No abstract

Delivery of ICD therapy in AVID patients was common, primarily due to VT. Inappropriate ICD therapy occurred frequently. Use of ICD therapy as a surrogate endpoint for death in clinical trials should be avoided.

Background: Device-detected atrial fibrillation (AF) is associated with increased risk of stroke; however, there are no clearly defined thresholds of AF burden at which to initiate oral anticoagulation (OAC). We sought to describe OAC prescription practice variation in response to new device-detected AF and the association with outcomes. Methods: We performed a retrospective cohort study using data from the Veterans Health Administration linked to remote monitoring data that included day-level AF burden. We included patients with cardiac implantable electronic devices and remote monitoring from 2011 to 2014, CHA 2 DS 2 -VASc score ≥2, and no prior stroke or OAC receipt in the preceding 2 years. We determined the proportion of patients prescribed OAC within 90 days after new device-detected AF across a range of AF thresholds (≥6 minutes to >24 hours) and examined site variation in OAC prescription. We used multivariable Cox proportional hazards regressions to determine the association of OAC prescription with stroke by device-detected AF burden. Results: Among 10 212 patients with cardiac implantable electronic devices, 4570 (45%), 3969 (39%), 3263 (32%), and 2469 (24%) had device-detected AF >6 minutes, >1 hour, >6 hours, and >24 hours, respectively. For device-detected AF >1 hour, 1712 patients met inclusion criteria (72±10 years; 1.5% female; CHA 2 DS 2 -VASc score 4.0±1.4; HAS-BLED score 2.6±1.1). The proportion receiving OAC varied based on device-detected AF burden (≥6 minutes: 272/2101 [13%]; >1 hour: 273/1712 [16%]; >6 hours: 263/1279 [21%]; >24 hours: 224/818 [27%]). Across 52 sites (N=1329 patients), there was substantial site-level variation in OAC prescription after device-detected AF >1 hour (median, 16%; range, 3%–67%; median odds ratio, 1.56 [95% credible interval, 1.49–1.71]). In adjusted models, OAC prescription after device-detected AF >24 hours was associated with reduced stroke risk (hazard ratio, 0.28; 95% CI, 0.10–0.81; P =0.02), although the propensity-adjusted model was significant when AF lasted at least 6 minutes. Conclusions: Among veterans with cardiac implantable electronic devices, device-detected AF is common. There is large practice variation in 90-day OAC initiation after new device-detected AF, with low rates of treatment overall, even for episodes that last >24 hours. The strongest association of OAC with reduction in stroke was observed after device-detected AF >24 hours. Randomized trials are needed to confirm these observational findings.

The atrial effective refractory period increases, sinus node function improves, and atrial conduction velocity goes up in the first week after cardioversion of long-standing atrial fibrillation in humans. Reverse electrical remodeling of the effective refractory period occurs at different rates in different regions of the atrium.