A prospective study of mitral valvular prolapse in young men

The prevalence of mitral valve prolapse in healthy men and women in Sweden. An echocardiographic study

An asymptomatic population of 100 women and 101 men was studied with M-mode echocardiogram to determine the prevalence of mitral valve prolapse (MVP). One of the two patterns characteristic for MVP was found in 8% of the females and 7% of the males. The diastolic mitral valve excursion was significantly higher in the MVP group (p less than or equal to 0.001). A typical M-mode pattern in combination with a high mitral valve excursion probably enhances the diagnostic specificity.

Angiotensin II type 1 receptor gene polymorphism and mitral valve prolapse syndrome

BACKGROUND

Mitral valve prolapse syndrome (MVPS), a term applied to patients who have a variety of symptoms, has been associated with autonomic or neuroendocrine dysfunction. Recent evidence suggests that effects of angiotensin II mediated by the angiotensin II type 1 (AT(1)) receptor are involved in modulation of cardiovascular autonomic control in human beings. Association of a genetic polymorphism (A-C(1166)) of the AT(1) gene with abnormal vasomotion and low blood pressure related to autonomic control has been reported recently. Because the role of this genetic variant in MVPS has not been studied, we performed a case-control study of the A-C(1166) variant in a group of 76 white subjects with MVPS.

METHODS AND RESULTS

All patients were genotyped by use of a mismatch polymerase chain reaction/Afl II restriction fragment length polymorphism analysis. Frequency of the C(1166) allele was 0.4 in patients with MVPS and 0.26 in control patients. The difference in genotype (chi square = 6.5; P <.05) and allele (chi square = 5.9; P =.02) frequencies between the groups was significant. The odds ratio in favor of carrying the C allele was 4 times greater for patients with MVP than for control patients (95% confidence interval 1.4 to 12.1).

CONCLUSIONS

The current results indicate that the A-C(1166) polymorphism of the angiotensin II type 1 receptor gene is associated with MVPS in the white population.

Anthropometric and physiologic correlates of mitral valve prolapse in a biethnic cohort of young adults: the CARDIA study

OBJECTIVE

To describe the epidemiology of echocardiographic mitral valve prolapse (MVP) and its anthropometric, physiologic, and psychobehavioral correlates with a cross-sectional analysis at 4 urban clinical centers.

PATIENTS

A biethnic, community-based sample of 4136 young (aged 23 to 35 years) adult participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study who had echocardiograms during their third examination between 1990 and 1991.

MEASUREMENTS

Echocardiographic mitral valve prolapse, Doppler mitral regurgitation, blood pressure, anthropometry, and 4 psychobehavioral scales.

RESULTS

Definite echocardiographic MVP prevalence was 0.6% overall and was similar across the 4 ethnicity/sex groups. Most participants (21 of 26, 80%) with definite echocardiographic MVP were unaware of their condition. Relative to persons with normal echocardiograms, those with echocardiographic MVP were taller (174.6 cm vs 171.0 cm, P <.01), leaner (26.7 mm vs 37.4 mm sum of triceps and subscapular skinfolds, P <.01), had lower body mass index (22.0 kg/m(2) vs 26.2 kg/m(2), P <.01), and more often has Doppler mitral regurgitation (34.8% vs 11. 8%, P <.01). Women with echocardiographic MVP had higher ethnicity-adjusted hostility scores (19.9 vs 16.1, P <.05) than women with no MVP. Among 111 (2.7%) of 4136 participants reporting prior physician diagnosis of MVP, only 5 (0.45%) of 111 had definite echocardiographic MVP.

CONCLUSIONS

These data document a low prevalence of definite echocardiographic MVP and suggest a constellation of anthropometric, physiologic, and psychobehavioral characteristics in young adults with echocardiographic MVP. Most definite echocardiographic MVP diagnoses were discordant with self-reported MVP status, and false-positive diagnoses of echocardiographic MVP were made more often in women and whites.

