Objective: Primary objective was to establish the prognostic value of the myocardial load of PVB19 genomes in patients presenting for work-up of myocarditis and/or unclear cardiomyopathy in comparison to clinical, and CMR parameters.
Methods: 108 consecutive patients who underwent EMB because of suspected myocarditis and/or unclear cardiomyopathy, and had evidence of myocardial PVB19 genome, were enrolled. Primary endpoint was all-cause mortality; secondary endpoint was a composite of cardiac mortality and hospitalization for heart failure.
Results: Mean LV-EF was 40%. We found n = 27 patients to have a viral load ≥ 500 GE (IQR 559-846), n = 72 had 100-499 GE, and n = 9 had <100 GE. Immunohistology revealed chronic myocarditis in n = 66, acute myocarditis in n = 1, DCM in n = 17, PVB19 genome only in n = 13, and other pathologies in n = 11. During follow-up 11 patients died, two suffered SCD but were successfully shocked by ICD, and 21 were hospitalized for heart failure. Interestingly, not the viral load, but functional parameters such as LV-EF, LV-EDV (endpoint 2), as well as the histologic diagnosis of DCM and the presence of LGE (for all endpoints) reached statistical significance. In fact, the presence of LGE yields an odds-ratio for a lethal event of 8.56 (endpoint 1), and of 5.52 for endpoint 2. No patient with normal LV-EF, or the absence of LGE, suffered cardiac death during long-term follow-up.
Conclusion: The viral load of PVB19 genomes in the myocardium is not related to the long-term outcome. Furthermore, this study suggests a growing role of imaging for risk stratification in non-ischemic myocardial disease.
Keywords: Cardiovascular magnetic resonance; Mortality; Myocarditis; PVB19; Prognosis.