Lesson topic №28. Болезни миокарда (Myocarditis and Cardiomyopathy)
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Dilated cardiomyopathy: echocardiography
Dilation of one or both of the ventricles. LV end-diastolic volume index above 74 mL/m2 in men and 61 mL/ m2 in women
Left ventricular ejection fraction (LVEF) less than 40%
Diffuse and severe left ventricular dysfunction
The relative wall thickness (RWT) less than 0.3
Dilated cardiomyopathy: genetic testing
Genetic testing for DCM aims to identify the rare pathogenic genetic variant that is the primary causal factor for disease in a patient. As per current guidelines, genetic testing is recommended for DCM probands with a family history of disease or sudden unexplained death or with clinical features suggestive of a particular/rare genetic disease.
Dilated cardiomyopathy: treatment
Patient education regarding medication compliance, dietary restrictions and regular follow-up, is critical for management of dilated cardiomyopathy.
All patients with DCM must be educated on the disorder and the importance of dietary restrictions in sodium and water.
Besides treating any identifiable and reversible underlying causes, the management and treatment of Dilated Cardiomyopathy (DCM) are in concordance with the standard heart failure guidelines.
Anticoagulation should be used for patients with artificial valves, atrial fibrillation, and known mural thrombus.
Implanted cardioverter defibrillators (ICD) for primary prevention of sudden cardiac death and cardiac resynchronization therapy (CRT) can be considered.
Patients with disease refractory to maximum medical therapy should be considered for cardiac transplantation.
Hypertrophic cardiomyopathy
Hypertrophic cardiomyopathy
Hypertrophic cardiomyopathy (HCM) is defined by the presence of increased left ventricular (LV) wall thickness that is not solely explained by abnormal loading conditions.
HCM is defined by a wall thickness ≥15 mm in one or more LV myocardial segments—as measured by any imaging technique (echocardiography, cardiac magnetic resonance imaging (CMR) or computed tomography (CT).
The clinical diagnosis of HCM in first-degree relatives of patients with unequivocal disease (LVH ≥15 mm) is based on the presence of otherwise unexplained increased LV wall thickness ≥13 mm in one or more LV myocardial segments.
Hypertrophic cardiomyopathy: etiology
In up to 60% of patients with HCM, the disease is an autosomal dominant trait caused by mutations in cardiac sarcomere protein genes.
Hypertrophic cardiomyopathy: Hemodynamic classification
Nonobstructive HCM: left ventricular outflow tract obstruction (LVOTO) gradient < 30 mm Hg, either at rest or on provocation.
Obstructive HCM: LVOTO gradient > 30 mm Hg.
HCM with latent obstruction (i.e. an LVOT gradient <30 mmHg at rest that increases to > 30 mmHg with provocation.
Hypertrophic cardiomyopathy: history and physical examination
Age is one of the most important factors to take into account when considering the possible causes for HCM.
Pedigree analysis can determine the likely mode of inheritance. Most genetic forms of HCM are autosomal-dominant and are therefore characterized by the presence of affected individuals in every generation, with transmission from parents of either sex and a 50% risk to offspring.
Many individuals with HCM complain of few, if any, symptoms. In such cases the diagnosis can be incidental or the result of screening.
Some patients experience angina, dyspnoea, palpitations and syncope.
Cardiovascular examination is often normal but, in patients with LV outflow tract obstruction (LVOTO), may be identified an ejection systolic murmur at the left sternal edge that radiates to the right upper sternal edge and apex.
Hypertrophic cardiomyopathy: evaluation
The standard 12-lead ECG generally shows a left ventricular hypertrophy, STand T-wave abnormalities, and pathological Q-waves.
Ambulatory ECG monitoring is recommended at the initial clinical assessment to assess the risk of sudden cardiac death and stroke.
Hypertrophic cardiomyopathy: evaluation
The classic ECG finding in hypertrophic obstructive cardiomyopathy is large daggerlike “septal Q waves” in the lateral — and sometimes inferior — leads due to the abnormally hypertrophied interventricular septum. Criteria for left ventricular hypertrophy is usually present.
The apical variant of HOCM, known as
“Yamaguchi Syndrome,” does not result in septal Q waves, as the septum is normal in thickness in this conduction. The cardiac apex is abnormally thickened, resulting in diffuse T wave changes throughout the precordial leads. This is sometimes referred to as “giant T Wave Inversion.”