Determinants of severe QT(c) prolongation in a real-world gerontopsychiatric setting

INTRODUCTION: QT(c) prolongation carries the risk of ventricular tachyarrhythmia (Torsades de Pointes) and sudden cardiac death. Psychotropic drugs can affect ventricular repolarization and thus prolong the QT(c) interval. The present study sought to investigate the risk factors (pharmacological and non-pharmacological) of severe QT(c) prolongation in gerontopsychiatric patients. METHODS: Electrocardiograms of patients on a gerontopsychiatric ward were screened for QT(c) prolongation. Medication lists were examined utilizing the AzCERT classification. Potential drug interactions were identified with the electronic drug interaction program mediQ. RESULTS: The overall prevalence of QT(c) prolongation was 13.6%, with 1.9% displaying severe QT(c) prolongation (≥ 500 ms). No statistically significant differences between patients with moderate and severe QT(c) prolongation were identified; however, patients with severe QT(c) prolongation tended to take more drugs (p = 0.063). 92.7% of patients with QT(c) prolongation took at least one AzCERT-listed drug, most frequently risperidone and pantoprazole. Risperidone and pantoprazole, along with pipamperone, were also most frequently involved in potential drug interactions. All patients displayed additional risk factors for QT(c) prolongation, particularly cardiac diseases. CONCLUSION: In addition to the use of potentially QT(c)-prolonging drugs, other risk factors, especially cardiac diseases, appear to be relevant for the development of QT(c) prolongation in gerontopsychiatric patients. Pantoprazole was frequently involved in potential drug interactions and should generally not be used for more than 8 weeks in geriatric populations. As clinical consequences of QT(c) prolongation were rare, potentially QT(c)-prolonging drugs should not be used overcautiously; their therapeutic benefit should be considered as well. It is paramount to perform diligent benefit–risk analyses prior to the initiation of potentially QT(c)-prolonging drugs and to closely monitor their clinical (side) effects.