Sudden Onset of Broad Complex Tachycardia in a Fit Young Man: A Case Report.

Wolff-Parkinson-White (WPW) syndrome is a clinical pre-excitation syndrome often strongly associated with tachyarrhythmias that are predominantly atrioventricular re-entrant tachycardia (AVRT). It is generally considered to be a relatively benign arrhythmogenic condition associated with a slightly higher risk of sudden cardiac death (SCD) in comparison to the general population. Epidemiological data suggests that 0.1%-0.3% of the general population have electrocardiographic (ECG) findings suggesting that during sinus rhythm, in addition to atrioventricular (AV) conduction over the AV node-His bundle pathway, there is an additional atrioventricular conduction across an accessory pathway. Whilst in most cases, such phenomenon is associated with WPW syndrome, other similar conditions, including Lown-Ganong-Levine (LGL) syndrome and Mahaim-type pre-excitation, have also been documented. Our patient is a young man in his late twenties admitted with broad complex tachycardia at 252 beats per minute associated with diaphoresis and pre-syncope. In our case report, we describe how we managed this emergency, eventually unveiling the underlying aetiology as well as a stepwise approach to dealing with adult broad-complex tachycardia.