Abstract Body (Do not enter title and authors here): Background: Deceleration time (DT) of mitral E wave is a well-researched predictor of clinical outcome in cardiovascular patients. It reflects cardiac chamber stiffness or impaired relaxation. However, one of the main limitations of DT is that it is influenced by the E wave peak velocity, which can lead to prolonged DT despite impaired compliance. In contrast, the deceleration slope (D-slope) of mitral E wave is an independent parameter regardless of E wave velocity, but its clinical significance in pulmonary hypertension (PH) remains unclear.

Purpose: This study aimed to retrospectively investigate the relationship between D-slope and clinical outcomes in patients with PH.

Methods: This was a single center cohort involving 118 patients diagnosed with PH between January 2010 and December 2022. Only WHO Group 1,2, or 4 PH patients were enrolled. Echocardiograms performed closest to the date of right heart catheterization were analyzed. All-cause mortality and hospitalization due to the disease were assessed.

Results: During a median 3.2 ± 2.6 follow-up years, all-cause death occurred in 19 patients. Mean D-slope was 493 cm/s². In the Kaplan-Meier analysis, low D-slope group (< 493cm/s²) showed a higher survival rate than high D-slope group (91.1% vs 58.2%, p=0.011). Although the hospitalization rate tended to be lower in the low D-slope group, the difference was not statistically significant (65.3% vs 54.9%, p=0.146). In the univariate Cox regression, D-slope showed an association with all-cause mortality (HR 1.002, 95% CI 1.0 – 1.003, p=0.009) and hospitalization (HR 1.001, 95% CI 1.000 – 1.002, p=0.019).

Conclusions: In patients diagnosed with pulmonary hypertension through right heart catheterization, the mitral E wave deceleration slope may serve as a valuable predictor of all-cause mortality.