Occult T wave alternans in long QT syndrome

J Cardiovasc Electrophysiol. 1996 Feb;7(2):144-8. doi: 10.1111/j.1540-8167.1996.tb00509.x.


T wave alternans that is visually apparent on the ECG is a known risk factor for sudden death in idiopathic long QT syndrome (LQTS). To determine if occult and visually undetectable forms of T wave alternans are also present in LQTS, we measured T wave alternans from a 16-year-old girl with LQTS during exercise using spectral analysis methods and a recording system designed to minimize exercise-related noise. While there was no alternans at rest, statistically significant, yet visually inapparent T wave alternans were measured both during exercise and recovery. Using identical recording techniques, no significant T wave alternans was detected from the subject's mother, who had a prolonged QT interval but was not experiencing arrhythmias, nor from five healthy volunteers with normal QT intervals. This report suggests that electrocardiographically occult, yet prognostically important forms of T wave alternans may be present in patients with LQTS.

Publication types

  • Case Reports
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Electrocardiography
  • Exercise Test
  • Female
  • Humans
  • Long QT Syndrome / diagnosis
  • Long QT Syndrome / physiopathology*
  • Risk Factors