When a lean, healthy, physically active person has a stroke, seemingly out of the blue, the cause may well be a heart rhythm abnormality called atrial fibrillation.
Such was the fate of Pamela Bolen of Brooklyn, then 67, who said she collapsed last year at home. Luckily, her husband, Jack, heard her fall, called an ambulance, and within minutes she was at New York Methodist Hospital. There she was given the drug tissue plasminogen activator, or tPA, to dissolve the clot that was blocking circulation in her brain. The treatment spared her lasting disability.
ďI had high blood pressure which was completely controlled with medication, but I didnít know I had atrial fibrillation until I had a stroke,Ē Bolen said in an interview. The condition slows blood flow from the heart and was the likely cause of the clot that resulted in her stroke.
About three million Americans have atrial fibrillation, characterised by multiple irregular electrical signals that cause the heartís upper chambers, the atria, to contract rapidly, without their usual coordination. This sends an erratic signal to the ventricles, the lower chambers that supply blood to the lungs and rest of the body. People with the disorder face a much higher risk of stroke, and most require treatment to prevent this potentially crippling and sometimes fatal consequence.
ďAs many as one in five or six strokes is due to atrial fibrillation, and in a lot of these people the rhythm disorder was undetected before the stroke,Ē said Dr. Christian T. Ruff, cardiologist at Brigham and Womenís Hospital in Boston, who studies new treatments for the disorder.
People with symptomatic A-fib, as it is commonly called, may experience periodic palpitations (a sense that the heart is pounding or fluttering), chest discomfort, shortness of breath, unusual fatigue or dizziness.
A-fib can show up during an electrocardiogram, or EKG, but because the abnormal rhythm may not occur all the time, people suspected of having the condition usually must wear a Holter monitor for days or weeks to obtain a certain diagnosis. This small portable device, connected to electrodes on the chest, continuously records the heartís rhythm and sends the data to a doctor or company for evaluation.
A-fib is more common in men, tall people and the elderly. As the population ages, the incidence is rising; more than 460,000 new cases are diagnosed annually, a number expected to double in the next 25 years. The condition is also becoming