Use of Corrected QT Cutoffs Derived from Biological Variation to Predict Adverse Events Due to Antipsychotic Drugs: Case Report

Figures

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  Figure A. Corrected QT results during a well-controlled disease period. The mean of four readings was 432 milliseconds (msec). Adding the reference change value (6.4% or 27 msec), the individualized cutoff point for QTc prolongation is 460 msec. QTc, corrected QT; msec, milliseconds; RCV, reference change value.

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  Figure B. Corrected QT measurements during periods of chest pain from October 2019–March 2021. The line denotes this patient’s cutoff of 460 milliseconds and the * denotes those values that exceed that reference change value. Note: The time axis is not to scale, and the QTc results between readings are not necessarily linear. msec, milliseconds; QTc, corrected QT.

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  Figure C. Corrected QT measurements during periods of chest pain from September 2023–August 2024. The line denotes this patient’s cutoff of 460 msec and those values above it that exceed that reference change value. Note: The time axis is not to scale, and the QTc results between readings are not necessarily linear. msec, milliseconds; QTc, corrected QT.

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  Figure D. Corrected QT measurements during periods of chest pain from October 2024–April 2025. The line denotes this patient’s cutoff of 460 milliseconds, and those values above that line exceed that reference change value. Note: The time axis is not to scale and the QTc results between readings are not necessarily linear. QTc, corrected QT; msec, milliseconds.