Abstract 10515: Mechanical Dyssynchrony in Patients With a Fontan Circulation and Its Relationship to Outcomes

Abstract

Introduction: The prevalence and significance of mechanical dyssynchrony is not well known in the Fontan population. Methods: Single-center, retrospective analysis of CMRs in Fontan patients compared to healthy controls. Feature tracking was performed on all slices of a short-axis cine stack and dyssynchrony index (DI) was defined as the standard deviation of time-to-peak circumferential strain for all segments. A composite outcome was defined as death, heart transplant listing, or new ventricular arrhythmias. Results: A total of 512 cases (17±9 y) and 42 controls (16±9 y) were included. Figure 1 depicts differences in EDV i , EF, DI, and QRS duration between the cohorts. DI correlated with EDV i (r=0.35; p<0.01), EF (r=-0.29; p<0.01), and QRS duration (r=0.29; p<0.01). At a median follow-up of 4.2 yrs, 10% had death or transplant listing and 4% had ventricular arrhythmias. RV dominance, EDV i , EF, DI, and QRS interval were associated with increased risk of the composite outcome (Table 1). Figure 2 demonstrates a significantly higher probability of the composite outcome in those with EDV i >120 ml/m 2 and DI>70 ms. Conclusion: Fontan patients have more mechanical dyssynchrony and longer QRS duration compared to controls. These abnormalities are more pronounced in RV or mixed ventricular morphology and are associated with a higher risk of ventricular arrhythmias, transplant listing, or death.