Dear Doctor: I've suffered from atrial fibrillation for several years now. I recently read that overall heart health could reduce the risk of the condition. Is it too late for me, considering I've already been diagnosed?
Dear Reader: You're not alone in asking this question, especially in light of this new report. Atrial fibrillation, or AFib, affects more than 2 million people in the United States, making it the most common heart-rhythm abnormality in the country.
For those not familiar with the condition: The atria are the chambers of the heart that pump blood into the ventricles, which are the more muscular chambers that then push blood out to the rest of the body. Injuries to the atria can happen for a variety of reasons, leading to abnormal electrical conduction and what is known as atrial fibrillation. In these circumstances, the atria quiver instead of contracting rhythmically, creating the possibility that the blood in the chambers will form a clot, travel to the brain and cause a stroke. In fact, 15 percent of all strokes are caused by AFib.
The new study you reference assessed ways to prevent AFib. Researchers analyzed data from 13,182 men and women, ages 45 to 64, who had filled out questionnaires from 1987 through 1989 about their health habits. The participants were reassessed four more times: from 1990 through 1992; from 1993 through 1995; from 1996 through 1998; and from 2011 through 2013. Data included height and weight, smoking status, blood pressure, cholesterol levels and blood sugar levels. Questionnaires also assessed participants' diet and level of physical activity.
From all of this information, the authors divided people into three different health categories: inadequate, average or optimal. Over the years of the study, up until Dec. 31, 2014, the authors also identified those in each category who developed atrial fibrillation.
After adjusting for confounding factors, the authors found that people in the average health category had a 37 percent decreased risk of AFib compared to those in the inadequate health category. And those in the optimal health category had a 57 percent decrease in risk compared to those with inadequate health.
Note that diet and cholesterol level did not appear to have any effect upon atrial fibrillation.
One problem with the study, however is that the authors didn't explain how they adjusted for binge drinking, which is a major risk factor for this condition. In fact, AFib occurs in 60 percent of binge drinkers. But even moderate amounts can cause the abnormal rhythm. A 2014 study found that, compared to people who had less than one drink per week, those who had seven to 14 drinks per week had a 14 percent greater risk of atrial fibrillation; those with 15 to 21 drinks per week had a 39 percent greater risk of AFib. Another factor on which the researchers were unclear is how they controlled for the impact of exercise; moderate exercise decreases the risk of AFib, while extreme exercise increases the risk.
If you have had atrial fibrillation for many years, it may be difficult for your heart to resume a normal rhythm.
However, removing risk factors such as hypertension, diabetes, smoking, sleep apnea and excessive alcohol consumption can reduce the frequency of AFib. Further, among people who underwent a heart ablation procedure to stop AFib, 62 percent of those who made lifestyle changes were able to eliminate the condition, compared to 26 percent of those who didn't make such changes. And, as we said, moderate exercise may slightly decrease the risk of AFib.
(Send your questions to email@example.com, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)