What Is Kim Soo Hyun's Heart Condition? Kim Soo Hyun Is a South Korean Actor Who Was Diagnosed with a Heart Condition at a Young Age. the Condition Is Called Arrhythmia, Which Is a Disorder of the Heart's Rhythm. Arrhythmia Can Cause the Heart to Beat Too Fast, Too Slow, or Irregularly. in Kim Soo Hyun's Case, His Arrhythmia Is Caused by a Condition Called Wolff-Parkinson-White Syndrome (Wpw). Wpw Is a Congenital Heart Defect That Causes an Extra Electrical Pathway Between the Heart's Atria and Ventricles. This Extra Pathway Can Cause the Heart to Beat Too Fast, Which Can Lead to Symptoms Such as Palpitations, Chest Pain, and Shortness of Breath.