The Rising Tide of Atrial Fibrillation: Is Primary Care Ready?

The incidence of atrial fibrillation (AF) is on the rise, and recent joint guidelines from the American College of Cardiology and American Heart Association (ACC/AHA) stress the role of primary care clinicians in prevention and management.

One in three White and one in five Black Americans will develop AF in their lifetime, and the projected number of individuals diagnosed with AF in the United States is expected to double by 2050.

Cardiologists who spoke to Medscape Medical News said primary care clinicians can help control AF by focusing on diabetes and hypertension, along with lifestyle factors such as diet, exercise, and alcohol intake.

“It’s not just a rhythm abnormality, but a complex disease that needs to be addressed in a multidisciplinary, holistic way,” said Jose Joglar, MD, a professor in the Department of Internal Medicine at the UT Southwestern Medical Center in Dallas and lead author of the guidelines.

Joglar said primary care clinicians can play an important role in counseling on lifestyle changes for patients with the most common etiologies such as poorly controlled hypertension, diabetes, and obesity.

The Primary Care Physicians ABCs: Risk Factors and Comorbidities

The three pillars of the new ACC/AHA guidelines include: Stroke risk assessment and management; optimize the patient’s risks; and symptom management.

“As a primary care physician or as a cardiologist, I often think that if I do these things, I’m going to help with a lot of conditions, not just atrial fibrillation,” said Manesh Patel, MD, chief of the Divisions of Cardiology and Clinical Pharmacology at the Duke University School of Medicine in Durham, North Carolina.

Lifestyle choices such as sleeping habits can play a big part in AF outcomes. Although the guidelines specifically address obstructive sleep apnea as a risk factor, he said more data are needed on the effect of sleep hygiene — getting 8 hours of sleep a night — a goal few people attain.

“What we do know is people that can routinely try to go to sleep and sleep with some regularity seem to have less cardiovascular risk,” Patel said.

Although existing data are limited, literature reviews have found evidence that sleep disruptions, sleep duration, circadian rhythm, and insomnia are associated with heart disease, independent of obstructive sleep apnea.

Use of alcohol should also be discussed with patients, as many are unaware of the effects of the drug on cardiovascular disease, said Joglar, who is also the program director of the Clinical Cardiac Electrophysiology Fellowship program at the UT Southwestern Medical Center.

“Doctors can inform the patient that this is not a judgment call but simple medical fact,” he said.

Joglar also said many physicians need to become educated on a common misconception.

“Every time a patient develops palpitations or atrial fibrillation, the first thing every patient tells me is, I quit drinking coffee,” Joglar said.

However, as the guidelines point out, the link between caffeine and AF is uncertain at best.

Preventing AF

A newer class of drugs may help clinicians manage comorbidities that contribute to AF, such as hypertension, sleep apnea, and obesity, said John Mandrola, MD, an electrophysiologist in Louisville, Kentucky, who hosts This Week in Cardiology on Medscape.

Although originally approved for treatment of diabetes, sodium-glucose cotransporter-2 inhibitors are also approved for management of heart failure. Mandrola started prescribing these drugs 2 years ago for patients, given the links of both conditions with AF.

“I think the next frontier for us in cardiology and AF management will be the GLP-1 agonists,” Mandrola said. He hasn’t started prescribing these drugs for his patients yet but said they will likely play a role in the management of patients with AF with the common constellation of comorbidities such as obesity, hypertension, and sleep apnea. 

“The GLP-1 agonists have a really good chance of competing with AF ablation for rhythm control over the long term,” he said.

Decisions, Decisions: Stroke Risk Scoring Systems

The risk for stroke varies widely among patients with AF, so primary care clinicians can pick among several scoring systems to estimate the risk for stroke and guide the decision on whether to initiate anticoagulation therapy.

The ACC/AHA guidelines do not state a preference for a particular instrument. The Congestive heart failure, Hypertension, Age, Diabetes mellitus, Stroke, Vascular disease, Sex (CHA₂DS₂-VASc) score is the most widely used and validated instrument, Joglar said. He usually recommends anticoagulation if the CHA₂DS₂-VASc score is > 2, dependent on individual patient factors.

“If you have a CHA₂DS₂-VASc score of 1, and you only had one episode of AF for a few hours a year ago, then your risk of stroke is not as high as somebody who has a score of 1 but has more frequent or persistent AF,” Joglar said.

None of the systems is perfect at predicting risk for stroke, so clinicians should discuss options with patients.

“The real message is, are you talking about the risk of stroke and systemic embolism to your patient, so that the patient understands that risk?” he said.

Patel also said measuring creatine clearance can be analogous to using an instrument like CHA₂DS₂-VASc.

“I often think about renal disease as a very good risk marker and something that does elevate your risk,” he said.

Which Anticoagulant?

Although the ACC/AHA guidelines still recommend warfarin for patients with AF with mechanical heart valves or moderate to severe rheumatic fever, direct oral anticoagulants (DOACs) are the first-line therapy for all other patients with AF.

In terms of which DOACs to use, the differences are subtle, according to Patel.

“I don’t know that they’re that different from each other,” he said. “All of the new drugs are better than warfarin by far.”

