Risk Factors for Atrial Fibrillation

Deepak L. Bhatt, MD, MPH, FACC, FAHA, FSCAI, FESC: Welcome to this Practical Cardiology™ CardioView presentation titled “Managing Patients With Heart Arrhythmia.” I’m Dr Deepak Bhatt, the executive director of interventional cardiovascular programs at Brigham and Women’s Hospital and a professor of medicine at Harvard Medical School in Boston, Massachusetts. This discussion will focus on an overview of heart arrhythmia and review new developments in monitoring atrial fibrillation [A-Fib] and syncope. Let’s begin.

Atrial fibrillation is the most common arrhythmia in the United States and worldwide, with a prevalence that’s growing. Why is the prevalence growing? Because of a number of trends. One is the aging of the population. In the United States and globally there are many older people, and atrial fibrillation and its prevalence increase markedly in both men and women as one gets older. In the 70s, 80s, 90s, the incidence of atrial fibrillation is much higher than at younger ages. So this is a real issue in terms of a growing burden of atrial fibrillation.

Beyond the aging population, several other factors appear to be contributing to atrial fibrillation. It wasn’t fully appreciated until relatively recently that obesity contributes to atrial fibrillation, and it appears that weight loss can decrease A-Fib burden. Obesity is a risk factor for cardiovascular disease, whether it’s ischemic heart disease or heart failure. That’s well known. But it turns out that it’s also a risk factor for developing atrial fibrillation. In people who have atrial fibrillation, it can also increase atrial fibrillation burden. Even in patients who’ve had an atrial fibrillation ablation, it appears that weight loss decreases the risk of occurrence or recurrence. Regardless of the stage of atrial fibrillation—at risk for it, has it, has had an ablation for it—it appears that weight loss decreases risks of recurrent atrial fibrillation, de novo atrial fibrillation, and atrial fibrillation after procedure. For patients who are overweight, particularly who are obese, if they’re asking what can they do to decrease atrial fibrillation risk, weight loss is definitely now on that list.

Another risk factor that’s relatively new is alcohol intake. A number of studies now point to the fact that even a single drink a day increases the risk of atrial fibrillation. This is true of people who have atrial fibrillation. It also appears to be true of people who are just at risk for atrial fibrillation but don’t have it yet. In terms of things patients can do to decrease atrial fibrillation risk, they can cut down or eliminate alcohol intake. That’s not always a popular answer, but that’s what the data show. We know that binge drinking can precipitate the occurrence of atrial fibrillation; that’s been known by physicians for years. There’s holiday heart syndrome, where they come in after, say, the Super Bowl and a weekend of partying, with lots of drinking and perhaps lots of chips and salt, and they have atrial fibrillation, even if they haven’t had it before. That can occur in relatively younger people, and it can occur in older folks. There’s no question that acute alcohol intake, especially large amounts, can trigger atrial fibrillation. But what’s novel and true is that more modest chronic intake can do it as well. Studies show that even a single drink can increase the risk of developing atrial fibrillation. So alcohol is a trigger.

Interestingly, we’ve thought coffee or caffeine intake is a trigger for atrial fibrillation. But there, rigorous trials are more ambiguous about whether that’s true. I’ve certainly met patients who are convinced that atrial fibrillation has been triggered by caffeine intake, so maybe there’s something to it. But that’s not been as clearly established by rigorous clinical trial data. It can get tricky because if someone is drinking a lot of caffeine, it might mean they’re also staying up all night, under a lot of stress, and not eating right, so there are other bad things going on that could also serve as triggers for atrial fibrillation. It gets tricky figuring out what an actual trigger for atrial fibrillation is. I’m not saying that an individual patient’s caffeine, stress, and lack of sleep might not be part of it. I’m sure it is, but in terms of very rigorous data, we can say with certainty that alcohol is a trigger for atrial fibrillation.

Other contributing factors are well known: patients with heart failure are at much higher risk of atrial fibrillation, patients with valvular heart disease are at high risk. In particular, increasing the left atrial dimensions—stretching the left atria—can be a trigger for atrial fibrillation. Mitral stenosis and mitral regurgitation are classic for increasing the risk. Even aortic stenosis and its downstream effects—or maybe upstream effects, depending on how you look at it—can lead to atrial fibrillation. Heart failure of any cause, valvular heart disease—in particular involving the mitral valve, but even other valvular lesions—can increase the risk of atrial fibrillation. Hypertension is a well-known risk factor for atrial fibrillation. Diabetes is another well-established risk factor for atrial fibrillation, heart failure, and associated conditions. There are a lot of potential factors that can lead to atrial fibrillation. There are other things that can trigger it. Infiltrative diseases such as amyloidosis can increase the risk of atrial fibrillation. Basically, anything that’s infiltrating or enlarging the left atrium, causing fibrosis, can provoke occurrence and maintenance of atrial fibrillation.

Transcript Edited for Clarity