An 18-year-old student is admitted from a night club in a state of collapse

An 18-year-old student is admitted from a night club in a state of collapse. On admission to A&E his blood pressure is 90/45 mmHg, and he has a pulse of 190 per minute. ECG reveals a narrow complex tachycardia, which is terminated with adenosine. ECG after termination of the tachycardia reveals a PR interval of approximately 100 ms, and a slurred QRS complex with delta wave. What diagnosis fits best with this clinical picture?

  • Amphetamine overdose
  • Cocaine overdose
  • Hypokalaemia-induced arrhythmia
  • Wolff–Parkinson–White syndrome (WPW)
  • Lown–Ganong–Levine syndrome

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WPW syndrome (due to accessory cardiac conduction pathway) presents with paroxysmal tachycardias in 10% of patients aged 20–40 years, and 35% of sufferers aged over 60 years.
Common types of arrhythmia at presentation include reciprocating tachycardia at 150–250 bpm (80%), atrial fibrillation (15%) and atrial flutter (5%). Thankfully, presentation with ventricular tachycardia is rare. Prevalence in the UK population is around 0.15%, being more frequent in males. Most WPW patients have a normal heart structure, but there may be associated mitral valve prolapse, cardiomyopathy or Ebstein’s anomaly in certain patients. ECG abnormalities are characterised by the presence of a PR interval < 120 ms and a QRS complex >120 ms with slurred, slowly rising onset (delta wave). The Lown–Ganong–Levine syndrome is characterised by a short PR interval and normal QRS complex on ECG.
Narrow complex tachycardias may be terminated acutely with adenosine or verapamil or cardioversion. Digoxin should not be used as it may accelerate tachycardias. In the non-acute stage, radiofrequency ablation of the accessory pathway may be attempted.