People with an abnormal heart rhythm called atrial fibrillation (A fib) typically take powerful blood thinners to prevent strokes. However, those who suffered only short bouts of A fib – estimated at 20 seconds or less – were at no more risk for stroke or other heart complications than people without atrial fibrillation, a new study shows.
“Some patients have atrial fibrillation 100% of the time, while others might have only a few seconds of atrial fibrillation once a year,” explained study author Dr. Steven Swiryn. He’s a clinical professor of cardiology at the Feinberg School of Medicine at Northwestern University in Chicago.
“Where atrial fibrillation only happens rarely and lasts a short time, it can be difficult to detect,” Swiryn said.
Implanted devices such as pacemakers and defibrillators monitor a patient’s heart rhythm constantly, and they can spot short episodes of atrial fibrillation, he said.
“We can then more accurately answer the question, ‘How much atrial fibrillation does the patient have to have in order to be at risk of stroke and benefit from anticoagulation?’ Swiryn said.
The answer seems to be that patients with only short episodes of atrial fibrillation aren’t at enough risk for a stroke to warrant blood thinners, he said. “This allows physicians to avoid prescribing anticoagulation unnecessarily, since the risk of bleeding may be more than the benefit of stroke prevention,” Swiryn said.
Atrial fibrillation is the most common abnormal heart rhythm condition, and affects about 2.7 million Americans.
For the study, Swiryn and his colleagues looked at 37,000 EKGs from more than 5,000 patients over two years. All the participants took part in the RATE Registry, an ongoing study that follows patients with pacemakers or defibrillators.
While those with long episodes of atrial fibrillation were more likely to be hospitalized or die than those without the condition, those with short episodes were not, the study found.
The report was published Oct. 17 in the journal Circulation.
It’s unfortunate that patients have to have the additional health complications associated with the need for a pacemaker or defibrillator in order to evaluate the need for a blood thinner. This is a population with severe health compromise and I’m not sure you can extrapolate these findings to a heathier population with very occasional A fib.
Furthermore, there are previous studies that question the value of blood thinners for a majority of patients with A fib as the use of these drugs does not reduce the incidence of stroke.
Finally, I suspect that all of the patients in this study are being treated with polypharmacy, the use of at least five medications. The average number of medications is probably closer to 10 per person and medication effects were not factored into the study.
The Bottom Line:
Blood thinners as a preventative in patients with atrial fibrillation is of questionable valve and should be the last course of treatment rather than the first.
Source: October 18, 2016 National Institutes of Health