 Amyl nitrite relaxes vascular smooth muscle and has been studied previously as a potential means to separate achalasia from pseudoachalasia. Amyl nitrite is approved by the Food and Drug Administration FDA for the treatment of cardiac angina. It is not approved for use in motility testing and its use in this study is considered investigational. Investigators hope that the results from the proposed study could have significant clinical implications for patient management by helping doctors distinguish between achalasia and pseudoachalasia and allow them to choose appropriate treatment. 