Lifetime risk for patients with mitral valve prolapse of developing severe valve regurgitation requiring surgery

Echocardiographic Assessment of Mitral Valve Prolapse Prevalence before and after the Year 1999: A Systematic Review

Background: Over the last five decades, a fair number of echocardiographic studies have evaluated the prevalence of mitral valve prolapse (MVP) in various cohorts of individuals, including heterogeneous study populations. The present systematic review has been primarily designed to summarize the main findings of these studies and to estimate the overall MVP prevalence in the general community. Methods: All echocardiographic studies assessing the MVP prevalence in various cohorts of individuals, selected from PubMed and EMBASE databases, were included. There was no limitation of time period. The risk of bias was assessed by using the National Institutes of Health (NIH) Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Results: The full texts of 21 studies with 1354 MVP individuals out of 63,723 participants were analyzed. The overall pooled prevalence of MVP was 4.9% (range of 0.6-21%). When dividing the studies in two groups according to the echocardiographic criteria used for MVP diagnosis (less specific old criteria or more specific new criteria, respectively), the estimated pooled prevalence of MVP was 7.8% (range of 2-21%) for the older studies (performed between 1976 and 1998) and 2.2% (range of 0.6-4.2%) for the more recent ones (conducted between 1999 and 2021). Potential selection bias, hospital- or referral-based series, and the use of less specific echocardiographic criteria for MVP diagnosis have been indicated as the main reasons for the higher MVP prevalence detected by the older studies. MVP was commonly associated with a narrow antero-posterior thoracic diameter, isolated ventricular premature beats and nonspecific ST-T-wave abnormalities on a resting electrocardiogram, mild-to-moderate mitral regurgitation (MR), the reduced probability of obstructive coronary artery disease, and a low frequency of serious complications, such as severe MR, infective endocarditis, heart failure, stroke, and atrial fibrillation. Conclusions: MVP has a low prevalence in the general population, regardless of age, gender, and ethnicity, and is associated with a good outcome.

Frequency of Cardiac Valvulopathies in Patients With Marfan Syndrome: A Systematic Review and Meta-Analysis

Marfan syndrome (MFS) is a progressive connective tissue disease with a broad range of clinical manifestations. We sought to establish the spectrum of structural valvular abnormalities as cardiovascular involvement has been identified as the most life-threatening aspect of the syndrome. This was a systematic review with a meta-analysis of studies indexed in Medline from the inception of the database to November 7, 2022. Using the random-effects model, separate Forest and Galbraith plots were generated for each valvular abnormality assessed. Heterogeneity was assessed using the I2 statistics whilst funnel plots and Egger's test were used to assess for publication bias. From a total of 35 studies, a random-effects meta-analysis approximated the pooled summary estimates for the prevalence of cardiac valve abnormalities as mitral valve prolapse 65% (95% CI: 57%-73%); mitral valve regurgitation 40% (95% CI: 29%-51%); aortic valve regurgitation 40% (95% CI: 28%-53%); tricuspid valve prolapse 35% (95% CI: 15%-55%); and tricuspid valve regurgitation 43% (95% CI: 8%-78%). Only one study reported on the involvement of the pulmonary valve (pulmonary valve prolapse was estimated at 5.3% (95% CI: 1.9%-11.1%) in a cohort of 114 patients with MFS). We believe this study provides a description of the structural valvular disease spectrum and may help inform providers and patients in understanding the clinical history of MFS in the current treatment era with its increased life expectancy.

The Potential of Intertwining Gene Diagnostics and Surgery for Mitral Valve Prolapse

Mitral valve prolapse (MVP) is common among heart valve disease patients, causing severe mitral regurgitation (MR). Although complications such as cardiac arrhythmias and sudden cardiac death are rare, the high prevalence of the condition leads to a significant number of such events. Through next-generation gene sequencing approaches, predisposing genetic components have been shown to play a crucial role in the development of MVP. After the discovery of the X-linked inheritance of filamin A, autosomal inherited genes were identified. In addition, the study of sporadic MVP identified several genes, including DZIP1, TNS1, LMCD1, GLIS1, PTPRJ, FLYWCH, and MMP2. The early screening of these genetic predispositions may help to determine the patient population at risk for severe complications of MVP and impact the timing of reconstructive surgery. Surgical mitral valve repair is an effective treatment option for MVP, resulting in excellent short- and long-term outcomes. Repair rates in excess of 95% and low complication rates have been consistently reported for minimally invasive mitral valve repair performed in high-volume centers. We therefore conceptualize a potential preventive surgical strategy for the treatment of MVP in patients with genetic predisposition, which is currently not considered in guideline recommendations. Further genetic studies on MVP pathology and large prospective clinical trials will be required to support such an approach.

