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Background: Although QT prolongation is associated with increased risk of torsade de pointes (TdP), the precise relationship is not well defined.

Aim: To evaluate the performance of a QT nomogram in assessing the risk of TdP from QT–RR combinations.

Design: Systematic review.

Methods: We systematically searched MEDLINE/EMBASE for cases of drug-induced TdP. Controls were patients taking non-cardiotoxic drugs in overdose. Inclusion criteria were definite TdP, normal ECG before or after the event, association with a drug/toxin and QT–RR measurements available. The upper bound of a QT–RR cloud diagram developed from human preclinical studies was converted into a QT nomogram [QT vs. heart rate (HR)]. QT–HR combinations for TdP cases and controls were plotted with the QT nomogram, and curves corresponding to a QTc = 440 ms and QTc = 500 ms for …