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Published on: October 18, 2014
JT interval: What does this interval mean?
Wojciech Zareba1, Scott McNitt1, Slava Polonsky1
1The Heart Research Follow-up Program, Cardiology Division, University of Rochester Medical Center, Rochester, NY, United States.
Abstract:
The JTp interval gained interest as a marker differentiating effects of drugs on cardiac ion channels. For JTp interval, both the beginning - identification of J point and identification of T wave end remains the subject of substantial variability. We aimed to analyze diagnostic and prognostic performance of JTp interval in the International LQTS Registry data. ECGs from 804 gene carriers and 1139 non-carriers from LQT1 families, 735 carriers and 1145 non-carriers from LQT2 families, and 238 carriers and 554 non-carriers from LQT3 families were evaluated. The diagnostic performance of JTpc was similar to QTc in LQT1 and LQT3 patients but inferior in LQT2 patients, whereas repolarization duration in general had limited diagnostic performance in LQT3 patients. The prognostic significance for predicting cardiac events in LQT1 and LQT2 patients was similar for JTpc and QTc. In LQT3 patients, JTpc fails to be associated with arrhythmic events.
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