The Risk of Breakthrough Cardiac Events Associated With Psychiatric Medications in Patients With Diagnosed and Clinically Treated Long QT Syndrome.

Background: Long QT syndrome (LQTS) is a potentially life-threatening genetic heart disease. Because many psychiatric medications have QT-prolonging potential, there is hesitation when prescribing them to LQTS patients with concomitant psychiatric disorders, which may lead to suboptimal mental health care.

Objectives: This study sought to evaluate the incidence of breakthrough cardiac events (BCEs) in patients with diagnosed and clinically treated LQTS on QT-prolonging psychiatric medications.

Methods: Review of LQTS patients seen at the Mayo Clinic between January 2000 and December 2023 with a concomitant psychiatric diagnosis requiring medications with a QT-prolonging potential was performed. Follow-up time was defined as time from first evaluation in our clinic to the last communication for any LQTS-associated BCEs.

Results: Among 195 of 1,787 patients (11%) placed on psychiatric drugs (150 [76%] female, mean age at LQTS diagnosis 27 ± 18 years), the most common psychiatric disorders were depression (141 [71%]) and anxiety (120 [62%]). The most common prescribed medications were fluoxetine (53 [26%]), sertraline (27 [14%]) and escitalopram (22 [11%]). Before their first Mayo Clinic evaluation, 61 of 195 patients (31%) had at least 1 BCE. This occurred while on psychiatric medications for 7 patients (11%). Following their first Mayo Clinic evaluation, 14 of 195 patients (7%) had at least 1 BCE. This occurred while on psychiatric medications for 3 patients (21%). The 3 events happened in the setting of other known arrhythmia triggers including treatment noncompliance and electrolyte abnormalities.

Conclusions: After correct diagnosis and treatment, LQTS patients with concomitant mental health issues may be safely and effectively treated with QT-prolonging psychiatric medications.