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Gastric myoelectrical and neurohormonal changes associated with nausea during tilt‐induced syncope
Author(s) -
Heyer G. L.,
Boles L. H.,
Harvey R. A.,
Cismowski M. J.
Publication year - 2018
Publication title -
neurogastroenterology and motility
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.489
H-Index - 105
eISSN - 1365-2982
pISSN - 1350-1925
DOI - 10.1111/nmo.13220
Subject(s) - nausea , medicine , syncope (phonology) , tilt table test , epinephrine , vasopressin , anesthesia , vasovagal syncope , blood pressure , cardiology , heart rate
Background Nausea is a common prodromal symptom of neurally mediated syncope, but the biological factors linking nausea with syncope have not been studied. We aimed to characterize nausea during tilt‐induced syncope by exploring related changes in gastric myoelectrical activity and plasma epinephrine, norepinephrine, and vasopressin concentrations across study phases of recumbency, tilt, syncope, and recovery. Methods Electrogastrographic and plasma hormone changes were compared between patients with tilt‐induced syncope and nausea (n = 18) and control subjects (n = 6) without symptoms or hemodynamic changes during tilt‐table testing. Key Results Over a 4‐minute period preceding syncope, sequential electrogastrography epochs demonstrated an increase over time in bradygastria ( P = .003) and tachygastria ( P = .014) power ratios, while the dominant frequency ( P < .001) and the percent normogastria ( P = .004) decreased. Syncope led to significant differences between cases and controls in electrogastrographic power ratios in each frequency range: bradygastria ( P = .001), tachygastria ( P = .005), and normogastria ( P = .03). Nausea always followed electrogastrographic changes, and nausea resolution always preceded electrogastrographic normalization. Plasma vasopressin (676.5 ± 122.8 vs 91.2 ± 15.3 pg/ mL , P = .012) and epinephrine (434 ± 91.3 vs 48.7 ± 2.5 pg/ mL , P = .03), but not norepinephrine ( P > .05), also differed with syncope between cases and controls. Conclusions and Inferences The nausea related to tilt‐induced syncope is temporally associated with changes in gastric myoelectrical activity and increases in plasma vasopressin and epinephrine. The biological mechanisms that induce syncope are physiologically distinct from other experimental models of nausea such as illusory self‐motion, yet nausea with syncope appears to have similarly associated electrogastrographic and hormone changes. Thus, tilt‐induced syncope could serve as an informative experimental model for nausea research.