Spontaneous conversion of supraventricular tachycardia followed by electromechanical dissociation.

We present this case to emphasize the potentially fatal outcome of supraventricular tachycardia in infancy, particularly if it has been undiagnosed for several days. Certainly, careful monitoring needs to take place during any attempt at cardioversion or any other noxious stimulation of the patient. Bicarbonate therapy should be provided if metabolic acidosis is present. Restoration of sinus rhythm may not guarantee an immediate return of normal cardiac function.