Does Mitral Valve Prolapse Cause Sudden Death?

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In the 2007 Chicago Marathon a runner collapsed and died, making national headlines. After performing an autopsy, the Chicago medical examiner announced that this man's sudden death definitively was not due to the oppressive heat and humidity that caused significant problems among many runners that day (and which eventually caused organizers to stop the race), but instead was due to "mitral valve prolapse" (MVP).

This verdict no doubt brought very great relief to the local officials responsible for going ahead with the race despite horrific weather conditions, and who were now officially not responsible in any way for this man's death.

Obviously, I have no way of knowing the actual cause of this unfortunate runner's death, and I will not speculate on it. However, while it took local race officials off the hook, the Chicago medical examiner's confident pronouncement also created at least some degree of panic among up to 75 million Americans who (by some estimates) might also have MVP. And for a few weeks American cardiologists were flooded with worried phone calls.

So, the question bears asking: Does MVP really cause sudden death?

The answer is that there does appear to be a slight increase in the risk of sudden death in people who have significant MVP - but not in the large majority of people who have received the diagnosis of MVP.


Initial evidence that MVP may be commonly associated with sudden death came mainly from autopsy series. When the heart is carefully examined in people who have died suddenly, evidence of MVP can be found in a substantial minority. In these victims, their deaths are most often attributed to MVP. 

What is not mentioned in these studies is that when you are determined to find MVP, you will be able to find at least some evidence of it in a large proportion of the general population.

In fact, when you perform echocardiography in randomly selected people, depending on the diagnostic criteria used, MVP could be diagnosed in up to 20% - 35%. The vast majority of these prolapsing mitral valves are physiologically insignificant, and pose no known threat.  Indeed, it seems obvious (to me, at least) that the condition "MVP" has been grossly over-diagnosed by cardiologists.

The ability to detect some amount of MVP if you look for it hard enough can be very convenient for doctors (or for that matter, for race officials), because it can absolve them of having to look any further to explain symptoms or conditions that are difficult or inconvenient to diagnose or manage (dysautonomia being the most prominent of these). Hence, the over-diagnosis of MVP.

In 2008, recognizing that the diagnosis of MVP had grown inappropriately to epidemic proportions, the American College of Cardiology and American Heart Association published more stringent criteria for diagnosing MVP.  Using these more appropriate criteria to make the diagnosis, there is indeed evidence of a somewhat increased risk of cardiac arrhythmias and sudden death, though that excess risk is still very small.

(The main risk for these patients is not sudden death, but the development of significant mitral regurgitation (valve leakage), and subsequent heart failure.) 

But the prevalence of this kind of MVP (that is, "real" MVP) in the general population is only around 1-2%, and not 35%. And even among this much smaller number of patients with MVP, fewer than 1 in 20 will ever develop significant mitral valve issues.

It was not clear from news reports whether the Chicago marathoner may have had a severe form of MVP - but given the fact that he apparently had trained for and was competing in a marathon, it seems relatively unlikely.

The bottom line is that it is not at all clear that MVP - at least, the mild form of MVP that the vast majority of people diagnosed with this condition have - is even associated with sudden death, let alone a cause of sudden death. For the large majority of patients who have been told they have MVP, the risk of sudden death is no higher than it is for the general population, and tragedies like the one in Chicago should not cause them undue concern.

If you have been told you have MVP, you should find out from your cardiologist whether the diagnosis was made using the newer, more stringent diagnostic criteria, or whether the diagnosis was made the old-fashioned way, where you can find MVP in almost anyone if you look for it hard enough.


Bonow RO, Carabello BA, Chatterjee K, et al. 2008 Focused update incorporated into the ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. Circulation 2008; 118:e523.

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