Coronary heart disease

Coronary heart disease is the term used to describe three clinical syndromes that result from insufficient coronary blood flow. These entities - sudden cardiac death, angina pectoris, and Myocardial Infarction - are the results of progressive atherosclerosis of the coronary arteries. The order of appearance may vary, with sudden death sometimes being the first manifestation of heart disease.

Though not all cases of sudden death are cardiac in origin, reports [1] have shown that 55% of deaths within 24 hours of symptoms are the results of coronary heart disease. Sudden death in males within one hour of symptoms has bee shown to be associated with coronary heart disease in as high as 91%. The role of Heart Attack 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 dysrhytmia.

Variant angina (Prinzmetal's angina) is an anginal syndrome that develops without obvious provocation and may occur regularly at certain time of the day. Coronary angiography has shown the cause to be coronary artery spasm. Relief occurs with nitroglycerin. Electrocardiogram (ECG) changes show ST elevations, whereas angina pectoris characteristically presents as ST depression on ECG. Calcium channel blockers have proves to be of great benefit in reducing both incidence and magnitude of attacks.

Angina pectoris is a symptom of underlying pathology, and is a reversible chest pain resulting from transient ischemia that falls short of ischemic necrosis. The pain of angina pectoris is described as choking, crushing pressure, tightness or heaviness and is defined as being longer than one minute and less than ten minutes in duration. Angina pectoris is precipitated by factors that increase myocardial oxygen demand (e. g. exercise, stress, intense emotion, heavy meals, tachycardia, or manual labor) and is characterized by a lag period and crescendo-type pain.

Other precipitating factors include hypotension, hypoxia, anemia, aortic valve disease, disease, dissecting aneurism, or thyreotoxicosis. These symptoms are reversed with discontinuation of provocative factor, rest, and nitroglycerin. Nitroglycerin relief is the secondary to decreased myocardial oxygen consumption and dilation of coronary vessels.

Unstable angina represents a progression through a series of symptoms toward those of an irreversible insult and is recognizes as a recent onset of angina (four to eight weeks); a worsening or change in character, frequency, or response to nitroglycerin of anginal symptoms; or angina at rest. Patients with angina are at high risk for Myocardial Infarction. Reports [2] have shown that without proper medical therapy 50% to 80% of patients suffer acute Heart Attacks within one month of symptoms. With early medical intervention, rates of infarction drop dramatically.

Myocardial Infarction occurs when necrosis of myocardial tissue is present. Generally, the most prominent feature is unrelenting chest pain greater than 20 minutes in duration, which is unrelieved with nitroglycerin. Many patients, however, have painless Myocardial Infarction experience breathlessness, syncope, or hypotension; this especially true diabetics or elderly.

Updated: January, 27 2010 08:41:55

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