Hypertrophic cardiomyopathy in children

Hypertrophic cardiomyopathy is a myocardial disease characterized by focal or diffuse hypertrophy of the myocardium of the left and/or right ventricle, often asymmetrical, with involvement of the interventricular septum in the hypertrophic process, normal or reduced volume of the left ventricle, accompanied by normal or increased contractility of the myocardium with a significant decrease in diastolic function.

ICD-10 code

• 142.1. Obstructive hypertrophic cardiomyopathy.
• 142.2. Other hypertrophic cardiomyopathy.

Epidemiology

Hypertrophic cardiomyopathy is common worldwide, but its exact incidence has not been established due to a significant number of asymptomatic cases. A prospective study by BJ Maron et al. (1995) showed that the prevalence of hypertrophic cardiomyopathy among young people (25-35 years) was 2 per 1000, with 6 out of 7 patients having no symptoms. This disease is more common in males, both among adult patients and among children. Hypertrophic cardiomyopathy in children is detected at any age. Its diagnosis is most difficult in children in the first year of life, in whom the clinical manifestations of hypertrophic cardiomyopathy are not clearly expressed, and they are often mistakenly regarded as symptoms of a heart disease of a different genesis.

Classification of hypertrophic cardiomyopathy

There are several classifications of hypertrophic cardiomyopathy. All of them are based on the clinical and anatomical principle and take into account the following parameters:

• pressure gradient between the left ventricular outflow tract and the aorta;
• localization of hypertrophy;
• hemodynamic criteria;
• severity of the disease.

In our country, the pediatric classification of hypertrophic cardiomyopathy was proposed by I.V. Leontyeva in 2002.

Working classification of hypertrophic cardiomyopathy (Leontyeva I.V., 2002)

Type of hypertrophy	Severity of obstructive syndrome	Pressure gradient, degree	Clinical stage
Asymmetrical Symmetrical	Obstructive form Non-obstructive form	I degree - up to 30 mm II degree - from 30 to 60 mm III degree - more than 60 mm	Compensations Subcompensations Decompensation

Causes of hypertrophic cardiomyopathy

At the present stage of development of our knowledge, sufficient data have been accumulated giving grounds to believe that hypertrophic cardiomyopathy is a hereditary disease transmitted by an autosomal dominant type with varying penetrance and expressivity. Cases of the disease are detected in 54-67% of parents and close relatives of the patient. The rest is the so-called sporadic form, in this case the patient has no relatives suffering from hypertrophic cardiomyopathy or having myocardial hypertrophy. It is believed that most, if not all cases of sporadic hypertrophic cardiomyopathy also have a genetic cause, i.e. are caused by random mutations.

Causes and pathogenesis of hypertrophic cardiomyopathy

Symptoms of hypertrophic cardiomyopathy

Clinical manifestations of hypertrophic cardiomyopathy are polymorphic and nonspecific, they vary from asymptomatic forms to severe impairment of functional status and sudden death.

In young children, the detection of hypertrophic cardiomyopathy is often associated with the development of signs of congestive heart failure, which develops in them more often than in older children and adults.

Symptoms of hypertrophic cardiomyopathy

Diagnosis of hypertrophic cardiomyopathy

The diagnosis of hypertrophic cardiomyopathy is established based on family history (cases of sudden death of relatives at a young age), complaints, and results of physical examination. Information obtained through instrumental examination is of great importance for establishing the diagnosis. The most valuable diagnostic methods are ECG, which has not lost its importance even now, and two-dimensional Doppler echocardiography. In complex cases, MRI and positron emission tomography help to conduct differential diagnostics and clarify the diagnosis. It is advisable to examine the patient's relatives in order to identify family cases of the disease.

Diagnosis of hypertrophic cardiomyopathy

Treatment of hypertrophic cardiomyopathy

Treatment of hypertrophic cardiomyopathy has not undergone significant changes in recent decades and remains essentially symptomatic. Along with the use of various drugs, surgical correction of the disease is currently also carried out. Considering that in recent years, ideas about the prognosis of hypertrophic cardiomyopathy have changed, the advisability of aggressive treatment tactics in most patients with hypertrophic cardiomyopathy is questionable. When conducting it, the assessment of sudden death factors is of paramount importance.

Symptomatic treatment of hypertrophic cardiomyopathy is aimed at reducing diastolic dysfunction, hyperdynamic function of the left ventricle and eliminating cardiac arrhythmia.

Treatment of hypertrophic cardiomyopathy

Forecast

According to recent research data based on the widespread use of echocardiography and (especially) genetic studies of families of patients with hypertrophic cardiomyopathy, the clinical course of this disease is obviously more favorable than previously thought. Only in isolated cases does the disease progress rapidly, ending in death.

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