1. Erroneous Diagnosis of Gastroesophageal Reflux Disease in Achalasia
Boudewijn F. Kessing, Albert J. Bredenoord, André J.P.M. Smout 
Clinical Gastroenterology and Hepatology 
Volume 9, Issue 12, Pages (December 2011)
DOI: /j.cgh
Copyright © 2011 AGA Institute Terms and Conditions

2. Figure 1
Fragment of 24-hour pH measurement in a patient with achalasia. Stasis of food with acidic contents is responsible for a long episode with pH <4.
Clinical Gastroenterology and Hepatology 2011 9, DOI: ( /j.cgh )
Copyright © 2011 AGA Institute Terms and Conditions

3. Figure 2
Impedance tracing measured in a normal subject and an achalasia patient. The impedance tracings in the achalasia patients are characterized by low distal baseline impedance levels.
Clinical Gastroenterology and Hepatology 2011 9, DOI: ( /j.cgh )
Copyright © 2011 AGA Institute Terms and Conditions

4. Figure 3
Classic achalasia, which is identified by absent LES relaxation and absent peristalsis as measured by conventional manometry.
Clinical Gastroenterology and Hepatology 2011 9, DOI: ( /j.cgh )
Copyright © 2011 AGA Institute Terms and Conditions

5. Figure 4
High-resolution manometry plot of classic achalasia, which is identified by the absence of LES relaxation and no peristaltic contractions of the esophagus after the onset of a swallow.
Clinical Gastroenterology and Hepatology 2011 9, DOI: ( /j.cgh )
Copyright © 2011 AGA Institute Terms and Conditions