An overview of measurements achievable by echocardiography (echo), cardiac magnetic resonance imaging (CMRI) and right heart catheterisation (RHC) during the assessment of pulmonary hypertension (PH)

 Pericardial effusionEasy to perform, relevant for follow-up [14]Can be useful as a supplement to echo [15]NA
 PAPEstimation of PAP based on TRV; some controversy versus invasive techniques, and pitfalls have been described, e.g. false interpretation of the spectral wave envelope, sweep velocity set too slow and valve closure artefacts [16]NAFundamental measurement for distinguishing PAH from other forms of PH [7, 17]
 Right atrial areaReference values for right atrial area in healthy adult subjects have been described [18]; easy to perform, accurateReference values for right atrial area in healthy adult subjects have been described [19]NA
 RV areaEthnicity, sex and training effects (Asians and females have smaller RV area, sportsmen have higher area [20]); not useful for screening; high variation, even in healthy subjectsConsidered the gold standard for measuring ventricular volume, mass and structure [21]NA
 RV massNANA
 RV dimensionsRV basal, mid-cavity and longitudinal dimensions on a four-chamber view should be measured in patients with PH [22]; high variationNA
 RV wall thicknessRV thickness can be assessed; thickness >5 mm may suggest RV pressure overload in the absence of other pathologies [22]Can be measured directly through evaluation of RV mass [23], or indirectly based on the need for increased myocardial perfusion [21]NA
 Eccentricity indexPredictive of poor outcomes [24]NANA
 Central pulmonary artery diameterReference values have not been determinedNANA
 RVEFThree-dimensional echo is more accurate and reproducible than two-dimensional echo [13]Can be calculated retrospectively from the stroke volume divided by the end-diastolic volume [25]NA
 TAPSEDirectly measures RV function; does not require post hoc analyses or expertise to measure [26]NANA
 Tei index (RV myocardial   performance index)Calculated as the sum of RV isovolumetric contraction time/ejection time and isovolumetric relaxation time/ejection time [27]NANA
 RV end-systolic elastance, arterial   elastanceNACMRI-derived indices have been combined with RHC variables to determine right ventriculo–arterial coupling [28]NA
  • PAP: pulmonary arterial pressure; RV: right ventricular; RVEF: right ventricular ejection fraction; TAPSE: tricuspid annular plane systolic excursion; NA: not applicable; TRV: tricuspid regurgitation velocity; PAH: pulmonary arterial hypertension.