Select the diagnostic pattern identified in HRM to visualize the Chicago v4.0 classification profile.
Guidelines & Evidence
Clinical Details
Section 1
When to Use
When to Use
General overview of High-Resolution Manometry (HRM) metrics
To understand the evolution of Achalasia subtyping from v1.0 to v4.0
Baseline education for trainees and clinicians transitioning to topography maps
Historical Context
Before the Chicago Classification, motility was assessed via conventional manometry, which often missed segmental contractions and EGJ relaxation nuances. The Chicago system defined the topographical "Clouse Plot," named after Ray Clouse, the father of modern HRM topography.
Section 2
Formula & Logic
The 3-Pillar Assessment
01
Pillar 1: EGJ Relaxation (IRP). Is the sphincter opening correctly?
02
Pillar 2: Peristaltic Vigor (DCI). Is the pump strong enough?
03
Pillar 3: Peristaltic Pattern. Is the contraction coordinated or spastic?
Basic Definitions
Hypercontractile
Overactive pump (e.g. Jackhammer)
Hypocontractile
Weak pump (e.g. Ineffective / Scleroderma-like)
Dyssynergic
Uncoordinated pump (e.g. DES / Type III Achalasia)
Section 3
Pearls/Pitfalls
Topography vs. Wavy Lines
The primary advantage of the Chicago system is the use of color-coded heat maps (Spatiotemporal plots). This allows for rapid identification of "Pan-esophageal pressurization," the hallmark of Type II Achalasia, which is often difficult to distinguish on conventional tracings.
Progression to v4.0
Clinicians should be aware that older "v3.0" reports may over-diagnose EGJOO. Always check if a report used supine and upright swallows (v4.0 standard) before considering surgery for outflow obstruction.
Section 4
Next Steps
Interpreting the Report
01
Check the IRP: If > 15 mmHg, look for Achalasia types.
02
Check the DCI: If < 450, document Ineffective Esophageal Motility (IEM).
03
Verify with clinical symptoms (Dysphagia vs. Chest Pain).
Complementary Motility Tools
Chicago Classification v4.0 (HRM)
Integrated Relaxation Pressure (IRP) Calculator
Distal Contractile Integral (DCI) Calculator
Section 5
Evidence Appraisal
Historical Foundations
AGA technical review on the clinical use of esophageal manometry.
Pandolfino JE et al. • Gastroenterology. 2005;128(1):209-24. Foundational document for modern manometry usage.
Pioneered at Northwestern University by Dr. Peter Kahrilas and John Pandolfino. The "Chicago" name honours the city where the consensus meetings first brought together the global motility community to standardize these complex maps.
