Lesson topic №28. Болезни миокарда (Myocarditis and Cardiomyopathy)
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Symptoms of acute myocarditis
In a recent retrospective registry about a quarter of patients had a presentation complicated by LV systolic dysfunction, ventricular arrhythmias, or cardiogenic shock (ie, fulminant myocarditis that accounted).
The majority of AMs had no such complications (uncomplicated AM) and presented chest pain in 97% of cases and ST-segment elevation on ECG in 62.3% of cases, and they had no deaths or heart transplantation (HTx) at 5 years.
Acute myocarditis: Laboratory Tests
Recommended laboratory tests for identification of patients with suspected AM are myocardial necrosis biomarkers (high-sensitivity troponins, creatinine kinase-MB).
Other laboratory tests routinely requested include markers of inflammation such as C-reactive protein that is positive in 80% to 95%
Erythrocyte sedimentation rate is also commonly increased.
Differential white blood count can show eosinophilia, suggesting the presence of eosinophilic myocarditis.
Measurement of the N-terminal fragment of B-type natriuretic peptide (NTproBNP) is also recommended.
Peripheral blood serological and virological tests are rarely informative.
A search for viral genomes with polymerase chain reaction in aerial tract fluids and pharyngeal swabs can identify viruses of the respiratory tract, such as influenza, and severe acute respiratory syndrome
Autoantibodies (eg, antinuclear antibody test) and other tests may be indicated in patients with known or possible history of autoimmune disorders.
Acute myocarditis: ECG
The ECG is abnormal in about 85% of cases,
ST-segment elevation mimicking acute myocardial infarctions is the most frequent abnormality; inferior and lateral leads are commonly involved.
QRS width >120 ms, atrioventricular block, symptomatic bradycardia, or tachycardia and ventricular arrhythmias should increase the suspicion of AM and suggest high-risk forms.
Secondor third-degree atrioventricular block is rarely observed in patients with normal LV ejection fraction (LVEF) >50%.
Acute myocarditis: Echocardiography
Echocardiography is part of the standard evaluation of patients with a suspected acute cardiac condition and may show a broad spectrum of findings.
Even when left ventricular ejection fraction is normal, the presence of increased wall thickness, mild segmental hypokinesia, in particular, in the inferior and inferolateral walls, diastolic dysfunction, abnormal tissue Doppler imaging, mild right ventricular dysfunction, pericardial effusion, and abnormal myocardial echogenicity may suggest AM.
Investigations recommended in all patients with suspected myocarditis
Laboratory investigations
Full blood count (an eosinophilia may be suggestive of an eosinophilic myocarditis)
C-reactive protein and erythrocyte sedimentation rate
Renal function and electrolytes
Liver function tests
Plasma troponin/CK
N-terminal fragment of B-type natriuretic peptide (NT-proBNP)
Imaging/Other investigations
Chest X-ray
Electrocardiography
Transthoracic echocardiography
Cardiovascular magnetic resonance imaging
Endomyocardial biopsy
Endomyocardial biopsy confirms the diagnosis of myocarditis and identifies the underlying etiology and the type of inflammation (e.g. giant cell, eosinophilic myocarditis, sarcoidosis) which imply different treatments and prognosis.
Endomyocardial biopsy may be performed in specific cases when it is deemed likely to significantly impact upon patient management.
An endomyocardial biopsy should be performed in a high-volume center with experience in the management of myocarditis as it is an invasive procedure with associated potential risks. If EMB is performed by experienced teams, its complication rate is low.
Endomyocardial biopsy
The indications for endomyocardial biopsy
New-onset heart failure (<2 weeks) with a normal or dilated left ventricle and haemodynamic compromise or within 2 weeks to 3 months if associated with ventricular arrhythmias, high-grade AV block (second or third degree) or failure to respond to usual care within 1 to 2 weeks.
Acute myocarditis or suspected chronic inflammatory cardiomyopathy associated with peripheral eosinophilia.
Acute myocarditis or chronic inflammatory cardiomyopathy with persistent or relapsing release of biomarkers of myocardial necrosis, particularly if associated to an autoimmune disorder or ventricular arrhythmias or high-degree atrioventricular block.
Myocarditis in the setting of immune checkpoint inhibitor therapy, where appropriate diagnosis has implications for patients receiving additional cancer therapy.
Clinical management
The core principles of treatment in myocarditis are optimal care of arrhythmia and of heart failure and, where supported by evidence, etiology-targeted therapy.
Patients with haemodynamically unstable heart failure should be managed promptly according to current guidelines for heart failure in intensive care units with respiratory and mechanical cardio-pulmonary support facilities.
When myocarditis is suspected in asymptomatic or mildly symptomatic patients, admission to hospital and clinical monitoring are recommended until a definite diagnosis is established, since the situation can evolve rapidly and a cardiopulmonary emergency (e.g. severe heart block or life threatening arrhythmia) is possible and unpredictable, even if systolic function is initially preserved.
Clinical management
Management of ventricular dysfunction should be in line with current guidelines on heart failure.
Physical activity should be restricted during the acute phase of myocarditis until the disease has completely resolved. Athletes should be temporarily excluded from competitive and amateur leisure time sport activity regardless of age, gender, severity of symptoms, or therapeutic regimen. After resolution of the clinical presentation (at least 6 months after the onset of the disease), clinical reassessment is indicated before the athlete resumes competitive sport. Although the duration of restricted physical activity in non-athletes is undefined, it seems reasonable to give similar recommendations.
Clinical management
It's recommended consideration of immunosuppression in proven autoimmune (e.g. infection negative) forms of myocarditis, with no contraindications to immunosuppression, including giant cell myocarditis, cardiac sarcoidosis, and myocarditis associated with known extra-cardiac autoimmune disease.
Immunosuppression may be considered, on an individual basis, in infection-negative lymphocytic myocarditis refractory to standard therapy in patients with no contraindications to immunosuppression.
Steroid therapy is indicated in cardiac sarcoidosis in the presence of ventricular dysfunction and/or arrhythmia and in some forms of infection-negative eosinophilic or toxic myocarditis with heart failure and/or arrhythmia.