Dr Sanjay Gupta is a consultant cardiologist who posts informative videos online about the heart, primarily to help patients (as opposed to students or fellow practitioners). His videos provide reassurance by improving people’s understanding of various conditions that they may have heard about or potentially suffer from. Dr Gupta recently created a video in which he stated that mild mitral regurgitation (MR) in the context of a visually normal valve was “normal.” I commended the video, but expressed my concern at the use of the term “normal” to refer to mild mitral regurgitation.
What is ‘normal’ mitral regurgitation?
The distinction between ‘clinically insignificant’ and ‘normal’ may seem arbitrary, even a little pedantic, but in my mind, it’s an important one to make not only from a patient’s point of view, but from a professional one, with real unobjective echocardiographic differences between the two (provided everybody is following the same accreditation standards and guidelines – discussed later).
From a patient perspective, the vast majority of individuals following Dr Gupta’s cardiology videos are doing so because they are concerned about some aspect of their heart. Most of us have either experienced first hard, or heard anecdotally, the experience of being repeatedly dismissed by doctors, only to find out – either with persistence or deterioration of health – that it really was something, after all. False reassurance (a false negative), even of something minor, can be as damaging as a false positive; and to an audience who are already highly engaged and looking for answers, maintaining trust is key. Once trust is compromised and the “there’s something wrong and I know it (no matter what they say)” feeling kicks in, differentiating the truly physiological from the psychological becomes almost impossible. Indeed, Dr Gupta addresses the psychosomatic aspect of palpitations in an excellent video, which I include in the list of references below (Gupta, 2015). Therefore, accuracy in terminology is key, because the experience of somebody with true mild mitral regurgitation and somebody with trivial regurgitation may be vastly different.
I would tentatively argue that, if mild MR is being considered a normal variant in some institutions, then those institutions may wish to readdress how they are grading MR in their patients. The clue that we may not be comparing apples with apples was in Dr Gupta’s use of the term “physiological mitral regurgitation.” I can only find this phrase in the title of one research paper (from 1990). Indeed, in general Google and Google Scholar searches, Dr Gupta’s own video is the top search result for this term. It is not in widespread use within the medical community precisely because it has no definition. If it has any definition at all, “physiological” must surely be the equivalent of the echocardiographer’s “trivial” grading – i.e. clinically insignificant. This would make mild mitral regurgitation something different.
Indeed, in one paper that I could find discussing the term “physiological mitral regurgitation,” the author states that “physiological regurgitation can be diagnosed with some confidence when the regurgitant flow on spectral or colour Doppler is confined to the area very close to the valve” – what most of us would consider a “closing jet” of MR. This is indeed “physiological,” but equally, so trivial as to barely receive a mention in an Echocardiographer’s report.
Why the discrepancy?
Low levels of regurgitation are notoriously difficult to quantify. Indeed, trivial and mild levels of mitral regurgitation pretty much evade quantification altogether with current ultrasound methods. This makes the judgement entirely qualitative, and potentially subject to different interpretations within and between institutions. The British Society of Echocardiography (BSE) runs annual meetings and publishes guidelines designed to keep us all ‘singing from the same hymn sheet,’ but not all Echo labs or Echocardiographers are BSE accredited. An Echocardiographer may be highly skilled and experienced, but if they have not kept up to date with the cardiology community as a whole, their reports are not necessarily comparable with those from other institutions. This could lead to a situation where the label of mild mitral regurgitation is accepted as clinically insignificant in one institution, but worthy of serial followup in another where mild mitral regurgitation is a label reserved only for significant leaks in valves or annuli demonstrating some degree of structural abnormality.
As technology and image quality have improved, our understand and terminology have evolved and are continually being refined. The truth is that, when it comes to the mitral valve, we still don’t know what normal is for any given patient. If we did, then the surgical literature would not be filled with debates around how to size annuloplasty rings or coaptation depths. 3D echo would not be being employed to model the valve. We’d already know that for a given body surface area, age and gender, ‘normal’ was x. But we don’t know.
To state that mild mitral regurgitation is “normal” is to effectively dismiss decades of work within the cardiology community. Audacious, to say the least. Instead, it should be recognised that there are differences in the way that MR is graded between institutions and even between individuals, and it should be remembered that any degree of regurgitation can only ever be interpreted within the context of the patient’s clinical history, the visual appearance of their heart, and their symptoms.
References
Gupta, S. (2015) Anxiety, ectopics and palpitations. YouTube.
Houston, A. (1993). Doppler ultrasound and the apparently normal heart. British Heart Journal, 69(2):99-100.
