ASSERT links pacemakers with increased risk of ischemic stroke

Sub-clinical atrial tachyarrhythmias without clinical atrial fibrillation (AF) occurred frequently in patients with pacemakers and were associated with a significantly increased risk of ischemic stroke or systemic embolism, according to a recent study.

The ASymptomatic AF and Stroke Evaluation in Pacemaker Patients and the AF Reduction Atrial Pacing Trial (ASSERT) was published January 12 in the New England Journal of Medicine.

One-quarter of strokes are of unknown cause, and sub-clinical AF may be a common etiologic factor. Pacemakers can detect sub-clinical episodes of rapid atrial rate, which correlate with electrocardiographically documented AF.

The study evaluated whether sub-clinical episodes of rapid atrial rate detected by implanted devices were associated with an increased risk of ischemic stroke in patients who did not have other evidence of AF.

Investigators enrolled 2,580 patients aged 65 years and older with hypertension and no history of AF and who recently received a pacemaker or defibrillator and monitored them for 3 months.

By 3 months, sub-clinical atrial tachyarrhythmias detected by implanted devices had occurred in 261 patients (10.1%). Sub-clinical atrial tachyarrhythmias were associated with an increased risk of clinical AF and of ischemic stroke or systemic embolism. Of 51 patients who had a primary outcome event, 11 had sub-clinical atrial tachyarrhythmias detected by 3 months, and none had clinical AF by 3 months.

Investigators in this study were financially supported by St. Jude Medical, as well as other pharmaceutical and medical device companies.