Genetics and pathophysiology of mitral valve prolapse

Mitral valve prolapse (MVP) is a common condition affecting 2-3% of the general population, and the most complex form of valve pathology, with a complication rate up to 10-15% per year in advanced stages. Complications include mitral regurgitation which can lead to heart failure and atrial fibrillation, but also life-threatening ventricular arrhythmia and cardiovascular death. Sudden death has been recently brought to the forefront of MVP disease, increasing the complexity of management and suggesting that MVP condition is not properly understood. MVP can occur as part of syndromic conditions such as Marfan syndrome, but the most common form is non-syndromic, isolated or familial. Although a specific X-linked form of MVP was initially identified, autosomal dominant inheritance appears to be the primary mode of transmission. MVP can be stratified into myxomatous degeneration (Barlow), fibroelastic deficiency, and Filamin A-related MVP. While FED is still considered a degenerative disease associated with aging, myxomatous MVP and FlnA-MVP are recognized as familial pathologies. Deciphering genetic defects associated to MVP is still a work in progress; although FLNA, DCHS1, and DZIP1 have been identified as causative genes in myxomatous forms of MVP thanks to familial approaches, they explain only a small proportion of MVP. In addition, genome-wide association studies have revealed the important role of common variants in the development of MVP, in agreement with the high prevalence of this condition in the population. Furthermore, a potential genetic link between MVP and ventricular arrhythmia or a specific type of cardiomyopathy is considered. Animal models that allow to advance in the genetic and pathophysiological knowledge of MVP, and in particular those that can be easily manipulated to express a genetic defect identified in humans are detailed. Corroborated by genetic data and animal models, the main pathophysiological pathways of MVP are briefly addressed. Finally, genetic counseling is considered in the context of MVP.

Mitral Valve Prolapse and Its Motley Crew-Syndromic Prevalence, Pathophysiology, and Progression of a Common Heart Condition

Mitral valve prolapse (MVP) is a commonly occurring heart condition defined by enlargement and superior displacement of the mitral valve leaflet(s) during systole. Although commonly seen as a standalone disorder, MVP has also been described in case reports and small studies of patients with various genetic syndromes. In this review, we analyzed the prevalence of MVP within syndromes where an association to MVP has previously been reported. We further discussed the shared biological pathways that cause MVP in these syndromes, as well as how MVP in turn causes a diverse array of cardiac and noncardiac complications. We found 105 studies that identified patients with mitral valve anomalies within 18 different genetic, developmental, and connective tissue diseases. We show that some disorders previously believed to have an increased prevalence of MVP, including osteogenesis imperfecta, fragile X syndrome, Down syndrome, and Pseudoxanthoma elasticum, have few to no studies that use up-to-date diagnostic criteria for the disease and therefore may be overestimating the prevalence of MVP within the syndrome. Additionally, we highlight that in contrast to early studies describing MVP as a benign entity, the clinical course experienced by patients can be heterogeneous and may cause significant cardiovascular morbidity and mortality. Currently only surgical correction of MVP is curative, but it is reserved for severe cases in which irreversible complications of MVP may already be established; therefore, a review of clinical guidelines to allow for earlier surgical intervention may be warranted to lower cardiovascular risk in patients with MVP.

DZIP1 regulates mammalian cardiac valve development through a Cby1-β-catenin mechanism

Background

Mitral valve prolapse (MVP) is a common and progressive cardiovascular disease with developmental origins. How developmental errors contribute to disease pathogenesis are not well understood.

Results

A multimeric complex was identified that consists of the MVP gene Dzip1, Cby1, and β‐catenin. Co‐expression during valve development revealed overlap at the basal body of the primary cilia. Biochemical studies revealed a DZIP1 peptide required for stabilization of the complex and suppression of β‐catenin activities. Decoy peptides generated against this interaction motif altered nuclear vs cytosolic levels of β‐catenin with effects on transcriptional activity. A mutation within this domain was identified in a family with inherited non‐syndromic MVP. This novel mutation and our previously identified DZIP1^S24R variant resulted in reduced DZIP1 and CBY1 stability and increased β‐catenin activities. The β‐catenin target gene, MMP2 was up‐regulated in the Dzip1^S14R/+ valves and correlated with loss of collagenous ECM matrix and myxomatous phenotype.

