Diagnosis of dilated cardiomyopathy in children

Diagnosis of dilated cardiomyopathy in a child is difficult, since the disease does not have specific criteria. The final diagnosis of dilated cardiomyopathy is established by the elimination of all diseases that can lead to increased heart cavities and circulatory insufficiency. The most important element of the clinical picture in patients with dilated cardiomyopathy is episodes of embolism, which often lead patients to death.

The survey plan is as follows.

• Collection of anamnesis of life, family history, anamnesis of the disease.
• Clinical examination.
• Laboratory research.
• Instrumental studies (Echocardiography, ECG, Holter monitoring, chest radiography, ultrasound [ultrasound] of the abdominal organs and kidneys).

The doctor should take into account that children rarely make complaints. However, when asked, parents note a lag in the increase in body weight and physical development. It turns out that it is difficult for children to participate in mobile games, climb the stairs, children of early age quickly get tired during feeding, note increased sweating, anxiety. Often changes in the lungs and cough are incorrectly interpreted as "frequent pneumonia", anorexia, abdominal pain, vomiting, dyspepsia, syncopal conditions are possible. It should be clarified whether there were cases of sudden death or death at a young age in the family, whether there are heart defects or other diseases of the cardiovascular system from the next of kin. It is important how the child developed, than it hurted.

[1], [2], [3], [4], [5]

Clinical examination in dilated cardiomyopathy

The clinical picture of dilated cardiomyopathy is variable and depends on the severity of circulatory insufficiency. Hemodynamic disorders are caused by a decrease in myocardial contractility and pumping function of the heart. This leads to an increase in pressure in the heart cavities, primarily in the left, then in the right. On examination, clinical manifestations of congestive heart failure are found. Among the most important and permanent diagnostic features of dilated cardiomyopathy are: cardiomegaly, leftward displacement and attenuation of the apical impulse, deformity of the chest in the form of a heart hump, lethargy, pallor of the skin, lag in physical development (cachexia), cervical vein swelling, cyanosis, acrocyanosis , enlargement of the liver (in children under 1 year old - and spleen), ascites, edema on the lower limbs. Auscultatory note is the weakening of 1 tone at the apex, systolic murmur of relative insufficiency of the mitral and / or tricuspid valve, the intensity of which varies; II tone over the pulmonary artery is accentuated and bifurcated. Characteristic tachycardia, extrasystole, rarely - bradycardia.

[6], [7], [8], [9],

Laboratory diagnostics of dilated cardiomyopathy

With the newly diagnosed cardiomegaly, it is advisable to perform a comprehensive serological, immunological and biochemical blood test to exclude acute myocarditis.

• Conduction of immunological studies allows revealing a decrease in the activity of natural killers, an increase in the content of tumor necrosis factor, the presence of specific circulating antibodies (anti-myosin antibodies to a- and beta-heavy chains of myosin, antimitochondrial antibodies, antibodies to beta adrenoreceptors), important markers of dilated cardiomyopathy.
• The detection of increased activity of CK and CK-MB may be indicative of acute myocarditis and neuromuscular disease.
• An increase in the content of iron and transferrin in the blood can indicate hemochromatosis as the cause of dilated cardiomyopathy.
• Hyponatremia combined with an increase in creatinine, urea (signs of impaired renal function), a decrease in the amount of fibrinogen, albumin, cholinesterase, increased activity of transaminases, bilirubin concentrations (signs of impaired liver function) reflect severe hemodynamic disorders.

Instrumental diagnostics of dilated cardiomyopathy

Electrocardiography

ECG results are very important, however they are not specific and reflect the severity of myocardial damage and the degree of its hemodynamic overload. ECG data:

• rhythm disturbances (sinus tachycardia, ventricular arrhythmia, supraventricular and ventricular extrasystole);
• conduction abnormalities (left bundle branch block, right bundle branch, distal AV-conduction abnormalities);
• signs of hypertrophy, more often left ventricle, less often both ventricles and left atrial overload;
• low voltage QRS in standard leads;
• nonspecific changes in the tooth T.

