Objective: Evaluate factors associated with significant pulmonary hypertension [PH] (≥2/3 systemic) and its impact on ventricular function at 36 weeks postmenstrual age (PMA).Study design: Retrospective cohort of infants born at <29 weeks who survived to their echocardiography screening for PH at 36 weeks PMA. Masked experts extracted conventional and speckle-tracking echocardiography [STE] data.Results: Of 387 infants, 222 were included and 24 (11%) categorized as significant PH. Significant PH was associated with a decrease in tricuspid annular plane systolic excursion (0.79 vs 0.87 cm, p = 0.03), right peak longitudinal strain [pLS] by STE (−19.6 vs −23.1%, p = 0.003) and left pLS (−25.0 vs −22.7%, p = 0.02). The association between biventricular altered function by STE and significant PH persisted after adjustment for potential confounders – LV-pLS (p = 0.007) and RV-pLS (p = 0.01).Conclusion: Our findings are suggestive that premature newborns with significant PH at 36 weeks PMA have a biventricular cardiac involvement to their pathophysiology.