TORONTO - The Canadian Cardiovascular Society has introduced a new set of guidelines for recognizing and treating patients who suffer from atrial fibrillation, or irregular heartbeat.
The condition -- sometimes asymptomatic, but often defined by heart palpitations -- affects about 250,000 Canadians, and increases the risk of stroke by three to five times.
Guidelines published Thursday in the Canadian Journal of Cardiology focus on recognizing the risk of stroke in patients with atrial fibrillation and using a new drug treatment -- an anticoagulant that's believed to be superior to the current standard treatment warfarin.
Dr. Laurent Macle, a cardiologist at the Montreal Heart Institute, said patients on warfarin need to have blood tests done to check anticoagulation levels every few weeks. Warfarin also interferes with many other drugs.
"This new drug does not have all these constraints, so you take this pill and your anticoagulation level is regular, and is predictable," said Macle, director of the institute's electrophysiology fellowship program.
He said a big study of the new drug -- dabigatran -- involving more than 18,000 patients compared it to warfarin and found a reduction in the risk of stroke.
"So the new guidelines mention that in patients who need oral anticoagulation, that we favour dabigatran over warfarin."
The drug is approved in Canada, but isn't reimbursed yet by many drug insurance plans -- although Macle suggested that will come in time.
"If you reduce the risk of stroke, then you save a lot of money compared to warfarin -- and if you don't need any blood tests all the time, and this and that, so economically, well, they have to prove it, but it's probably not more expensive than the usual warfarin."
Some people with atrial fibrillation don't have any symptoms, while others might have palpitations, reduced tolerance to exercise, heart failure, shortness of breath, angina or dizziness.
Patients with atrial fibrillation who aren't at risk of stroke would be treated with Aspirin according to the guidelines, Macle said.
Stroke risk factors for people with irregular heartbeat include age -- people over 75 are at higher risk -- having had a previous stroke, diabetes, high blood pressure or heart failure.
"Once we have these risk factors and they're identified, it's a stratification of Aspirin versus oral anticoagulation in these patients, and oral anticoagulation can be either dabigatran or Coumadin (warfarin), in favour of dabigatran."
Macle also noted that some people have infrequent arrhythmias -- every three or six months or so.
"In these patients instead of taking a medication every day to prevent that episode to occur in six months, then when it happens -- the episode -- they take a pill to try to stop the episode and only when it's needed," Macle said.
The updated guidelines include a new rhythm control therapy called dronedarone, which Macle said is safer than the four current medications -- notably in patients who are sicker.
And finally, a key change in the guidelines involves the treatment of atrial fibrillation through catheter ablation -- a procedure that involves cauterizing, or burning, an area in the left atrium of the heart, the area responsible for the arrhythmia.
The procedure has evolved over the years, and works about 75 to 80 per cent of the time to prevent recurrences, Macle said.
"This is why we go early to the intervention compared to before when we would try drugs and drugs and drugs. So now if you have a failure of one or two drugs, we can go to this procedure."
