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Updated: Mar 18, 2026

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Published on: June 16, 2020
Microvolt T-wave alternans amplifies spatial dispersion of repolarization in human subjects with ischemic
Tilak Pasala1, Mary Dettmer1, Peter J Leo1
1Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, OH, USA.
Introduction:
In experimental models, spatial dispersion of repolarization (DOR) due to discordant cellular alternans predisposes to ventricular fibrillation. To test the hypothesis that microvolt T-wave alternans (MTWA) in humans causes spatial DOR, we measured Tpeak-Tend interval (Tpe) and Tpe/QT ratio, electrocardiographic indices of spatial DOR.
Methods:
Mean Tpe and Tpe/QT were compared in ischemic cardiomyopathy patients with positive and negative MTWA studies.
Results:
MTWA was positive in 12 and negative in 24 patients. Tpe and Tpe/QT were higher in MTWA+ subjects compared to MTWA- subjects during exercise (64.5±6.8 vs. 54.9±8.7ms, p=0.001 and 0.218±0.03 vs. 0.177±0.02, p=0.001) but not at rest.
Conclusion:
Ischemic cardiomyopathy patients have increased Tpe and Tpe/QT when MTWA is induced during exercise, suggesting that MTWA causes increased spatial DOR in humans. Future studies are needed to determine if Tpe and Tpe/QT during exercise might predict increased risk of SCD alone or in combination with measurement of MTWA.
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