Temporal variability in occasional drug-induced type 1 Brugada pattern

Brugada syndrome (BrS) is an ion channelopathy that results in characteristic electrocardiographic (ECG) changes and predisposes to sudden cardiac death (SCD). The SCD risk stratification is influenced by many factors, primarily the ECG pattern and symptoms presented [1]. Asymptomatic patients are considered to be of relatively low risk, especially those with drug-induced Brugada pattern without other risk factors (VF, syncope, etc.) [2]. It is well known that Brugada pattern (BrP) temporal variability is associated with event risk increase (higher temporal of type 1 ST-segment elevation in the 24-hour monitoring period seems to be associated with cardiac events) [3]. However, no cases of BrP variability related to heart rhythm are described.
A 68-year-old man was scheduled for paroxysmal atrial fibrillation (AF) ablation (mEHRA score 2b). No drug attempts were made before the procedure, and no family SCD history or syncope were reported in the medical history. We performed AF ablation, under conscious sedation with intermittent midazolam and fentanyl administration, with isolation of pulmonary veins using the CARTO electroanatomic mapping system, Thermocool Smarttouch SF Catheter and Pentaray catheter (Biosense Webster, Inc.). At the end of the procedure, sustained atrial fibrillation was triggered (Figure 1 A). Therefore, having not planned further treatments in the left atrium and having already withdrawn the catheters in the right atrium, we decided to administer flecainide 2 mg/kg over 10 min. After 3 min ECG gradually showed the ST segment coved-type elevation in V1–V2. Then we moved the V5-V6 electrodes to the second intercostal space continuing the infusion according to the protocol. At the end of the infusion, a clear BrP was observed, particularly evident in the V2 derivation shorter RR longer beats, but at arrhythmia interruption, the pattern surprisingly disappeared (Figure 1 B), and then gradually reappeared after 50 s with a diagnostic BrP (Figure 1 C). Based on the patient’s clinical history, the occasional drug-induced BrP finding and considering him to be at low risk of SCD, we decided to evaluate the follow-up without performing an electrophysiological study (EPS). The patient was therefore discharged without antiarrhythmic therapy, with the indication for family electrocardiographic screening and compliance with behavioral rules.
Several hypotheses have been proposed to explain the pathophysiology behind BrS. The...


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