Aims: The relationship of cardiac magnetic resonance (CMR) late gadolinium enhancement (LGE) with myocardial biomarkers and markers of inflammation in acute viral myocarditis is not clearly defined. We assessed the relationship of LGE with myocardial and inflammatory biomarkers measured during the acute phase of myocarditis and their predictive value on clinical outcome.
Methods: Patients with first clinical episode of acute viral myocarditis and complete CMR study, including cine and LGE images, were included. The peak values of troponin I, creatine kinase, C-reactive protein value at admission and LGE extent were reported for each case. A 29-month clinical follow-up was performed, and cardiac symptoms and adverse cardiac events (all-cause death, heart transplant, hospitalization for heart failure) were reported.
Results: Forty-one patients (39 ± 15 years and 78% men) were included. Median LGE extent was 13% [interquartile range (IQR) (9%, 19%)] of left-ventricular mass and mean left-ventricular ejection fraction was 56 ± 11%. There was a significant correlation between peak troponin I and LGE extent (r = 0.51, P < 0.001), and between peak creatine kinase and LGE extent (r = 0.66, P < 0.001). There was no correlation between C-reactive protein at admission and LGE extent (r = 0.27, P = 0.09). At follow-up, eight (20%) patients had an adverse clinical event. LGE extent was significantly associated with a worse New York Heart Association status at follow-up [odds ratio (OR) 1.21, 95% confidence interval (CI) 1.07, 1.37, P = 0.002]. After adjustment for left-ventricular ejection fraction, age and clinical presentation category, LGE extent remained an independent predictor of cardiovascular events (hazard ratio 1.42; 95% CI 1.05, 1.95, P = 0.027).
Conclusions: LGE extent on CMR studies is significantly correlated to biomarkers of myocardial injury in patients with acute viral myocarditis, and is a significant independent predictor of adverse cardiovascular outcome.