Abstract Body (Do not enter title and authors here): Background
Right ventricular (RV) dysfunction is a common complication after myocardial infarction (MI) and a risk factor for adverse events. Effect of sacubitril/valsartan (S/V) on RV function in patients after MI is unknown.

Hypothesis
RV dysfunction is associated with adverse events following high-risk MI and treatment with S/V attenuates adverse RV remodeling and functional impairments in high-risk post-MI patients.

Aims
To compare the baseline clinical and echocardiographic parameters by quartiles of RV fractional area change (RVFAC), and to evaluate the effect of S/V (compared to ramipril) on RV size and function from randomization to 8 months in post-MI patients with LVEF≤40% and/or pulmonary congestion.

Methods
Among the 5,661 participants in PARADISE-MI trial, 544 were enrolled in the echocardiographic sub-study. Baseline characteristics were assessed across quartiles of RVFAC (N=446). Cox proportional hazards model was used to assess the association between RVFAC and clinical outcomes. Treatment effects of S/V compared to ramipril on were assessed using linear regression. The primary outcome was cardiovascular (CV) death or incident HF (defined as HF hospitalization or outpatient symptomatic HF).

Results
Baseline clinical characteristics were similar across quartiles of RVFAC, with the exception that patients with higher RVFAC were more likely to be female (Table 1). Higher RVFAC was associated with higher LVEF, smaller LV chamber size, and lower E/e’ ratios (Table 1). A lower baseline RVFAC was associated with a higher risk of incident HF, but not associated with a higher risk of primary outcome or CV death (Figure 1). Changes of RVFAC, RV end-diastolic area, RV end-systolic area, tricuspid annular S’, and RV outflow tract velocity-time integral from randomization to 8 months were similar in those randomized to S/V compared to ramipril. Baseline RVFAC did not modify the treatment effect of S/V on RV size or RVFAC (p-interaction > 0.16).

Conclusion
In high-risk post-MI patients, a lower RVFAC was associated with worse LV systolic and diastolic function and higher risk of incident HF. Compared to ramipril, S/V was not superior in improving RV systolic function.