Marilyn Eardley had just returned from a vigorous aqua fitness class and lunch with friends when the phone rang. Her daughter, calling for a run-of-the-mill chat, immediately became alarmed.
"She was panicking, but I didn't know what her problem was. I felt fine," Ms. Eardley said.
She wasn't fine. Her words were slurred and jumbled, her mouth drooping - classic signs of a stroke.
Ms. Eardley, 63, was rushed to the hospital and received clot-busting drugs. She has virtually no sequelae.
But the Oakville, Ont., woman still suffers from atrial fibrillation, an irregular heart rhythm that places sufferers at markedly higher risk of stroke.
"Atrial fibrillation is a fairly common condition but a lot of people are unaware they have the condition and many more are not treated," said Paul Dorian, a cardiologist and spokesman for the Heart and Stroke Foundation.
About 250,000 Canadians suffer from atrial fibrillation. Recent research shows that the condition increases the risk of stroke five-fold, but a mere 4 per cent of patients are aware of the danger.
"Stroke can be devastating. The best thing we can do is prevention," Dr. Dorian said.
He said treatment with warfarin, a commonly-used blood thinner often known by the brand name Coumadin, can reduce stroke risk for people with atrial fibrillation by about 80 per cent.
"Unfortunately, fewer than half of patients are getting treatment," Dr. Dorian said.
Atrial fibrillation is an electrical malfunction of the heart. The atria - small chambers of the heart - become scarred by heart disease or aging and that can cause the heart to beat very rapidly and irregularly.
When this occurs, a person usually feels their heart beating rapidly, along with palpitations and shortness of breath.
Meanwhile, inside the heart, blood swirls instead of flowing and this allows the formation of clots, creating the risk of stroke.
Ms. Eardley learned she suffered from atrial fibrillation eight years ago when her heart started racing while she was shopping. "My heart was pounding so fast I could see it," she said.
Most heart problems occur due to blockages in the arteries, in the plumbing; atrial fibrillation affects the heart's rhythm, an electrical problem.
It's also an intermittent condition. Mrs. Eardley, for example, has attacks 2-3 times monthly.
The difficulty is that the condition can only be diagnosed definitely during an attack, and a physician conducts an electrocardiogram test.
Also, about one-third of patients don't feel any discomfort at all when they are having an attack of atrial fibrillation, so the condition remains hidden, often until they have a stroke.
"One thing that seems illogical is that having a little atrial fibrillation is as much as a risk as having it all the time," Dr. Dorian noted. "It's important that you get treated even if you have it only once a month."
Hypertension, or high blood pressure, is the most common underlying cause of atrial fibrillation. Heart failure and diabetes are also risk factors.
The condition also increases with age: After the age of 55, the incidence of atrial fibrillation doubles with each decade of life
Cardiovascular disease is the Canada's top killer, claiming more than 70,000 lives annually. In addition, an estimated two million Canadians are living with the after-effects of heart disease or stroke.
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