Conclusion

Dzip1 functions to restrain β‐catenin signaling through a CBY1 linker during cardiac development. Loss of these interactions results in increased nuclear β‐catenin/Lef1 and excess MMP2 production, which correlates with developmental and postnatal changes in ECM and generation of a myxomatous phenotype.

Phonocardiography-based mitral valve prolapse detection with using fractional fourier transform

Mitral Valve Prolapse (MVP) is a common condition among people, which is often benign and does not need any serious treatment. However, this doesn't mean that MVP can't cause any problems. In malignant conditions, MVP can cause mitral failure and also heart failure. Early diagnosis of MVP is significantly important to control and reduce its complications. Since the phonocardiogram signal provides useful information about heart valves function, it can be used for MVP detection. To detect MVP, the signal was denoised and segmented into heart cycles and constant three-second pieces in the first and second approaches, respectively. Next, based on the Fractional Fourier Transform (FrFT), the desired features were extracted. Then, the extracted features were windowed by a Moving Logarithmic Median Window (MLMW) and optimum features were selected using Mahalanobis, Bhattacharyya, Canberra, and Minkowski distance criteria. Finally, using the selected features, classification was performed by using the K-Nearest Neighbor (KNN) and the Suppor Vector Machine (SVM) classifiers to find out whether a segment is prolapsed. The best results of the experiment on the collected database contain 15 prolapsed and 6 non-prolapsed subjects using the A-test method show 96.25 ± 2.43 accuracy, 98.5 ± 3.37 sensitivity, 94.0 ± 5.16 specificity, 96.0 ± 3.44 precision, 92.5 ± 4.86 kappa, and 96.6 ± 2.34 f-score with the SVM classifier.

Stress-induced remodelling of the mitral valve: a model for leaflet thickening and superimposed tissue formation in mitral valve disease

AIMS

In mitral valve prolapse (MVP), leaflet thickening has recently been suggested to be due, in addition to a myxomatous degeneration, to the presence of a superimposed tissue (SIT), defined as an additional fibrous layer on top of the original leaflet. The mechanisms of SIT formation are currently unknown. We hypothesized that SIT formation would result from excessive leaflet stress and we used a unique ex vivo model to assess the correlation between leaflet remodelling and the type and location of mechanical stress and to elucidate the mechanisms underlying SIT formation.

METHODS AND RESULTS

Human diseased mitral valves (MVs; n = 21) were histologically analysed for SIT formation and original leaflet thickening. The SIT comprised of various compositions of extracellular matrix and could reach more than 50% of total leaflet thickness. Original leaflet and SIT thickness did not show significant correlation (r = -0.27, P = 0.23), suggesting different regulatory mechanisms. To study the role of the mechanical environment on MV remodelling, mouse MV were cultured in their natural position in the heart and subjected to various haemodynamic conditions representing specific phases of the cardiac cycle and the MVP configuration. SIT formation was induced in the ex vivo model, mostly present on the atrial side, and clearly dependent on the duration, type, and extent of mechanical stress. Specific stainings and lineage tracing experiments showed that SIT comprises of macrophages and myofibroblasts and is associated with the activation of the transforming growth factor-beta and bone morphogenetic protein signalling pathways. Migration of valvular interstitial cells and macrophages through breakages of the endothelial cell lining contributed to SIT formation.

CONCLUSIONS

Mechanical stresses induce specific cellular and molecular changes in the MV that result in SIT formation. These observations provide the first insights in the mechanism of SIT formation and represent an initial step to identify potential novel and early treatment for MVP.

Risk of Mitral Valve Prolapse in Patients with Keratoconus in Taiwan: A Population-Based Cohort Study

This retrospective, nationwide, matched-cohort study included 4488 new-onset keratoconus (KCN) patients, ≥12 years old, recruited between 2004 and 2011 from the Taiwan National Health Insurance Research Database. The control group included 26,928 non-KCN patients selected from the Taiwan Longitudinal Health Insurance Database 2000. Information for each patient was collected and tracked from the index date until December 2013. The incidence rate of mitral valve prolapse (MVP) was 1.77 times (95% confidence interval (CI) = 1.09–2.88; p = 0.0206) higher in KCN patients ≥40 years old and 1.49 times (95% CI = 1.12–1.98; p = 0.0060) higher in female KCN patients than in controls. After using the Cox proportional hazard regression analysis to adjust for potential confounders, including hypertension, hyperlipidemia, and congestive heart failure, KCN maintained an independent risk factor, MVP being 1.77 times (adjusted hazard ratio (HR) = 1.77, 95% CI = 1.09–2.88) and 1.48 times (adjusted HR = 1.48, 95% CI = 1.11–1.97) more likely to develop in patients ≥40 years old and female patients in the study cohort, respectively. We found that KCN patients ≥40 years of age and female KCN patients have increased risks of MVP. Therefore, it is recommended that KCN patients should be alerted to MVP.

