Assessment of ECG interval and restitution parameters in the canine model of short QT syndrome
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Updated: Jun 16, 2026
Methods for ECG Evaluation of Indicators of Cardiac Risk, and Susceptibility to Aconitine-induced Arrhythmias in Rats Following Status Epilepticus
Published on: April 5, 2011
Anusak Kijtawornrat1, Yaowalak Panyasing, Carlos Del Rio
1QTest Labs, LLC., 6438 Fiesta Dr, Columbus, OH 43235, USA.
Introduction:
The short QT syndrome (SQTS) is characterized by a short QT interval resulting from accelerated ventricular repolarization, and may be associated with ventricular fibrillation but not torsades de pointes. There are abundant data on the adverse effects of long QT, but knowledge of SQTS is sparse. The aim of this study was to examine whether analyses of several ECG biomarkers (QT, QTcB, QTcF, QTcV, QT(btb), and QT(RR1000)) and dynamic restitution of the beat-to-beat QT-TQ relationship (TQ(min), %QT/TQ ratio>1, QT/TQ ratio(max)) can be used to assess ECG changes in conscious dogs.
Methods:
Sling-trained dogs were infused with escalating concentration of levcromakalim (0, 1.0, 3.3, and 10.0 microg/kg/min), pinacidil (0, 3.3, 10.0, and 33.3 microg/kg/min), and nicorandil (0, 0.03, 0.1, and 0.3 mg/kg/min), drugs known to shorten QT. The RR, QT, QTcB, QTcF, QTcV, QT(RR1000), and TQ were measured before and after each concentration of the QT shortening test compounds.
Results:
Levcromakalim, pinacidil, and nicorandil but not vehicle significantly shortened RR, QT, QT(btb), QT(RR1000), and TQ but not QTc(B,F,V). The QT-RR cloud also shifted to the lower bounds of the normal QT-RR boundary by the test compounds. The percentage of beats with a QT/TQ ratio>1 was significantly increased in a dose response manner with levcromakalim and pinacidil and the lower TQ interval boundary (5th percentile) was decreased when compared to baseline or vehicle.
Discussion:
QT(btb), QT(RR1000), and dynamic beat-to-beat measurements of restitution constitute clinically applicable ECG biomarkers for assessment of changes associated with arrhythmogenic risk of ventricular fibrillation due to QT abbreviation.
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