There are very few people in the world of echocardiography for whom we have more respect than Dr Feigenbaum. In fact, it is quite difficult to argue with someone of his stature and dispute some of the points he raised in his letter. However, we were given the opportunity to respond and would like to explain our perspective without any biases.
In his letter, Dr Feigenbaum raises several interesting issues, some more philosophical and others more practical. The first one that falls into the former category is the role of echocardiography among today’s cardiac imaging modalities. We certainly agree with Dr Feigenbaum’s perspective that in many ways echocardiography is unique; it differs from other modalities in the manner in which imaging is performed, and it is more difficult for someone to excel in echocardiography in terms of acquiring images tailored to answer specific clinical questions.
On the other hand, Dr Feigenbaum focuses on the perceived competition among cardiac imaging modalities. One example is the change in the anatomic nomenclature convention, specifically the name of the myocardial segment echocardiographers used to refer to as the “posterior” wall but was later renamed in an American Heart Association, American College of Cardiology, and American Society of Echocardiography guidelines as “inferolateral” to establish uniformity across imaging modalities. Dr Feigenbaum describes this change of name as a “mistake” and suggests that we should go back to calling this segment “posterior” again. We have no problem with either name, as long as cardiologists who discuss a case and make a joint decision regarding optimal treatment understand one another and as long as the use of different naming conventions does not impede communication.
Dr Feigenbaum gives another example in which “we made a mistake” by trying to improve uniformity with nuclear cardiology. This refers to the orientation of the schematic diagram of the short-axis view of the left ventricle. His point is that on echocardiographic short-axis views, the anteroseptal segment is at the top, while nuclear cardiology and other imaging modalities commonly show the same diagram rotated 30° counterclockwise. This results in the anterior segment’s being at the top, reflecting the actual human anatomy. He also notes that the 2005 American Society of Echocardiography chamber quantification guidelines depict myocardial segments in this latter orientation, and he states that this scheme was not adopted by most laboratories. In his view, “this fact means that the primary goal of the 2005 guideline document was not met.” With all due respect, this statement would be true only if one were to assume that the primary goal of that guideline document was indeed to force the world of echocardiography to use the nuclear segmentation scheme and always show the short-axis views with the anterior wall at the top.
As members of the writing committee charged by the American Society of Echocardiography and the European Association of Echocardiography with the task of writing the chamber quantification guidelines, published in both 2005 and 2015, we would like to clarify that this has never been the primary goal or a goal that was consciously discussed and decided upon. These documents are the product of many months of work by a large group of experts carefully selected by the two societies, on the basis of their expertise and track records of publications. The goals of these documents were carefully determined and prioritized by the writing group in comprehensive and in-depth discussions that preceded the writing process. The goals of both chamber quantification guideline documents were numerous and most importantly included the establishment of normal values and a detailed description of how different measurements should be performed to ensure uniformity, which is extremely important for the correct interpretation of quantitative data. We believe that these goals were indeed met. Over the decade since their publication in JASE , the 2005 guidelines have been cited in the scientific literature more than 5,500 times, which is more than all the remaining articles combined that were published in the journal that year. We also believe that it is reasonably easy for an echocardiographer to mentally rotate the segmentation scheme 30° to correctly identify the left ventricular segments, with the understanding that the parasternal short-axis view is not acquired with the transducer in the anatomically anterior position.
The final example of a problem, according to Dr Feigenbaum’s letter, is the leading edge–to–leading edge measurement convention to quantify the size of the aorta proposed by the guidelines. We completely agree that contemporary ultrasound imaging technology has evolved to a point that in most patients, the spatial resolution of the images is such that one can easily see both the inner and outer boundaries of the aorta. Nevertheless, the committee’s choice to continue prior recommendations to use the leading edge–to–leading edge measurements was driven by its wish to avoid confusion, because most published normal echocardiography-derived values for these dimensions have been based on this convention. Moreover, indications for surgery on the ascending aorta have been established using criteria based on leading edge–to–leading edge measurements. Therefore, in some diseases, such as Marfan syndrome, the use of inner edge–to–inner edge measurements (approximately 3 mm smaller) could delay intervention and significantly increase the risk for dissection or rupture. This was one of the reasons why the decision was made to avoid changing cutoff values for aortic interventions, as described in the guideline documents. We believe that over time, this methodology will likely be updated, when the body of knowledge is sufficient to support normal values for inner edge–to–inner edge measurements.
By definition, when decisions are reached by consensus, there is someone in the group who would have done it differently. For that reason, decisions in writing groups are made on the basis of the majority opinion. We understand that there are probably other echocardiographers who share the concerns expressed in Dr Feigenbaum’s letter, including the above practical issues and also the perspective that echocardiography is threatened by other “competitive” imaging modalities. We understand this realistic concern, but we would argue that we all should strive to work together to achieve the best care for our patients, which includes choosing the diagnostic tools that are best suited to answer the specific clinical question at hand for each patient.