Mitral Valve Prolapse in Active Patients: Recognition, Treatment, and Exercise Recommendations
Elizabeth Joy, MDTHE PHYSICIAN AND SPORTSMEDICINE - VOL 24 - NO. 7 - JULY 96
If your browser does not support tables click here.
In Brief: In most people, mitral valve prolapse, which affects women more than men, is a benign condition with few or no symptoms. But in some patients it poses a significant problem. Potential sequelae include endocarditis, serious arrhythmia, and sudden death. Although a midsystolic click followed by a late systolic murmur is characteristic, definitive diagnosis requires echocardiography. Treatment ranges from education and reassurance in those who have mild disease to valve replacement in severe cases. Most athletes who have mitral valve prolapse can safely participate in all activities. Those with evidence of significant valvular disease, serious arrhythmia, or a family history of sudden death due to mitral valve prolapse, however, should participate only in low-intensity competitive sports.
Mitral valve prolapse (MVP) affects up to 5% of the general population and up to 17% of young women and girls (1). Because of its relatively high prevalence, this disorder is of particular concern to physicians caring for athletes and other active patients. In most individuals, MVP is benign and causes few, if any, symptoms. People with more significant valvular abnormalities, however, appear to be at greater risk for serious complications, including bacterial endocarditis, arrhythmia, and sudden death (2). Identifying patients at risk for complications of MVP, therefore, is paramount before optimal treatment and exercise recommendations can be implemented.
Pathophysiology and Epidemiology
MVP is, by definition, abnormal systolic displacement of the mitral valve leaflets superiorly and posteriorly from the left ventricle into the left atrium (3). MVP appears to be a heterogeneous disease, with affected patients demonstrating a continuum of both valvular disease severity and symptomatology.
MVP is most often a primary, autosomally dominant condition (3). Inherited abnormalities of valvular connective tissue result in redundancy and/or thickening of valve leaflets. This leads to various degrees of distensibility, poor leaflet opposition, and subsequent prolapse. Recent evidence suggests that these aberrations of leaflet microarchitecture may also be accompanied by widespread abnormalities of connective tissue elsewhere in the body (4). MVP may also be present in people with other connective tissue diseases such as Marfan syndrome and Ehlers-Danlos syndrome (3,4).
In addition to the valvular changes in MVP, a subset of patients have associated neuroendocrine abnormalities and autonomic dysfunction. This results in a wide variety of symptoms involving multiple organ systems and has been referred to as mitral valve prolapse syndrome (MVPS) (4,5). Patients complain of fatigue, dyspnea, chest pain, palpitations, panic attacks, and many other symptoms that cannot be explained on the basis of their valvular abnormalities alone (5). Research has demonstrated high adrenergic activity in people with MVPS. This is thought to be a result of increased serum levels of catecholamines coupled with adrenergic hyperresponsiveness (4). This may explain the "hypersensitivity" to certain stressful stimuli demonstrated by some MVPS patients.
MVP can affect both men and women; however, more than 60% of adults with MVP are women (3). The prevalence of MVP in athletes is unknown.
Symptoms of Valvular Disease
Two groups of patients with documented prolapse emerge from the literature: those whose symptoms are directly related to their valvular disease, and those whose symptoms cannot be explained on the basis of their valvular disease alone. The first group has been referred to as MVP-anatomic, and the second group as having MVPS (4,5). Some symptom crossover exists between the two groups, and researchers disagree as to whether these two distinct groups even exist (3). It is believed that palpitations are one of the few symptoms experienced by patients who have MVP that has a basis in valve dysfunction alone (3).
Those with MVPS have a constellation of systemic symptoms. The pathogenesis of these symptoms is not well understood but is thought to be multifactorial, including adrenergic hyperresponsiveness, autonomic dysfunction, and an abnormal renin aldosterone response to volume depletion. These patients often have low resting blood pressure, thought to be related to low intravascular volume. Hypotension is thought to contribute to the dizziness or syncope that some patients who have MVP experience (4). This is of particular importance to athletes with MVP because they may be more sensitive to dehydration induced by vigorous physical activity, and thus at higher risk for exercise-induced syncope.
