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There are various definitions of a sudden cardiac death.
Myerburg and Castellanos (2001) give the following definition:
The sudden cardiac death is the nonviolent, caused by heart diseases death demonstrating a sudden loss of consciousness within 1 h from the moment of emergence of acute symptoms, at the same time the previous heart disease can be known or it is unknown, but the death is always unexpected.
Similar definitions are given also by WHO experts (1964, 1979), distinction consists only in terms of occurrence of cordial death. WHO experts consider that the sudden cardiac death comes within 1 — 6 hours from the moment of emergence of the first symptoms of heart attack.
Depending on duration of an interval between the beginning of heart attack and the moment of occurrence of death distinguish instant cordial death (the patient perishes within several seconds, i.e. almost instantly) and fast cordial death (the patient perishes within an hour). In the USA suddenly about 300 000 — 400 000 people annually die that makes about 0.1 — 0.2% of number of all inhabitants. Nearly 50% of all cases of death of cardiovascular diseases are the share of a sudden cardiac death.
About 80% of cases of a sudden cardiac death are caused by coronary heart disease (N. A. Masur, 1999). Such sudden death can be designated as sudden coronary death. In classification of an ischemic heart disease it is specified that one of the ischemic heart diseases forms is the sudden coronary death which can give the following definition.
The sudden coronary death (primary cardiac standstill) as a form of coronary heart disease is the death in the presence of witnesses which occurred instantly or within 1 ~ 6 h, caused most often by fibrillation of ventricles and is not connected with existence of the signs allowing to put any another except coronary heart disease, the diagnosis.
Further it will be a question of a sudden cardiac death as clinical manifestations of sudden cardial and coronary death are identical.
There are certain age and sexual features of a sudden cardiac death.
Allocate two age types of a sudden cardiac death: among newborns (in the first 6 months of life) and at adults (at the age of 45-75) (Burch and soavt., 1965). Among newborns the frequency of a sudden cardiac death makes about 0.1 — 0.3%. At the age of 1 — 13 flying only 1 of 5 cases of sudden death is caused by heart diseases, at the age of 14 — 21 year this indicator increases up to 30%, and on average and advanced age of 88% of all cases of sudden death are a sudden cardiac death.
There are also sexual distinctions in the frequency of a sudden cardiac death. The sudden cardiac death at young and middle age is noted at men by 4 times more often than at women, at the age of 45-64 at men the sudden cardiac death is registered 7 times more often in comparison with women and only in an age group 65-74 years the frequency of a sudden cardiac death at men and women is expressed by a ratio 2:1.
Thus, the frequency of a sudden cardiac death increases in process of increase in age and higher at men in comparison with women.
Basic reasons of sudden cardiogenic death, are given below.
Basic reasons of a sudden cardiac death (Myerburg, Castellanos, 2001, with amendment)
Atherosclerosis of coronary arteries
Chronic ischemic disease with a tranzitorny imbalance of need of a myocardium for oxygen and its receipt
Acute myocardial infarction
Inborn pathology of coronary arteries
Abnormal otkhozhdeniye from a pulmonary artery
Otkhozhdeniye of the left coronary artery from the right sine of Valsalva
Coronary arteriovenous fistula
Hypoplasia or aplasia coronary arteries
Otkhozhdeniye of the right coronary artery from the left sine of Valsalva
Coronary intrakardialny shunt
Nodular polyarteritis, system scleroderma, giant-cell arteritis
Illness of Kawasaki
Syphilitic stenosis of the mouth of coronary arteries
Embolism of coronary arteries
Endocarditis with defeat of aortal or mitral valves
The artificial aortal or mitral valve with thrombosis
Blood clots on valves or pristenochny blood clot of a left ventricle
The mixed mechanical obstruction of coronary arteries
Stratification of a coronary artery at Marfan's syndrome
