Long-Term Follow-Up of Biopsy-Proven Myocarditis: Predictors of Mortality and Incomplete Recovery
Study Questions:
What are predictors of poor outcome in patients with viral myocarditis?
Methods:
This was a single-center analysis of consecutive patients with biopsy-proven viral myocarditis (myocardial inflammation and viral genome), who underwent cardiac magnetic resonance imaging (CMR) within 5 days of presentation. The primary endpoints of interest were all-cause mortality and cardiac mortality.
Results:
Of the 222 patients with viral myocarditis, 203 (91.5%) completed a median 4.7 years of follow-up and 77 of these had a follow-up CMR. Median [interquartile range] patient age was 52 [40-54] years. By CMR, mean left ventricular ejection fraction (LVEF) was 45%, LV end-diastolic volume was 167 ml, and late gadolinium enhancement (LGE) was present in 108 (53%) at diagnosis. All-cause mortality was 19% (n = 28), cardiac mortality was 15%, and sudden cardiac death was 9.9%. On univariate analysis, older age, worse New York Heart Association (NYHA) class, and CMR abnormalities (including lower LVEF, LV dilation, LGE) were associated with increased risk of death on follow-up. LGE was associated with an adjusted 8.4-fold (p = 0.004) higher risk of death and 12.8 risk of cardiac death (p < 0.01). In the 77 patients with follow-up CMRs, NYHA class >1 at hospital presentation was associated with a higher likelihood of persistent myocardial dysfunction on follow-up.
Conclusions:
The authors concluded that viral myocarditis affords a high risk of death and LGE is associated with poor outcome.
Perspective:
Patients with myocarditis tend to be young and outcome can be highly variable. In this analysis, the authors show that patients with biopsy-proven myocarditis warrant close clinical follow-up, especially if abnormalities on CMR are noted. Examining survival based on the presence of LGE, the survival curves separated late (more than 1 year after presentation). Because LGE represents scar, LGE likely identifies a ventricle less likely to recover after the initial viral insult. While this is a low-powered study due to the fact that it is a single-center analysis of an uncommon disease, LGE identified 97% (28 of 29) of patients who had a cardiac death from myocarditis. However, only 28% (28 of 99) of myocarditis patients with LGE died. While CMR sensitivity for the detection of myocarditis is poor (53%), it identifies higher risk myocarditis patients. Patients with myocarditis who have LGE should be watched closely for several years. However, data are insufficient to become complacent in those without LGE.
Keywords: Biopsy, Gadolinium, Virus Diseases, Myocarditis, Magnetic Resonance Imaging
< Back to Listings