Exercise-induced mitral regurgitation is a predictor of morbid events in subjects with mitral valve prolapse

OBJECTIVES

This study attempted to determine whether a subset of patients with mitral valve prolapse and no mitral regurgitation at rest will develop mitral regurgitation during exercise and have a higher than anticipated risk of morbid cardiovascular events.

BACKGROUND

Mitral regurgitation in patients with mitral valve prolapse identifies a subset of patients at higher risk for morbid events. However, mitral regurgitation in patients with mitral valve prolapse may be intermittent and could go unrecognized. A provocative test to unmask mitral regurgitation in these patients would be useful.

METHODS

Ninety-four adult patients with mitral valve prolapse and no mitral regurgitation at rest were studied during supine bicycle ergometry using color flow Doppler echocardiography in the apical four-chamber and long-axis views. Patients were prospectively followed up for morbid events.

RESULTS

Thirty (32%) of 94 patients had exercise-induced mitral regurgitation. Prospective follow-up (mean 38 months) showed more morbid events in the group with than without mitral regurgitation and included, respectively, syncope (43% vs. 5%, p < 0.0001), congestive heart failure (17% vs. 0%, p < 0.005) and progressive mitral regurgitation requiring mitral valve replacement surgery (10% vs. 0%, p < 0.05). Cerebral embolic events, endocarditis or sudden death were rare and not different between groups.

CONCLUSIONS

In patients with mitral valve prolapse without mitral regurgitation at rest, exercise provokes mitral regurgitation in 32% of patients and predicts a higher risk for morbid events.

Coexistence of mitral valve prolapse in a consecutive group of 528 patients with hypertrophic cardiomyopathy assessed with echocardiography

Hypertrophic cardiomyopathy and mitral valve prolapse are both conditions that may be genetically transmitted and incur a risk for sudden cardiac death. Although the small left ventricular cavity and distorted geometry characteristic of hypertrophic cardiomyopathy might suggest a predisposition to mitral valve prolapse, the frequency with which these two entities coexist and the potential clinical significance of such an association are not known. To further define the relation of hypertrophic cardiomyopathy and mitral valve prolapse, 528 consecutive patients with hypertrophic cardiomyopathy were studied by echocardiography. Patients ranged in age from 1 to 86 years (mean 45); 335 (63%) were male. Unequivocal echocardiographic evidence of systolic mitral valve prolapse into the left atrium was identified in only 16 (3%) of the 528 patients. The mitral valve excised at operation from three of the patients had morphologic characteristics of a floppy mitral valve, which was judged to be responsible for the echocardiographic findings. Occurrence of clinically evident atrial fibrillation was common in patients with hypertrophic cardiomyopathy and mitral valve prolapse (9 [56%] of 16). Hence, in a large group of patients with hypertrophic cardiomyopathy, the association of echocardiographically documented mitral valve prolapse was uncommon. The coexistence of mitral valve prolapse in patients with hypertrophic cardiomyopathy appears to predispose such patients to atrial fibrillation.

