Long-Term Follow-Up of Biopsy-Proven Viral Myocarditis: Predictors of Mortality and Incomplete Recovery
Do certain clinical or radiologic features of myocarditis confer prognosis?
Consecutive patients (n = 203) presenting with biopsy-proven myocarditis (inflammation and viral genome presence) underwent cardiac magnetic resonance imaging (MRI) within 5 days of presentation. Patients were followed clinically and 77 underwent repeat MRI. The outcomes of interest included all-cause death and cardiac death (sudden cardiac death [SCD], heart failure, aborted SCD).
The median [interquartile range] patient age was 52 [40-54] years, 22% had a positive troponin at presentation, and 35% and 10% of patients had New York Heart Association (NYHA) class III and IV heart failure, respectively. On cardiac MRI, the median ejection fraction (EF) was 45% [31-60], 53% had evidence of late gadolinium enhancement (LGE), and left ventricular end-diastolic volume (LVEDV) was 167 [129-210] ml. On biopsy, 56% of patients had parvoB19 virus present and 24% had HHV-6. There were 28 deaths (14%) and 11 (5%) survivors of SCD over a median follow-up of 4.7 years. The presence of LGE on initial MRI afforded an 8.4 higher hazard for all-cause mortality and 12.8 hazard for cardiac mortality (p < 0.05). In the 77 patients who underwent follow-up CMR, NYHA class >1 at presentation was associated with increased risk of incomplete recovery (defined as LVEF <60% and LVEDV >180 ml, p = 0.03).
In this cohort with myocarditis, the finding of LGE at presentation was associated with worse outcome.
Outcomes following myocarditis presentation can be highly variable, and a means of predicting survival would be helpful. In this analysis of patients with biopsy evidence of myocarditis, it appears that abnormal gadolinium enhancement on index hospitalization MRI affords worse prognosis. While the Kaplan-Meier curves cannot be shown in this summary, a very interesting finding is that the mortality curves based on LGE presence begin to separate at 1 year following myocarditis presentation. The reasons for this warrant further study: Does LGE identify a patient presenting ‘later’ (subacute or chronic myocarditis), or does it suggest the patient has a more detrimental immune response? Finally, many patients have presumed myocarditis with evidence of inflammation on biopsy, but no viral particles in the myocardium. The significance of LGE in this cohort would be of interest as well.
Keywords: Inflammation, Gadolinium, Herpesvirus 6, Human, Myocarditis, Survivors, Heart Diseases, Prognosis, Heart Failure, Virus Diseases, Stroke Volume, Virion, Hospitalization, Death, Sudden, Cardiac, Troponin
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