Myocardial infarction - the disease of heart caused by an acute failure of its blood supply, with occurrence of the center of a necrosis in a cardiac musle; the major clinical form of ischemic illness of heart.

Pathogenesis. An immediate cause of a myocardial infarction is the acute ischemia of a myocardium, more often owing to break or splitting of an atherosclerotic plaque with formation of a thrombus in a coronary artery and rising of aggregation of thrombocytes. The activated thrombocytes can allocate vasoactive bonds that leads to a segmentary spastic stricture near to an atherosclerotic plaque and to aggravation of an ischemia of a myocardium. The megalgia arising at it causes emission of catecholamins, the tachycardia which enlarges need of a myocardium for oxygen develops and shortens time of diastolic filling, aggravating thus an ischemia of a myocardium. Other "vicious circle" is bound to local disturbance of function of a myocardium owing to its ischemia, a dilatation of a left ventricle and the further deterioration of a coronary circulation.

Signs, current. As the beginning of a myocardial infarction consider occurrence of an attack of an intensive and long pain behind a breast bone or in the left half of thorax. Patients describe a pain as compressing, pressing, tearing apart, burning. Usually it irradiates in the left brachium, an arm, a scapula. Quite often at an infarct unlike an attack of a stenocardia the pain extends to the right from a breast bone, sometimes grasps an anticardium and "gives" in both scapulas. Intensity hurt at an infarct considerably exceeds those at a usual stenocardia; its duration is estimated in tens minutes, hours, and sometimes day (the anginous status). During an attack there are periods of some weakening of a pain, however completely it does not disappear and after the short period of weakening renews with new force. Repeated, repeated reception of Nitroglycerinum at a myocardial infarction does not take out a pain. Often painful attack is accompanied by pavor of mors. At inspection the restless behaviour of the patient in an initial stage of a painful attack pays attention. Such picture is characteristic for a classical anginous variant of the beginning of a myocardial infarction.