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Myocardial akinesia
In the diagnosis of cardiac diseases, akinesia of the myocardium, that is, its immobility or the inability to contract certain areas of the muscle tissue of the heart, can be detected.
Thus, akinesia of the myocardium is not a disease but a pathological condition, a disorder of the normal motor function of the heart muscle, which is determined by ultrasound diagnosis of the heart and is one of the structural and functional signs of a number of diseases of the cardiovascular system.
Causes of the akinesia of the myocardium
Why does the heart muscle cease to shrink, that is, what are the causes of myocardial akinesia?
In cardiological practice, the pathogenesis of loss of normal contractile function of the myocardium (which, as is known, is automatically performed by a healthy heart) is most often associated with myocardial infarction and the necrosis of a part of the working cardiomyocytes. Postinfarction reparative changes (remodeling) of the myocardium first leads to an increase in the infarction zone, and then the ventricle forms distortion and its expansion with the transformation of the cardiomyocyte necrosis zone into a scar with the formation of a myocardial akinesia. Fibrotic changes may also affect the ventricular septum, and then an ultrasound examination shows an akinesia in the area of the interventricular septum.
Myocardial infarction is an acute condition of cardiac ischemia or ischemic heart disease (CHD) that develops when blood circulation in the coronary artery system is disrupted, which leads to myocardial hypoxia and the death of its cells.
With post-infarction thinning of the muscle heart and its bulging - aneurysm - ultrasound cardiography reveals akinesia of the left ventricle. Almost two thirds of patients have aneurysm formation in the left ventricle - on its anterior wall or on the apex, and here akinesia of the apex of the heart is noted.
In addition, there is a correlation of echocardiographic results visualizing myocardial akinesia with postinfarction myocardial syndrome - focal or diffuse postinfarction cardiosclerosis with a characteristic replacement of damaged cardiomyocytes with fibrous tissue, as well as damage to the conduction system of the heart (violation of the bioelectric pulse by cells of the sinoatrial or atrioventricular nodes).
In cases of degeneration or dystrophy of the myocardium, which has a histomorphological pattern similar to cardiosclerosis, a change in the structure of the heart muscle tissue also demonstrates focal akinesia of the myocardium.
Often there are damage to the cells of the sinoatrial node with a decrease in the amplitude of motion of the muscular wall and the absence of its contraction, that is, a combination of hypokinesia and akinesia in patients with infectious myocarditis. This disease can be accompanied by the formation of inflammatory infiltrates in the interstitium and localized myocytolysis due to inflammation caused by viruses (adeno and enterovirus, Picornaviridae, Coxsackie virus, Parvovirus B, Rubella virus, HSV-6), bacteria (Corynebacterium diphtheriae, Haemophilus influenzae, Borrelia burgdorferi, Mycoplasma pneumoniae), as well as protozoa (Trypanosoma cruzi, Toxoplasma gondii), fungi (Aspergillus) or parasites (Acaris, Echinococcus granulosus, Paragonimus westermani, etc.). As shown by clinical statistics, most cases of infectious myocarditis is caused by diphtheria, influenza, enteroviruses and toxoplasma.
And with myocarditis autoimmune etiology (associated with systemic lupus erythematosus, scleroderma, rheumatoid arthritis, Whipple's disease, etc.), left ventricle akinesia and its dysfunction, fraught with life-threatening arrhythmias, may occur.
Separately, cardiologists distinguish stress-cardiomyopathy (Takotsubo cardiomyopathy), which the domestic specialists call the syndrome of a broken heart. This sudden transient systolic dysfunction of the median-apical segments of the left ventricle often occurs in stressful situations in elderly women who do not have an ischemic heart disease. In particular, at the base of the left ventricle the hyperkinesis zone is revealed, and above it - akinesia of the apex of the heart. Also on the ultrasound of the heart, diagnosticians can detect a lack of movement in the area of the interventricular septum.
Risk factors
The main risk factors for disorders of normal motor function of the cardiac muscle regions in the form of myocardial akinesia are the development of coronary heart disease. And the factors of risk of its development, in turn, are:
- age over 45 in men and over 55 in women;
- family history of early heart disease;
- a lower level of HDL cholesterol (high-density lipoproteins) in the blood and an elevated level of low-density lipoprotein (LDL), which contribute to the deposition of cholesterol on the walls of the vessels - atherosclerosis;
- high level of triglycerides in the blood (associated with the nature of nutrition);
- high blood pressure;
- metabolic disorders (metabolic syndrome), promoting blood pressure and deposition of cholesterol in the coronary vessels;
- Smoking (including passive), obesity, lack of physical activity, psychological stress and depression.
Myocardial infecting viral and bacterial infections, as well as autoimmune pathologies, trigger such a risk factor for myocardial ischemia as an increase in the level of C-reactive protein (CRP) in the blood. And the normal state of the heart vessels is disturbed by the imbalance of tissue plasminogen activators (tPA) and their inhibitors (PAI), which threatens thrombosis of coronary veins with their complete occlusion.
