Prolonged Cardiac Monitoring to Detect Atrial Fibrillation after Cryptogenic Stroke or Transient Ischemic Attack: A Meta-Analysis of Randomized Controlled Trials

Background: The cause of ischemic stroke or transient ischemic attack (TIA) remains unclear after initial cardiac monitoring in approximately one-third of patients. Randomized controlled trials (RCTs) showed that the prolonged cardiac monitoring of patients with cryptogenic stroke or TIA increased detection of atrial fibrillation (AF). We aimed to perform a meta-analysis of all RCTs that evaluated the prolonged monitoring ≥7 days in patients with cryptogenic stroke or TIA. Methods: We searched PubMed, EMBASE, Cochrane CENTRAL, and relevant references for RCTs without language restriction (inception through December 2014) and performed meta-analysis using random effects model. Detection of AF, use of anticoagulation at follow-up, recurrent stroke or TIA, and mortality were major outcomes. Results: Four RCTs with 1149 total patients were included in the meta-analysis. Prolonged cardiac monitoring ≥7 days compared to shorter cardiac monitoring of ≤48 hours duration increased the detection of AF (≥30 seconds duration) in patients after cryptogenic stroke or TIA (13.8% vs. 2.5%; odds ratio [OR], 6.4; 95% confidence interval [CI], 3.50–11.73; P < 0.00001; I², 0%]. It also increased the odds of AF detection of any duration (22.6% vs. 5.2%; 5.68[3.3–9.77]; P < 0.00001; I², 0%). The patients who underwent prolonged monitoring were more likely to be on anticoagulation at follow-up (2.21[1.52–3.21]; P < 0.0001; I², 0%). No differences in recurrent stroke or TIA (0.78[0.40–1.55]; P = 0.48; I², 0%) and mortality (1.33[0.29–6.00]; P = 0.71; I², 0%] were observed between two strategies. Conclusion: Prolonged cardiac monitoring improves detection of atrial fibrillation and anti-coagulation use after cryptogenic stroke or TIA and therefore should be considered instead of shorter duration of cardiac monitoring.