Open-loop, clockwise QT-RR hysteresis immediately before the onset of torsades de pointes in type 2 long QT syndrome

Gen Nakaji, Masahiko Fujiwara, Mitsuhiro Fukata, Shioto Yasuda, Keita Odashiro, Toru Maruyama, Koichi Akashi

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Delay of QT interval adaptation to sudden heart rate change causes hysteresis in dynamic QT-RR relationship. We analyzed QT-RR plotting during and after exercise in a patient with genetically identified type 2 long QT syndrome before and after starting oral propranolol. Blunted QT shortening by exercise and augmented postexercise QT prolongation resulted in an open-loop, clockwise QT-RR hysteresis immediately before the onset of torsades de pointes before propranolol. However, this hysteresis was eliminated by propranolol. QT-RR analysis provided insight into the mechanisms of the onset of torsades de pointes at least in this case of type 2 long QT syndrome.

Original languageEnglish
Pages (from-to)261-263
Number of pages3
JournalJournal of Electrocardiology
Volume43
Issue number3
DOIs
Publication statusPublished - May 2010

All Science Journal Classification (ASJC) codes

  • Cardiology and Cardiovascular Medicine

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