We aimed to assess accuracy of Doppler Tissue Imaging (DTI) to detect right ventricle (RV) dysfunction and electromechanical coupling alteration following pulmonary hypertension (PHT) in rat. PHT was induced by chronic hypoxia exposure (hypoxic-PHT) or monocrotaline treatment (monocrotaline-PHT). In both PHT-models, we observed transparietal RV pressure increase and remodeling including hypertrophy and dilation. Conventional echocardiography provided evidence for pulmonary outflow impairment with midsystolic notch and acceleration time decrease in PHT-groups (21.7±1.6 ms and 13.2±2.9 ms in hypoxic-PHT- and monocrotaline-PHT groups vs 28.1±1.0 ms in control). RV shortening-fraction was decreased in monocrotaline-PHT group (15±6 %) compared to hypoxic-PHT- and control groups (36±5 % and 36±8 %, respectively). Combinating conventional Doppler and DTI was more helpful to detect RV diastolic dysfunction in monocrotaline-PHT group (E/Ea ratio = 17.0±1.4) compared to hypoxic-PHT- and control groups (11.5±0.7 and 10.2±0.4, respectively). Tei index measured by DTI highlighted global RV dysfunction in monocrotaline-PHT group (1.36±0.24 vs 0.92±0.05 and 0.86±0.05 in hypoxic-PHT- and control groups, respectively). Q-S_m time measured from the onset of Q wave to the onset of DTI S_m wave was increased in both PHT-groups (48.4±7.1 ms and 44.9±3.1 ms in monocrotaline-PHT- and hypoxic-PHTgroups vs 24.3±1.5 ms in control). PHT-induced electromechanical coupling alteration was confirmed by in vitro activation-contraction delay measurements on isolated RV papillary muscle, and both Q-S_m time and activation-contraction delay were correlated with PHT severity. We demonstrated that Q-S_m time measured in DTI was an easily and convenient index to detect early RV electromechanical coupling alteration in both moderate- and severe-PHT.