Right heart function measured with echocardiography
| Lowlanders | Highlanders | Mean difference (95% CI) | p-value | |
| Subjects | 76 | 97 | ||
| sPAP mmHg# | 23±5 | 30±10 | 7 (5 to 10) | <0.001 |
| mPAP mmHg | 17±4 | 22±6 | 5 (3 to 7) | <0.001 |
| TTPG mmHg# | 20±5 | 26±8 | 6 (4 to 9) | <0.001 |
| TR Vmax m·s−1# | 2.2±0.3 | 2.5±0.4 | 0.3 (0.2 to 0.4) | <0.001 |
| RAP mmHg | 3±1 | 4±3 | 1.0 (0.1 to 1.5) | 0.033 |
| AT RVOT m·s−1 | 127±21 | 93±14 | −33 (−39 to −28) | <0.001 |
| PCWP mmHg | 11±2 | 10±3 | −0.4 (−1.2 to 0.4) | 0.354 |
| PVR WU | 1.5±1.1 | 2.9±1.8 | 1.4 (0.9 to 1.9) | <0.001 |
| PVR (haematocrit- adjusted) WU | 1.6±1.3 | 2.8±1.9 | 1.2 (0.6 to 1.7) | <0.001 |
| Cardiac output L·min−1 | 4.3±0.9 | 4.3±1.0 | −0.0 (−0.3 to 0.3) | 0.906 |
| TAPSE cm | 2.1±0.3 | 2.0±0.3 | −0.1 (−0.2 to −0.0) | 0.039 |
| TASV cm·s−1 | 13.4±2.4 | 12.5±2.1 | −0.9 (−1.6 to −0.2) | 0.008 |
| RV FAC % | 42±6 | 39±8 | −3 (−6 to −1) | 0.003 |
| RV end-systolic area cm2 | 9.4±2.3 | 12.1±3.7 | 2.7 (1.7 to 3.8) | <0.001 |
| RV end-diastolic area cm2 | 16.1±3.2 | 19.7±5.2 | 3.6 (2.1 to 5.0) | <0.001 |
| RV/LV ratio | 0.7±0.1 | 0.8±0.2 | 0.1 (0.4 to 0.1) | <0.001 |
| LV EI systolic | 1.0±0.1 | 1.1±0.1 | 0.1 (0.0 to 0.1) | <0.001 |
| LV EI diastolic | 1.0±0.0 | 1.0±0.1 | 0.0 (0.0 to 0.1) | 0.002 |
| RV wall thickness cm | 0.38±0.08 | 0.43±0.11 | 0.05 (0.02 to 0.08) | 0.002 |
| RA volume index mL·m−2 | 19.6±6.0 | 22.9±8.3 | 3.3 (0.9 to 5.6) | 0.006 |
| RA diameter cm | 4.5±0.5 | 4.4±0.6 | 0 (0 to 0) | 0.386 |
| RA area cm2 | 13.8±3.3 | 14.8±5.0 | 1.1 (−0.3 to 2.5) | 0.120 |
| RVA cm·s−1 | 38.8±10.5 | 39.3±11.1 | 0.5 (−3.3 to 4.4) | 0.782 |
| RVE cm·s−1 | 57±9 | 45±12 | −13 (−17 to −9) | <0.001 |
| RVE/A | 1.6±0.4 | 1.2±0.4 | −0.4 (−0.5 to −0.2) | <0.001 |
| RVa′ cm·s−1 | 13.1±3.9 | 13.1±3.9 | −0.1 (−1.3 to 1.1) | 0.903 |
| RVe′ cm·s−1 | 11.8±2.6 | 11.0±3.3 | −0.7 (−1.6 to 0.2) | 0.116 |
| RVE/e′ | 5.1±1.4 | 4.2±1.4 | −0.9 (−1.4 to −0.4) | 0.001 |
| TAPSE/sPAP mm·mmHg−1 | 1.0±0.3 | 0.7±0.2 | −0.3 (−0.4 to −0.2) | <0.001 |
Data are presented as n or mean±sd, unless otherwise stated. sPAP: systolic pulmonary arterial pressure; mPAP: mean pulmonary arterial pressure; TTPG: transtricuspid pressure gradient; TR Vmax: maximal tricuspid regurgitation velocity; RAP: right atrial pressure; AT RVOT: acceleration time right ventricular outflow tract; PCWP: pulmonary capillary wedge pressure; PVR: pulmonary vascular resistance; WU: Woods units; TAPSE: tricuspid annular plane systolic excursion; TASV: tricuspid annular systolic velocity; RV: right ventricle; FAC: fractional area change; LV: left ventricle; EI: eccentricity index; RA: right atrium; RVA: pulsed wave Doppler A-wave for late diastolic active filling of the right ventricle; RVE: pulsed wave Doppler E-wave for early passive filling of the right ventricle; RVE/A: right ventricular ratio of the early to late ventricular filling velocities; RVe′: tissue Doppler of the early diastole; RVa′: tissue Doppler of the atrial contraction. #: trans-tricuspid regurgitation was present in 64 (84%) out of 76 lowlanders and in 83 (85%) out of 97 highlanders.