WPW (Wolff-Parkinson-White) Syndrome

This patient presented with episodic palpitations and lightheadedness. She was otherwise in excellent health. She presented to the emergency room with palpitations and had "SVT". WPW was diagnosed after the ECG shown below demonstrated the presence of a Delta wave when she was in sinus rhythm. WPW was confirmed and treated during electrophysiologic testing performed by Drs. Thomas Park and Greg Lewis

This is the initial surface ECG demonstrating preexcitation. It is a little subtle because she has relatively brisk AV nodal conduction, but is clearly evident in the lateral leads. Note the prominent R waves in the early precordial leads as well as the deep S wave in aVL consistent with a probably left sided accessory pathway.

This tracing was made with atrial pacing at 320 ms (183 bpm). Because of the decremental properties of the AV node, the faster you atrially pace, the more you will conduct down the accessory pathway. Thus, you see a marked wide complex right bundle-like pattern with maximal preexcitation again consistent with a left sided pathway.

This is the final tracing obtained after successful radiofrequency catheter ablation