QTc-interval abnormalities in a forensic population

Antipsychotic drugs have been linked to sudden death among psychiatric patients, with a suggestion that prolongation of the QT-interval detectable on a standard electrocardiogram may be linked to fatal cardiac arrhythmias in these circumstances. Patients in secure forensic psychiatric facilities may be particularly likely to be on high-dose antipsychotic medication, and yet, as far as the authors are aware, no study of QT-intervals among such patients has been reported.

To investigate the prevalence of QT-interval abnormalities and associated known risk factors for fatal cardiac arrhythmias in a sample of forensic patients.

Participants had a 12-lead electrocardiogram taken at 50 mm/s. Information was collected on their age, gender, psychiatric diagnosis, history of cardiovascular, liver and kidney diseases, and smoking, on all medications and on history of seclusion over the previous 12 months. Analysis was carried out using binary logistic regression.

Lower rates of QT-interval abnormalities than might be expected for this population were found. It was also found that a high dose of antipsychotics was associated with QTc prolongation (Adjusted OR = 9.5, 95% CI 2.6-34.2), a result consistent with previous literature.

Forensic patients need not be at increased risk of QTc abnormality provided risk factors are properly managed. A high dose of antipsychotic medication increases the risk of QTc prolongation.