I commend the work of Groh et al . looking at the differences in estimating right ventricular pressures (i.e., tricuspid valve gradients) using Doppler echocardiography compared with catheter-measured pressures. Doppler-derived tricuspid valve gradients are ubiquitous in pediatric echocardiography, so understanding their accuracy is a very important matter. I especially commend the authors’ including the assessment of spectral Doppler envelope quality in their work (which is a step missing in numerous previously published works from others) and their decision to compare maximal right ventricular–right atrial pressure differences calculated from Doppler velocity recordings with invasive results, while others have generally compared calculated right ventricular systolic pressures determined by Doppler, which requires estimation of right atrial pressures.

Having said that, I have concerns regarding the statements the authors make in their conclusions. The data they present do not support such definitive conclusions, because there are at least two major concerns with their study design. One concern is actually in one sense a strength and in another sense a weakness of the study. The authors state that one sonographer scanned 80% of the patients and that this lowered the risk for interobserver variability in image acquisition. Although true, to support such strong conclusions, it would not be wise to disregard the use of tricuspid regurgitation gradients on the basis of the results of one investigation from scans from primarily one sonographer. The other concern, which the authors bring up themselves, regards the possibility that they were unable to capture the highest tricuspid regurgitation Doppler spectral velocities. It may be a bit old fashioned, but perhaps further investigation may show that the use of a continuous-wave PEDOF transducer and/or a nonsupine position will correct many of the discrepancies seen.