Abstract 8640: Sudden Cardiac Death and Supraventricular Tachycardia Incidence in Patients with Asymptomatic Pre-excitation - A Meta-analysis

Abstract

Background: The risk of sudden cardiac death (SCD) and management of this risk in patients with asymptomatic pre-excitation is controversial. The purpose of this meta-analysis was to define the incidence of SCD and supraventricular tachycardia (SVT) in patients with asymptomatic pre-excitation. Methods: We performed a systematic search of prospective, retrospective, randomized or cohort, English language studies in EMBASE and Medline to February 2011. Inclusion criteria were studies of asymptomatic patients with pre-excitation who did not undergo ablation. When studies reported on symptomatic patients and/or catheter ablation of asymptomatic patients, only asymptomatic patients who did not undergo catheter ablation were included. Incidence of SCD/aborted SCD and incidence of SVT were extracted and pooled using a DerSimonian-Laird random effects model and fixed effects model to construct 95% confidence intervals (CI). Heterogeneity analyses were performed. Results: Twenty-one studies involving 12096 person-years (PYrs) of follow-up met our inclusion criteria. Follow-up ranged from a mean of 15 months to 21.8 years. Participants were primarily male (weighted average 67%). Mean ages in the studies ranged from 7 to 43 years. The weighted mean age was 26.5 years. SCD episodes were reported in 7 studies with 4283 PYrs of follow-up. Rates of SCD ranged from 0.7 to 8 per 1000 PYrs. No events were seen in 14 studies with a total follow-up of 7813 PYrs. Considering all patients the unadjusted rate was 1.1 SCD events per 1000 PYrs. We found moderate evidence of statistical heterogeneity (p=0.064, I 2 34.2%). Using a fixed effects model the SCD risk was estimated at 1.0 (95% CI: 0.5 to 1.7) per 1000 PYrs. Using a random effects model the risk of SCD is estimated at 1.6 (95% CI: 0.7 to 2.6) per 1000 PYrs. The development of SVT was described as an outcome in 19 studies involving 10258 PYrs. Rates in individual studies varied from 0 to 50 events per 1000 PYrs. There was no statistical evidence of heterogeneity (p<0.0001, I 2 85.3%). Using a random effects model, the overall risk of SVT was 18 (95% CI: 11 to 26) events per 1000 PYrs. Conclusions: The exceedingly low risk of SCD and low risk of SVT may argue for a conservative approach in managing patients with asymptomatic pre-excitation.