Patel pointed out that dabigatran at 150 mg is the only DOAC shown to reduce the incidence of ischemic stroke. For patients with renal dysfunction, he has a slight preference for a 15-mg dose of rivaroxaban.

Mandrola said he mainly prescribes apixaban and rivaroxaban, the latter of which requires only once a day dosing.

“We stopped using dabigatran because 10% of people get gastrointestinal upset,” he said.

Although studies suggest aspirin is less effective than either warfarin or DOACs for the prevention of stroke, Joglar said he still sees patients who come to him after being prescribed low-dose aspirin from primary care clinicians.

“We made it very clear that it should not be recommended just for mitigating stroke risk in atrial fibrillation,” Joglar said. “You could use it if the patient has another indication, such as a prior heart attack.”

Does My Patient Have to Be in Normal Sinus Rhythm?

The new guidelines present evidence maintaining sinus rhythm should be favored over controlling heart rate for managing AF.

“We’ve focused on rhythm control as a better strategy, especially catheter ablation, which seems to be particularly effective in parallel to lifestyle interventions and management of comorbidities,” Joglar said. Rhythm control is of particular benefit for patients with AF triggered by heart failure. Control of rhythm in these patients has been shown to improve multiple outcomes such as ejection fraction, symptoms, and survival.

Patel said as a patient’s symptoms increase, the more likely a clinician will be able to control sinus rhythm. Some patients do not notice their arrhythmia, but others feel dizzy or have chest pain.

“The less symptomatic the patient is, the more likely they’re going to tolerate it, especially if they’re older, and it’s hard to get them into sinus rhythm,” Patel said.

When to Refer for Catheter Ablation?

The new guidelines upgraded the recommendation for catheter ablation to class I (strong recommendation) for patients with symptomatic AF in whom anti-arrhythmic therapy is unsuccessful, not tolerated, or contraindicated; patients with symptomatic paroxysmal AF (typically younger patients with few comorbidities); and patients with symptomatic or clinically significant atrial flutter. The previous iteration recommended trying drug therapy first.

Multiple randomized clinical trials have demonstrated the effectiveness of catheter ablation.

“In somebody who is younger, with a healthy heart, the 1-year success rate of the procedure might be about 70%,” Joglar said. While 70% of patients receiving a catheter have no AF episodes in the following year, Joglar said 20%-25% of those who do have recurrences will experience fewer or shorter episodes.

Conversations about rate vs rhythm control and whether to pursue catheter ablation often come down to preference, Patel said. He would tend to intervene earlier using ablation in patients with heart failure or those experiencing symptoms of AF who cannot be controlled with a heart rate

But he said he prefers using medication for rate control in many of his patients who are older, have chronic AF, and do not have heart failure.

Mandrola takes a more conservative approach, reserving catheter ablation for patients in whom risk factor management and anti-arrhythmic drugs have not been successful.

“In my hospital, it’s done for patients who have symptomatic AF that’s really impacting their quality of life,” he said. But for those with fewer symptoms, his advice is to provide education, reassurance, and time because AF can resolve on its own.

What About Data From Implantables and Wearables?

The guidelines provide an algorithm for when to treat non-symptomatic atrial high-rate episodes detected by a cardiovascular implantable electronic device such as a pacemaker or defibrillator. Episodes less than 5 minutes can be ignored, while treatment could be considered for those with episodes lasting 5 minutes up to 24 hours with a CHA₂DS₂-VASc score ≥ 3, or lasting longer than 24 hours with a CHA₂DS₂-VASc score ≥ 2.

But whether anticoagulation improves outcomes is unclear.

“That is a $64,000 question,” Mandrola said. “I would bet every day I get a notification in the electronic health record that says Mr Smith had 2 hours of AFib 2 weeks ago.”

He also hears from patients who report their Apple Watch has detected an episode of AF.

Mandrola cited evidence from two recent studies of patients who had an atrial high-rate episode longer than 6 minutes detected by implantable devices. The NOAH-AFNET 6 trial randomized patients over 65 years with one or more risk factors for stroke to receive a DOAC or placebo, while the ARTESIA trial used similar inclusion criteria to assign patients to receive either DOAC or aspirin. Both studies reported modest reductions in stroke that were outweighed by a higher incidence of major bleeding in the group receiving anticoagulation.

Shared decision-making should play a role in deciding how aggressively to treat episodes of AF detected by implantable or wearable devices.

He said some patients fear having a stroke, while others are adamantly opposed to taking an anticoagulant.

For patients who present with a documented episode of AF but who otherwise have no symptoms, Patel said clinicians should consider risk for stroke and frequency and duration of episodes.

“One way clinicians should be thinking about it is, the more risk factors they have, the lower burden of AF I need to treat,” Patel said. Even for patients who are having only short episodes of AF, he has a low threshold for recommending an anticoagulation drug if the patient’s CHA₂DS₂-VASc score is high.

Patel reported research grants from Bayer, Novartis, Idorsia, NHLBI, and Janssen Pharmaceuticals and served as a consultant on the advisory boards of Bayer, Janssen Pharmaceuticals, and Esperion Therapeutics. 

Joglar and Mandrola had no disclosures. 

A former pediatrician and disease detective, Ann Thomas is a freelance science writer living in Portland, Oregon.