PROGNOSTIC ROLE AND HEMODYNAMIC MECHANISM OF IMPAIRED AEROBIC CAPACITY IN ADULTS WITH EBSTEIN ANOMALY

Abstract Background Patients with Ebstein anomaly have impaired aerobic capacity, but the relationship between aerobic capacity and clinical outcomes are unknown. The purpose of this study was to determine the prognostic role of aerobic capacity and the hemodynamic mechanism underlying temporal deterioration in aerobic capacity in this population. Methods Retrospective cohort study of adults with Ebstein anomaly that underwent exercise test (2000–2018). Primary objective was to determine the relationship between aerobic capacity (%-predicted peak oxygen consumption, VO2) and cardiovascular adverse events (death, heart transplant, aborted sudden death, and heart failure hospitalization). Secondary objective was to delineate the relationship between temporal change in hemodynamic indices and subsequent decline in peak VO2. Results We studied 248 patients (peak VO2 22.4 ​± ​7.1 ​ml/kg/min; 64 ​± ​21 %-predicted), and these events occurred during follow-up (death n ​= ​12, transplant n ​= ​1, aborted sudden death n ​= ​7, and heart failure hospitalization n ​= ​11). Peak VO2 was an independent predictor of cardiovascular adverse events (hazard ratio 1.32; 95% confidence interval 1.18–1.59, p ​= ​0.002 per 5%-point decrease). Of 101 patients with ≥2 exercise tests, %-predicted peak VO2 decreased by 2.3%-points/year, and rate of decline correlated with change in right atrial (RA) strain and left heart hemodynamics. Hemodynamic deterioration started with RA dysfunction, followed by left heart hemodynamic impairment, and then decline in peak VO2. Conclusions Peak VO2 is a predictor of cardiovascular adverse events in Ebstein anomaly. Temporal decline in peak VO2 was preceded by RA dysfunction and left heart hemodynamic impairment suggesting that impaired aerobic capacity represents a late stage in disease pathogenesis.