Pacemakers Can Detect Asymptomatic Atrial Fibrillation

New research provides further evidence that data collected by pacemakers can be used to speed the detection of atrial fibrillation (AF).

A study team identified 223 patients who had received pacemakers in the past 5 years. None of the patients had ever been diagnosed with AF at baseline, but analysis of data from the pacemakers detected at least 1 episode of AF in 27 (12%) of the patients. The researchers then calculated the CHA₂DS₂-VASc score of each of those 27 patients and found that all but 1 of them should begin taking anticoagulants to reduce the risk of stroke and other adverse events.

“The proportion of pacemaker patients with undiagnosed AF was higher than expected. Nearly all of them should have been receiving anticoagulation to prevent stroke. Pacemaker checks are simple to perform and our study shows that it is worthwhile using them to identify patients at risk,” said Nathan Denham, MD, a cardiologist at Warrington Hospital in the UK who presented the study findings at Acute Cardiovascular Care 2015.

Because pacemaker data from stable patients are checked only once a year in the UK, an average of 6 months elapsed between the first time a pacemaker detected signs of AF and the data analysis that led to the patient’s diagnosis, along with the recommendation to begin anticoagulation. In theory, a patient who first experienced AF the day after a checkup would wait an entire year for diagnosis — a fact that led the study authors to suggest further research into increased use of telemonitoring to diagnose AF and other problems.

Telemonitoring systems allow pacemakers to automatically transmit data over wireless networks, first to home computers and then to computers maintained by healthcare providers. Once captured on a provider computer, software could analyze the data for signs of AF.

“Telemonitoring would identify AF much earlier so that anticoagulation could be started," Denham said. "The fact that we found such a high proportion of patients with AF who should have been on anticoagulation suggests that telemonitoring is worth pursuing. Although we can't conclude this from our study, the cost of telemonitoring may be offset by the savings from preventing strokes.”

The British study is not the first to note the ability of pacemakers to detect AF. A study that appeared in Circulation more than a decade ago noted that pacemakers could be programed to detect atrial high rate events (AHREs) and that those events predicted AF stroke and death.

Of 312 patients in that study, 160 (51.3%) patients experienced at least 1 AHRE that lasted 5 minutes or longer during a median follow-up of 27 months. Cox proportional hazards analysis that adjusted for prognostic variables and baseline covariates then found AHCREs were an independent predictor of total mortality (hazard ratio [HR], 2.48; 95% confidence interval [CI], 1.25-4.91; p=0.0092); fatal or nonfatal stroke (HR, 2.79; 95% CI, 1.51-5.15; p=0.0011) and AF (HR,5.93; 95% CI, 2.88-12.2; p=0.0001).

A study that appeared a decade later in the Canadian Journal of Cardiology also found that pacemaker data could lead to the initial detection of AF in a significant percentage of users and that it could be used to see just how frequently AF occurred in patients prone to temporary heart arrhythmia.