Sudden cardiac arrest in a young adult with long QT syndrome and negative mutation studies

Abstract

Cardiac arrest in young healthy adults usually results from undiagnosed structural heartdisease or an undiagnosed predisposition to cardiac arrhythmias. We report a 19-year-old manwho developed a cardiac arrest while playing golf. He required cardiopulmonary resuscitationon 5 separate occasions and then was treated with targeted temperature management. Hisinitial laboratory tests included hypokalemia (2.5 mmol/L); he also had several episodes ofhypoglycemia during his intensive care unit stay. A serum insulin level was within normallimits, but a C-peptide level was increased. He had a long QT interval (QTc-551 ms) afterrewarming. Extensive cardiac workup was negative for structural abnormalities. In addition,mutation testing for channelopathies was negative. This patient recovered and has done well.This patient illustrates a case of sudden cardiac death in a young healthy adult who had a longQT syndrome but a negative mutation analysis. These patients might benefit from evaluationin specialized centers which can undertake additional genetic testing.