Myocarditis endomyocardial biopsy

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-In-Chief: Varun Kumar M.B.B.S., Maliha Shakil, M.D. [2]

Overview[edit | edit source]

Endomyocardial biopsy remains the gold standard test to evaluate for the presence of and to subclassify the type of myocarditis. A small tissue sample of the endocardium and myocardium is obtained via right sided cardiac catheterization. The sample is then evaluated by a pathologist using immunochemistry and special staining techniques as necessary. Histopathological features include abundant edema in the myocardial interstitium and an inflammatory infiltrate which is rich in lymphocytes and macrophages. Focal destruction of myocytes as a result of the inflammatory process results in left ventricular dysfunction.^[1] Endomyocardial biopsy is recommended when the results would identify an underlying disease that is amenable to therapy. Routine performance of endomyocardial biopsy is not recommended in all patients with myocarditis.

Endomyocardial Biopsy[edit | edit source]

• The Heart Failure Society of America recommends that performance of endomyocardial biopsy should be considered when cardiac function deteriorates acutely with an unknown etiology that is unresponsive to medical therapy (Strength of Evidence = B).^[2]

• Non-specific findings such as hypertrophy, cell loss, and fibrosis may be noted on biopsy. However, biopsy findings that significantly impact patient management have not been conclusively established.^[3] Although inflammatory changes in the myocardium may be detected in viral myocarditis, the majority of patients with biopsy proven myocarditis improve with supportive therapy alone without the need for antiviral or anti-inflammatory treatment.^[4] Endomyocardial biopsy has a low sensitivity and specificity which could be explained by the focal and transient nature of the inflammatory infiltrates.^[5][6]

Standardizing the Interpretation of Endomyocardial Biopsies: The Dallas Criteria[edit | edit source]

Histologically, both active inflammatory infiltrate within the myocardium and associated myocyte necrosis (the Dallas pathologic criteria) are present in myocarditis. Despite its limitations, the Dallas criteria have established uniform histologic criteria diagnosing myocarditis and have substantially reduced the variability in diagnosing the disease. Some of the criteria are as follows:^[7]

Scenarios in Which Endomyocardial Biopsy May Be Useful^[8][9][edit | edit source]

• Subacute or acute symptoms of heart failure refractory to standard management
• Rapid worsening of ejection fraction despite standard pharmacological therapy
• Development of cardiac arrhythmias such as ventricular tachycardia and/or heart block
• Heart failure with concomitant rash, fever, or peripheral eosinophilia
• Cardiac dysfunction thought to be secondary to the following conditions as the results of endomyocardial biopsy may alter the therapy:
  • Collagen vascular diseases:
    • Systemic lupus erythematosus
    • Scleroderma
    • Polyarteritis nodosum
  • Infiltrative diseases:
    • Amyloidosis: These patients are not eligible for cardiac transplantation.
    • Sarcoidosis
    • Hemachromatosis
  • Giant cell myocarditis: Myocardial biopsy may optimize the management of these patients by identifying patients who may benefit from early heart transplantation.^[10]

Complications of Endomyocardial Biopsy[edit | edit source]

• Complications may be as high as 6% as observed in a series where 546 patients with cardiomyopathy underwent right ventricular endomyocardial biopsy.^[11] Several other studies reported the incidence of complications to be 0.5 to 1.5%.^[12][13]

• Complications of endomyocardial biopsy include:^[12][14]

• Myocardial perforation leading to pericardial tamponade
• Heart block
• Pulmonary embolization
• Pneumothorax
• Nerve injury
• Hematoma
• Tricuspid valve damage
• Arteriovenous fistula
• Deep venous thrombosis
• Bleeding at the puncture site (venous/arterial due to accidental arterial puncture)
• Arrhythmias (supraventricular tachycardia/ventricular tachycardia/complete heart block)
• Tricuspid valve damage
• Coronary artery to right ventricle fistula

2009 ACC/AHA Focused Update and 2005 Guidelines for the Diagnosis and Management of Chronic Heart Failure in the Adult (DO NOT EDIT) ^[15][edit | edit source]

Endomyocardial Biopsy in Patients Presenting With Heart Failure (DO NOT EDIT) ^[15][edit | edit source]

2007 AHA/ACCF/ESC Scientific Statement: The Role of Endomyocardial Biopsy (EMB) in Fourteen Clinical Scenarios^[14][edit | edit source]

References[edit | edit source]

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