Swallow-induced syncope in 5 patients: Electrophysiologic evaluation during swallowing

Background: We sought to characterize a cohort of participants with swallow-induced syncope (SIS) with clinical and electrophysiologic evaluations. Methods: Using electrocardiographic monitoring and neurophysiologic methods of swallowing, we evaluated a cohort of 5 patients with SIS, 4 of whom had longitudinal follow-up. Results: We determined electrophysiologically that the duration between the onset of swallow and a bradyarrhythmia or asystole is extremely short (2-3 seconds) in SIS. Most participants with SIS do not have a neurologic or esophageal disorder. SIS can occur with different food types, in sitting or standing position, and has varying frequency in different participants. Permanent pacemaker placement is a curative measure in SIS. Conclusions: Our findings suggest that SIS is elicited by reflex afferent pathways originating in the oropharynx, rather than an esophageal origin, as previously proposed. Our longitudinally followed cohort with detailed clinical and electrophysiologic characterization should aid the clinician in the diagnosis and treatment of this potentially life-threatening condition. © 2017 American Academy of Neurology