Sudden cardiac arrest in a young adult with long QT syndrome and negative mutation studies
Cardiac arrest in young healthy adults usually results from undiagnosed structural heart
disease or an undiagnosed predisposition to cardiac arrhythmias. We report a 19-year-old man
who developed a cardiac arrest while playing golf. He required cardiopulmonary resuscitation
on 5 separate occasions and then was treated with targeted temperature management. His
initial laboratory tests included hypokalemia (2.5 mmol/L); he also had several episodes of
hypoglycemia during his intensive care unit stay. A serum insulin level was within normal
limits, but a C-peptide level was increased. He had a long QT interval (QTc-551 ms) after
rewarming. 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 long
QT syndrome but a negative mutation analysis. These patients might benefit from evaluation
in specialized centers which can undertake additional genetic testing.
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