Outcomes and predictors of recovery in acute-onset cardiomyopathy: A single-center experience of patients undergoing endomyocardial biopsy for new heart failure

Background About one-third of patients with unexplained acute-onset heart failure (HF) recover left ventricular (LV) function; however, characterization of these patients in the setting of contemporary HF therapies is limited. We aim to describe baseline characteristics and predictors of recovery in patients with acute-onset cardiomyopathy. Methods We previously described 851 patients with unexplained HF undergoing endomyocardial biopsy. In this study, 235 patients with acute-onset HF were further retrospectively examined. Results Follow-up LV ejection fraction (LVEF) was available for 138 patients. At 1 year, 48 of 138 (33%) had LVEF recovery (follow-up LVEF ≥50%), and 90 of 138 (65%) had incomplete or lack of recovery. Higher cardiac index (P = .019), smaller LV diastolic diameter (P = .002), and lack of an intraventricular conduction delay (IVCD) (P = .002) were associated with LVEF recovery. IVCD (P = .001) and myocarditis (P = .016) were independent predictors of the composite end point of death, LV assist device placement, and/or transplant at 1 year. Those with an IVCD had a significantly lower 1-year survival than those without (P = .007). Conclusions Patients with a smaller LV end-diastolic diameter, higher cardiac index, and lack of IVCD at presentation for acute-onset HF were more likely to have LVEF recovery. IVCD was a poor prognostic marker in all patients presenting with acute cardiomyopathy.