Background: Although implantable cardiac monitors (ICM) demonstrate improved detection of atrial fibrillation (AF) relative to traditional Holter or other ambulatory cardiac monitors (ACMs, i.e. event monitors, patches, or MCOTs), their use and impact on risk of subsequent stroke remains uncertain.
Objective: To evaluate the use of ICM compared with Holters and ACMs and associated risk of subsequent stroke in the community setting.
Methods: The national, prospectively acquired MarketScan^® dataset was used to identify patients with 36 months of continuous database enrollment, 12 mos pre- and 24 mos post- receiving ICMs, Holter monitors, or ACMs. Post-monitoring incidences of new atrial fibrillation (AF), anticoagulation (AC) use, and stroke were identified in each group.
Results: Between 2004-2015, 982,620 patients met selection criteria. 670,360 received only a Holter, 302,425 an ACM, and 9,835 underwent ICM placement. ICM patients were older (62 vs 54 yrs [Holter], vs 52 yrs [ACM], p<0.001 for all) and demonstrated higher pre-existing AF (37% vs 15% [Holter] vs 21% [ACM]), history of stroke (47% vs 18% [Holter] vs 18% [ACM]), and history of heart failure (17% vs 9% [Holter] vs 8% [ACM]) (p<0.001 for all comparisons). ICM patients also had improved rate of AF detection, greater initiation of anticoagulation (AC), and greater risk of subsequent bleeding. The incidence of new strokes was comparable between groups (See Figure).
Conclusion: In the community setting, despite use in older and higher risk patients, ICMs were associated greater AF diagnosis, initiation of anticoagulation, and comparable risk of stroke as noninvasive cardiac monitoring, but with higher risk of bleeding.