In contrast to those with<unk>  secondary to atherosclerosis, people with<unk>  are generally younger and have fewer risk factors for coronary artery disease except for smoking, which is a common and very significant risk factor for both types of<unk> . Sufferers usually have repeated episodes of unexplained (e.g., in the absence of exertion and occurring at sleep or in the early morning hours) chest pain, tightness in throat, chest pressure, light-headedness, excessive sweating, and/or reduced exercise tolerance that, unlike atherosclerosis-related<unk> , typically does not progress to myocardial infarction (heart attack). Unlike cases of atherosclerosis-related stable<unk> , these symptoms are often unrelated to exertion and occur in night or early morning hours. (However, individuals with atherosclerosis-related unstable<unk>  may similarly exhibit night to early morning hour symptoms that are unrelated to exertion.) Cardiac examination of individuals with<unk>  is usually normal in the absence of current symptoms. Two-thirds of these individuals do have concurrent atherosclerosis of a major coronary artery, but this is often mild or not in proportion to the degree of their symptoms. Persons who have atherosclerosis-based occlusion that is ≥70% in a single coronary artery or that involves multiple coronary arteries are predisposed to develop a<unk>  form that has a poorer prognosis than most other forms of this disorder. In these individuals but also in a small percentage of individuals without appreciable atherosclerosis of their coronary arteries, attacks of coronary artery spasm can have far more serious presentations such as fainting, shock, and cardiac arrest. Typically, these presentations reflect the development of a heart attack and/or a potentially lethal heart arrhythmia; they require immediate medical intervention as well as consideration for the presence of, and specific treatment regimens for, their disorder.<unk>  should be suspected by a cardiologist when a) an individual's symptoms occur at rest or during sleep; b) an individual's symptoms occur in clusters; c) an individual with a history of<unk>  does not develop<unk>  during treadmill stress testing<unk>  is exercise tolerant); d) an individual with a history of<unk>  shows no evidence of other forms of cardiac disease; and/or e) an individual without features of coronary artery atherosclerotic heart disease has a history of unexplained fainting. Complaints of chest pain should be immediately checked for an abnormal electrocardiogram (ECG). ECG changes compatible but not indicative of<unk>  include elevations rather than depressions of the ST segment or an elevated ST segment plus a widening of the R wave to create a single, broad QRS complex peak termed the "monophasic curve". Associated with these ECG changes, there may be small elevations in the blood levels of cardiac damage marker enzymes, especially during long attacks. Some individuals with otherwise typical<unk>  may show depressions, rather than elevations in the ST segments of their ECGs during<unk>  pain; they may also show new U waves on ECGs during<unk>  attacks. A significant percentage of those with<unk>  have symptom-free episodes of coronary artery spasm. These episodes may be far more frequent than expected, cause myocardial ischemia (i.e. insufficient blood flow to portions of the heart), and be accompanied by potentially serious abnormalities in the rhythm of heart beats, i.e. arrythmias. The only evidence of the presence of totally asymptomatic<unk>  would be detection of diagnostic changes on fortuitously conducted ECGs.
Variant angina
Microvascular angina
Unstable angina
Coronary steal
Bundle branch block
Atopy
Palisade 
Renal angina