Abstract 4138514: From Treatment to Trigger: A Case of Atomoxetine-Induced Brugada Pattern

Introduction: Brugada syndrome is an inherited cardiac disorder characterized by specific ECG patterns, notably the coved-type ST-segment elevation in the right precordial leads (V1-V3), leading to an increased risk of sudden cardiac death. This condition often stems from mutations in the SCN5A gene, which impair cardiac sodium channel function. The manifestation of Brugada Pattern, showing typical ECG findings without clinical criteria like sudden cardiac arrest or syncope, is significant. We highlight a case where atomoxetine, a selective norepinephrine reuptake inhibitor used for ADHD, unveiled a type 1 Brugada pattern. Case Presentation: A 26-year-old male with a history of ADHD on atomoxetine only presented to the emergency department with sudden substernal chest pain radiating to his left arm. His initial ECG showed right bundle branch block and type 1 Brugada pattern (Figure.1). Despite normal troponin levels and a negative coronary CT angiography, the patient's ECG abnormalities raised concerns. With no personal or familial history of arrhythmia or SCD and no other medications, atomoxetine was suspected as the trigger. Upon discontinuation, the patient's ECG type 1 Brugada pattern resolved (Figure. 2), and he remained asymptomatic with a normal Holter monitor at a 1-month follow-up. Discussion: Brugada syndrome is marked by dynamic ECG abnormalities, which can surface due to triggers like fever, certain medications, and electrolyte imbalances. Atomoxetine, an ADHD treatment and selective norepinephrine reuptake inhibitor, affects the human cardiac sodium channel (hNav1.5), encoded by the SCN5A gene. This interaction can disrupt heart action potentials, leading to conditions like long QT syndrome and Brugada pattern, by slowing cardiomyocyte depolarization and conduction. Its effect on hNav1.5 resembles that of antidepressants like Fluoxetine, increasing the risk of Brugada pattern. In our case, a patient's type 1 Brugada pattern, with no underlying heart disease or family history, pointed to atomoxetine as the cause. Discontinuing the drug resolved the ECG abnormalities. Conclusion: This case emphasizes the importance of assessing cardiovascular risk before prescribing atomoxetine, especially in individuals at risk for cardiac sodium channel dysfunctions. Immediate intervention and monitoring are critical to prevent severe arrhythmias.