Open AccessHead-up tilt test induces T-wave alternans in long QT syndrome with KCNQ1 gene mutation
Author(s) -
Beiyin Gu,
Tingliang Liu,
Lei Yang,
Haiyan Zhang,
Yili Xin,
Jian Wang
Publication year - 2020
Publication title -
medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.59
H-Index - 148
eISSN - 1536-5964
pISSN - 0025-7974
DOI - 10.1097/md.0000000000019818
Subject(s) - medicine , qt interval , long qt syndrome , cardiology , electrocardiography , heart rate , t wave alternans , vasovagal syncope , sudden death , anesthesia , sudden cardiac death , syncope (phonology) , blood pressure
Long QT syndrome (LQTS) is a congenital disorder characterized by a prolongation of the QT interval on electrocardiograms (ECGs) and a propensity to ventricular tachyarrhythmias, which may lead to syncope, cardiac arrest, or sudden death. T-wave alternans (TWA) refers to the periodic beat-to-beat alternation of T-wave shape, polarity and amplitude on surface ECG during regular heart rhythm. In this report, a case of long QT syndrome with KCNQ1 gene mutation induced TWA in the head-up tilt test (HUTT), which has not been reported yet. Patient concerns: A 6-year-old boy presented with loss of consciousness twice, 5 months in duration. The boy's ECG showed prolonged QT interval (QTc = 600 ms, QTc = QT/RR 1/2 ). During HUTT test, QT interval was significantly prolonged (QTc = 716 ms) based on macroscopic TWA. Diagnosis: The patient was diagnosed with 1. Long QT syndrome type 1(LQT1); 2. Vasovagal syncope (VVS) Interventions: Metoprolol 12.5 mg was given orally twice a day. The child was told avoid standing for a long time and strenuous exercises. Outcomes: There was no syncope or arrhythmia occurred during hospitalization and follow-up for 1 year. Conclusions: VVS may exist in patients with long QT syndrome. Increased sympathetic tone during the early stage of HUTT may induce macroscopic TWA in long QT syndrome with KCNQ1 gene mutation.