A 6-year-old boy with secondary long QT syndrome

Abstract Secondary long QT syndrome (LQTS) is caused by several drugs, cardiac conditions, and noncardiac conditions. One of the main metabolic causes is hypokalemia. We experienced treating a boy with secondary LQTS due to primary aldosteronism. The boy had been followed annually since he was 6 years old because his resting electrocardiogram (ECG) showed a prolonged QT interval. When he was 9 years old, he developed general fatigue and myalgia. The QT interval in his resting ECG became longer and serum data indicated rhabdomyolysis. The aldosterone level was high and renin activity was low. He was diagnosed with primary aldosteronism. When we, pediatricians, see children with LQTS, we are apt to think that their condition is congenital in nature. However, secondary or acquired LQTS should be always taken into consideration and be excluded not only in adults but also in the pediatric population.