Brugada-type electrocardiogram in a patient with hypothyroidism

SummaryWe encountered a case of hypothyroidism showing Brugada-type electrocardiogram (ECG). A 52-year-old man was referred to our hospital in August 2009. Past medical history showed that liver dysfunction and face edema of unknown origin had been pointed out 1 year earlier. He was diagnosed with primary hypothyroidism at this admission. ECG exhibited first-degree atrio-ventricular block (0.24 s) and showed Brugada-type ST-segment elevation ≥2 mm followed by a negative T wave (coved type) in the V1, V2 leads. On genetic analysis, the patient demonstrated three common variants in the SCN5A gene, L1988R (c.5963 T>G), H558R (c.1673 A>G), and R1193Q (c.3578 G>A).Brugada-type ECG disappeared when the thyroid function normalized. We hypothesize that Brugada-type ECG in hypothyroidism is modified not only by a direct effect of thyroid hormone, but also due to SCN5A variants.Some SCN5A gene polymorphisms or mutations will induce changes on ECG when ion channels are affected by hypothyroidism.