Sept. 11, 2024 — In the first national estimate in two decades, researchers at the University of California-San Francisco (UCSF) report that 10.5 million Americans have atrial fibrillation.
Atrial fibrillation, a rapid, irregular heart beat that can lead to stroke or sudden death, is three times more common than previously thought, affecting nearly 5 percent of the population, or 10.5 million U.S. adults, according to new estimates from University of California-San Francisco.
A-Fib, as the condition is commonly known, has been on the rise for at least the past decade, driven by the aging of the population, along with increasing rates of hypertension, diabetes and obesity. Earlier projections had estimated that 3.3 million U.S. adults had atrial fibrillation, but these reportedly have not been updated in more than two decades.
The study appears Sept. 11 in the Journal of the American College of Cardiology JACC.
“Atrial fibrillation doubles the risk of mortality, is one of the most common causes of stroke, increases risks of heart failure, myocardial infarction, chronic kidney disease and dementia, and results in lower quality of life,” said first author Jean Jacques Noubiap, MD, PhD, a postdoctoral scholar at UCSF with a specialty in global cardiovascular health.
“Fortunately, atrial fibrillation is preventable, and early detection and appropriate treatment can substantially reduce its adverse outcomes,” he said.
UCSF investigators reviewed the medical records of nearly 30 million adult patients who received some form of acute or procedural care in California from 2005 to 2019. About 2 million of these people had been diagnosed with A-Fib, and the numbers grew over time, rising from 4.49 percent of the patients treated between 2005 and 2009 to 6.82% of the patients treated between 2015 and 2019.
The data were standardized to reflect the entire country, and researchers estimated the current national prevalence to be at least 10.55 million. They also found that during the study timeframe, A-Fib patients skewed younger, were less likely to be female and more likely to have hypertension and diabetes.
“Physicians recognize that atrial fibrillation is often encountered in essentially every field of practice,” said senior and corresponding author Gregory M. Marcus, MD, MAS, a cardiologist and electrophysiologist at UCSF Health. “These data provide objective evidence to demonstrate that prior projections severely underestimated how common it truly is.”
“With the growing use of consumer wearables designed to detect atrial fibrillation combined with safer and more effective means to treat it, this current prevalence of atrial fibrillation in health care settings may soon be dwarfed by future healthcare utilization that will occur due to the disease,” Marcus said.
March 12, 2025 