Stratification of a coronary artery at pregnancy
Prolapse of a polyp of the aortal valve in the mouth of a coronary artery
Stratification or rupture of a sine of Valsalva
Functional obstruction of coronary arteries
Spasm of coronary arteries against atherosclerosis or without atherosclerotic defeat
The diseases causing a myocardium hypertrophy
Arterial hypertension without atherosclerosis of coronary arteries
Hypertrophy of a myocardium of a left ventricle at ischemic heart disease patients
Myocardium hypertrophy at valve heart diseases
Primary or secondary pulmonary hypertensia
The myocardium diseases leading to heart failure
Chronic congestive heart failure
ischemic cardiomyopathy idiopathic dilatatsionny cardiomyopathy alcoholic cardiomyopathy hypertensive dekompensirovanny heart postmiokarditichesky cardiosclerosis
Acute heart failure
massive acute myocardial infarction
acute alcoholic kardiolatiya
outside and internal cardiorrheses
Inflammatory, tumoral and degenerative diseases of a myocardium
Myocarditis at vasculites
Acute gigantokpetochny isolated myocarditis
Aritmogenny dysplasia of a right ventricle
Neuromuscular diseases (muscular dystrophies, Fridreykh's ataxy, miotonichesky dystrophy)
Tumors (high-quality, malignant, primary, metastatic, intra myocardial, endocardiac obstructive)
Diseases of valves of heart
Subaortic stenosis, aortic incompetence
Rupture of the mitral valve
Prolapse of the mitral valve
Dysfunction of the artificial valve
Inborn heart diseases
Stenosis of valves of an aorta or pulmonary artery
Pathology of electrophysiologic processes in heart
Disturbances of the carrying-out system (fibrosis of system of Purkinye — primary degeneration or Lenegre's illness; secondary fibrosis and calcification or Levi's illness; post-viral fibrosis of the carrying-out system; inborn disturbances of the carrying-out system)
The acquired and inborn forms of lengthening of an interval of QT
Blockade of the right leg of a ventriculonector and raising of the ST segment in the absence of ischemia
Fibrillation of ventricles of the known or unknown etiology, including
The electric instability of a myocardium caused by influence
factors and central nervous system
The Katekholaminzavisimy lethal arrhythmia Caused by influence of the central nervous system
The reasons of the mixed character
Sudden cardiac death owing to an extreme exercise stress
Injury of area of heart
Mechanical obstacles to venous return of blood (acute cardiac tamponade, massive thromboembolism of a pulmonary artery, acute
The stratifying aortic aneurysm
Toksiko-metabolichesky disturbances (electrolytic, metabolic disturbances, pro-arhythmic effect of antiarrhytmic means and means)
The reasons of a sudden cardiac death of children are not given in the table.
At persons of young age inflammatory diseases of a myocardium, a cardiomyopathy, a syndrome of the extended QT interval, heart diseases (in particular, a subaortic stenosis), anomalies of a chest aorta are the most frequent reasons of a sudden cardiac death at Marfan's syndrome, anomaly of coronary arteries, disturbances of a cordial rhythm and conductivity, sometimes — not diagnosed coronary atherosclerosis.
The major factors provoking a sudden cardiac death among persons of young age are: a physical extreme overstrain (for example, during sports competitions); alcohol intake and drugs (for example, cocaine causes a strong and long spasm of coronary arteries up to development of a myocardial infarction); reception of some medicines (for example, tricyclic antidepressants are capable to cause considerable delay of carrying out excitement); the expressed electrolytic disturbances; alcoholic excesses (especially use of alcoholic substitutes).
At persons 40 years are more senior, especially at elderly and old men, is a basic reason of a sudden cardiac death an ischemic heart disease, and it is, as a rule, about the heavy stenosing atherosclerosis of two or three main coronary arteries. Usually on autopsy of such patients erosion or anguishes in atherosclerotic plaques, signs of an aseptic inflammation and instability of plaques, a mural thrombosis of coronary arteries and a considerable hypertrophy of a myocardium are found. At 25 — 30% of patients the necrosis centers in a myocardium come to light.