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Myocardial infarction – the center of an ischemic necrosis of a cardiac muscle developing as a result of sharp violation of coronary blood circulation. It is clinically shown by the burning-down, pressing or squeezing pains behind a breast giving to the left hand, a clavicle, a shovel, a jaw, short wind, the sensation of fear cold then. The developed myocardial infarction serves as the indication to the emergency hospitalization in cardiological resuscitation. At not rendering the timely help the lethal outcome is possible.

Myocardial infarction

Myocardial infarction – the center of an ischemic necrosis of a cardiac muscle developing as a result of sharp violation of coronary blood circulation. It is clinically shown by the burning-down, pressing or squeezing pains behind a breast giving to the left hand, a clavicle, a shovel, a jaw, short wind, the sensation of fear cold then. The developed myocardial infarction serves as the indication to the emergency hospitalization in cardiological resuscitation. At not rendering the timely help the lethal outcome is possible.

At the age of 40-60 years the myocardial infarction 3-5 times more often is observed at men in connection with earlier (for 10 years earlier, than at women) development of atherosclerosis. After 55-60 years incidence among persons of both sexes is approximately identical. The lethality indicator at a myocardial infarction makes 30 — 35%. Statistically 15 — 20% of sudden death are caused by a myocardial infarction.

Violation of blood supply of a myocardium for 15-20 and more minutes leads to development of irreversible changes in a cardiac muscle and disorder of warm activity. Sharp ischemia causes death of a part of functional muscle cells (necrosis) and the subsequent their replacement with fibers of connecting fabric, i.e. formation of a postinfarction hem.

In the clinical course of a myocardial infarction allocate five periods:

  • 1 period – preceding infarction (prodromalny): increase and strengthening of attacks of stenocardia, can continue several hours, days, weeks;
  • 2 period – the sharpest: from development of ischemia before emergence of a necrosis of a myocardium, proceeds of 20 minutes till 2 o'clock;
  • 3 period – sharp: from formation of a necrosis to a miomalyation (enzymatic fusion of nekrotizirovanny muscular tissue), duration from 2 to 14 days;
  • 4 period – subsharp: initial processes of the organization of a hem, development of granulyatsionny fabric on the place necrotic, duration are 4-8 weeks;
  • 5 period – postinfarction: maturing of a hem, adaptation of a myocardium to new operating conditions.

Myocardial infarction reasons

The myocardial infarction is the IBS sharp form. In 97 — 98% of cases the atherosclerotic damage of coronal arteries causing narrowing of their gleam forms a basis for development of a myocardial infarction. Quite often the sharp thrombosis of an affected area of a vessel causing the complete or partial cessation of blood supply of the respective area of a cardiac muscle joins atherosclerosis of arteries. Tromboobrazovany is promoted by the increased viscosity of blood observed at patients with IBS. In some cases the myocardial infarction arises against the background of a spasm of branches of coronal arteries.

Development of a myocardial infarction is promoted by diabetes, a gipertonichesy disease, obesity, psychological tension, hobby for alcohol, smoking. The sharp physical or emotional pressure against the background of IBS and stenocardia can provoke development of a myocardial infarction. More often the myocardial infarction of the left ventricle develops.

Classification of a myocardial infarction

According to the amount of focal damage of a cardiac muscle allocate a myocardial infarction:

  • krupnoochagovy
  • melkoochagovy

About 20% of clinical cases fall to the share of melkoochagovy myocardial infarctions, however quite often small centers of a necrosis in a cardiac muscle can be transformed to a krupnoochagovy myocardial infarction (at 30% of patients). Unlike krupnoochagovy, at melkoochagovy heart attacks there are no aneurism and a cardiac rupture, the current of the last is complicated by heart failure, fibrillation of ventricles, a thrombembolia less often.

Depending on depth of necrotic damage of a cardiac muscle allocate a myocardial infarction:

  • transmuralny - with a necrosis of all thickness of a muscular wall of heart (krupnoochagovy is more often)
  • intramuralny – with a necrosis in the thickness of a myocardium
  • subendokardialny – with a myocardium necrosis in a prileganiye zone to an endokard
  • subepikardialny - with a myocardium necrosis in a prileganiye zone to an epikard

On the changes fixed on the ECG distinguish:

  • "Q-heart attack" - with formation of a pathological tooth of Q, sometimes the ventricular QS complex (the krupnoochagovy transmuralny myocardial infarction is more often)
  • "not the Q-heart attack" – is not followed by emergence of a tooth of Q, is shown by negative T-teeth (the melkoochagovy myocardial infarction is more often)

And depending on defeat of certain branches of coronary arteries the myocardial infarction is divided by topography on:

  • right ventricular
  • left ventricular: forward, side and back walls, interventricular partition