Mitral valve repair, how to make volume not matter; techniques, tendencies, and outcomes, a single center experience

Background

Recent evidence has showed us that quality of mitral valve repair is strongly related to volume. However, this study shows how low-volume centers can achieve results in mitral valve repair surgery comparable to those reported by referral centers. It compares outcomes of mitral valve repair using resection versus noresection techniques, tendencies, and rates of repair.

Methods

Between 2004 and 2017, 200 patients underwent mitral valve repair for degenerative mitral valve disease at Fundación Cardioinfantil-Institute of Cardiology. Fifty-eight (29%) patients underwent resection and 142 (71%) noresection.

Results

Follow-up was 94% complete, mean follow-up time was 2.3 years. There was no 30-day mortality. Five patients required mitral valve replacement after an average of 5.3 years (Resection = 2; Noresection = 3). Freedom from severe mitral regurgitation was 98% at 6.6 years of follow-up for the noresection group, and 92.5% at 7 years for the resection group (log rank: 0.888). At last follow-up, two patients died of cardiovascular disease related to mitral valve, 181 patients (86%) showed no or grade I mitral regurgitation. Patients with previous myocardial infarction had increased risk of recurrent mitral regurgitation (p = 0,030). Within four years, we inverted the proportion of mitral valve replacement and repair, and in 2016 we achieved a mitral valve repair rate of 96%.

Conclusion

This study suggests that resection and noresection techniques are safe and effective. Recurrence of severe mitral regurgitation and need for mitral valve replacement are rare. We show that low-volume centers can achieve results comparable to those reported worldwide by establishing a mitral valve repair team. We encourage hospitals to follow this model of mitral valve repair program to decrease the proportion of mitral valve replacement, while increasing mitral valve repair.

New insights into mitral valve dystrophy: a Filamin-A genotype-phenotype and outcome study

Aims

Filamin-A (FLNA) was identified as the first gene of non-syndromic mitral valve dystrophy (FLNA-MVD). We aimed to assess the phenotype of FLNA-MVD and its impact on prognosis.

Methods and results

We investigated the disease in 246 subjects (72 mutated) from four FLNA-MVD families harbouring three different FLNA mutations. Phenotype was characterized by a comprehensive echocardiography focusing on mitral valve apparatus in comparison with control relatives. In this X-linked disease valves lesions were severe in men and moderate in women. Most men had classical features of mitral valve prolapse (MVP), but without chordal rupture. By contrast to regular MVP, mitral leaflet motion was clearly restricted in diastole and papillary muscles position was closer to mitral annulus. Valvular abnormalities were similar in the four families, in adults and young patients from early childhood suggestive of a developmental disease. In addition, mitral valve lesions worsened over time as encountered in degenerative conditions. Polyvalvular involvement was frequent in males and non-diagnostic forms frequent in females. Overall survival was moderately impaired in men (P = 0.011). Cardiac surgery rate (mainly valvular) was increased (33.3 ± 9.8 vs. 5.0 ± 4.9%, P < 0.0001; hazard ratio 10.5 [95% confidence interval: 2.9-37.9]) owing mainly to a lifetime increased risk in men (76.8 ± 14.1 vs. 9.1 ± 8.7%, P < 0.0001).

Conclusion

FLNA-MVD is a developmental and degenerative disease with complex phenotypic expression which can influence patient management. FLNA-MVD has unique features with both MVP and paradoxical restricted motion in diastole, sub-valvular mitral apparatus impairment and polyvalvular lesions in males. FLNA-MVD conveys a substantial lifetime risk of valve surgery in men.

The evaluation and management of respiratory disease in children with Down syndrome (DS)

Children with Down syndrome (DS) have wide range of respiratory problems. Although underlying abnormalities in the respiratory system are important causes of morbidity and mortality in children with DS, particularly in the young, abnormalities in other organ systems may also impact respiratory function. A comprehensive evaluation of the child with DS and respiratory disease may prevent short-term morbidity and mortality, and reduce the incidence of complications in the long term. This review provides an overview of the various causes of respiratory disease, and insight into some of the newer therapies available to treat obstructive sleep apnea, in this population.

