A 6-lead mobile ECG device successfully recorded QTc in 75% of clozapine-treated patients, showing a 3% to 9.3% prevalence of prolonged QTc and no significant correlation with clozapine plasma levels.
Cohort (n=184)
No
Does a 6-lead mobile ECG device provide feasible QTc monitoring, and does QTc correlate with clozapine plasma levels in patients with treatment-resistant schizophrenia?
Portable 6-lead ECG devices are feasible for routine QTc monitoring in clozapine-treated patients, though QTc prolongation prevalence varies by correction formula and does not significantly correlate with clozapine plasma levels.
Effect estimate: R2=0.038
p-value: p=0.19
Background and objetives: Cardiovascular risk assessment is crucial to reduce excess mortality in schizophrenia. We aimed to evaluate the use of a recently developed portable electrocardiography (ECG) device to measure the corrected QT interval (QTc) in a United Kingdom National Health Service (UK NHS) clinical setting and to explore its relationship with clozapine plasma levels. Methods: Electronic health records were reviewed over one year of routine clinical practice (Sep 2022–Sep 2023) in a cohort of clozapine-treated patients. Use of the portable ECG device and data from different QTc correction formulae were analysed. Correlations between QTc, clozapine dose, and plasma levels were tested. Results: A total of 300 consecutive clinical appointments were included, covering 184 patients. QTc was recorded in 75% (N=138) of patients. The prevalence of prolonged QTc varied by formula, ranging from 3% to 9.3% (N=9-28 patients depending on the QTc used formula). In 63 patients with plasma clozapine concentrations measured within two months of ECG, no significant correlation was found between clozapine levels and QTc interval (p=0.1). Conclusions: Portable ECG devices provide a simple and accessible tool for cardiac monitoring in patients on antipsychotics in routine clinical care. Our findings indicate a non-significant trend towards an association between QTc duration and plasma clozapine levels, highlighting the value of integrated monitoring strategies. Keywords: Treatment-resistant schizophrenia, QT interval, portable ECG device, clozapine, monitoring
Egea et al. (Fri,) conducted a cohort in Treatment-resistant schizophrenia (n=184). 6-lead mobile ECG device was evaluated on Correlation between QTc interval and plasma clozapine levels (R2=0.038, p=0.19). A 6-lead mobile ECG device successfully recorded QTc in 75% of clozapine-treated patients, showing a 3% to 9.3% prevalence of prolonged QTc and no significant correlation with clozapine plasma levels.