Mitral valve prolapse, panic disorder, and chest pain

Mitral valve prolapse is a common cardiac disorder that can readily be diagnosed by characteristic auscultatory and echocardiographic criteria. Although many diseases have been associated with mitral valve prolapse, most affected individuals have the primary form of the disorder. Mitral valve prolapse is an inherited condition commonly associated with myxomatous degeneration of the mitral valve and its support structures. Complications of mitral valve prolapse, including cardiac arrhythmias, sudden death, infective endocarditis, severe mitral regurgitation (with or without chordae tendineae rupture), and cerebral ischemic events, occur infrequently considering the wide prevalence of the disorder. Panic disorder is a specific type of anxiety disorder characterized by at least three panic attacks within a 3-week period or one panic attack followed by fear of subsequent panic attacks for at least 1 month. It too is a common condition with a prevalence and age and gender distribution similar to that of mitral valve prolapse. Panic disorder and mitral valve prolapse share many nonspecific symptoms, including chest pain or discomfort, palpitations, dyspnea, effort intolerance, and pre-syncope. Chest pain is the symptom in both conditions that most commonly brings the patient to medical attention. The clinical description of chest pain in patients with mitral valve prolapse is highly variable, possibly reflecting multiple etiologies. Chest pain in panic disorder is usually characterized as atypical angina pectoris and as such bears resemblance to the chest pain commonly described by patients with mitral valve prolapse. Multiple investigative attempts to elucidate the mechanism of chest pain in both conditions have failed to identify a unifying cause. Review of the literature leaves little doubt that mitral valve prolapse and panic disorder frequently co-occur. Given the similarities in their symptomatology, a high rate of co-occurrence is, in fact, entirely predictable. There is, however, no convincing evidence of a cause-effect relationship between the two disorders, nor has a single pathophysiologic or biochemical mechanism been identified that unites these two common conditions. Until specific biologic markers for these disorders are identified, it may be impossible to do so. The lack of a proven cause-and-effect relationship between mitral valve prolapse and panic disorder and the absence of a unifying mechanism do not diminish the clinical significance of the high rate of co-occurrence between the two conditions. Primary care physicians and cardiologists frequently encounter patients with mitral valve prolapse and nonspecific symptoms with no discernible objective cause who fail to respond to beta-blockade. Panic disorder should be considered as a possible explanation for symptoms in such patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Genetic segregation analysis of familial mitral valve prolapse shows no linkage to fibrillar collagen genes

Three pedigrees were identified in which mitral valve prolapse seemed to be inherited as a mendelian autosomal dominant trait. The segregation of the genes encoding the major fibrillar collagens present in valve tissue, collagens I and III, was analysed by use of restriction enzyme site variants as genetic markers. In one pedigree there was discordance between the segregation of the disease and markers for all three collagen genes. In another, there was discordance between the disease and markers for both collagen I loci. This is evidence against the disease being generally the result of mutations of the genes encoding the major fibrillar collagens.

Genetic evidence that mutations in the COL1A1, COL1A2, COL3A1, or COL5A2 collagen genes are not responsible for mitral valve prolapse

DNA markers were used to assess the segregation of genes encoding the collagen types that predominate in the mitral valve (types I, III, and V) in two family pedigrees that are phenotypically different but showed dominantly inherited mitral valve prolapse. The inheritance of these markers was compared with the segregation of the phenotype for mitral valve prolapse in both families. In one family it was shown that the COL1A1, COL1A2, COL3A1, and COL5A2 genes segregated independently of the phenotype; in the other family the results for COL1A1, COL1A2, and COL5A2 were similar but analysis at the COL3A1 locus was not possible. These data indicate that in these families mitral valve prolapse does not arise from a defect in one of these collagen genes.

Reconsideration of echocardiographic standards for mitral valve prolapse: lack of association between leaflet displacement isolated to the apical four chamber view and independent echocardiographic evidence of abnormality

Mitral valve prolapse by current echocardiographic criteria can be diagnosed with surprising frequency in the general population, even when preselected normal subjects are examined. In most of these individuals, however, prolapse is present in the apical four chamber view and absent in roughly perpendicular long-axis views. Previous studies have shown that systolic annular nonplanarity can cause apparent prolapse in the four chamber view without actual leaflet displacement above the most superior points of the anulus, and there is evidence for such nonplanarity in vivo. It is then reasonable to ask whether superior leaflet displacement limited to the four chamber view has any pathologic significance or complications. The purpose of this study, therefore, was to address the following hypothesis: that patients with superior leaflet displacement confined to the four chamber view have no higher frequency of associated echocardiographic abnormalities than do patients without displacement in any view. Such abnormalities, which would provide independent evidence of mitral valve pathology or dysfunction, include leaflet thickening, left atrial enlargement and mitral regurgitation. Leaflet displacement was measured in the parasternal long-axis and apical four chamber views in 312 patients who were studied retrospectively and selected for the absence of forms of heart disease other than mitral valve prolapse. Leaflet thickness and left atrial size were measured and mitral regurgitation was graded. Patients with leaflet displacement limited to the four chamber view were no more likely to have associated abnormalities than were patients without displacement in any view (0 to 2% prevalence, p greater than 0.5). In contrast, patients with leaflet displacement in the long-axis view were significantly more likely to have associated abnormalities (12 to 24%, p less than 0.005), the frequency of which increased with the extent of leaflet displacement in that view (p less than 0.0001). These results suggest that displacement limited to the apical four chamber view is, in general, a normal geometric finding unassociated with echocardiographic evidence of pathologic significance.

