Wide QRS complex tachycardia

Diagnostic Challenge

CJEM 2008;10(6):572-573

A 45-year-old man presented to the emergency department complaining of palpitations. He had no history of chest pain, shortness of breath, presyncope, diaphoresis or calf pain. He had no known structural heart disease or risk factors for atherosclerotic heart disease. The patient denied history of excessive caffeine intake, smoking or recreational drug use. Medications included celecoxib 100 mg twice daily and sotalol 160 mg twice daily. On examination, his blood pressure was 129/65 mm Hg, his pulse was 147 beats/min, his respiration rate was 20 breaths/min and his temperature was 36.5°C. Physical examination was unremarkable. The patient's initial electrocardiogram is shown in Figure 1. The on-call cardiologist was unavailable for consultation at the time.

The most likely mechanism for this patient's tachycardia and the most appropriate corresponding management are

1. supraventricular tachycardia with aberrant conduction; intravenous (IV) adenosine;
2. supraventricular tachycardia with aberrant conduction; IV verapamil;
3. ventricular tachycardia; electrical cardioversion with conscious sedation;
4. hyperkalemia; IV calcium gluconate and IV sodium bicarbonate;
5. tricyclic antidepressant overdose; IV sodium bicarbonate and activated charcoal by mouth;
6. torsades de pointes; stop sotalol, administer magnesium sulfate.

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