Results from a study sponsored by Medtronic (NYSE:MDT), published today in the New England Journal of Medicine, found that the medical device company’s Reveal XT cardiac monitor bested conventional follow-up for detecting atrial fibrillation in patients who suffered a stroke of unknown origin.

The Crystal AF study, a randomized, controlled trial of 441 patients 40 years of age or older with no evidence of atrial fibrillation during at least 24 hours of ECG monitoring, set a primary endpoint of time to 1st detection of atrial fibrillation lasting more than 30 seconds within 6 months. Secondary endpoints included time to 1st detection of atrial fibrillation within 12 months.

At 6 months, the study found, atrial fibrillation was detected in 8.9% of the Reveal XT cohort (19 patients), compared with just 1.4% of the control group (3 patients). At 12 months, atrial fibrillation had been detected in 12.4% of the Reveal XT group (29 patients), compared with 2.0% of the control group (4 patients), according to the NEJM report.

"ECG monitoring with an [insertable cardiac monitor] was superior to conventional follow-up for detecting atrial fibrillation after cryptogenic stroke," the researchers wrote.

"The publication of these data further necessitates the need for us to reconsider our approach to patients with cryptogenic stroke. If we can pinpoint the cause of stroke, we then can apply the most appropriate treatment," Dr. Johannes Brachmann, of the Coburg Hospital in Germany and 1 of Crystal AF’s investigators, said in prepared remarks. "As AF is often intermittent and asymptomatic, we can’t rely on symptoms to decide who has AF or who needs ECG monitoring. Continuous monitoring of the heart rhythm can help us find those stroke patients whose AF is often missed with short-term monitoring. This can be explained by the amount of time that passes between episodes."