Mitral valve prolapse

Mitral valve prolapse is a common mitral valve disorder manifested clinically as a midsystolic click and/or a late systolic murmur (the click-murmur syndrome) and pathologically as billowing or prolapsing mitral leaflets (the floppy valve syndrome). Not only is it one of the two most common congenital heart diseases and the most common valve disorder diagnosed in the United States, but it is also prevalent throughout the world. Mitral valve prolapse may be associated with a variety of other conditions or diseases. Diagnosis of mitral valve prolapse should be made on clinical grounds and, if necessary, supported by echocardiography. The majority of patients with mitral valve prolapse suffer no serious sequelae. However, major complications such as disabling angina-like chest pains, progressive mitral regurgitation, infective endocarditis, thromboembolism, serious arrhythmias, and sudden death may occur. Unless these serious complications occur, most of the patients with mitral valve prolapse need no treatment other than reassurance, including those with atypical chest pain or palpitation unconfirmed by objective data. Therapy with a beta-blocker for disabling chest pain and/or arrhythmias and antiplatelet therapy for cerebral embolic events may be indicated. In occasional patients with significant mitral regurgitation surgery may be necessary.

The relationship of mitral annular shape to the diagnosis of mitral valve prolapse

The geometric or anatomic diagnosis of mitral valve prolapse, as opposed to the pathologic diagnosis of myxomatous valve disease, is based on the relationship of the mitral leaflets to the surrounding anulus. Current echocardiographic criteria for this diagnosis include leaflet displacement above the annular hinge points in any two-dimensional view; implicit in this equivalent use of intersecting views is the assumption that the mitral anulus is a euclidean plane. Prolapse by these criteria is found in a surprisingly large proportion of the general population. In most of these individuals, however, prolapse is present in the apical four-chamber view and absent in roughly orthogonal long-axis views of the left ventricle. This frequently observed discrepancy between leaflet-annular relationships in intersecting views suggests an underlying geometric property of the mitral apparatus that would produce the appearance of prolapse in one view without actual leaflet distortion. To address this possibility, a model of the mitral valve and anulus was constructed. When the model anulus was given a nonplanar, saddle-shaped configuration, the clinical observations were reproduced: the leaflets appeared to lie above the low points of the anulus in one plane, and below its high points in a perpendicular plane. Therefore, the appearance of mitral valve prolapse can occur without actual leaflet displacement above the most superior points of the mitral anulus if the anulus is nonplanar. To determine whether this pattern is reflected in the human mitral anulus, two-dimensional echocardiographic views of the mitral apparatus were obtained by rotation about the cardiac apex in 20 patients without evident annular or rheumatic valvular disease. In all cases the mitral anulus, as reconstructed from these views, had a nonplanar systolic configuration, with high points located anteriorly and posteriorly. This is consistent with the findings of other groups in animals, and would favor the appearance of prolapse in the four-chamber view and its absence in long-axis views that are oriented anteroposteriorly. This model can therefore explain the frequently observed discrepancy between leaflet-annular relationships in roughly orthogonal views. It challenges the assumption that the mitral anulus is planar as well as the diagnosis of prolapse in many otherwise normal individuals based on that assumption.

Pulsed Doppler echocardiographic evaluation of valvular regurgitation in patients with mitral valve prolapse: comparison with normal subjects

