Medical Record: The patient, a 51-year-old married male, was admitted for "episodic chest pain, belching, and acid reflux for 3 months." Over the past 3 months, the patient repeatedly experienced episodic dull or burning pain behind the sternum without any obvious trigger. The frequency was 1-5 times per day, often occurring while lying flat. Each episode lasted from 10 minutes to 1 hour.