2016 Volume 36 Issue 3 Pages 187-197
An 18-year old man collapsed while playing softball. He was resuscitated by a witness using an automatic external defibrillator (AED) and was transferred to a hospital. An analysis of the AED revealed that the cause of collapse was ventricular fibrillation. He was referred to our hospital for the purpose of catheter ablation. An accessory pathway in the lateral side of the mitral valve was detected in an electrophysiological study. The antegrade refractory period of this pathway was short enough (230msec) to fulfill the requirement for a high risk of sudden cardiac death. Tachycardia with a wide and narrow QRS was induced both by atrial extra stimulation. Neither pseudo ventricular tachycardia nor ventricular tachycardia could be confirmed. During a wide QRS tachycardia, a slow pathway and an accessory pathway were used as a retrograde and an antegrade pathyway, respectively. A narrow QRS tachycardia was still induced after ablation of the accessory pathway. After ablation of the retrograde slow pathway, no tachycardia was induced. Wide QRS tachycardia was diagnosed as an antidromic atrioventricular reentrant tachycardia from the above result.
