Electrocardiographic variables associated with underlying Brugada syndrome or drug‐induced Type 1 Brugada pattern in patients with slow/fast atrioventricular nodal reentrant tachycardia

Background The coexistence of clinical atrioventricular nodal reentrant tachycardia (AVNRT) and drug‐induced type 1 Brugada pattern (DI‐Type 1 BrP) has been previously reported. The present study was designed to determine the 12‐lead ECG characteristics at baseline and during AVNRT and to identify a subset of 12‐lead ECG variables of benefit associated with underlying Brugada syndrome (BrS)/DI‐Type 1 BrP among patients with slow/fast AVNRT. Methods A total of 40 (11 numerical/29 categorical) 12‐lead ECG parameters were analyzed and compared between patients with ( n  = 69) and without ( n  = 104) BrS/DI‐Type1‐BrP matched for age, female gender, body mass index, left ventricular ejection fraction and comorbid conditions. Five distinct types of ECG pattern (Type A/B/C/D/E) in V1–V2 leads during AVNRT were defined. Results A total of nine electrocardiographic variables, four at baseline, and five during AVNRT were identified. At baseline, patients with BrS/DI‐Type 1 BrP had higher prevalence of interatrial block, leftward shift of frontal plane QRS axis, the absence of normal QRS pattern (the presence of rSr’ pattern or type 2/3 Brugada pattern) in V1–V2 and QRS fragmentation in inferior leads compared to patients without BrS/DI‐Type 1 BrP. During AVNRT, patients with BrS/DI‐Type 1 BrP had higher prevalence of Type A ECG pattern (“coved‐type” ST‐segment elevation) in V1–V2, Type C ECG pattern (pseudo‐r’ deflection in V 1 and “RBBB‐like” pattern in V 2 ), pseudo‐r’ deflection in V 1 , QRS fragmentation in inferior leads and “isolated” QRS fragmentation/notching/slurring in aVL compared to patients without BrS/DI‐Type 1 BrP. Conclusions We identify several electrocardiographic variables that point to an underlying type 1 BrP among patients with slow/fast AVNRT.