Introduction: Dysfunction of the systemic right ventricle (RV) in hypoplastic left heart syndrome (HLHS) remains a primary determinant of transplant free survival. However, a subgroup of those with systemic dysfunction successfully undergo staged surgical palliation. The natural history of ventricular dysfunction over a patient lifetime is not well understood. We describe trends in RV function in a cohort of patient with HLHS and delineate the relationship with transplant free survival.
Methods: The SickKids Heart Failure (HF) Database is a retrospective cohort of HF patients from 2001 to 2017, including all patients with HLHS and at least mild RV dysfunction on echocardiogram lasting >30 days, or death or transplant within 30 days of onset of dysfunction. Normalization of ventricular function was defined as normal RV function lasting > 30 days after dysfunction onset. The primary endpoint was death or transplant. Descriptive statistics and time to event analysis were used.
Results: Our cohort included 99 patients with a median (IQR) age at onset of dysfunction of 2.6 (1 - 5.3) months. Normalization of RV function was observed in 51 (52%) for a median (IQR) duration of 3.5 (0.8 - 9.1) years and 28 (55%) had multiple periods of normal function. There was no significant difference in incidence of severe dysfunction between the two groups (41 vs 52%, p=0.6). Transplant free survival was improved in those with normalization of RV function (78 % vs. 14 %, p<0.001, Figure 1C) independent of surgical stage (p=0.03, figure 1D).

Conclusion: Right ventricular dysfunction in HLHS correlates with poor transplant free survival, but outcomes improve in those with persistent normalization of function. This data should inform decision making regarding likelihood of success of staged surgical palliation versus consideration for transplant listing.