Pathogenesis
It is suggested that the pathogenesis of this cardiomyopathy lies in the inadequate response of the heart vessels (coronary arteries and / or arterioles and capillaries) to the release into the blood of catecholamine neurotransmitters, and that short anomalies of myocardial contraction arise because of the vasospasm they provoke.
Symptoms of the akinesia of the myocardium
With akinesia of the myocardium - an echocardiographic indication of diseases of the cardiovascular system - the clinical picture is determined by the symptoms of these pathologies. These include: shortness of breath, pain of varying intensity in the heart, arrhythmia (ciliated or ventricular), ventricular flutter, fainting.
So, with takotsubo cardiomyopathy, the patients most often complain about the pain in the left shoulder blade behind the sternum (compressive nature) and the feeling of lack of air during inspiration.
And pain in myocarditis can be both acute and prolonged (with no effect when using nitroglycerin), and muffled (squeezing). In addition, cardiac symptoms in this disease of infectious origin include shortness of breath, fever, increased heart rate, heart flutter; a lightning impairment of hemodynamics (a drop in the volume velocity of the blood flow), loss of consciousness and sudden cardiac death are possible .
Complications and consequences
Certainly, akinesia of the myocardium compared with dyskinesia of the postinfarction cicatrix presents a more serious danger to the life of patients with myocardial infarction. Studies have shown that in about 40% of cases of myocardial infarction with timely restoration of blood flow in the ischemic segment (reperfusion), myocardial contractility will resume within two to six weeks after the infarction. However, its consequences and complications are sudden cardiac tamponade, electromechanical dissociation and death.
The consequences and complications of myocardial dystrophic changes with partial akinesia lead to the practically inevitable atrophy of muscle fibers, which can manifest not only in arrhythmia and a decrease in systolic ejection, but also in the expansion of chambers of the heart with chronic circulatory failure.
Left ventricular akinesia with its systolic dysfunction and heart failure are among the strongest predictors of the risk of sudden cardiac death.
Diagnostics of the akinesia of the myocardium
Only instrumental diagnosis of the myocardium with the help of ultrasound of the heart - echocardiography - makes it possible to identify the zones of its akinesia.
Trace and fix all movements of the heart wall allows a special technique for automatic segmental analysis of cardiac contractions.
Differential diagnosis
Differential diagnosis of chest pain - in patients with an atypical clinical picture or a diagnostically uncertain electrocardiogram result - also involves the use of echocardiography.
In patients without disturbance of the movement of the myocardium, echocardiography can be used to identify other life-threatening conditions with a similar clinical picture: massive pulmonary embolism or aortic dissection.
In addition, the diagnosis of the myocardium, including with violations of its contractile function, includes blood tests for ESR, C-reactive protein level, antibodies (serum serum analysis for IgM level), electrolyte level, markers of myocardial damage (isoenzymes troponin I and T, creatine kinase).
Patients are made an electrocardiogram (ECG), they perform radiopaque coronary angiography, tomographic scintigraphy (with radioisotope substances), color tissue dopplerography, MRI. Diagnosis of heart aneurysms requires the use of radiopaque ventriculography.
In some cases, differential diagnosis of the myocardium is possible only with the help of endomyocardial biopsy followed by a histology of the obtained sample.
Treatment of the akinesia of the myocardium
Treatment of the myocardium is aimed at restoring the blood supply to its damaged areas (perfusion) and the function of their conductivity, limiting the zone of localized necrosis of cardiomyocytes, and activating the cellular metabolism.
In clinical practice, drugs of several pharmacological groups are used. In acute coronary syndromes and occlusive thrombosis of the epicardial coronary artery, reperfusion therapy with thrombolytic drugs (Streptokinase, Prourokinase, Alteplase) and antiplatelet agents (Ticlopidine, clopidogrel sulfate or Plavix) is performed.
In chronic heart failure, drugs that inhibit blood pressure regulating angiotensin-converting enzyme (ACE inhibitors): captopril, enalapril, ramipril, fosinopril are used. Their dosage is determined by the cardiologist, depending on the specific disease and ECG readings. For example, Captopril (Capril, Alopresin, Tenziomin) can be administered at 12.5-25 mg three times a day before meals (inside or under the tongue). As side effects of this drug and most of the drugs in this group, tachycardia, falling blood pressure, kidney failure, liver failure, nausea and vomiting, diarrhea, urticaria, increased anxiety, insomnia, paresthesia and tremor, shifts in the biochemical composition of the blood including leukopenia). It should be borne in mind that ACE inhibitors are not used for ideopathic pathologies of the myocardium, increased blood pressure, stenosis of the aorta and vessels of the kidneys, hyperlastic changes in the adrenal cortex, ascites, pregnancy and childhood of patients.
