Pulmonary hypertension is defined as a mean arterial pressure of ≥25 mmHg as confirmed on right heart catheterisation. Traditionally, the pulmonary arterial systolic pressure has been estimated on echo by utilising the simplified Bernoulli equation from the peak tricuspid regurgitant velocity and adding this to an estimate of right atrial pressure. Previous studies have demonstrated a correlation between this estimate of pulmonary arterial systolic pressure and that obtained from invasive measurement across a cohort of patients. However, for an individual patient significant overestimation and underestimation can occur and the levels of agreement between the two is poor. Recent guidance has suggested that echocardiographic assessment of pulmonary hypertension should be limited to determining the probability of pulmonary hypertension being present rather than estimating the pulmonary artery pressure. In those patients in whom the presence of pulmonary hypertension requires confirmation, this should be done with right heart catheterisation when indicated. This guideline protocol from the British Society of Echocardiography aims to outline a practical approach to assessing the probability of pulmonary hypertension using echocardiography and should be used in conjunction with the previously published minimum dataset for a standard transthoracic echocardiogram.

The error relates to the calculation of RVSP given on page G13. The original text stated:'When estimating right ventricular systolic pressure (RVSP) from the TRV using the Bernoulli equation, the TRV is squared and multiplied by 4, so even small errors in the absolute measurement of TRV can result in significant changes to the estimate of RVSP. Secondly, in order to obtain an estimate of PASP, the RVSP needs to be added to an estimate of the RAP derived from measurement of the inferior vena cava (IVC) dimensions and response to inspiration. However, in many patients, IVC dimensions cannot be obtained and even in those where measurement is possible, the accuracy between echo estimation of RAP and invasive measurement is as low as 34%'. This should have stated:'When estimating the peak pressure difference between the right ventricle (RV) and the right atrium (RA) from the tricuspid regurgitation velocity (TRV) using the simplified Bernoulli equation, the TRV is squared and multiplied by 4, so even small errors in the absolute measurement of TRV can result in significant changes to the estimation of the RV-RA pressure gradient. Secondly, in order to obtain an estimate of pulmonary artery systolic pressure (PASP), an estimate of the right atrial pressure (RAP) (derived from measurement of the inferior vena cava (IVC) dimensions and response to inspiration) needs to be added to the estimate of the RV-RA pressure gradient. However, in many patients, IVC dimensions cannot be obtained and even in those where measurement is possible, the accuracy between echo estimation of RAP and invasive measurement is as low as 34%'.

LA function is independently associated with surgery-free survival in patients with mitral valve prolapse and moderate to severe mitral regurgitation. Quantitative assessment of LA function may have clinical utility in guiding early surgical intervention in these patients.

Ring et al. 1 It is a very well-documented report assessing the need for earlier surgical intervention in patients with mitral valve prolapse and moderate to severe mitral regurgitation, using novel echocardiographic indices such as left atrial (LA) wall strain derived from speckle-tracking imaging. The authors stated that contractile and reservoir strain of the left atrium displays subtle early alterations that precede the development of clinical or classical echocardiographic features regarding LA function. It is well established that a dilated left atrium has impaired compliance and contractility, 2 leading to tissue remodeling, which changes the stress/strain distribution because of altered pressure/flow and stress realationship. 3 In their Table 1, as LA functional indices, the authors used both volumetric (total LA emptying fraction) and myocardial (reservoir and contractile strain) indices. 1 We suggest that the impaired myocardial indices are due to the change of geometry of the left atrium (dilated left atrium, impaired total LA emptying fraction), not vice versa. The authors did not clearly state in their statistical analysis regarding the multivariate Cox proportional-hazard models that the possible confounding versus effect modification or interaction was examined, 4 because the LA volume variable may act as an effect modifier and a confounder at the same time.We would like to thank the authors for their intriguing work and to emphasize that myocardial-derived speckle-tracking imaging indices of the left atrium may reflect the degree of tissue remodeling that occurs in the stretched LA wall. Figure 1 Sequential Cox proportional-hazard models demonstrating the incremental discriminatory value of differing echocardiographic markers in the identification of patients with MR who are at risk for surgical intervention: (A) including maximal LA volume and (B) including minimal LA volume. EROA, Effective regurgitant orifice area; LVIDd, LV internal diameter in diastole; PA, pulmonary artery.