Figure 5 - Esophageal wall thickness in patients with chest pain and controls.

Peak (black bar) and mean (striped bar) percentage increases in total esophageal muscle thickness during sustained esophageal contractions (SECs) associated with chest pain periods, control periods, and swallows. SEC was defined by the following criteria: (1) initiation by two or more consecutive images (2 seconds apart) with muscle thickening greater than the baseline thickness + 2 standard deviations (SD), and (2) total duration of muscle thickening above baseline greater than the mean + 3 SD duration of a swallow-associated contraction. (Source: Balaban et al.,⁵⁵ with permission from American Gastroenterological Association.)