Kewcharoen, Jakrin

Introduction: Brugada syndrome is associated with ventricular arrhythmia leading to sudden cardiac death. Risk stratification is challenging, as major arrhythmic events (MAE) are rare. We assessed the utility of drug challenge testing in Brugada syndrome by a systematic review and meta-analysis. Methods and results: We comprehensively searched the databases of MEDLINE and EMBASE from inception to May 2019. Included studies compared the incidence of MAE between spontaneous and drug challenge induced Type-1. Data were combined using the random-effects, generic inverse variance method, to calculate pooled incidence and odds ratio (OR). Mixed-effects Poisson regression was used to calculated incidence rate ratio (IRR). Eighteen studies from 2006 to 2018 were included (4,099 patients, mean follow-up 4.5 years). Pooled annual incidences of MAE in spontaneous, drug challenge induced (regardless of symptoms), asymptomatic drug challenge induced, and symptomatic drug challenge induced Type-1 were 23.8 (95% confidence interval [CI]: 19.8-27.8), 6.5 (95% CI: 3.9-9.1), 2.1 (95% CI: -0.3-4.4), and 19.6 (95% CI: 9.9-29.3) per 1,000 person-years respectively. The incidence of MAE between symptomatic drug challenge induced and asymptomatic spontaneous Type-1 was not statistically different (IRR=1.0, 95%CI: 0.6-1.7). The presence of ventricular tachyarrhythmia during drug challenge testing was a predictor of MAE (OR=3.73, 95% CI: 1.77-7.86, p=0.001). Conclusions: The incidence of MAE in drug challenge induced Type-1 in asymptomatic patients is low. The incidence of MAE between symptomatic drug challenge induced and asymptomatic spontaneous Type-1 was similar. Ventricular tachyarrhythmia during drug challenge testing could be a useful risk marker for MAE in Brugada syndrome.

AbstractBackgroundBrugada syndrome (BrS) is an inherited arrhythmic disease associated with an increased risk of major arrhythmic events (MAE). Previous studies reported that a wide QRS complex may be useful as a predictor of MAE in BrS patients. We aimed to assess the correlation of wide QRS complex with MAE by a systematic review and meta‐analysis.MethodsWe comprehensively searched the databases of MEDLINE and EMBASE from inception to June 2019. Included studies were cohort and case control studies that reported QRS duration and the relationship between wide QRS complex (>120 milliseconds) and MAE (sudden cardiac death, sudden cardiac arrest, ventricular fibrillation, sustained ventricular tachycardia, or appropriate shock). Data from each study were combined using the random‐effects model.ResultsTwenty‐two studies from 2007 to 2018 were included in this meta‐analysis involving 4,814 BrS patients. The mean age was 46.1 ± 12.8 years. The patients were predominately men (77.6%). Wide QRS duration was an independent predictor of MAE (pooled risk ratio 1.55, 95% confidence interval: 1.04‐2.30, P = .30, I2 = 38.4%). QRS duration was wider in BrS who had history of MAE (weight mean difference = 8.12 milliseconds, 95% confidence interval: 5.75‐10.51 milliseconds).ConclusionsOur study demonstrated that QRS duration is wider in BrS who had history of MAE, and a wide QRS complex is associated with 1.55 times higher risk of MAE in BrS populations. Wide QRS complex can be considered for risk stratification in prediction of MAE in patients with BrS, especially when considering implantable cardioverter‐defibrillator placement in asymptomatic patients.