title: Extreme QT prolongation during therapeutic hypothermia after cardiac arrest due to long QT syndrome.
abstract: During therapeutic hypothermia, QT interval is prolonged. In patients with congenital long QT syndrome (LQTs), a longer QT interval was associated with significantly increased risk of cardiac arrest (CA). Therefore, therapeutic hypothermia may have proarrhythmic effects in survivors of CA due to congenital LQTs. A 27-year-old man was resuscitated from CA due to congenital LQTs type 3 and Brugada syndrome. Torsade de pointes (TdP) recurred spontaneously on admission (body temperature, 36.9°C). During mild hypothermia therapy, QTc increased from 499 (36.9°C) to 667 milliseconds (33.8°C), although TdP was not induced. A 13-year-old boy with congenital LQTs type 1 underwent therapeutic hypothermia after resuscitation. Short-acting β-blocker was administered intravenously during this treatment. The QTc increased from 534 (36.4°C) to 626 milliseconds (34.3°C). However, TdP did not recur during mild hypothermia therapy. In both patients, electrolyte abnormalities were checked frequently and corrected immediately. QT prolongation remained a couple of days after completion of rewarming. The withdrawal of sedative drugs and extubation were not pursued before QT shortening reached to a plateau. Both patients were fully recovered from neurologic damage. During therapeutic hypothermia, QT interval was extremely prolonged, although TdP did not recur in 2 patients with congenital LQTs. Therapeutic hypothermia may be beneficial for comatose survivors of CA due to LQTs.
authors: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.
authors: Nobuhiro
authors: N
authors: Nishiyama
authors: Toshiaki
authors: T
authors: Sato
authors: Yoshiyasu
authors: Y
authors: Aizawa
authors: Satoshi
authors: S
authors: Nakagawa
authors: Hideaki
authors: H
authors: Kanki
mesh_terms: D000293:Adolescent; D000328:Adult; D004562:Electrocardiography; D006321:Heart / Q000503:physiopathology; D006323:Heart Arrest / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D007036:Hypothermia, Induced / Q000009:adverse effects*; D008133:Long QT Syndrome / Q000150:complications* / Q000209:etiology / Q000503:physiopathology; D008297:Male