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Slow heart rate not linked to increased risk of heart disease: study

Xinhua, January 20, 2016 Adjust font size:

A slower than normal heartbeat, known as bradycardia, does not increase the risk of developing heart disease, a U.S. study said Tuesday.

"For a large majority of people with a heart rate in the 40s or 50s who have no symptoms, the prognosis is very good," lead author Ajay Dharod, instructor in internal medicine at the Wake Forest Baptist Medical Center, said in a statement.

"Our results should be reassuring for those diagnosed with asymptomatic bradycardia," Dharod said.

The heart usually beats between 60 and 100 times a minute in an adult at rest. But with bradycardia, the heart beats fewer than 50 times a minute. The condition can cause light-headedness, shortness of breath, fainting or chest pain due to the heart not pumping enough oxygen-rich blood through the body.

However, until now, there had not been any research to determine if a slow heart rate contributed to the development of cardiovascular disease.

In the new study, researchers looked at 6,733 participants aged 45 to 84 who did not have cardiovascular disease when first recruited into this study, but who may have been on heart rate-modifying medications frequently used to treat hypertension.

Study participants were followed for more than 10 years to monitor cardiovascular events and mortality.

The researchers found that a heart rate of less than 50 was not associated with an elevated risk of cardiovascular disease in participants regardless of whether they were taking heart rate-modifying drugs, such as beta blockers and calcium channel blockers.

However, the study did show a potential association between bradycardia and higher mortality rates in individuals taking heart rate-modifying drugs.

"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 findings were published online in the Journal of American Medical Association Internal Medicine. Endit