On frequency rate of emergence distinguish a myocardial infarction:

  • primary
  • recuring (8 weeks after primary develop in time)
  • repeated (develops 8 weeks later after previous)

On development of complications the myocardial infarction is subdivided on:

  • complicated
  • uncomplicated
On existence and localization of a pain syndrome

allocate myocardial infarction forms:

  1. typical – with localization of pain behind a breast or in prekardialny area
  2. atypical - with atypical painful manifestations:
  • peripheral: left scapular, left-handed, guttural and pharyngeal, mandibular, verkhnepozvonochny, gastralgichesky (abdominal)
  • bezbolevy: kollaptoidny, asthmatic, edematous, arhythmic, cerebral
  • malosimptomny (erased)
  • combined

According to the period and dynamics of development of a myocardial infarction allocate:

  • ischemia stage (sharpest period)
  • necrosis stage (sharp period)
  • stage of the organization (subsharp period)
  • scarring stage (postinfarction period)

Myocardial infarction symptoms

Preceding infarction (prodromalny) period

About 43% of patients note sudden development of a myocardial infarction, at a bigger part of patients the period, various on duration, of the unstable progressing stenocardia is observed.

The sharpest period

Typical cases of a myocardial infarction are characterized by extremely intensive pain syndrome with localization of pains in a thorax and irradiation in the left shoulder, a neck, teeth, an ear, a clavicle, the lower jaw, an interscapular zone. The nature of pains can be squeezing, holding apart, burning, pressing, sharp ("dagger"). Than more zone of damage of a myocardium, especially is expressed pain.

The painful attack proceeds wavy (amplifying, weakening), proceeds of 30 minutes till several o'clock, and sometimes and days, is not stopped by repeated reception of nitroglycerine. Pain is accompanied by sharp weakness, excitement, sensation of fear, short wind.

Perhaps atypical current of the sharpest period of a myocardial infarction.

At patients sharp pallor of integuments, sticky cold sweat, , concern is noted. Arterial pressure in the period of an attack is increased, then moderately or sharply decreases in comparison with initial (systolic tachycardia, arrhythmia.

Sharp left ventricular insufficiency (cardiac asthma, hypostasis of lungs) can develop in this period.

Sharp period

In the sharp period of a myocardial infarction the pain syndrome, as a rule, disappears. Preservation of pains is caused by the expressed degree of ischemia of an okoloinfarktny zone or accession of a perikardit.

As a result of processes of a necrosis, miomalyation and perifokalny inflammation fever (from 3-5 to 10 and more days) develops. Duration and height of rise in temperature at fever depend on the area of a necrosis. Arterial hypotension and symptoms of heart failure remain and accrue.

Subsharp period

Pain is absent, the condition of the patient improves, normalized body temperature. Symptoms of an acute heart failure become less expressed. Tachycardia, systolic noise disappears.

Postinfarction period

In the postinfarction period clinical manifestations are absent, laboratory and fizikalny data practically without deviations.

Atypical forms of a myocardial infarction

Sometimes the atypical course of a myocardial infarction meets localization of pains in atypical places (in a throat, fingers of the left hand, in a zone of a left shoulder-blade or cervicothoracic department of a backbone, in an epigastriya, in the lower jaw) or bezbolevy forms which leading symptoms can be cough and heavy suffocation, a collapse, hypostases, arrhythmias, dizziness and obscuring of consciousness.

Atypical forms of a myocardial infarction meet at elderly patients with the expressed cardiosclerosis signs, insufficiency of blood circulation, against the background of a repeated myocardial infarction more often.

However usually only the sharpest period atypically proceeds, further development of a myocardial infarction becomes typical.

The erased course of a myocardial infarction happens bezbolevy and incidentally it is found on the ECG.

Myocardial infarction complications

Quite often complications arise already during the first hours and days of a myocardial infarction, making heavier its current. At most of patients in the first three days different types of arrhythmias are observed: premature ventricular contraction, sinusovy or paroksizmalny tachycardia, vibrating arrhythmia, total intra ventricular block. Blinking of ventricles which can turn into fibrillation is the most dangerous and lead of the patient to death.

Left ventricular heart failure is characterized by stagnant rattles, the phenomena of cardiac asthma, hypostasis of lungs and quite often develops in the sharpest period of a myocardial infarction. Extremely heavy degree of left ventricular insufficiency is the cardiogenic shock developing at an extensive heart attack and usually leading to a lethal outcome. Falling systolic HELL lower than 80 mm of mercury is signs of cardiogenic shock., consciousness violation, tachycardia, cyanosis, reduction of a diuresis.

The rupture of muscle fibers in a zone of a necrosis can cause a heart tamponada - hemorrhage in a pericardium cavity. At 2-3% of patients the myocardial infarction is complicated by tromboemboliya of system of a pulmonary artery (can become the reason of a heart attack of lungs or sudden death) or a big circle of blood circulation.

