A Reminder of Treatments Past

Abstract

The Wolff-Parkinson-White (WPW) syndrome was initially described in 1930 as a clinical syndrome of paroxysmal tachycardias in healthy young people that demonstrated bundle-branch block and short P-R interval. These tachycardias were eventually determined to be macro-reentrant arrhythmias utilizing accessory pathways. Surgical approaches for transecting these accessory pathways were being developed as early as the 1960s. Since 1984, catheter ablation has developed into a safe and highly effective therapy option, and the treatment of choice for WPW syndrome today. We present a unique case of a patient with previous surgically treated WPW syndrome that serves as a reminder of treatments past and caution for current therapies. A 54-year-old man with a remote history of WPW syndrome, treated in 1989 with surgical cryoablation of a left ventricular free wall accessory pathway, now presented with an hour of sustained palpitations after a triathlon practice session. He was found to have ventricular tachycardia at a rate of 180 bpm on EKG requiring external cardioversion. The troponin I level peaked at 2.59 ng/mL. Left heart catheterization revealed a peculiar truncated 100% occlusion of the proximal circumflex artery with extensive bridging collaterals to the mid circumflex artery, and also confirmed an infero-basal aneurysm. The cause of the ventricular tachycardia (VT) was deemed non-ischemic and he was referred for electrophysiology study. 3D electroanatomic mapping of the left ventricular (LV) endocardial surface was performed, revealing a discrete posterior wall scar. Reentrant VT was repeatedly induced utilizing a zone of slow conduction along the border zone of the scar. Radiofrequency ablation of Purkinje potentials on the LV septum, running alongside the scar border zone, eliminated the VT. The entire endocardial surface of the postero-basal scar was electrically silenced to prevent further VT events. Typically, during the surgical approach of WPW, a wide endocardial (rarely an epicardial) incision was made along the atrial surface of the mitral valve annulus, dissecting deeply and caudally until ventricular myocardium was exposed. Despite the close proximity of the circumflex artery to the epicardial incision line during these surgeries, there are only rare reports of coronary artery complications, generally considered to be either catheter-induced dissections or embolic events. The development of a network of extensive bridging collaterals in our patient supports progressive stenosis of the left circumflex artery from cryoablation thermic injury, leading to scar formation and VT years later. In conclusion, this case reminds us that current ablative therapies are still relatively new, and long-term follow-ups for delayed complications remain a necessity.




J Med Cases. 2016;7(6):216-219
doi: https://doi.org/10.14740/jmc2488w