Low Heart Rate on HR-Reducing Meds Bodes Higher CV, Death Risk: MESA Analysis

According to an analysis based on an ethnically diverse US population-based cohort Bradycardia per se does not increase mortality or cardiovascular risk overall, but it may be associated with those risks in persons taking medications that lower heart rate

People having slower than normal heartbeat, known as bradycardia, do not face an increased risk of developing cardiovascular disease, finds a new study. The research was carried out with an aim to know if the condition without any symptom could lead to cardiovascular disease.

“I think caution is in order if somebody has a reason to be on drugs that lower the heart rate, and their heart rate is consistently below 50 beats per minute,” Dr Alain Bertoni (Wake Forest School of Medicine, Winston-Salem, NC) commented to heart wire from Medscape.

“We believe doctors should look carefully at people who have really slow heart rates when they’re on these medications and consider the possibility that the dose needs adjustment or that other diseases that aren’t well controlled need to be addressed,” he said.

The report explained heart-rate–lowering agents as beta-blockers, digitalis, nondihydropyridine calcium-channel blockers, and all other antiarrhythmic drugs. Bertoni is the senior author on the analysis from the Multi-Ethnic Study of Atherosclerosis (MESA) published January 19, 2016 in JAMA Internal Medicine with lead author Dr Ajay Dharod (Wake Forest University).

Study researcher Dr. Ajay Dharod, an instructor of internal medicine at Wake Forest Baptist Medical Center said, “For a large majority of people with a heart rate in the 40s or 50s who have no symptoms, the prognosis is very good. Our results should be reassuring for those diagnosed with asymptomatic bradycardia”.

In the study, the researchers have assessed data of 6,733 people collected as part of the Multi-Ethnic Study of Atherosclerosis conduced from 2000 to 2002. The participants aged between 45 and 84 were followed for a decade.

When the participants were enrolled, they did not have the cardiovascular disease. As per the researchers, people having an average heart rate lower than 50 beats per minute were not found to be linked with cardiovascular disease.

The mortality risk among people not taking the heart rate improvement drugs was the same for people whose heart rates were below 50 or above 80. In the case of 902 participants who were taking heart rate modifying drugs, the risk for cardiovascular disease was no higher than the ones not on the drugs. But the researchers did not notice that the risk for death has increased.

“The current analysis does a good job in highlighting the complexity of this issue,” Dr Jeffrey Goldberger (University of Miami, FL) said for heart wire. “We’re never going to have a clear one-line statement on what it means to have bradycardia, because bradycardia’s complex. It’s not one physiologic entity across all patients,” explained Goldberger, who is not associated with the current MESA analysis. “It’s worth trying to understand which patients with bradycardia may be at risk for cardiac events and what types of interventions could be done to improve their care,” he concluded.