Distal contraction latency: a measure of propagation velocity optimized for esophageal pressure topography studies.
OBJECTIVE
A defining feature of peristalsis is propagation velocity, which determines the timing of the distal contraction relative to the swallow. This study aimed to exploit a coordinate-based strategy to quantify the normal latency of the distal esophageal contraction as a measure of propagation velocity optimized for high-resolution esophageal pressure topography (EPT) studies.


METHODS
EPT studies for 75 healthy volunteers were merged in a computer simulation. Swallows were synchronized and analyzed as a 100 × 200 pixel grid that normalized esophageal length from the pharynx to the stomach for a 20-s period to first calculate a composite for each individual and then to establish normative values for the morphology and latency of the distal contraction among individuals.


RESULTS
Stereotyped landmarks in composite EPT studies were pressure troughs in the proximal and distal esophagus isolating the distal segment and the contractile deceleration point (CDP) localizing the termination of peristalsis in the distal segment. Distal contractile latency was timed to the CDP (median 6.0 s, 95% confidence interval 4.8-7.6 s) and to lower esophageal sphincter (LES) contraction (median 9.2 s, 95% confidence interval 6.5-11.5 s). Illustrative examples are shown of rapidly conducted contractions with normal or short latency, suggesting short latency to be the preferable EPT metric of rapid propagation.


CONCLUSIONS
The proposed scheme, utilizing the topographic coordinates of contraction relative to the swallow as an alternative to conventional measures of peristaltic velocity, lays the foundation for a physiologically grounded classification of peristaltic abnormalities in EPT. Future studies will test the clinical utility of this scheme.
Roman
Sabine
S
Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611-2951, USA. roman.sabine@gmail.com
Lin
Zhiyue
Z
Pandolfino
John E
JE
Kahrilas
Peter J
PJ
D000328:Adult; D000465:Algorithms; D003679:Deglutition; D004935:Esophageal Diseases / Q000503:physiopathology; D049630:Esophageal Sphincter, Lower / Q000502:physiology; D004947:Esophagus / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D009119:Muscle Contraction; D010528:Peristalsis / Q000502:physiology*; D011312:Pressure; D012016:Reference Values