Pulsed Doppler echocardiography was used to determine prospectively the prevalence of mitral, aortic, tricuspid and pulmonary regurgitation in 80 consecutive patients with mitral valve prolapse and 85 normal subjects with similar age and sex distribution. Mitral valve prolapse was defined by posterior systolic displacement of the mitral valve on M-mode echocardiography of 3 mm or more (40 patients), the presence of one or more mid- or late systolic clicks (61 patients), or both. Mitral regurgitation, detected by pulsed Doppler techniques in 53 patients with prolapse, was holosystolic in 24, early to mid-systolic in 6, late systolic in 15 and both holosystolic and late systolic behind different portions of the valve in 8. Definitive M-mode findings were present in only 27 of the 53 patients, and only 21 had mitral regurgitation audible on physical examination. Tricuspid regurgitation was evident by pulsed Doppler echocardiography in 15 patients (holosystolic in 9, early to mid-systolic in 1, late systolic in 4 and both holosystolic and late systolic in 1); 12 of these 15 patients, including all with an isolated late systolic pattern, had an echocardiographic pattern of tricuspid prolapse, but none had audible tricuspid regurgitation. A Doppler pattern compatible with aortic regurgitation was recorded in seven patients, all without echocardiographic aortic valve prolapse and only two with audible aortic insufficiency. A Doppler shift in the right ventricular outflow tract in diastole, suggestive of pulmonary regurgitation, was recorded in 16 of the 78 patients with an adequate Doppler examination: only 1 of the 16 had audible pulmonary insufficiency. Of the 85 normal subjects without audible regurgitation, pulsed Doppler examination detected mitral regurgitation in 3 subjects (holosystolic in 1 and early to mid-systolic in 2), aortic regurgitation in none, tricuspid regurgitation in 9 (holosystolic alone in 8 and both holosystolic and late systolic in 1) and right ventricular outflow tract turbulence compatible with pulmonary insufficiency in 15. The prevalence of valvular regurgitation, detected by pulsed Doppler echocardiography, is high in patients with mitral valve prolapse. Regurgitation may involve any of the four cardiac valves and is clinically silent in the majority of patients. The prevalence rates of mitral and aortic regurgitation are significantly higher in patients with mitral prolapse than in normal subjects, suggesting that alterations in underlying valve structure in the prolapse syndrome may indeed be responsible for this regurgitation.(ABSTRACT TRUNCATED AT 400 WORDS)

Prevalence of mitral-valve prolapse in the Stickler syndrome

An increased prevalence of mitral-valve prolapse occurs in several connective tissue dysplasias, including Marfan syndrome, Ehlers-Danlos syndrome, and pseudoxanthoma elasticum. We evaluated 57 patients diagnosed as having the Stickler syndrome for mitral-valve prolapse by auscultation and two-dimensional echocardiography. The diagnosis was made on the basis of craniofacial and musculoskeletal abnormalities, sensorineural hearing loss, eye defects, and a family history of Stickler syndrome. Twenty-six patients (45.6%) had mitral-valve prolapse, including 11 of 22 females (50.0%) and 15 of 35 males (42.9%). The age range of our study population was 4 to 60 years. Prevalence of mitral-valve prolapse did not increase with age. Nine patients (34.6% of those with mitral-valve prolapse) had the click-murmur syndrome; only one of them was symptomatic. Because of the growing list of complications associated with mitral-valve prolapse, all patients with Stickler syndrome should be evaluated by auscultation, electrocardiogram, and echocardiography. Those with mitral-valve prolapse should be advised to have periodic follow-up and to instruct physicians caring for them of their need for antibiotic prophylaxis with certain surgical procedures.

Complex ventricular arrhythmias associated with the mitral valve prolapse syndrome. Effectiveness of moricizine (Ethmozine) in patients resistant to conventional antiarrhythmics

On the basis of epidemiologic studies, more than 10 million Americans have echocardiographic evidence of mitral valve prolapse. Although ventricular arrhythmias occur frequently (over 50 percent of patients with mitral valve prolapse), they rarely result in sustained ventricular tachycardia or sudden cardiac death. However, a common problem in clinical practice is a patient with mitral valve prolapse and symptomatic complex ventricular arrhythmias refractory or intolerant to both beta blockers and conventional type I antiarrhythmics. These drugs are known to have frequent side effects, toxicity, and proarrhythmic effects. In 17 patients with mitral valve prolapse who presented with symptomatic complex ventricular arrhythmias and who were unresponsive to an average of the three conventional agents, moricizine (Ethmozine) was effective in suppressing 90 percent of ventricular premature depolarizations, 99 percent of nonsustained runs of ventricular tachycardia, as well as all sustained runs of ventricular tachycardia, resulting in abolition of palpitations, dizziness, and syncopal episodes. Its efficacy as well as its low frequency of minor side effects makes it ideal for future consideration in the population with mitral valve prolapse, who are frequently young and may therefore require therapy for many years.

