Weng M, et al. - The risk of recurrent cardiac arrhythmic events (CAEs) associated with antidepressant drugs (ADs) was investigated in long QT Syndrome (LQTS) patients. LQT1 patients had a higher risk of recurrent CAEs associated with time-dependent ADs, while this was not found to be true in LQT2 patients. Overall, findings indicated a LQTS genotype-specific impact of ADs on the risk of arrhythmic events.

Methods

• Researchers performed this study on 59 LQT1 and 72 LQT2 patients from the Rochester-based LQTS Registry with QTc prolongation and a history of AD therapy.
• They used multivariate Anderson-Gill models to estimate the LQTS genotype specific risk of recurrent CAEs (ventricular tachyarrhythmias, aborted cardiac arrest, or sudden cardiac death) associated with time-dependent ADs.
• Specifically, they assessed the risk associated with all ADs, SSRIs, and ADs classified on the CredibleMeds list (www.CredibleMeds.org) as “Conditional” or “Known risk of Torsades de pointe (TdP)”.

Results

• Findings demonstrated that LQT1 patients were at increased risk of recurrent CAEs associated with Ads, after adjusting for baseline QTc, sex, and time-dependent beta blocker usage (HR=3.00, 95%CI: 1.55-5.84, p=0.001), but this was not found in LQT2 patients (HR=1.05, 95%CI: 0.56-1.99, p=0.872; LQT1 vs LQT2 interaction, p<0.001).
• Similarly, a higher risk of recurrent CAEs was reported in LQT1 patients who were on SSRIs or ADs with “Known risk of TdP” than those off all ADs, whereas there was no association in LQT2 patients.
• Researchers noted that ADs with “Conditional risk of TdP” were not related to the risk of recurrent CAEs in any of the groups.