Abstract 4041: Prognostic Stratification of Biopsy-proven Active Myocarditis Presenting With Heart Failure: Are There Predictors of Long Term Prognosis?
Background: The natural history of active myocarditis (AM) remains incompletely delineated and understood, especially with regard to some subsets of patients (pts). Our aims were to describe the long-term clinical course and identify predictors of outcomes in AM pts presenting with hear failure (HF).
Methods: From 1981 to 2006, 80 pts with clinically manifest and biopsy-proven AM were consecutively enrolled in the Trieste Heart Muscle Disease Registry (mean follow-up 133±100 months). According to the mode of disease onset, the pts were categorized as presenting with HF (Group A, n=51, 64%), arrhythmias (Group B, n=20, 25%), or ischemic-like chest pain (Group C, n=9, 11%). Based on 6-month changes in left ventricular ejection fraction (LVEF), pts of Group A were further classified as “improved” (normalisation or ≥20 points% increase in LVEF) or “not improved”.
Results: Two-, 5-, and 10-year death/heart transplant (D/HTx) free-survival rates in Group A were, respectively, 82, 73 and 63% versus 100, 100 and 79% in Group B, and 100, 100 and 100% in Group C (p=0.001). In Group A, multivariable analysis of characteristics at baseline identified indexed left atrial diameter (iLAD) as the only predictor of D/HTx (for 2 mm/m2 increase: HR 1.42, CI 95% 1.16 –1.75, p=0.001). After 6 months from diagnosis 28 (55%) pts were classified as “improved; no baseline characteristics were predictive of 6-month LVEF changes. Six-month normalization/near-normalization of LV function was a protective factor (HR 0.13, CI 95% 0.03– 0.57, p=0.007); 10-year survival of ”improved“ pts was 100% versus 51% of those ”not improved“ (p<0.001). A model incorporating both 6-month and baseline evaluations showed an incremental prognostic power (AUC 0.82 versus 0.76 of baseline evaluation alone, p<0.001).
Conclusion: AM pts presenting with HF have a poorer long-term outcome as compared to those with other patterns of clinical presentation; still, there are HF pts who are likely to recover spontaneously. Detection of myocardial recovery early in the course of the disease may allow clinicians to identify, by extension, this subset of pts with exceptionally favourable long-term outcome who do not need aggressive management.