Background Several psychotropic drugs can induce QT prolongation, which is a well known risk factor for developing Torsade de Pointes (TdP) and sudden death. The clinical relevance of this side effect of psychotropic medication remains unclear, especially in patients hospitalised in an acute hospital.

Purpose To interpret the clinical importance of psychotropic drug induced QT prolongation, we investigated the prevalence of these electrocardiographic changes.

Material and methods A prospective study was conducted on four psychiatric wards in a general hospital: two acute short-term psychiatric units (ASP1 and ASP2), one additional service unit (ASU) and one geriatric–psychiatric ward (GPW). All adult patients admitted between 1 October 2015 and 15 March 2016 to a psychiatric ward were eligible for inclusion. At admission, an ECG (ECG0) was performed and creatinine and potassium levels were measured. A second ECG (ECG1) was performed at least 7days after the start of a psychotropic drug associated with a risk of QT prolongation.¹ QTc prolongation was defined as 470 ms for men and 480 ms for women. Clinically relevant QTc prolongation was defined as ≥500 ms.² Statistical analysis (R software) was done as appropriate.

Results 268 patients (mean age 55 years, 59% women) were enrolled in the analysis. In 85 patients, ECG1 was performed. QTc₀₊₁ were prolonged in 2.3% (5/220) of women and 3.7% (5/136) of men. No clinically relevant prolongation (≥500 ms) was registered. Higher QTc intervals were measured in the geriatric population. 28.5% (36/126) of all measured QTc (450≥QTc₀₊₁≤500 ms) occurred in the GPW versus 9.4% (22/233) in the other units. Significant difference in QTc changes was associated with sex (p=0.02246). There was no correlation between QTc prolongation and age, number of psychotropic drugs or a specific single psychotropic drug (p>0.05).

Conclusion In this study, QTc prolongation due to psychotropic drugs was less common than previously described.^{3 4} ECG monitoring may be unnecessary in the follow-up of patients without risk factors and could reduce hospital and community costs. However, considering the potential harm associated with TdP, QT prolongation should be avoided. We recommend recording an ECG before the start of a QT prolonging psychotropic drug in at risk patients: patients with chronic alcohol or drug addiction, cardiac history, on concomitant therapy with at least two QT prolonging psychotropic drugs, or in geriatric patients (>65 years).

References and/or acknowledgements

1. https://www.crediblemeds.org (January 2015).

2. Drew, et al. Circulation2010.

3. Girardin, et al. Am J Psychiatry2013.

4. Reilly, et al. The Lancet 2000.

References and/or acknowledgementsNo conflict of interest