Irregular wide complex tachycardia in a young man

A 19-year-old man presented to the emergency department with an episode of syncope, tachycardia, and hypotension. A 12-lead electrocardiogram showed rapid, irregular, wide complex tachycardia, a very rapid heart rate (up to 300 bpm in places), and there was a subtle beat-to-beat variation in the QRS width which is more typical of Wolff–Parkinson–White syndrome (WPW) associated with atrial fibrillation (Fig. 1). Fast atrial fibrillation could not be seen in any lead but instead atrial fibrillation was suggested by the completely irregular ventricular actions.

Figure 1.

Fast atrial fibrillation with irregular wide QRS tachycardia.

Elective cardioversion restored sinus rhythm. Subsequent electrocardiogram in sinus rhythm (Fig. 2) showed features of left-sided WPW accessory pathway, short PR interval, and delta waves, positive in V1, and negative in aVL. Successful radiofrequency ablation of the accessory pathway completely prevented further inducible atrial fibrillation.

Figure 2.

Electrocardiogram in sinus rhythm with short PR interval.

Atrial fibrillation with underlying WPW presents with irregular wide complex tachycardia, and can cause sudden cardiac death by precipitating ventricular fibrillation. The usual rate-slowing drugs used in atrial fibrillation are not effective, and digoxin and the nondihydropyridine calcium channel blockers (e.g., verapamil and diltiazem) are contraindicated because they may increase the ventricular rate and cause ventricular fibrillation. Irregular wide complex tachycardia may be the first presentation of this underlying conduction abnormality in young patients. Treatment of choice for WPW syndrome is radiofrequency ablation.

Disclosure: Author has nothing to disclose with regard to commercial support.