Echocardiography in mitral valve disease: a review

Echocardiographic evaluation of the mitral valve has attracted much attention and generated much discussion since its beginnings, some thirty years ago. Echocardiography affords the physician a detailed assessment of mitral valve integrity unequalled by any other non-invasive test. Aside from the normal appearance of the valve, a variety of pathological conditions have been studied in detail; mitral stenosis was the first and over the years the state-of-the-art has evolved from simply looking at the EF slope as an indicator of severity to the accurate quantification utilizing planimetry and 'pressure half-time.' Mitral regurgitation, although not as well quantified as mitral stenosis, can be detected and its etiology usually determined. Mitral valve prolapse may easily be overdiagnosed by echocardiography, however together with auscultation, ultrasound remains the best way to evaluate this common condition. Echocardiography is also invaluable in the evaluation of endocarditis and prosthetic mitral valves.

Current issues in prevention of infective endocarditis

Prevention of infective endocarditis continues to concern health care providers in many specialties. The well-known lack of primary clinical trials in this area is not expected to change. Therefore, the evolution of recommendations and practice must be based on theoretic considerations and continuing assessment of secondary sources of information. Recent developments include a report of 52 cases in which antibiotic prophylaxis for infective endocarditis was attempted but appeared to fail. Most of these patients had undergone dental procedures after oral penicillin prophylaxis, with subsequent development of streptococcal endocarditis. In two thirds, the organism was sensitive to the antibiotic used. Notably, the most common underlying cardiac lesion among these patients was mitral valve prolapse. However, two recent independent analyses have concluded that providing endocarditis prophylaxis for all patients with mitral valve prolapse during procedures that might cause bacteremia would not be cost-effective. This is primarily because mitral valve prolapse is common and endocarditis is relatively rare, resulting in an adverse risk-benefit ratio. Parenteral prophylaxis for mitral valve prolapse might even cause a net loss of life from anaphylaxis. On the other hand, for the individual patient or physician, the reassurance provided by attempted prophylaxis with oral penicillin can be purchased at low cost and low risk. Very few cases of infective endocarditis have been reported after gastrointestinal and other endoscopic procedures; most of these do not need antibiotic coverage. Prophylactic antibiotics should be restricted to those situations in which both the procedure and the underlying cardiac condition seem to pose significant risk, for example, endoscopic sclerotherapy of esophageal varices in patients with prosthetic heart valves. Newly revised recommendations have been issued by the Medical Letter, the American Heart Association, and the American Dental Association. These regimens are shorter and simpler than earlier versions.

Prevalence of mitral valve prolapse in presumably healthy Korean adults

This cross-sectional study on mitral valve prolapse (MVP) in Korean adults revealed a relatively low overall prevalence at 2.5% (5 of the 200 subjects). Three of 5 subjects with MVP were females and the majority (4 of 5 subjects) were under 30 years of age. All subjects with MVP had thoracic skeletal deformities (4 straight back syndrome and 1 pectus excavatum). All subjects with MVP did not have cardiac history and they were all asymptomatic except for one who had intermittent palpitation of mild degree.

Electrocardiography and echocardiography in patients with chest pain and mitral leaflet prolapse

34 patients with catheter verified, haemodynamically trivial mitral leaflet prolapse with chest pain and normal coronary arteries were studied. Nineteen had no auscultatory signs of MLP despite clear catheter or echocardiographic evidence of prolapse. Infero-lateral repolarisation changes on the resting electrocardiogram were present in 29%. 50% had false positive exercise tests. M-mode echocardiography proved diagnostically disappointing but sector scans revealed mitral leaflet prolapse in 62%. The apical 4 chamber acoustic window was markedly superior to the parasternal long axis acoustic window.