Macrophages and cytotoxic T cells infiltrate the destructed mitral tissue in Kawasaki disease

Kawasaki disease (KD) is an acute febrile systemic vasculitic syndrome especially affecting medium-sized arteries, including the coronary artery. Inflammation may involve all organs, and valvulitis is one of the cardiovascular complications that occurs in the acute phase of KD. However, details regarding the mechanism are unclear. An infant developed KD and severe mitral regurgitation with deformity and prolapse of the mitral tissue and underwent mitral valvotomy 1 year later. Histopathological study was conducted, and infiltrating cells consisted of mainly macrophages and cytotoxic T cells were found in resected mitral valve tissue. In addition, inflammation remained a long time after KD had developed.

Mitral valve prolapse and Marfan syndrome

Marfan syndrome is a multisystemic genetic condition affecting connective tissue. It carries a reduced life expectancy, largely dependent on cardiovascular complications. More common cardiac manifestations such as aortic dissection and aortic valve incompetence have been widely documented in the literature. Mitral valve prolapse (MVP), however, has remained poorly documented. This article aims at exploring the existing literature on the pathophysiology and diagnosis of MVP in patients with Marfan syndrome, defining its current management and outlining the future developments surrounding it.

Mitral Valve Chordae Tendineae: Topological and Geometrical Characterization

Mitral valve (MV) closure depends upon the proper function of each component of the valve apparatus, which includes the annulus, leaflets, and chordae tendineae (CT). Geometry plays a major role in MV mechanics and thus highly impacts the accuracy of computational models simulating MV function and repair. While the physiological geometry of the leaflets and annulus have been previously investigated, little effort has been made to quantitatively and objectively describe CT geometry. The CT constitute a fibrous tendon-like structure projecting from the papillary muscles (PMs) to the leaflets, thereby evenly distributing the loads placed on the MV during closure. Because CT play a major role in determining the shape and stress state of the MV as a whole, their geometry must be well characterized. In the present work, a novel and comprehensive investigation of MV CT geometry was performed to more fully quantify CT anatomy. In vitro micro-tomography 3D images of ovine MVs were acquired, segmented, then analyzed using a curve-skeleton transform. The resulting data was used to construct B-spline geometric representations of the CT structures, enriched with a continuous field of cross-sectional area (CSA) data. Next, Reeb graph models were developed to analyze overall topological patterns, along with dimensional attributes such as segment lengths, 3D orientations, and CSA. Reeb graph results revealed that the topology of ovine MV CT followed a full binary tree structure. Moreover, individual chords are mostly planar geometries that together form a 3D load-bearing support for the MV leaflets. We further demonstrated that, unlike flow-based branching patterns, while individual CT branches became thinner as they propagated further away from the PM heads towards the leaflets, the total CSA almost doubled. Overall, our findings indicate a certain level of regularity in structure, and suggest that population-based MV CT geometric models can be generated to improve current MV repair procedures.

Surgery for mitral regurgitation in patients with aortic root aneurysm: Transaortic or transseptal approach?

OBJECTIVE

Mitral regurgitation is common in patients with aortic root aneurysm. Mitral valve repair (MVP) or replacement (MVR) can be performed for these patients through either a transverse aortotomy (TA) or transseptal approach (TS). This study sought to compare the early outcomes of mitral valve surgery through the TA and TS approaches and decide which is optimal for this subset of patients.

METHODS

Between March 2013 and April 2015, we operated on 99 patients (81 males, 81.8%) with aortic root aneurysm who developed mitral regurgitation. Mean age was 47.8±16.5years. MVR was performed in 66 patients (TAR=27; TSR=39) and MVP in 33 (TAP=8; TSP=25). The baseline and operative outcomes data were compared between patients with MVR and MVP through the TA vs TS approaches.