With IHD and cardiomyopathies, anti-ischemic drugs of the group of peripheral vasodilators, for example, Molsidomine (Motazomin, Corvaton, Sidnofarm) or Advokard can be prescribed. Molsidomin is taken orally - one tablet (2 mg) three times a day; contraindicated with low blood pressure and a state of cardiogenic shock; the side effect is a headache.
Antiarrhythmic and hypotensive drug Verapamil (Verakard, Lekoptin) is used in IHD with tachycardia and with angina pectoris: on a tablet (80 mg) three times a day. There may be side effects in the form of nausea, dry mouth, intestinal problems, headache and muscle pain, insomnia, hives, heart rate disorders. This remedy is contraindicated for severe heart failure, atrial fibrillation and bradycardia, low blood pressure.
Cardiotonic and antihypoxic action is medicated by Mildronate (Meldonium, Angiocardil, Vasonat, Cardionate and other trade names). It is recommended to take one capsule (250 mg) twice a day. This tool can be used only for adult patients and is contraindicated in cases of cerebral circulation disorders and the presence of structural pathologies of the brain. When using Mildronate, there may be side effects such as headaches, dizziness, cardiac arrhythmia, shortness of breath, dry mouth and cough, nausea, and bowel disorders.
Preparations of the group of β1-adrenoblockers in IHD (Metoprolol, Propranolol, Atenolol, Acebutolol, etc.), primarily reduce blood pressure, and by reducing the sympathetic stimulation of receptors on the membranes of myocardial cells reduce heart rate, reduce cardiac output, increasing consumption oxygen cardiomyocytes and alleviating pain. For example, Metoprolol is prescribed one tablet twice a day, Atenolol is enough to take one tablet a day. However, the drugs of this group increase the risk of acute heart failure and blockade of the atria and ventricles, and their use is contraindicated in the presence of congestive and decompensated heart failure, bradycardia, circulatory disorders. Therefore, at present, many specialists question the antiarrhythmic effect of these drugs.
Relieving pain in the heart is of paramount importance, since sympathetic activation during pain causes narrowing of the blood vessels and increases the burden on the heart. To stop the pain, it is customary to use Nitroglycerin. Details in the article - Effective pills that relieve pain in the heart
Doctors recommend taking vitamins B6, B9, E, and to maintain the conductive system of the heart - drugs containing potassium and mania (Panangin, Asparcum, etc.).
Surgery
In infarcts with lesions of the coronary arteries (leading to the formation of a site of myocardial ischemia and its akinesia with the expansion of the heart chambers), surgical treatment is shown to restore blood flow in the heart - aortocoronary bypass.
In coronary heart disease, coronary dilatation (dilating the lumen) - stenting.
Surgical treatment is most often used for a dyskinetic aneurysm: either by an aneurysmectomy (resection), or by suturing the aneurysmal cavity (aneurysmoplasty), or by strengthening its wall.
A method of dynamic cardiomyoplasty has been developed, which involves the restoration or increase of myocardial contractility using an electrically stimulated skeletal muscle (usually a flap of the latissimus of the back) wrapped around the part of the heart (with a partial resection of the second rib). The muscle flap is sewn around the ventricles, and its synchronous stimulation with cardiac contractions is carried out with the help of intramuscular electrodes of an implantable cardiomyostimulator.
Prevention
Go back to the section on Risk Factors, and the methods by which cardiovascular pathologies can be prevented will become apparent. The main thing is not to add weight, move more and prevent cholesterol from settling in the form of plaques on the walls of blood vessels, and for this it is useful after 40 years (and the presence of heart pathologies in blood relatives) to observe a diet in atherosclerosis
And, of course, cardiologists consider smoking cessation as the most important condition for preventing ischemic damage to the myocardium. The fact is that when smoking hemoglobin proteins of red blood cells are combined with gases of inhaled tobacco smoke, forming a very harmful to the heart compound - carboxyhemoglobin. This substance prevents blood cells from carrying oxygen, which leads to cardiac muscle cardiomyocyte hypoxia and the development of myocardial ischemia.
Also read - Prevention of postinfarction cardiosclerosis
Forecast
Prognostic information cardiologists voice reluctantly: an accurate prognosis of postinfarction dyskinesia, hypokinesia and akinesia is difficult.
To assess the prognosis of mortality after acute myocardial infarction, the American Society of Echocardiography experts entered the Wall motion index (WMI). However, it does not have a full-fledged long-term prognostic value.
As for myocarditis, then, according to statistics, almost 30% of cases culminate in recovery, and in others, chronic left-ventricular dysfunction becomes a complication. In addition, about 10% of cases of myocarditis of viral and microbial nature lead to death of patients. Total akinesia of the myocardium leads to cardiac arrest.
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