Mitral valve prolapse in sickle cell disease: manifestation of a generalized connective tissue disorder

Previous studies have shown an association of sickle cell disease with generalized connective tissue disorders such as pseudoxanthoma elasticum. We recently documented an unexpectedly high prevalence of mitral valve prolapse, a connective tissue disorder, in sickle cell disease. To investigate this association, skin biopsies were analyzed from 32 sickle cell disease patients, 11 of whom had mitral prolapse. Total and type III collagen, collagen solubility, and uronic acid were not different between the patients with or without mitral prolapse (p greater than 0.05). Computerized morphometric quantitation of the volume fraction of elastic fibers was greater in sickle cell disease patients than in 10 normals (3.1 +/- 0.1 mean +/- SEM vs 2.0 +/- 0.3%; p less than 0.01) but less than in three patients with pseudoxanthoma elasticum (9.7 +/- 0.6%; p less than 0.001). Desmosine radioimmunoassay (an index of elastic fibers) was greater in sickle cell disease patients with mitral prolapse than those without (239.3 +/- 9.3 vs 171.7 +/- 25.4 ng/mg wet weight; p less than 0.02). Histopathologic grading showed a similar trend (p = 0.07). The combined probabilities of these three independent tests of elastic fiber quantity showed an increased elastic fiber concentration in mitral prolapse patients compared to those without mitral prolapse (p less than 0.02). Thus, there is no evidence for a specific collagen defect; rather, sickle cell disease appears to be associated with a spectrum of elastic tissue disorders, a feature that could predispose to mitral valve prolapse.

Prevalence of mitral valve prolapse in normal children

Although echocardiography has become the standard noninvasive method of diagnosing mitral valve prolapse, the diagnostic criteria have been established without clearly defining the range of normal patterns for mitral valve closure. The current study reports the analysis of mitral valve closure patterns in 193 children (aged 5 days to 18 years) making scheduled visits for well child care who were screened by history and physical examination to exclude structural heart disease. Mitral valve systolic leaflet position was analyzed for the appearance of any portion of either leaflet superior to the plane of the anulus. Superior systolic motion was noted in 13% of the overall study group; this pattern was uncommon in infants but more frequent in older children, with a prevalence of 35% in the 10 to 18 year age group. There was no statistically significant difference between male and female children at any age. The prevalence of superior systolic motion decreased markedly if consideration was given to its presence in more than one echocardiographic view (1%) or to displacement of the coaptation point of the mitral valve leaflets (0.5%). Superior systolic motion occurs with such frequency in normal children as to call into question the reliability of this pattern of mitral valve closure as a standard for the diagnosis of mitral valve prolapse. More restrictive diagnostic criteria which consider the degree of leaflet displacement or its presence in multiple echocardiographic views may be necessary to identify those subjects whose mitral valve closure patterns truly fall outside the range of normal.

A quantitative assessment of pre-dental antibiotic prophylaxis for patients with mitral-valve prolapse

Because antibiotic prophylaxis for dental procedures in patients with mitral-valve prolapse (MVP) has been controversial, we performed a decision analysis to assess the costs and effects of the oral and parenteral penicillin regimens currently recommended for patients at high risk for bacterial endocarditis. The analysis suggests that there is a very small risk of post-dental endocarditis in MVP (4.1 cases per 10(6) procedures) which is outweighed by a greater risk of fatal reactions to parenteral penicillin (15 deaths per 10(6) courses). Parenteral penicillin prophylaxis therefore causes a net loss of life. For oral penicillin the risk of a fatal reaction is lower (0.9 deaths per 10(6) courses). However, oral penicillin prophylaxis appears to spare life only in older adults with MVP and at an extremely high cost: Over +1 million must be spent to spare one year of life. Personal preferences may still make antibiotic prophylaxis desirable for individual MVP patients. However, from a societal perspective, routine predental antibiotic prophylaxis for MVP is a very expensive preventive strategy.

