Atrial fibrillation (Afib) is the most common form of heart arrhythmia, and doctors treating this condition are primarily concerned with preventing stroke. In an attempt to do so, warfarin or other blood-thinning drugs are often prescribed to ward off any blood clots that could contribute to stroke. Yet, for various reasons many people stop taking their medication, especially after receiving surgery intended to treat their arrhythmia.
"We don't know if changing the heart to a normal rhythm, by either cardioversion or ablation, always removes the risk of stroke," says Geoffrey Barnes, M.D., M.Sc. "It's an ongoing debate, whether to continue the patient on blood thinners after a procedure."
Barnes mentioned two procedures designed to address Afib. Electrical cardioversion shocks the heart back into a regular rhythm, and radiofrequency ablation scars the damaged parts of the heart to prevent dangerous rhythm in the first place.
However, Afib patients are more likely to stop taking warfarin if they have also recently received one of these procedures for the purpose of treating their arrhythmia. Researchers from the University of Michigan investigated this tendency, in a study of 734 Afib patients who began taking warfarin between 2011 and 2013. Within one year of the study, over one-third of the subjects were off of warfarin.
Many of these patients stopped taking warfarin after they received surgery. However, said study researcher James Froehlich, MD, PhD, “when someone's had a recent procedure, there may be good reason to interrupt anticoagulant therapy."
Less than 30 percent of the study participants stopped taking warfarin if they did not undergo any Afib surgeries. But what about the minority who stopped taking warfarin even though they didn’t receive any procedure for their Afib? Researchers have yet to completely understand, but some explanations could be doctor recommendations, side effects, or a simple aversion to regular blood draws.
Regardless of the case, Froehlich stressed the importance of communicating to patients the danger of stopping treatment for Afib, given the risk for stroke. "We need to understand why they are stopping warfarin and figure out what other medications might be better adhered to in order to prevent strokes.”
Froehlich’s study was recently published in JAMA Cardiology.