The current estimate that 2.2 million Americans have atrial fibrillation has to be drastically revised upward, to 5.1 million, concludes a report in the July 4 issue of Circulation by physicians at the Mayo Clinic College of Medicine.
What's more, if current trends continue, the investigators are predicting a threefold increase in the condition over the next five decades, with as many as 16 million Americans affected by 2050.
That prediction was based on a 21-year study of more than 4,600 adults in Olmsted County, Minn., home of the Mayo Clinic.
"We found a significant increase in the number of people who newly developed this rhythm problem over the past two decades in Olmsted County, and this increase was not just because people were living longer," senior researcher Dr. Teresa S. M. Tsang, an associate professor of medicine at the Mayo Clinic, said in a prepared statement.
In atrial fibrillation, the upper chambers of the heart quiver irregularly rather than beating steadily. The clots that form as blood pools in the heart can then move to the brain, causing stroke as they block blood vessels there. Atrial fibrillation is associated with other major problems, including heart failure.
The report said the reason for the increase was not clear, but that the growing incidence of obesity probably plays a large role.
As for the current estimate of 2.2 million Americans, that was based on a study of members of a health plan. The new estimate is more accurate, the research team said, because it comes out of a large population study.
In addition, the Minnesota population included a larger percentage of whites, who are typically at higher risk of atrial fibrillation than other ethnic groups, according to the experts.
The study is an "important, newsworthy paper," said Dr. Kenneth A. Ellenbogen, a professor of cardiology at Virginia Commonwealth University and a spokesman for the American Heart Association. No other study of atrial fibrillation has followed so many Americans for such a long period, he said.
"We need to concentrate a lot more on primary prevention, or we will have an even bigger epidemic," Ellenbogen warned.
The Mayo researchers also concluded the same thing.
"We need to prevent the first episode of atrial fibrillation and the risk factors contributing to its development if we are to turn the tide of this growing epidemic," Tsang said.
"I would concentrate on high blood pressure, obesity and diabetes," Ellenbogen said.
More information
There's more on atrial fibrillation at the American Heart Association.
