A method for constructing and estimating the RR-memory of the QT-interval and its inclusion in a multivariate biomarker for torsades de pointes risk.

The problem of drug-induced QT-interval prolongation has become a major economic and health issue in the pharmaceutical industry. Little has been done to link analytically the QT-interval prolongation and the risk of torsades de pointes. This paper introduces a method for analyzing the dynamic characteristics of a 24-hour electrocardiograph and offers an algorithm to measure the long-term memory of the RR-interval history in a single statistic. The memory statistic seems to improve the discrimination between healthy normal subjects and arrhythmia cases using only beat-to-beat information from the QT and RR intervals producing an impulse response function, which is completely independent of heart rate.