Other symptoms reported by those with both MVP and MVPS include chest pain, fatigue, dyspnea, exercise intolerance, headache, sleep disorders, anxiety and panic attacks, irritable bowel symptoms, and vascular symptoms such as flushing and cold extremities (5).
Key Diagnostic Findings
The workup for MVP and MVPS is the same. MVP is usually recognized by its characteristic auscultatory findings: a midsystolic click followed by a late systolic murmur. The click results from a tightening of the chord-leaflet structures at the time of maximum prolapse, and the murmur from mitral regurgitation (5). Neither the presence nor absence of these findings, however, confirms or excludes the diagnosis of MVP. Maneuvers that reduce left ventricular volume, such as having the patient sit or stand, cause the click and murmur to move closer to the first heart sound. Conversely, having the patient squat will increase left ventricular volume, causing the murmur to either disappear or decrease in intensity. When a click or murmur is present and responds appropriately to the aforementioned maneuvers, an auscultatory diagnosis of MVP can be made.
Echocardiography has markedly improved recognition and assessment of MVP. Patients with auscultatory findings and/or a history suggestive of MVP should undergo an echocardiogram to further evaluate leaflet structure and identify any regurgitation. The echocardiographic diagnosis is made when one or both mitral valve leaflets protrudes or billows into the left atrium in the apical long-axis view (3). Mild bowing of normal-appearing leaflets seen in the four-chamber view probably represents a normal variant and does not warrant a diagnosis of MVP.
Echocardiography can also help classify patients as having low, mild, moderate, or high risk of complications (table 1). Those who show no evidence of mitral regurgitation or valve thickening or redundancy are at lowest risk. Echocardiography is particularly useful for evaluating abnormalities in more severe forms of the disease. Thickening of the leaflets, enlargement of both leaflets and annulus, and significant systolic protrusion of one or more of the leaflets are associated with severe mitral regurgitation and convey a poorer prognosis (6,7). Two-dimensional echo also allows evaluation of atrial and ventricular anatomy and function (which can be altered by chronic mitral regurgitation).
Doppler echocardiography is useful in evaluating the size and intensity of the mitral regurgitant flow or jet. The severity of mitral regurgitation is determined by the regurgitant volume. Mitral regurgitation results in increased diastolic filling of the left ventricle and increased left atrial pressure. Patients with chronic regurgitation consequently have a hard time effectively increasing their cardiac output, and the increases in left atrial pressure and volume can lead to left atrial enlargement and atrial fibrillation. Eventually, both left and right heart failure can result if the mitral regurgitation is not treated appropriately (8).
Other tests to consider in the patient with MVP include electrocardiography to screen for conduction disturbance, 24-hour Holter monitoring to evaluate those with palpitations, graded exercise stress testing to monitor exercise tolerance, and stress echocardiography. The stress echo may prove helpful in identifying those at highest risk for certain complications. A recent study (8) shows that compared with a control group, patients with exercise-induced mitral regurgitation are more likely to develop congestive heart failure, syncope, and progressive mitral regurgitation leading to valve replacement. (For a primer on common sequelae, see "Complications of Mitral Valve Prolapse".)
The evaluation of chest pain in a patient with MVP is difficult. The etiology of chest pain in MVP is unclear, making the choice of diagnostic tests challenging. There are no characteristic electrocardiographic features. Graded exercise stress testing is unlikely to show evidence of ischemia, unless the patient also has risk factors for coronary artery disease. One should evaluate each patient individually with respect to the medical history, symptoms, and the situation in which symptoms occur.
Management and Risk Stratification
Management of MVP should be centered on patient education, symptom and risk management, and ongoing risk stratification (table 1). For those in the low-risk category, patient education is the only treatment indicated. It should focus on the generally benign nature of the condition and reassure patients that they can live long, healthy lives. Oral antibiotic prophylaxis is not required. Follow-up echocardiography in 5 years is reasonable, unless other symptoms warrant evaluation sooner (3).
