He was surprised because, he said, he felt fine and hadn't noticed any symptoms, except for three brief, isolated periods of complete lethargy that had occurred over three months. When the atriums function erratically, they can disrupt the rhythm of the ventricles, causing the heart to race one minute and crawl the next. People with atrial fibrillation, or A.F., often experience palpitations, a strong, racing heart that typically beats 140 to 180 times a minute. Other symptoms like dizziness, faintness, shortness of breath and fatigue can result when the heart cannot pump enough blood to the body and brain.
Experts say that atrial fibrillation is often underappreciated and undertreated.
The condition, estimated to affect 2.2 million Americans, is the most common heart rhythm disorder seen by practicing physicians. Its prevalence increases with age, from 0.5 percent in people ages 50 to 59 to nearly 10 percent among those 80 and older. Uncorrected, A.F. may lead to congestive heart failure or aggravate other heart problems. But by far the most serious problem associated with it is an increased risk of stroke. The rate of stroke among elderly people with A.F. averages 5 percent a year, or six times that of people without the condition.