Death risk high soon after arrhythmia diagnosis

NEW YORK (Reuters Health) - People who are diagnosed for the first-time with a dangerous heart rhythm disturbance called atrial fibrillation have a significantly greater early risk of dying compared with those without this condition, Minnesota-based researchers report.

Atrial fibrillation is a condition in which the heart's upper chambers quiver instead of beating regularly. This arrhythmia increases the risk of stroke, heart failure, cognitive impairment and death.

Atrial fibrillation is a growing public health problem, but little is known about the overall mortality trends of these patients after diagnosis, Dr. Teresa S. M. Tsang and colleagues at the Mayo Clinic, Rochester, point out.

To investigate further, they studied 4,618 Minnesota residents who had first atrial fibrillation confirmed between 1980 and 2000. The average age of the patients was 73 years.

A total of 3,085 subjects died during roughly 5 years of follow up.

Tsang's group found that mortality was high shortly after diagnosis. Compared with controls without atrial fibrillation, those with atrial fibrillation had a greater than 9-fold increased hazard of death within the first 4 months after diagnosis. However, after 4 months, the risk fell significantly.

The researchers found several factors strongly associated with death in atrial fibrillation patients including faster heart rate at diagnosis, being thin, history of chronic kidney disease, and malignancy.

Atrial fibrillation "was probably not the primary cause of death in the majority of patients but a result of an underlying cascade of pathologic changes and events to which conventional atrial fibrillation treatment would not make a positive impact," the investigators speculate in a report in the Journal of the American College of Cardiology.

"Obviously, it is very disturbing that survival in these patients had not improved over the last 2 decades, despite multiple advances in the treatment of this arrhythmia," Tsang commented to Reuters Health. "However, the impact on mortality trend was likely multifactorial and complex."

"Studies are warranted to determine the factors that lead to and perpetuate atrial fibrillation," she continued, "and prevention of these antecedent factors, as well as the very first episode of atrial fibrillation, may be critical in the control of this public health problem and its consequences."

SOURCE: Journal of the American College of Cardiology, March 6, 2007.