Patients with an extensive transmuralny myocardial infarction in the first 10 days can die from a rupture of a ventricle owing to the sharp termination of blood circulation. At an extensive myocardial infarction there can be an insolvency of cicatricial fabric, its vybukhaniye with development of sharp aneurism of heart. Sharp aneurism can be transformed in chronic, leading to heart failure.

Adjournment of fibrin on walls of an endokard leads to development of a pristenochny tromboendokardit dangerous by a possibility of an embolism of vessels of lungs, a brain, kidneys by the come-off trombotichesky masses. In later period the postinfarction syndrome which is shown perikardity, pleurisy, artralgiya, an eozinofiliya can develop.

Diagnosis of a myocardial infarction

Among diagnostic criteria of a myocardial infarction the anamnesis of a disease, characteristic changes on the ECG, indicators of activity of enzymes of serum of blood are the major. Complaints of the patient at a myocardial infarction depend on a form (typical or atypical) a disease and extensiveness defeat warm a muscle. The myocardial infarction should be suspected at heavy and long (longer than 30-60 minutes) an attack of zagrudinny pains, violation of conductivity and a rhythm of heart, an acute heart failure.

Treat characteristic changes of the ECG formation of a negative tooth of T (at a melkoochagovy subendokardialny or intramuralny myocardial infarction), the pathological QRS complex or a tooth of Q (at a krupnoochagovy transmuralny myocardial infarction). At EhoKG violation locally of a ventricle sokratimost, thinning of its wall comes to light.

In the first 4-6 hours after a painful attack in blood increase in a myoglobin - the protein which is carrying out oxygen transport in cages is defined. Increase in activity of a kreatinfosfokinaza (KFK) in blood more than for 50% is observed later 8 — 10 h from development of a myocardial infarction and decreases to norm in two days. Determination of the KFK level is carried out every 6-8 hours. The myocardial infarction is excluded at three negative results.

For diagnosis of a myocardial infarction on later terms resort to definition of enzyme of a laktatdegidrogenaza (LDG) which activity increases after KFK – 1-2 days later after formation of a necrosis and comes to normal values in 7-14 days. For a myocardial infarction increase in isoforms of miokardialny sokratitelny protein of a troponin - troponina-T and troponina-1, increasing also at unstable stenocardia is highly specific. In blood increase in SOE, leukocytes, activities of aspartateaminotransferase (Asat) and alanineaminotransferases (Alat) is defined.

The coronary angiography (coronary angiography) allows to establish trombotichesky occlusion of a coronary artery and decrease in a ventricular sokratimost, and also to estimate possibilities of performing aortocoronary shunting or angioplasty - the operations promoting restoration of a blood-groove in heart.

Treatment of a myocardial infarction

At a myocardial infarction the emergency hospitalization in cardiological resuscitation is shown. In the sharp period the bed rest and mental rest, the fractional, limited on the volume and caloric content food is offered to the patient. In the subsharp period of the patient it is transferred from resuscitation to office of cardiology where treatment of a myocardial infarction continues and gradual expansion of the mode is carried out.

Knocking over of a pain syndrome is carried out by a combination of narcotic analgetics (fentanyl) to neuroleptics (droperidoly), intravenous administration of nitroglycerine.

Therapy at a myocardial infarction is directed to the prevention and elimination of arrhythmias, heart failure, cardiogenic shock. Appoint antiarrhytmic means (lidocaine), ß-adrenoblokatory (), trombolitik (heparin, acetilsalicylic to - that), antagonists of Sa (verapamil), magnesia, nitrates, spazmolitik etc.

In the first 24 hours after development of a myocardial infarction it is possible to make restoration of perfusion by a trombolizis or the emergency balloon coronary angioplasty.

The forecast at a myocardial infarction

The myocardial infarction is the heavy, interfaced to dangerous complications disease. The most part of lethal outcomes develops in the first days after a myocardial infarction. Pump ability of heart is connected with localization and volume of a zone of a heart attack. At damage more than 50% of a myocardium, as a rule, heart cannot function that causes cardiogenic shock and death of the patient. Even at less extensive damage heart not always copes loadings therefore heart failure develops.

After the sharp period forecast for recovery good. Adverse prospects at patients with the complicated course of a myocardial infarction.

Prevention of a myocardial infarction

Necessary conditions of prevention of a myocardial infarction are maintaining healthy and active lifestyle, refusal of alcohol and smoking, the balanced food, an exception of a physical and nerve strain, control HELL and blood cholesterol level.

Myocardial infarction - treatment should be carried out only under the supervision of a doctor. Self-treatment is unacceptable!!!

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