Before reading this, if you haven’t read the first few posts, go ahead and read them so you have a good understanding of what mitral valve prolapse is, and how the valve is affected. Mitral valve prolapse has had several names over the years, including floppy valve syndrome, click syndrome, and click murmur syndrome. Up until the 1960’s it was mainly diagnosed by hearing a click when listening to the heart with a stethoscope, thought to be from the prolapsing valve, and often a murmur, that resulted from leakiness through the prolapsing valve. At that point it was recognized that most people with this were never troubled by it, had no symptoms and did well. It was also recognized however, that a small but significant number of those with MVP might have complications such as palpitations, development of severe leakiness that may require surgery to fix it, or rarely develop infection of the valve.
Then in the 70’s echocardiography (ultrasound scan) emerged as a way to image the heart, and visualize the prolapsing leaflet. Everyone was excited as the diagnosis of MVP could now be made by echocardiography and we no longer had to rely on the stethoscope. We could now see the valve buckling back in to the top chamber of the heart, or so we thought! The problem is that we didn’t have a full understanding of the normal structure of the valve, and although in some views it looked like valves were prolapsing, they were in fact normal. Unfortunately that was not realized at the time. This led to an apparent epidemic of MVP with several studies from that time reporting that between 5-10% of the population was affected and some studies suggesting an even higher percentage. One study reported that almost 40% of teenage girls were affected! Suddenly almost every symptom imaginable was attributed to an apparently prolapsing mitral valve. Unfortunately, echocardiography techniques were not refined at that time, and there was little consensus as to the true definition of MVP, leading to a period of great over-diagnosis, and confusion. Some refer to that period as the ‘mitral valve prolapse fiasco.’
Then over the decades, echocardiography continued to develop and we learnt large amounts about the structure and the function of both normal and diseased mitral valves, and we were able to develop a consensus regarding the true definition of mitral valve prolapse. It turned out that many people that were thought to have mitral valve prolapse, did not have it when the accurate criteria were applied (buckling back of the valve of at least 2mm in to the top chamber). More recent studies that applied the correct criteria for diagnosis reported that rather than the 5-10% previously thought, it is more like 2%. This was good and bad.
Bad because it left a lot of people with symptoms that had been attributed to mitral valve prolapse without a diagnosis, (which of course was highly frustrating for affected patients) and left a relative stigma regarding the diagnosis in the medical world. Also many of the studies looking at people with MVP in the past had included people who in fact did not technically have MVP, which severely limited the findings from those studies. The good thing though, is that it then allowed us to focus on those people with true mitral valve prolapse and try to determine accurately the truly MVP associated complication rates, and their outcomes. We will discuss these in more detail in the next post.