Failure of pacemaker therapy in a pediatric patient with neurally mediated complete heart block and syncope: A case report.

Neurally mediated syncope (NMS) is a well-known condition that can be subdivided into three subgroups: vasopressor type, cardioinhibitory type, and mixed type. While different degrees of sinus bradycardia occur at the time of syncope in all types, complete heart block is a rare event that can lead to pulselessness during syncope. We present a case of a 14-year-old girl with documented NMS before and after temporary pacemaker implantation, who had complete heart block during syncope. The patient's temporary pacemaker placement was ineffective in preventing syncope during a repeat head-up tilt test, indicating that permanent pacing may not be effective in this patient. Midodrine, an alpha-adrenergic agonist, was started, and the patient experienced complete control of syncope episodes without recurrence during a 2-month follow-up.