Patients with mild regurgitation and/or valve abnormalities require oral antibiotic prophylaxis. Even mild hypertension should be treated, and weight loss should be encouraged in those who are overweight. Echocardiographic reevaluation at 2- to 3-year intervals is appropriate (3).
At highest risk are those who suffer from moderate-to-severe mitral regurgitation. This group is most likely to require valve replacement, and every effort should be made to reduce factors that increase regurgitation. In addition to reducing weight and controlling blood pressure, static exercise such as weight lifting should be avoided because it may result in dramatic increases in blood pressure, thereby worsening mitral regurgitation. High-risk patients require yearly Doppler evaluation. Valve replacement should be considered in patients who have worsening dyspnea and diminished left ventricular function (3).
In patients who have symptoms suggestive of MVPS, lifestyle modification is the key to reducing symptoms. Dietary changes such as avoidance of caffeine may reduce palpitations. Avoidance or restriction of products containing a lot of sugar may lessen the fatigue experienced by some MVPS sufferers. Liberal fluid intake and minimal alcohol and caffeine intake will minimize the effect that dehydration has on the hypovolemia experienced by some patients (5). Encouraging adequate sodium chloride intake in those with symptomatic hypotension may also help (4).
Medication management in patients who have MVP is fairly limited. In those with documented, hemodynamically stable, nonsustained tachyarrhythmias, or in those who have distressing palpitations, a cardioselective beta-blocker may be helpful. Patients who have atrial fibrillation need anticoagulation therapy, and they may need rate control with digoxin.
A family physician should seek cardiology consultation for anyone who has mitral valve disease with mitral regurgitation, significant arrhythmias, or a family history of sudden death due to MVP.
Aerobic exercise should be encouraged for all patients with MVP. One study (9) demonstrated that a 12-week aerobic exercise program improved the symptoms and functional capacity of women with documented MVP. Compared with the control group, the exercise group showed a significant decrease in anxiety, as well as increases in general well-being and functional capacity, and a decline in symptoms such as chest pain, fatigue, dizziness, and mood swings. A supervised program is recommended for those who have significant cardiac compromise.
The 26th Bethesda Conference (2,10,11) addressed the topic of exercise for athletes who have either MVP or mitral regurgitation. The recommendations:
Mitral valve prolapse. Athletes with MVP (having a structurally abnormal valve manifested by leaflet thickening and elongation) and without any of the following criteria can engage in all competitive sports:
Athletes with MVP and one or more of the aforementioned criteria can participate in only low-intensity competitive sports (class 1A, table 2: not shown) (11).
Mitral valve regurgitation (mild). Exercise recommendations vary for patients who have MVP with mild mitral regurgitation. Athletes in sinus rhythm with normal left ventricular size and function can participate in all competitive sports. Athletes in sinus rhythm or atrial fibrillation with mild left ventricular enlargement and normal left ventricular function at rest can participate in low and moderate static and moderate dynamic competitive sports (classes 1A, 1B, 2A, and 2B, table 2: not shown). Selected athletes can engage in some low and moderate static and low, moderate, and high dynamic competitive sports (classes 1A, 1B, 1C, 2A, 2B, and 2C, table 2: not shown). When a patient has atrial fibrillation, exercise testing can help ensure that the ventricular rate response to exercise will not be excessive.
Athletes with definite left ventricular enlargement or any degree of left ventricular dysfunction at rest should not participate in any competitive sports. Patients on chronic anticoagulation therapy should avoid sports involving body contact.
It's important to remember that MVP rarely results in serious complications. Nonetheless, people who have MVP must be identified—and their risk level assessed—for optimal management of symptoms and risk. Pursuing the appropriate work-up and proceeding with targeted therapy will allow patients to lead safe, healthy, active lives.
Dr Joy is a family physician in private practice in Salt Lake City and a fellow of the American College of Sports Medicine. Address correspondence to Elizabeth Joy, MD, 2295 Foothill Dr, Salt Lake City, UT 84109.