The rhythm and rate of distension-induced esophageal contractility: A physiomarker of esophageal function

Background Distention of the esophagus elicits a unique pattern of repetitive contractions in healthy controls. We aimed to assess the rhythm and rate of distension-induced contractile patterns between achalasia and controls and identify factors that distinguish the normal contractile response to distension. Methods Twenty asymptomatic controls and 140 adult patients with treatment-naive achalasia defined by HRM (29 type I, 81 type II, 30 type III) were prospectively evaluated with functional luminal imaging probe (FLIP) during sedated endoscopy. 16-cm FLIP balloons were positioned within the distal esophagus during stepwise balloon distension. Functional luminal imaging probe panometry studies were retrospectively analyzed using a customized program. Key results All controls had contractility in a repetitive antegrade contraction (RAC) pattern with a rate of mean (10-90th) 6 (4-8) contractions per minute. 19/20 controls had > 6 consecutive antegrade contractions (ACs), that is, duration > 6 ACs, >6 cm in length, at a rate of 6 +/- 3 contractions per minute (met the "Rule-of-6s"). 50 achalasia patients had repetitive contractions that occurred at a rates of 11 (7 - 15) ACs per minute; P < .001 compared with controls, or 12 (8-15) repetitive retrograde contractions per minute. Only 1/140 achalasia patients had a contractile response that met the "Rule-of-6s." Conclusion The normal contractile response to sustained distention is associated with > 6 RACs with a consistent rate of 6 +/- 3 per minute, which was exceptionally rare in achalasia. These findings support that the RAC pattern is disrupted in achalasia and the faster rate may be a manifestation of abnormal inhibition and/or a reduced refractory period.