Appearance of J wave in the inferolateral leads and ventricular fibrillation provoked by mild hypothermia in a patient with Brugada syndrome

J‐wave change during rewarming therapy for accidental hypothermia

“…Although previous studies suggested that the degree of hypothermia correlated with the height of J waves, 8,9 none of them reported the detailed and serial changes in the J‐wave amplitude and morphology during rewarming therapy for accidental hypothermia, which was secondary to a medical history of old cerebral infarction and dementia. J waves were observed at the R‐ST junction (J point) of the ECG, usually in leads II, III, aVR, and aVF, and the midlateral precordial leads 2,5,8 . Aizawa et al 10 reported that J waves were associated with fatal arrhythmia; the clinical significance of this association is under investigation.…”

“…Aizawa et al 10 reported that J waves were associated with fatal arrhythmia; the clinical significance of this association is under investigation. On the basis of cellular electrophysiology, J waves were caused by a more prominent Ito‐mediated spike‐and‐dome action potential morphology in ventricular epicardium than in endocardium 2,5,8 . Severe hypothermia could precipitate fatal arrhythmia and lead to a high mortality rate 7 .…”

“…They are observed in various pathological conditions 1,2 . Previous studies have reported a high prevalence of J wave as a risk marker for fatal arrhythmia under specific conditions, including idiopathic ventricular fibrillation, 2–4 Brugada syndrome, 2–4 vasospastic angina, acute myocardial infarction, and hypothermia 5 …”