[10], [11], [12], [13], [14], [15], [16], [17]

Radiography of chest organs

When X-ray examination in all cases, increase the size of the heart (cardiothoracic index more than 0.60). The heart shape is more often spherical, mitral or trapezoid. From the side of the vessels of the small circle of blood circulation, the phenomena of venous stasis are more often in children, and less often moderate signs of pulmonary hypertension.

Echocardiography

Echocardiography is the most important non-invasive diagnostic tool for dilated cardiomyopathy. With the help of echocardiogram exclude heart disease, exudative pericarditis and other causes of cardiomegaly. In dilated cardiomyopathy, echocardiographic examination reveals a sharp widening of the heart cavities, especially the left ventricle, often in combination with atrial dilatation. The intact valves of the heart are determined, the amplitude of the opening of the mitral valve flaps is reduced due to a violation of the compliance of the dilated left ventricle and an increase in the end-diastolic pressure in its cavity. A quantitative analysis of the functional state of the left ventricle is characterized by a significant increase in the values of its end-diastolic and systolic diameter, as well as a decrease in left ventricular contractility (the left ventricular ejection fraction is below 30-40%). Doppler echocardiography allows to identify mitral and tricuspid regurgitation. With the help of this method, the diastolic function of the left ventricle is recognized (the phase of its isometric relaxation is prolonged and the final diastolic pressure in its cavity is increased). It is possible to detect intracavitary thrombus and signs of pulmonary hypertension.

[18], [19], [20], [21], [22]

Radionuclide research methods

• With radionuclide ventriculography, the following changes are determined:
  • expansion of the cavities of the heart;
  • violation of local contractility on the background of a diffuse decrease in myocardial contractility;
  • a significant decrease in the left ventricular and right ventricular ejection fraction.
• When scintigraphy of the myocardium with thallium-201, diffuse and focal defects in the accumulation of the drug are revealed.
• In myocardial scintigraphy with gallium-67, the isotope accumulates in the inflammatory foci of myocarditis and does not accumulate during dilated cardiomyopathy.

Puncture (catheter, endomyocardial) biopsy

In our country, with dilated cardiomyopathy in children, this method is not used because of its invasive nature, the risk of complications, high costs. In addition, the diagnostic value of endomyocardial biopsy in dilated cardiomyopathy is limited by the absence of pathognomonic morphological criteria for this disease. However, the study makes it possible to exclude the clinical diagnosis of dilated cardiomyopathy in the case of pathological changes specific for myocardial diseases such as myocarditis, amyloidosis, sarcoidosis and hemochromatosis of the heart.

Differential diagnosis of dilated cardiomyopathy in children

Differential diagnosis of dilated cardiomyopathy in children should be conducted with congenital heart defects, chronic myocarditis, arrhythmogenic myocardial dysfunction, rheumatic carditis, exudative pericarditis and specific cardiomyopathies.

Differential diagnosis with recurrent rheumatic carditis (against the background of formed mitral and aortic heart defects) is based on the absence of characteristic rheumatic history, extracardiac manifestations of rheumatic fever, increased body temperature and humoral activity, persistent and more intense noise of rheumatic malformations in dilated cardiomyopathy. Rheumatism has been taking place for many years without signs of congestive heart failure and has a positive dynamics on the background of therapy, while the clinical manifestation of dilated cardiomyopathy is manifested by marked signs of heart failure, often refractory to the treatment.

Differential diagnostics with congenital heart defects (coarctation of the aorta, abnormal passage of the coronary artery from the pulmonary trunk, insufficiency of the mitral valve, etc.), pericarditis and other diseases accompanied by the development of heart failure, are performed with the help of echocardiography.

Differential diagnosis with chronic myocarditis is difficult and in the world practice is based on the results of endomyocardial biopsy. Due to the fact that this method is not used in children in our country, it is necessary to take into account the history (communication with a viral infection, body temperature increase, humoral activity), the effectiveness of anti-inflammatory and symptomatic therapy, against which the chronic myocarditis is marked by a positive trend .

[23], [24], [25], [26], [27], [28], [29]