Complex mechanism of brugada phenocopy: moderate hyponatremia and right ventricular compression by liver metastatic tumor - case report.

Brugada phenocopy (BrP) occurs in various clinical conditions and manifests as a Brugada-like ECG pattern with coved (type 1) or saddle-back (type 2) ST-segment elevation in the right precordial leads. Unlike Brugada syndrome (BrS), which is an inherited channelopathy, BrP is not associated with an increased risk of malignant arrhythmia. BrP has been reported in severe metabolic disturbances (significant hyponatremia, hypokalemia or hyperkalemia), mechanical heart compression, coronary artery disease, pulmonary embolism and myocarditis/pericarditis. The authors described a case of a 69-year-old female whose Brugada-like ECG was atypically associated with only moderate hyponatremia (127 mmol/l). She was admitted due to a skin and subcutaneous tissue infection of the left shank and coexistent urinary tract infection (without a fever). She had the history of advanced melanoma with multiple liver metastases. Her cardiac history was negative, especially the patient has never suffered from ventricular arrhythmias. ECG on admission showed saddle-back ST-segment elevation in the right precordial leads; however, the patient did not report any chest pain. Troponin I level and left ventricular function in echocardiography were normal while regional longitudinal strain in RV apex was decreased and showed post-systolic shortening. The substernal view revealed compression of the right ventricle (RV) by liver metastatic tumor. ECG changes disappeared quickly during natrium chloride supplementation and did not recur during hospitalization. This case illustrates that even moderate hyponatremia may be a reversible cause of BrP when other predisposing conditions (e.g. heart compression by tumor) coexist.