Onset On effort or emotion Spontaneous Location Substernal Apical

T H E increasing frequency of chest pain, due to the lengthening of the life span, and the importance of differentiating between chest pain of cardiac and non-cardiac origin cannot be overemphasized. Chest pain of cardiac origin is usually associated with coronary artery disease. Heberden * first described angina pectoris in 1772, and until recently little had been added to his detailed observations. During the past several decades, however, the diagnosis of coronary disease has been greatly facilitated. As a result, many mild and atypical cases can now be discovered.2 This explains in large part the present increase in the incidence of coronary disease, and has broadened our understanding of angina pectoris. The differential diagnosis between cardiac and non-cardiac pain, hitherto often based on the history of the attack, has now become less sharp, and at times is very difficult. The criteria usually employed in differentiating between angina and non-cardiac chest pain are