A study found that in the absence of related symptoms, people who have slow heart rate don't have higher risks of developing cardiovascular disease. Bradycardia or slow heart rate is clinically defined as having less than 50 beats per minute. Slow heart rate can cause many people to experience shortness of breath, light-headedness, chest pain and fainting.
The research team analyzed the data of 6,733 people who took part in the 2000-2002 Multi-Ethnic Study of Atherosclerosis (MESA). The men and women who participated in the study were between 45 and 84 years old and didn't have prior cardiovascular disease diagnosis when they joined the original study. The participants, who live in the United States, were monitored for 10 years.
"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, Wake Forest Baptist Hospital's internal medicine professor. Dharod added that the study results should reassure people who are diagnosed with asymptomatic bradycardia.
Findings showed that participants whose average heart rate is lower than 50 heartbeats per minute were not linked to increased risks of developing cardiovascular disease. Patients who took heart rate-reducing drugs such as calcium channel blockers and beta blockers have nearly the same mortality risk as patients whose heart rates were beyond 80 or below 50 beats per minute. Notably, the study found a possible link between bradycardia and increased mortality rates among people who take heart rate-reducing drugs.
"Bradycardia may be problematic in people who are taking medications that also slow their heart rate," added Dharod.
The Wake Forest study was not designed to determine the cause-and-effect association of the factors presented. The team added that more research is needed to conclude if the increased mortality risk is informally linked to the heart rate or to the heart rate-reducing medications.
The study was conducted by researchers from the Wake Forest Baptist Medical Center and supported by the National Heart Lung and Blood Institute. The research was published in the JAMA Internal Medicine journal on Jan. 19.
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