Relation of the Brugada Phenocopy to Hyperkalemia (from the International Registry on Brugada Phenocopy).

Brugada phenocopies (BrPs) are clinical entities that differ in etiology from true congenital Brugada syndrome but have identical electrocardiographic (ECG) patterns. Hyperkalemia is known to be one of the causes of BrP. The aim of this study was to determine the clinical characteristics and evolution of hyperkalemia-induced BrP. Data from 27 cases of hyperkalemia-induced BrP were collected from the International Registry at www.brugadaphenocopy.com. Data were extracted from publications. Of the 27 patients included in the analysis, 18 (67%) were male; mean age was 53 ± 15 years (range 31 to 89). Mean serum potassium concentration was 7.45 ± 0.89 mmol/L. Type-1 Brugada ECG pattern was observed in 21 cases (78%), whereas 6 cases (22%) showed a type-2 Brugada ECG pattern. The Brugada ECG pattern resolved once the hyperkalemia was corrected, with no arrhythmic events. Estimated time to resolution was 7 ± 3 hours. In 4 cases (16%), a concurrent metabolic abnormality was detected: 3 (11%) presented with acidosis, 2 (7%) with hyponatremia, 1 (4%) with hypocalcaemia, 1 (4%) with hyperphosphatemia, and 1 (4%) with hyperglycemia. In 7 cases (26%), provocative testing using sodium channel blockers was performed, and all failed to reproduce a BrS ECG pattern (BrP class A). Additionally, no sudden cardiac death or malignant ventricular arrhythmias were detected. Hyperkalemia was found a common cause of BrP in our International Registry. The Brugada ECG pattern appears to occur at high serum potassium concentrations (>6.5 mmol/L). The ECG normalizes within hours of correcting the electrolyte imbalance. Importantly, hyperkalemia-induced BrP has not been associated with sudden cardiac death or ventricular arrhythmia.