Mitral Valve Prolapse (MVP)
by DrRich
Mitral valve prolapse (MVP) is one of the most commonly
made cardiac diagnoses. Unfortunately, it is also one of the most
commonly misunderstood - both by patients and their doctors. As
a result, many of the millions of Americans carrying this diagnosis have
no clear understanding of what MVP is, what significance it has, what, if
anything, they should be doing about it – or indeed, whether they even really
have it.
What is MVP?
Click here for a quick and easy review of the heart's chambers and valves.
Mitral Valve Prolapse (MVP) occurs when abnormalities in the mitral valve allow it
to flop (i.e., to prolapse) back into the left atrium as the left ventricle
contracts, thus allowing a certain amount of backflow of blood (i.e. regurgitation)
from the ventricle to the atrium.
The diagnosis of MVP is generally suspected when the doctor
hears the classic “click-murmur” while listening to the heart (the click
being caused by the prolapsing of the mitral valve; the murmur by the subsequent
regurgitation of blood), and is confirmed with an echocardiogram (a test in
which an image is generated by bouncing sound waves off the heart.)
MVP is extremely common.
Roughly 2% to 4% of the general population will have MVP on
echocardiographic screening (a much lower proportion, however, than previously
thought). Further, there is often a
genetic predisposition to MVP. If a
person has true MVP, it is likely that about 30% of his/her close relatives will
also have it.
Why is MVP significant?
Two clinical problems are caused directly by MVP:
significant mitral regurgitation, and
bacterial endocarditis (i.e., infection of
the mitral valve).
If severe
enough, mitral regurgitation can lead to enlargement of the cardiac
chambers, weakening of the heart muscle, and ultimately, to heart failure.
The risk of developing a cardiac infection – endocarditis
– increases any time a leaky valve is present within the heart.
Fortunately endocarditis associated with MVP is rare, but prophylactic
antibiotics should be prescribed for these individuals prior to any procedure
likely to “seed” the bloodstream with bacteria.
(The most common procedure that does this is a visit to the dentist.)
What is the prognosis with MVP?
The vast majority of patients with MVP can expect to lead
completely normal lives, without any symptoms due to their MVP and without any
decrease in longevity. Indeed, some
studies suggest that patients with MVP may enjoy an increased lifespan as
compared to the general population.
What other clinical problems have been attributed to
MVP?
Because MVP is common, it has been associated with a myriad
of conditions that probably do not have anything to do with the MVP itself.
Here are the more common conditions that have been
associated with MVP, but whose actual relationship to MVP is tenuous at best.
Anxiety, chest pain, palpitations. While it is commonly believed that MVP causes these symptoms, most individuals with MVP do not experience them, and most individuals with anxiety, chest pain and palpitations do not have MVP.
Stroke or sudden death.
It has never been shown that MVP itself causes either stroke or
sudden death, or that the incidence of MVP is higher than normal in patients who
experience these problems. Patients
with severe mitral regurgitation – from any cause – have an increased risk
of stroke and sudden death, but those with run-of-the-mill MVP probably have the
same risk as the general population.
The dysautonomia syndromes: chronic fatigue syndrome,
vasovagal (or neurocardiogenic) syncope, panic attacks, fibromyalgia.
(Click here for a review of dysautonomia.)
It is not at all clear that patients with MVP have an increased propensity to
the symptoms associated with the dysautonomias (palpitations, anxiety, fatigue,
aches and pains.) But in their desperation to make a diagnosis in
patients complaining of such symptoms, and thus by ordering every test known to
man, doctors have found (naturally) that a proportion of these difficult
patients have MVP. Doctors have
thus coined the phrase “Mitral Valve Prolapse Syndrome” (MVPS) to explain it.
Again, however, these conditions are very often present without any sign
of MVP (no matter how urgently one looks).
Whether the MVP actually has anything whatever to do with these symptoms
is very doubtful.
The overdiagnosis of MVP
It now appears that MVP has been systematically overdiagnosed
for many years.
Indeed, in some studies, up to 35% of the general population was found to have
MVP by echocardiography
In a landmark article in the New England Journal of Medicine in 1999, researchers documented that, when using strict diagnostic criteria, MVP is seen in only 2% of the population. This figure still means that millions of Americans have MVP, but underscores the gross overdiagnosis that has been seen habitually with this condition during the past decades.
This overdiagnosis is a problem for several reasons. Patients are labeled as having a “cardiac condition” when in fact they have none. Such a label has possible insurability implications. Patients are placed on prophylactic antibiotics inappropriately. But more importantly, difficult but treatable conditions (like the dysautonomia syndromes) are “written off” as being caused by MVP, and potentially effective therapies ignored.
General recommendations
If you have been told you have MVP, you ought to consider
doing the following:
1) Make sure the diagnosis is correct. Ask your doctor if she made the diagnosis of MVP using the Freed criteria (the criteria used by the authors of the New England Journal study mentioned above). If she did not, or if she doesn’t know what you’re talking about, you should consider getting a second opinion.
2) If you do have true MVP, make sure you have been fully instructed about antibiotic prophylaxis for endocarditis.
3) If you do have true MVP, make sure you understand from your physician the degree of mitral regurgitation you have (i.e., minimal vs. moderate or severe), and that your doctor has outlined a schedule for following the degree of regurgitation over time.
4) If you have chest pain or palpitations, these symptoms ought to be evaluated as separate entities. If your doctor merely writes these symptoms off as being due to MVP, without ever performing an evaluation, remember the First Rule in being an effective patient: You hired him; you can fire him.
5) If you think you may have one of the dysautonomia syndromes, make sure your doctor is well-versed in managing these conditions, works with you to develop a treatment plan, and is committed to working with you long-term to alleviate your symptoms. Again, don’t waste time with a doctor who seems too willing to write off your symptoms as "just one of those things" that goes along with MVP. The dysautonomias are real, honest-to-goodness physiologic disorders. While their treatment is often difficult, they can be treated. And while they’re enough to make anyone crazy, they are not to be dismissed as being caused by either MVP or craziness.
Relevant sites
Sites giving acceptable overviews of MVP. (Some of these sites, as do most websites and textbooks discussing MVP, continue to attribute the symptoms of dysautonomia to MVP itself. This medical lore is so deeply ingrained that it may take a generation or two to correct it. The actual information on MVP itself at these sites, however, is accurate and timely.)
The American Heart Association
The MV Prolapse Center of Alabama
Recent information on the incidence and symptoms of MVP (These sites relate some of the more carefully conducted and up-to-date research on MVP, and the implications of that research.)
Freed et al. on the actual prevalence of MVP - this is an abstract of the 1999 landmark article in the New England Journal of Medicine that should change much of the thinking on MVP within the medical community.
Lack of association of MVP with stroke - also from the New England Journal in 1999.
NHLBI press release on MVP - The National Heart, Lung and Blood Institute responds to recent data on MVP
Sites focusing on MVPS and/or dysautonomia (An understanding of the dysautonomia syndromes is slowly being elucidated. These sites address dysautonomia, but often persist in referring to it as "Mitral Valve Prolapse Syndrome" despite the lack of a proven relationship between dysautonomia and MVP.)
The Society for Mitral Valve Prolapse Syndrome
National Dysautonomia Research Foundation
A review by DrRich on Dysautonomia
Personal web pages and support groups (Some of the personal stories on MVP appearing on the web are truly heart rending, but in fact are stories about dysautonomia. If you ignore the MVP aspect - and think of the prolapse as just an incidental finding in this person with a significant autonomic nervous system imbalance - these stories can be quite enlightening.)
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