Coexistence of atrioventricular accessory pathways and drug‐induced type 1 Brugada pattern

Abstract

Abstract Background Atrial arrhythmias, particularly atrioventricular nodal reentrant tachycardia, can coexist with drug‐induced type 1 Brugada electrocardiogram (ECG) pattern (DI‐Type1‐BrP). The present study was designed to determine the prevalence of DI‐Type1‐BrP in patients with atrioventricular accessory pathways (AV‐APs) and to investigate the clinical, electrocardiographic, electrophysiologic, and genetic characteristics of these patients. Methods One‐hundred twenty‐four consecutive cases of AV‐APs and 84 controls underwent an ajmaline challenge test to unmask DI‐Type1‐BrP. Genetic screening and analysis was performed in 55 of the cases (19 with and 36 without DI‐Type1‐BrP). Results Patients with AV‐APs were significantly more likely than controls to have a Type1‐BrP unmasked (16.1 vs 4.8%, P = 0.012). At baseline, patients with DI‐Type1‐BrP had higher prevalence of chest pain, QR/rSr’ pattern in V 1 and QRS notching/slurring in V 2 and aVL during preexcitation, rSr’ pattern in V 1 ‐V 2 , and QRS notching/slurring in aVL during orthodromic atrioventricular reentrant tachycardia (AVRT) compared to patients without DI‐Type1‐BrP. Abnormal QRS configuration (QRS notching/slurring and/or fragmentation) in V 2 during preexcitation was present in all patients with DI‐Type1 BrP. The prevalence of spontaneous preexcited atrial fibrillation (AF) and history of AF were similar (15% vs 18.3%, P = 0.726) in patients with and without DI‐Type1‐BrP, respectively. The prevalence of mutations in Brugada‐susceptibility genes was higher (36.8% vs 8.3%, P = 0.02) in patients with DI‐Type1‐BrP compared to patients without DI‐Type1‐BrP. Conclusions DI‐Type1‐BrP is relatively common in patients with AV‐APs. We identify 12‐lead ECG characteristics during preexcitation and orthodromic AVRT that point to an underlying type1‐BrP, portending an increased probability for development of malignant arrhythmias.