Abstract 18051: High Prevalence of Active Myocarditis in Patients with Takotsubo Cardiomyopathy: A Magnetic Resonance-endomyocardial Biopsy Study
Background: Tako-tsubo cardiomyopathy (TTC) was recently classified as a cardiomyopathy with distinct clinical and angiographic features, but mechanisms of cardiac dysfunction and histological substrate are still largely unclear. We evaluated cardiac magnetic resonance (CMR) and endomyocardial biopsy (EMB) findings in patients with TTC.
Methods: Twenty consecutive patients (19 F, 58±12 years) with clinical and angiographic features of TTC underwent CMR with edema (STIR images) and delayed enhancement (DE) studies. Of these, 15 patients also underwent EMB. Myocardial samples obtained from apical akinetic left ventricular segments were processed for histology, immunohistochemistry and polymerase chain reaction (PCR) for cardiotropic viruses.
Results: All patients presented acute chest pain with ST-segment elevation in anterior leads and evidence of myocardial necrosis. Symptoms were precipitated by emotional stress in 12 (60%) cases. At CMR DE was observed in 11 patients (55%) in all cases with a subepicardial or midventricular pattern; edema was observed in 10 (50%) patients, associated with DE in 8 cases. Neither DE nor edema was observed in 7 patients. In 11 patients (73%) EMB showed an active lymphocytic myocarditis with evidence of activated T lymphocytes. In 4 patients (27%) contraction band necrosis was observed. PCR identified parvovirus B19 viral genome in 3 patients with myocarditis. Among patients with a histological diagnosis of myocarditis CMR showed DE in 10 and edema in 8 cases. One patient with myocarditis had neither DE nor edema at CMR. Patients with contraction-band necrosis showed no DE or edema at CMR. Three myocarditis virus-negative patients failing to recovery after 6 weeks from clinical presentation, received prednisone and azathioprine for 8 weeks with significant improvement of left ventricular contractility.
Conclusions: Acute myocarditis represents a frequent substrate of TTC. CMR may help to identify myocardial inflammation in TTC patients. Immunohistochemical and virological diagnosis through EMB may affect both treatment and prognosis. Further studies are needed to clarify the prevalence of acute myocarditis among TTC patients and the possible association between emotional stress and viral infection.
- © 2011 by American Heart Association, Inc.