Mitral valve dysfunction in the Marfan syndrome. Clinical and echocardiographic study of prevalence and natural history

Although mitral regurgitation and fibromyxomatous thickening of the mitral leaflets have long been recognized as such, mitral valve prolapse has only recently been added as one of the pleiotropic features of the Marfan syndrome. The prevalence, age of onset, and natural history of mitral valve dysfunction in this condition are uncertain. Therefore, all patients in one clinic who met strict diagnostic criteria for the Marfan syndrome and who had clinical and echocardiographic examinations before age 22 years were reviewed. Of the 166 patients (84 males, aged 11.9 +/- 0.6 years [mean +/- SEM]; and 82 females, 11.0 +/- 0.6 years), 52 percent had auscultatory and 68 percent had echocardiographic evidence of mitral valve dysfunction, generally mitral valve prolapse. Prevalence did not differ between the sexes. Follow-up in 115 patients averaged five examinations over a mean of four years; 17 percent were followed for more than six years. Criteria for progression of mitral valve dysfunction were: (1) on auscultation, the appearance of new systolic clicks or apical systolic murmurs, a mitral regurgitant murmur increased by two grades, or appearance of congestive heart failure not due to aortic regurgitation; and (2) on echocardiography, the new appearance of mitral valve prolapse or abnormally increased left atrial dimension. Nearly half the patients met at least one criterion and one quarter had both auscultatory and echocardiographic evidence of progressive mitral valve dysfunction. Twice as many females demonstrated worse mitral valve function with time. Eight of the 166 patients either died as a result of mitral valve dysfunction or required mitral valve replacement. Severe mitral regurgitation developed in an additional 15 patients. Rupture of chordae tendineae was uncommon. Antibiotic prophylaxis was routine, and no cases of bacterial endocarditis of the mitral valve occurred. These results suggest that mitral valve dysfunction is extremely common in young patients with Marfan syndrome and usually presents as mitral valve prolapse. Serious mitral regurgitation develops in one of every eight patients by the third decade. Thus, the prevalence and natural history of mitral valve prolapse in the Marfan syndrome appear distinct from mitral valve prolapse associated with other conditions, including idiopathic or familial mitral valve prolapse.

Association of mitral-valve prolapse with low body-weight and low blood pressure

Subjects with mitral-valve prolapse (MVP) have been observed to have an asthenic body build. To determine whether body-weight differed between individuals with inherited MVP and normal subjects, 177 relatives of 45 patients with MVP were studied, 35 female and 19 male relatives had MVP, and 51 female and 72 male relatives did not. There was no difference in mean height between relatives with and without MVP, but those with MVP weighed significantly less. Blood pressure was also significantly lower in relatives with MVP than in normal relatives. It is suggested that the lower blood pressure and the possible beneficial effects of lower weight on other cardiovascular risk factors may provide a selective advantage to carriers of the MVP gene, explaining its high prevalence in the general population. These findings may provide the first example of a common inherited condition which is systematically associated with changes in body-weight and blood pressure.

Update: mitral valve prolapse syndrome

A contemporary "in" diagnosis in the field of cardiology is the mitral valve prolapse syndrome. This abnormality is evident in populations ranging from very young children to older adults. It is being recognized with increasing frequency among college and university students. In many cases, the syndrome is of limited consequence, while in others, it may be life threatening. This paper (1) defines what it is, (2) reports on its occurrence, (3) depicts some relationships with related health entities and (4) discusses certain implications for health professionals and heart health education.

The effect of amyl nitrite on the mitral valve echocardiogram in presumably healthy young adults

We analyzed the use of amyl nitrite as a provocative factor in the diagnosis of mitral valve prolapse in a population of healthy young adults. Sixty-five men and 11 women underwent continuous M-mode echocardiographic and phonocardiographic monitoring before, during and after the administration of inhaled amyl nitrite. All of the 76 subjects had normal baseline echocardiograms, and all had a satisfactory hemodynamic response to amyl nitrite. Mitral valve prolapse, defined by echocardiography and phonocardiography, was not provoked in any of the subjects. Therefore, we concluded that, although this technique may be difficult, significant false-positive results should not occur if adherence to strict diagnostic criteria takes place.