Myocarditis as a Precipitating Factor for Heart Failure: Evaluation and 1-year Follow-Up Using Cardiovascular Magnetic Resonance and Endomyocardial Biopsy

AIMS: The aim of this study was to evaluate myocarditis as a precipitating factor for heart failure using cardiovascular magnetic resonance (CMR) and endomyocardial biopsy. METHODS AND RESULTS: Eighty-five patients with suspected myocarditis and 20 controls were evaluated. Seventy-one patients with positive CMR were referred for endomyocardial biopsy and re-evaluation after 1 year. Cardiovascular magnetic resonance was performed using STIR T2-weighted (T2W), early T1-weighted (EGE), and late gadolinium-enhanced (LGE) images. Immunohistological and polymerase chain reaction (PCR) analysis of myocardial specimens was employed. In patients with myocarditis, T2 and EGE were increased compared with controls (2.6 ± 0.9 vs. 1.57 ± 0.13, P < 0.001 and 7.9 ± 5.5 vs. 3.59 ± 0.08, P < 0.001, respectively). Late gadolinium enhancement was found in all myocarditis patients. Endomyocardial biopsy performed in 50 of 71 patients with positive CMR showed positive immunohistology in 48% and presence of infectious genomes in 80% (mainly Chlamydia, Herpes, and Parvovirus B19). Left ventricular ejection fraction (LVEF) was significantly decreased compared with controls (47.7 ± 19.2 vs. 64 ± 0.2, P < 0.001). After 1 year, CMR showed normalization of T2 and EGE, and decreased LGE. Left ventricular ejection fraction increased in 36.5% of patients, remained stable in 56.5% and decreased in 7% of patients, in whom biopsy showed persistence of the initial infective agents. A negative correlation was identified between EGE, LGE, and LVEF. Patients with positive biopsies had lower LVEFs. CONCLUSION: In a Greek population with myocarditis, Chlamydia with viruses was a common finding. Cardiovascular magnetic resonance and PCR proved useful for the detection of myocarditis; EGE and LGE had the best correlation for the development of heart failure. Persistence of the initially detected infective agents was identified in patients who deteriorated further.