Heartburn is due to reflux (backflow) of gastric acid and sometimes bile into the stomach.  This can be temporary and of no significance if it is merely associated with overindulgence.  If heartburn occurs regularly over time, however, it may indicate the presence of a serious medical condition called Gastro-esophageal Reflux Disease (GERD).

Patients with GERD have abnormal function of the esophageal sphincter, allowing acid from the stomach (and sometimes bile from the duodenum) to regurgitate back into the stomach, causing heartburn.

Complications of GERD are as follows:

1.  Erosion of the lining of the distal esophagus that can lead to an ulcer with pain and bleeding

2.  Scarring and narrowing of the esophagus, called esophageal stricture

3.  Precancerous change involving the distal esophageal epithelium (Barrett’s Esophagus)

4.  Esophageal cancer

The major medical concern in GERD is the effect of the acid over time on the lining cells of the distal esophagus.  The cells are irritated and may undergo pre-cancerous change and, rarely, progress to esophageal cancer.  Therefore, patients with severe GERD are monitored by upper GI Endoscopy (inserting a scope into the esophagus, stomach and duodenum) with biopsy of abnormal areas.

GERD is treated with antacids, stronger medications, elevation of the head of the bed, avoidance of food and drink before bedtime and, in severe cases, surgery.

Here are two organs other than the stomach that are affected by heartburn:

1.  Esophagus:  See above

2.  Teeth and tissues in the mouth:  During sleep, patients with severe reflux often end up with gastric fluids in the mouth.  This can cause painful tongue and oral tissues in general, plus alteration of tooth enamel and ultimate dental decay.

The reference gives an excellent overall review of GERD including symptoms, causes, risk factors, complications, tests and treatment.

List two possible organs(other than Stomach) could be affected by heartburn and why they are affected?

Heartburn is caused by the acids in the stomach flowing up the esophagus. The foods and liquids that are eaten pass through the esophagus into the stomach where further digestion takes place. The acids in the stomach are very strong and aid in breaking down the substances eaten into simpler compounds that can be absorbed in the other organs of the digestive system.

The lower esophageal sphincter is a valve that opens for very short durations of time either to allow food to flow in or gases created in the stomach to be released when we belch.

If the valve does not close completely or stays open for a duration of time that is longer than necessary the acids in the stomach can flow up the esophagus. This can burn the delicate lining of the esophagus and if it reaches the throat can cause damage to it. The immediate effect of the action of the acid on the esophagus or in the throat is a sharp burning sensation and pain.