Atrial Fibrillation: A Review

EMBARGOED by the Journal of the American Medical Association until 11 a.m. ET, Dec.16, 2024

(Boston)—In the U.S., atrial fibrillation (AF), a heart condition that causes an irregular heartbeat in the upper chambers of the heart, affects up to one in three people in their lifetime. Significant complications associated with this condition include ischemic stroke, heart failure, myocardial infarction, chronic kidney disease, dementia and mortality.

In a new review article in the Journal of the American Medical Association, researchers from Boston University Chobanian & Avedisian School of Medicine and Boston Medical Center summarize the current evidence regarding the epidemiology, pathophysiology, diagnosis and management of AF.

“Given the increasing incidence, prevalence and lifetime risk of AF, it is imperative that we promote the most effective protocols to help reduce risk factors and prevent the onset, recurrence, and complications of AF in our patients,” says Emelia J. Benjamin, MD, ScM, FACC, FAHA, the Jay and Louise Coffman Professor of Vascular Medicine and professor of medicine in cardiovascular medicine at the school and a cardiologist at Boston Medical Center (BMC).

The researchers conducted a PubMed search for English-language articles published between January 1990, and August 15, 2024, concerning the epidemiology, pathophysiology, clinical presentation, prognosis, and management of AF.

Their results included insights into the epidemiology, pathophysiology, screening and detection, clinical presentation, and management of atrial fibrillation.

In terms of epidemiology, the age-adjusted incidence per 1,000 person years increased from 3.7 to 13.4 in men and from 2.5 to 8.6 in women and the prevalence increased from 20.4 to 96.2 in men and from 13.7 to 49.4 in women between 1990 and 2024. The highest prevalence was observed in high-income countries in North America, Australasia and Western Europe. The global prevalence was higher in men (approximately 28 million) vs women (approximately 25 million). Additionally, older age was associated with higher incidence of atrial fibrillation. The authors also observed that more research is needed to address health inequities in AF outcomes in individuals from minoritized races and ethnicities, or with lower socioeconomic backgrounds.

In regard to pathophysiology, the researchers observed diseases such as hypertension, obesity and valvular heart disease (such as mitral valve stenosis and mitral valve regurgitation), to be associated with atrial pathology and AF.

For atrial fibrillation screening and detection, they noted that the probability of detection increased with electrocardiogram (ECG) monitoring duration, however experts are uncertain about the benefits of screening for AF in the general population to detect asymptomatic AF. An implantable loop recorder (ILR) (a subcutaneous device that continuously monitors heart rhythm for about four years), found AF was diagnosed in a third of patients while in the Apple Heart Study, only 34% of those who received the smartwatch’s notification for atrial fibrillation were subsequently diagnosed with AF using ECG patch monitoring.

As to clinical presentation, the researchers found typical symptoms of AF included palpitations with or without labored breathing, chest pain, presyncope (remaining conscious while feeling you are about to faint), exertional intolerance and fatigue. Asymptomatic initial presentation of AF was more common in men (10% in men vs 3% in women) and older adults (74 years vs 62 years for symptomatic people). Diabetes was more common in those with asymptomatic AF.

Concerning management of AF, the recommended initial treatment of patients at risk for AF (stages 1 or 2) or with AF (stages 3 or 4) consisted of lifestyle and risk factor modification, such as weight loss, exercise, targeted blood pressure control, smoking cessation, and limitation of alcohol intake. “Consensus opinion is now moving in the direction of early intervention for AF to favorably influence outcomes.  Technologic advances in catheter ablation have made this an attractive option for many patients,” says senior author Robert Helm, MD, FHRS, assistant professor of medicine at the school and a clinical electrophysiologist at BMC.

Catheter ablation is an invasive procedure where areas of heart muscle cells are destroyed with heat, freezing or high-voltage pulses to eliminate sources that cause the heart to beat irregularly. It was found to be the first-line therapy in patients with symptomatic paroxysmal AF to improve symptoms and slow progression to persistent AF. Catheter ablation was also recommended for patients with AF who have heart failure with reduced ejection fraction, (a type of heart failure that occurs when the left ventricle of the heart is too weak to pump enough blood to the body) to improve quality of life, left ventricular systolic function, and cardiovascular outcomes, such as rates of mortality and heart failure hospitalization.

These findings appear in the Journal of the American Medical Association.

Note to Editors:

Dr. Benjamin reported receiving grants from NIH/National Heart, Lung, and Blood Institute (R01HL092577) and AHA AF (AHA_18SFRN34110082) during the conduct of the study. Dr. Ko reported receiving grants from Boston Scientific; and personal fees from Windrose Consulting Group and Academic CME outside the submitted work. Dr. Chung reported receiving research grants from National Institutes of Health (NIH) and American Heart Association (AHA) during the conduct of the study. Dr Helm reported receiving grants to institution from Boston Scientific to study racial and ethnic disparities in the use of left atrial appendage occlusion devices in patients with atrial fibrillation and Cardathea to test a novel mapping system for conduction system pacing outside the submitted work. No other  disclosures were reported.