QTc Interval in psychiatric inpatients: A retrospective study

Introduction: Several psychotropic medications (i.e. antipsychotics, antidepressant) have been recently associated with QTc prolongation. Despite literature data report only mild prolongation of QTc following the use of antidepressants or typical antipsychotics, post-marketing studies have clearly evidenced an increased risk of QTc prolongation and potentially lethal arrhythmias (i.e. torsade de pointes) in psychiatric patients. Objectives: We aimed to evaluate the prevalence of prolonged QTc and to identify potential predictors influencing QTc in a psychiatric inpatient population. Methods: Medical records of 200 patients admitted to our psychiatric ward between 2007 and 2012 were retrospectively reviewed. Results: Prevalence of prolonged QTc at admission was very low (0.1%). No significant differences in QTc interval were observed between patients taking or not antipsychotics (P = 0.66), mood stabilizers (P = 0.36), or antidepressants (P = 0.07). A statistically significant difference was observed between patients on depot formulation and patients who were taking oral antipsychotic (P = 0.02). However, the pharmaceutical class of the medications appeared not significant. Conclusions: We observed a very low rate of QTc prolongation in psychiatric inpatients at admission. Surprisingly we did not find a significant effect of specific medications; however, in our sample intramuscular formulation was associated with lower QTc interval.