Hooke, Patrick

Introduction: Drug challenge testing is performed to unmask Type-1 Brugada pattern. The safety and prevalence of its complications during the test are unclear. We aimed to assess the relation of complications in patients with positive and negative results by a systematic review and meta-analysis. Hypothesis: The prevalence of arrhythmic complications is higher in patients with positive drug challenge testing. Methods: We comprehensively searched the databases of MEDLINE and EMBASE from inception to June 2020. Included studies were cohort studies that reported ventricular arrhythmia that required interventions (VAI) (sustained ventricular tachycardia [VT], polymorphic VT, ventricular fibrillation, appropriate implantable cardioverter defibrillator [ICD] shock, or sudden cardiac arrest) and ventricular arrhythmias that did not required interventions (VANI) (premature ventricular complexes and non-sustained VT) during drug challenge testing. Data were combined using the random-effects model. Results: Thirteen studies involving 2,688 patients (62.7% positive) were included. The overall prevalence of VAI and VANI were 3.7% (95% confidence interval [CI]: 1.8-5.7) and 0.5% (95% CI: 0.1-0.9), respectively. VAI were more common in positive when compared to negative test result patients (1.5% [95% CI: 0.6-2.4] and 0%, respectively) but the prevalence of VANI were similar (2.7% [95% CI: 0.8-4.6] and 2.6% [95% CI: 0.8-4.6], respectively). VAI in positive result patients were more common with flecainide followed by pilsicainide and ajmaline (2.4% [95% CI: -4.3 to 9.2], 2.2% [95% CI: 0.5-4.0], and 1.5% [95% CI: 0.6 to 2.4], respectively). Most of patients with VAI during drug challenge testing underwent ICD implantation (94%). VAI during drug challenge testing in positive result patients carries an increased risk of VAI during 8.6 ± 4.9 years follow-up (odds ratio 3.73, 95% CI: 1.77-7.86, p=0.001). Conclusions: VAI were more common in patients with positive drug challenge testing, more often occurring with positive flecainide challenge, and carries an increased risk of VAI over long-term follow-up in patients with positive drug challenge testing.