Antiarrhythmic drugs administered intravenously run the risk of producing a hemodynamic collapse even when used by expert and well trained hands. The arrhythmias in the focal point of a preexcitation syndrome constitute a very special situation in which extreme caution must be used when using intravenous drugs, because the conduction through accessory channels can vary, depending on multiple factors. We describe a case of a patient with an accessory atrioventricular pathway and orthodromic tachycardia who developed cardiac arrest by wide QRS tachycardia after receiving intravenous amiodarone.