking heart rate modifying drugs for hypertension. They were followed for 10 years.
The results of the study showed that having bradycardia did not increase the participants' risk of developing cardiovascular disease. However, they found a link between slow heart rate and increased mortality rate in participants who were on heart rate modifying drugs, suggesting that the drugs could have an adverse effect.
"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."
The study was published online Jan. 19 in JAMA Internal Medicine.
