Coronary Heart Disease (CHD)

Coronary Heart Disease is the term used to describe three clinical syndromes that result from insufficient blood overflow:

• Sudden cardiac death
  
• Angina pectoris
  
• MI (Myocardial Infarction)

Theses entities are the result of progressive atherosclerosis of the coronary arteries. The order of appearance may vary, with sudden death sometimes being the first manifestation of the heart disease.
Coronary Heart Disease (CHD) is the end result of the accumulation of atheromatous plaques within the walls of the arteries that supply the myocardium (the muscle of the heart) with oxygen and nutrients.
Thought not all cases of sudden death are cardiac, reports have shown that 55% of deaths within 24 hours of symptoms are the result of coronary heart disease. Sudden death in males within one hour symptoms has been shown to be associated with coronary heart disease in as high as 91%. The role of Myocardial Infarction (MI) as the cause of most sudden deaths remains a source of controversy, perhaps reflecting our inability to pathologically verify early infarctions. Most of the patients probably die from ventricular disrhythmia.

You may want to read more about Coronary Heart disease on:
Coronary heart disease Introduction - Health encyclopaedia
Coronary Heart Disease
MedlinePlus - Coronary heart disease

Chest pain - is it infarction or not?

The presentation of the chest pain, then, can be a final pathway of a large number of abdominal lesions. What appears to be a indigestion may well prove to be a Myocardial Infarction, or an Heart Attack; what is perceived by the patient to be angina may prove to be indigestion/ the list of possibilities can be narrowed through a careful history and physical examination.

Physical examination may disclose the chest pain to be reproducible with palpation, respiration, or certain motions. History might indicate the chest pain was associated with inhalation of certain vapors, was slow or rapid in onset, or began after a cough or fever. Careful attention should be directed toward family history and the review of major coronary risk factor such as Hypertension, cigarette smoking, obesity, diabetes mellitus, and hypercholesterolemia.

The characteristics of the chest pain are important in developing a differential diagnosis. Patients with chest pain should be questioned regarding several factors relating to their pain:

The chest pain should be described in terms of PQRS as follows:

• Palliative-provocative factors - What makes it better? Worse? What initiates the pain?
  
• Quality - pressure, sharp, dull, aching, squeezing, burning, tearing
  
• Region and radiation - where does it starts? Does it irradiate? Where?
  
• Severity - is it severe, mild or moderate?
  
• Timing - does it start right away? Is it intermittent or continuous? Is there a lag period? How long does it last?
  

Also, I thought you may be interested in reading also the symptoms of the chest pain

The Symptom of Chest Pain

The symptom of chest pain in the retrosternal or precordial region is indicative of pain in T1 to T6 dermatome pattern. This dermatome patterns cover the area of the chest and back from the upper sternum (T2) to below, the xiphoid process (T6). The sensory distribution travels down the anteromedial surface of the arms, with T1 more distal (as you can see in the picture below).

The sensory input from this levels interconnects in the spinal cord. Visceral sensation from the structures innervated by these nerves will produce a deep and poorly localized pain indistinguishable in source of origin

T1 to T4 receive innervation from thoracic organs. The visceral pain produced usually lies retrosternal or in the precordium. Such a pain may travel down T1 or T2 to the arm or up to the neck. T5 and T6 supply visceral sensation of the lower thoracic organs, diaphragm, and upper abdominal organs; these include the gallbladder, pancreas, stomach, duodenum, and their peritoneal surfaces. The pain produced here may be maximal in the xiphoid or midback regions, but can extend to any area of the T1 or T6 dermatomes.

Frequently, irritation of these pathways causes nausea and vomiting, especially of the lower dermatomes.