Some forms of myocarditis may show a predominance of lymphocytes.
Presentations:
(1) heart failure unresponsive to usual therapy
(2) ST-segment elevation mimicking an acute myocardial infarct
(3) cardiac arrhythmias with variable syncope
Endomyocardial biopsy shows lymphocytes without giant cells or significant numbers of eosinophils. There is usually myocyte necrosis.
Potential causes:
(1) viral infection (coxsackie B, adenovirus, EBV, parvovirus B19, HCV, other)
(2) autoimmune-associated, which may show cardiac autoantibodies
Extracardiac involvement may include:
(1) myositis (mimics giant cell myositis except no giant cells, raising the possibility of sampling error or small numbers of giant cells)
(2) flu-like symptoms
Patients with autoimmune disease or HCV may respond to immunosuppression. Fulminant disease may require heart transplant.
