Abstract 4147606: The Risk of Cardiac Events Associated with Psychiatric Drugs in Patients with Long QT Syndrome.

Introduction: Long QT syndrome (LQTS) is a potentially life-threatening genetic heart disease. Patients with LQTS may also have co-existent mental health illnesses that may benefit from psychiatric medications. However, because many of these medications have QT-prolonging potential (www.crediblemeds.org), many of these patients receive suboptimal mental health care. Objective: To evaluate the frequency, management, and incidence of breakthrough cardiac events (BCEs) in patients with LQTS and concomitant mental health issues treated with psychiatric medications. Methods: A retrospective review was conducted on patients cared for in Mayo Clinic's Windland Smith Rice Genetic Heart Rhythm Clinic between 2000 and 2024 focusing on patients with LQTS and a concomitant psychiatric diagnosis requiring medication with known, possible or conditional risk of torsades de pointes (TdP). Electronic medical records were reviewed for data. BCEs were defined as LQTS-triggered syncope, seizures, appropriate ICD therapy, sudden cardiac arrest (SCA), or sudden cardiac death (SCD). Patients with missing information were excluded. Results: Overall, 195 /1899 LQTS patients [10%, 86 (43%) with LQT1, 83 (42%) with LQT2, and 16 (8%) with LQT3] had a concomitant psychiatric diagnosis requiring medication [150 female (76%), mean age at diagnosis 27 ± 18 years, median follow-up time 6.6 years (IQR 2.9-13)]. The most common psychiatric conditions were depression (71%), anxiety (62%), and ADHD (9%). The mean duration of therapy was 3.36 +/- 3.48 years and the most common medications used were fluoxetine (26%), sertraline (14%), and escitalopram (11%). There was no significant difference in QTc after starting the first psychiatric medication when compared to baseline (473 ± 33 vs 474 ± 35 ms, p=0.6). Prior to their LQTS diagnosis and while therefore untreated, 61/195 (31%) had at least 1 LQTS-associated cardiac event. This occurred in the setting of a psychiatric drug in 7 patients (11%). Following LQTS diagnosis and treatment, 14/195 patients (7%) have experienced a non-lethal BCE of which only 3/14 (21%) while on psychiatric medications. Conclusions: Although avoidance of medications with known QT-prolonging potential is prudent, attention to patient’s overall well-being besides just their LQTS must be given. After correct diagnosis and treatment, LQTS patients with concomitant mental health issues may be safely and effectively treated with medications known to prolong QTc.