Lesson topic №28. Болезни миокарда (Myocarditis and Cardiomyopathy)
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Clinical management
Arrhythmia management outside the acute phase should be in line with current guidelines on arrhythmia and device implantation.
Non-steroidal anti-inflammatory drugs (NSAIDs), which are a mainstay of therapy in pericarditis, are not recommended in myocarditis.
Dilated cardiomyopathy
Dilated cardiomyopathy
Dilated cardiomyopathy (DCM) is a heart muscle disease characterized by left ventricular (LV) or biventricular dilatation and systolic dysfunction in the absence of either pressure or volume overload or coronary artery disease sufficient to explain the dysfunction.
Dilated cardiomyopathy
Commonly, the onset of the disease occurs in the third or fourth decade of life with a 3:1 male to female predominance.
By time the patients are diagnosed, they often have severe contractile dysfunction and remodeling of both ventricles, reflecting a long period of asymptomatic silent disease progression.
Dilated cardiomyopathy is the most frequent indication for cardiac transplantation.
Dilated cardiomyopathy
The American Heart Association classifies DCM as genetic, mixed or acquired, whereas the European Society of Cardiology (ESC) groups cardiomyopathy into familial (that is, genetic) or nonfamilial (that is, nongenetic) forms.
Decades of research have revealed diverse etiologies for DCM, including genetic mutations, infections, inflammation, autoimmune diseases, exposure to toxins and endocrine or neuromuscular causes.
Idiopathic and familial disease are the most commonly reported causes of DCM.
Dilated cardiomyopathy: etiology
Genetic mutations: mutations in genes involved in several cardiac functions
Infection: several pathogens can cause inflammatory dilated cardiomyopathy (DCM), including:
Viruses: adenovirus spp., coronavirus spp., coxsackievirus spp. (groups A and B), cytomegalovirus spp., dengue virus, echovirus spp., Epstein–Barr virus, hepatitis B virus, hepatitis C virus, herpes simplex virus, human herpesvirus 6, HIV, influenza A and influenza
B viruses, mumps rubulavirus, parvovirus (B19), poliovirus, rabies virus, respiratory syncytial virus, rubella virus, measles virus and Varicella-zoster virus
Bacteria: β-haemolytic streptococci, Borrelia burgdorferi, Brucella spp., Campylobacter jejuni, Chlamydia spp., Clostridium spp., Corynebacterium diphtheriae, Neisseria spp.,
Haemophilus influenza, Legionella pneumophila, Listeria monocytogenes, Mycoplasma pneumoniae, Neisseria meningitidis, Salmonella (Berta and Typhi), Streptococcus pneumoniae, Staphylococcus spp. and Treponema pallidum
Protozoa: Entamoeba histolytica, Leishmania spp., Plasmodium vivax, Plasmodium falciparum, Toxoplasma gondii and Trypanosoma cruzi
Helminths: Taenia spp., Echinococcus spp., Schistosoma spp., Toxocara spp. and Trichinella spp.
Fungi: Actinomyces spp., Aspergillus spp., Candida spp., Coccidioides immitis and
Cryptococcus neoformans
Dilated cardiomyopathy: etiology
Autoimmunity: autoimmune diseases, including systemic sclerosis, rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis, sarcoidosis, Dressler syndrome, post-cardiotomy syndrome, post-infectious autoimmune disease and post-radiation autoimmune disease
Toxin exposure: alcohol, amphetamines, anthracyclines, cannabis, catecholamines, cocaine, 5-fluorouracil, lithium, heavy metals (cobalt, lead and mercury) and carbon monoxide
Metabolic or endocrine dysfunction: Cushing disease, hypothyroidism, hyperthyroidism, phaeochromocytoma, chronic hypocalcaemia, hypophosphataemia and inborn errors of metabolism such as mitochondrial diseases and nutritional deficiency (carnitine, thiamine and selenium)
Neuromuscular diseases: various forms of muscular dystrophy and myotonic dystrophy, dystrophinopathies, Friedreich ataxia and myotonic dystrophy
Pregnancy and peripartum cardiomyopathy
Dilated cardiomyopathy: history and physical
A large number of patients with DCM may have a long latent period where they are clinically asymptomatic.
In addition to a focused cardiac history and examination, a more thorough evaluation is recommended to identify any systemic disease or secondary causes.
Classic symptoms include paroxysmal nocturnal dyspnea, orthopnea, leg swelling, and shortness of breath. Nonspecific symptoms of fatigue, malaise, and weakness also can be present. More severe cases can present with thromboembolic complications, conduction disturbances, arrhythmias or even sudden cardiac death.
Physical examination findings are largely not specific to other causes of cardiomyopathy and consist of typical findings seen with congestive heart failure.
Dilated cardiomyopathy: evaluation
Evaluation for secondary causes of dilated cardiomyopathy (DCM) always should be pursued prior to making the diagnosis of idiopathic DCM. Workup is focused on identifying any possible reversible causes.
Basic investigations such as serum urea and electrolytes, creatinine, full blood count, liver function tests, creatine kinase, troponin I, BNP are recommended. Recommended laboratory testing includes thyroid function tests, HIV serology, electrolytes, and iron studies (to rule out hemochromatosis).
Dilated cardiomyopathy: evaluation
Echocardiography is crucial in making the diagnosis of DCM and provides an objective assessment of ventricular size, function, and any associated valvular abnormalities.
Electrocardiogram (EKG) may show nonspecific ST segment and T wave abnormalities. ECG may also reveal atrial fibrillation.
Chest X-ray may show cardiomegaly and evidence of pulmonary effusions and venous congestion.
Coronary angiography should be performed in patients with a high pretest probability of CAD. Computed tomography coronary angiography (CTCA) may be considered in patients with a low to intermediate pre-test probability of CAD.
In certain familial cases, genetic testing should be considered.
Very rarely, a myocardial biopsy is needed for the evaluation of storage diseases or infiltrative causes when suspected.