Abstract
We appreciate the review provided by Dr Blanco. 1 We agree that the angle of insonation is critical when obtaining the left ventricular outflow tract (LVOT) velocity-time integral (VTI). As the calculated velocity of blood is proportional to the angle of insonation (cosine theta), significant error is introduced in the calculation as the angle exceeds 20° (i.e. up to 13% error when theta is equal to 30°). Our sonographers are trained to obtain velocities minimizing the angle of insonation so as not to exceed 20°; however, we recognize variation in anatomy and imaging windows may render this challenging in certain patients. The images we provided with our manuscript were not created with sufficient precision to demonstrate this concept. 2 We appreciate the modified images, which demonstrate angle measurement technique.
Footnotes
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
