Supplementary Material for: Corrected QT Interval Prolongation in Psychopharmacological Treatment and Its Modulation by Genetic Variation

Several antipsychotics and antidepressants have been associated with electrocardiogram alterations, the most clinically relevant of which is the heart rate-corrected QT interval (QT<sub>c</sub>) prolongation, a risk factor for sudden cardiac death. Genetic variants influence drug-induced QT<sub>c</sub> prolongation and can provide valuable information for precision medicine. The effect of genetic variants on QT<sub>c</sub> prolongation as well as the possible interaction between polymorphisms and risk medications in determining QT<sub>c</sub> prolongation were investigated. Medications were classified according to their known risk of inducing QT<sub>c</sub> prolongation (high-to-moderate, low, and no risk). QT<sub>c</sub> duration and risk of QT<sub>c</sub> > median value were investigated in a sample of 77 patients with mood or psychotic disorders being treated with antidepressants and antipsychotics, and who had at least 1 ECG recording. A secondary analysis considered QT<sub>c</sub> percentage change in patients (<i>n</i> = 25) with 2 ECG recordings. Single-nucleotide polymorphisms previously associated with QT<sub>c</sub> prolongation during treatment with psychotropic medications were investigated. No association survived after multiple-testing correction. The best results for modulation of QT<sub>c</sub> duration were identified for rs10808071 (the <i>ABCB1</i> gene, nominal <i>p</i> = 0.007) when at least 1 medication with a moderate-to-high risk was prescribed, and for rs12029454 (the <i>NOS1AP</i> gene) in patients taking at least 1 medication with a cardiovascular risk (nominal <i>p</i> = 0.008). In the secondary analysis, rs2072413 (the <i>KCNH2</i> gene) was the top finding for the modulation of QT<sub>c</sub> percentage change (nominal <i>p</i> = 0.001) when 1 drug with a moderate-to-high risk was added compared to baseline. Despite the limited power of this study, our results suggest that <i>ABCB1</i>, <i>NOS1AP</i>, and <i>KCNH2</i> may play a role in QT<sub>c</sub> duration/prolongation during treatment with psychotropic drugs.