HANCOCK - People who have atrial fibrillation may not always feel symptoms, however, Dr. Sigurds Janners said, if the heart condition goes unnoticed, it can increase one's risk of stroke.
Atrial fibrillation, or AF, is defined as a type of irregular and often rapid heart rate that commonly causes poor blood flow to the rest of the body.
Janners oversees Portage Health's Cardiac Rehab clinic. "The four chambers of the heart are not beating synchronously,"?Janners said. He said the lack of synchronisity is caused by an electrical problem affecting the conduction system in the heart.
Kelly Fosness/Daily Mining Gazette
Cardiopulmonary nurse Rhiannon Schmidt checks the blood pressure of Ellen Varney of L’Anse in the cardiac rehab clinic of Portage Health Tuesday. Varney, who underwent a double lung transplant 16 years ago due to a hereditary disease called Alpha1-Antitrypsin Deficiency, was also diagnosed with atrial fibrillation tachycardia. For the past few years she’s been undergoing cardiac rehab at Portage Health in Hancock.
In AF, blood pools in the atria instead of pumping as it should. This can lead to the formation of blood clots in the heart, Janners said, which can cause strokes.
"In atrial fibrillation the atrium is contracting 300 times a minute," he said. "But we know that the normal heartbeat is 80 beats per minute."
AF is a disease that's much more common among the elderly. By age 80, Janners said approximately 10 to 12 percent of the population has AF and the causes are many.
"It could be because there's a structural problem to the heart, such as a blocked valve (aortic stenosis) or a leaky valve (mitral regurgitation)," he said. "Other causes ... would be thyroid problems. People with hyperthyroidism, or thyrotoxicosis, where their thyroids are overactive will stimulate the heart and make the heart go into atrial fibrillation."
AF is commonly discovered in patients during a routine physical exam. In that case, Janners said they must consider their options for either correcting or controlling AF in one way or another.
The process of diagnosing AF may involve a variety of tests including an electrocardiogram, or EKG, which measures the electrical impulses given off by the heart. Patients may also undergo an echocardiogram to detect any underlying structural heart disease.
Janners said the goals of treating AF are to control the heart rate and prevent a stroke.
"Your options are usually to thin the blood, or anticoagulate," he said, naming medications like cumudin and warfarin as examples. "Now there are some other drugs that have been coming out that are the next generation. Pradaxa would be an example of that."
The fallback would be simply taking aspirin to thin the blood, Janners said, although it's not recommended on its own as a management of AF and prevention of stroke.
To estimate a patient's risk of stroke, Janners said they use a "CHAD" score.
"That's based on age, diabetes, hypertension and previous heart failure or stroke," he said. "You add those factors up and you can determine what the risk of a stroke is."
For an individual who is younger than 75 and has none of the above factors, their risk is low.
"It's probably about 2 percent," Janners explained. "If you have all of those, it's closer to 20 percent and that would be a per year risk of stroke."
Another AF treatment option is cardioversion and that involves resetting the heart to its regular sinus rhythm.
A third option for management of AF ablation.
"That's where they put a catheter in the heart and they measure voltages, trying to find the area where the abnormal fast rhythm is going; where that conduction is going, and put a heater probe and cut the wire basically."
Calling the procedure "tricky and expensive," ablation is not commonly used.
"That would be a resort where everything is failing and you're having a hard time managing this either because you can't control the heart rate, they have some unusual problem with bleeding and they can't take blood thinners, or reasons they cannot take drugs," Janners said.