A new approach to measure ventricular repolarization duration in 24-hour Holter ECG based on T-wave morphology classification

The interval from the Q onset to the T wave apex (Q-aT) is known to be heart rate dependent. this study investigated the relation between Q-aT and R-R interval in the case where the T waves have complicated morphology. Holter ECGs recorded from one normal subject and three patients with long QT syndrome were used for the investigation. It is found that when the T wave is monophasic, Q-aT is well correlated to Q-T interval. On the other hand, if the T wave is biphasic or bipolar, the correlation between Q-aT1 (the interval from Q onset to the first T maximum) and conventional Q-T is poor, but Q-aT2 (the interval from Q onset to the second T maximum) is well correlated with conventional Q-T. This study suggests that by taking T wave morphology into consideration, Q-aT is possible to be used for the investigation of ventricular repolarization duration.<>