QT interval prolongation in the coronary intensive care unit: prevalence, associated drugs and clinical-genetic risk factors

We aimed to investigate the prevalence of QTc interval prolongation (QTcIP), QTc-prolonging drug exposure, and associated clinical and genetic risk factors in adult patients hospitalized in the Coronary Intensive Care Unit. This observational cohort study included 207 patients hospitalized for ≥24 h. Clinical, laboratory, and electrocardiographic data were analyzed, and QTcIP was defined using sex-specific thresholds (>470 ms in women, >450 ms in men). In addition, 33 genes were analyzed using an arrhythmia next-generation sequencing panel. QTcIP was detected in 31 patients (15.0%). Proton pump inhibitors were the most commonly used QTc-prolonging drugs (96.1%), while QTcIP was most frequently observed among patients receiving sertraline; however, the number of exposed patients was small. Acute coronary syndrome, myocardial infarction, and the presence of hypertension were significantly associated with QTcIP (p<0.05). In two patients with QTcIP, likely pathogenic, heterozygous variants were identified in the SCN5A and LMNA genes. In four additional patients, variants of unknown significance were detected in the RYR2, TTN, KCNH2, and GPD1L genes. These findings suggest that QTc prolongation in clinical practice may occur in the context of diverse clinical conditions and rare genetic variants. Careful clinical monitoring remains essential when initiating QTc-prolonging medications, particularly in patients with cardiovascular comorbidities.