The contractile deceleration point: an important physiologic landmark on oesophageal pressure topography.

BACKGROUND: This study aimed to correlate oesophageal bolus transit with features of oesophageal pressure topography (OPT) plots and establish OPT metrics for accurately measuring peristaltic velocity.
METHODS: About 18 subjects underwent concurrent OPT and fluoroscopy studies. The deglutitive Contractile Front Velocity (CFV) in OPT plots was subdivided into an initial fast phase (CFV(fast)) and subsequent slow phase (CFV(slow)) separated by a user-defined deceleration point (CDP). Fluoroscopy studies were analyzed for the transition from the initial rapidly propagated luminal closure associated with peristalsis to slow bolus clearance characteristic of phrenic ampullary emptying and to identify the pressure sensors at the closure front and at the hiatus. Oesophageal pressure topography measures were correlated with fluoroscopic milestones of bolus transit. Oesophageal pressure topography studies from another 68 volunteers were utilized to develop normative ranges for CFV(fast) and CFV(slow). KEY
RESULTS: A distinct change in velocity could be determined in all 36 barium swallows with the fast and slow contractile segments having a median velocity of 4.2 cm s(-1) and 1.0 cm s(-1), respectively. The CDP noted on OPT correlated closely with formation of the phrenic ampulla making CFV(fast) (mean 5.1 cm s(-1)) correspond closely to peristaltic propagation and CFV(slow) (mean 1.7 cm s(-1)) to ampullary emptying. CONCLUSIONS & INFERENCES: The deceleration point in the CFV on OPT plots accurately demarcated the early region in which the CFV reflects peristaltic velocity (CFV(fast)) from the later region where it reflects the progression of ampullary emptying (CFV(slow)). These distinctions should help objectify definitions of disordered peristalsis, especially spasm, and improve understanding of impaired bolus transit across the oesophagogastric junction.