RESULTS

Preoperatively, the mitral regurgitation area was significantly larger in the MVR than MVP groups (8.9±2.0 vs 7.8±3.8 cm², p=0.0009), and in the TSP vs TAP groups (8.5±4.1 vs 5.6±1.3cm², p=0.0049), but no significant difference was found between the TAR and TSR groups (8.7±2.2 vs 9.0±1.8cm², p=0.4681); the aortic sinus size was significantly larger in the TAR than TSR group (66.7±15.8 vs 52.1±8.8mm, p=0.0061). Subvalvular structure was preserved in 12 MVR patients (18.2%). In MVP patients, Kay annuloplasty was used in 11 (33.3%) and annuloplastic ring in 22 (66.7%). The times of cardiopulmonary bypass (CPB) and cross-clamp in patients with TA approach were significantly shorter compared to those with the TS approach (139±34 vs 176±38min, p=0.0001; 101±26 vs 129±31min, p=0.0002). No cases of mortality, stroke and renal failure occurred in the whole series. The amount of transfusion, lengths of ICU and hospital stay did not differ between patients with MVR and MVP, and between the TA and TS approaches.

CONCLUSIONS

Both the TA and TS approaches achieved good early outcomes in MV surgery for patients with root aneurysm. The transverse aortotomy was associated with shorter CPB and cross-clamp times. Surgical approaches should be selected according to the underlying mitral valve etiology and the size of the aortic root.

Mitral Valve Prolapse in Pregnancy

Mitral valve prolapse is a benign condition. Mitral regurgitation is only complicated in patients with severe mitral valve prolapse. Women with mitral valve prolapse in the absence of other cardiovascular disorders tolerate pregnancy well and do not develop remarkable cardiac complications. Nevertheless, serious complications of mitral valve prolapse, including arrhythmia, infective endocarditis and cerebral ischemic events, can be present in pregnancy. Debates remain with regard to the use of prophylactic antibiotics and β-blockers in the pregnant women with mitral valve prolapse. The prognosis of the pregnant patients might be closely related to the pathological and (or) functional changes of the mitral valve. Non-myxomatous mitral valve prolapse poses no or little obstetric risks in terms of pregnancy, labor and neonatal complications; whereas myxomatous mitral valve prolapse is a major etiology of valvular heart disease in women of childbearing age. In the pregnant patients with mitral valve prolapse progressing into major complications, surgical interventions are considered. Medicinal treatment of such patients with β-blockers should be a concern for the fetal safety.

Understanding the Role of Sex in Heart Valve and Major Vascular Diseases

Cardiovascular disease (CVD) is the major cause of mortality in the elderly population. The cost of CVD treatment and surgeries was over $300 billion in the United States alone in 2010, making this disorder a critical healthcare issue. Many studies have suggested sex as a risk factor for heart valve and major vascular diseases, such as aortic valve stenosis, mitral prolapse and regurgitation, atherosclerosis, coronary artery disease, and abdominal aortic aneurysm. Unfortunately, only a handful of studies have illustrated the role of sex in the etiology and progression of these disorders. Moreover, knowledge of biomolecular factors that affect these diseases in men and women is very limited. Numerous clinical studies have revealed obvious differences in the prevalence of these diseases between the sexes. These reports were supported by a few molecular and cellular physiology studies that associated this difference to sex and sex hormones. In particular, male sex has commonly been identified as a risk factor for majority of heart valve and vascular diseases, whereas females have been identified as higher risk for certain disorders as well. In addition, menopause is a critical issue that turns the tables against women and enhances complications in their cardiovascular structure due to hormonal change. In this review, major vascular and heart valve diseases for which sex is associated as a risk factor have been reviewed to highlight the importance of this risk factor in CVDs.

Heart rate turbulence and heart rate variability in patients with mitral valve prolapse

AIMS

Heart rate turbulence (HRT) and heart rate variability (HRV) have been shown to be independent and powerful predictors of mortality in a specific group of cardiac patients. However, the predictive values of HRV alone is modest and information on HRV in patients with mitral valve prolapse (MVP) has so far been conflicting. In addition, no studies have previously evaluated HRT in patients with MVP. To define better the effects of MVP on cardiac autonomic function, we assessed HRT and time-domain parameters of HRV in patients with MVP.

METHODS AND RESULTS

Fifty patients with MVP and 70 controls without MVP were investigated. The diagnosis of MVP was confirmed by cross-sectional echocardiography in the parasternal long-axis view and apical 4-chamber view. The HRV and turbulence analysis were assessed from a 24-hour Holter recording. When HRT parameters were compared, the values of the HRT onset and slope were significantly lower in MVP patients than in the controls group (-0.109+/-0.207 vs. -0.289+/-0.170%, P=0.001 and 8.6+/-7.2 vs. 11.5+/-7.4 ms/RRI, P=0.043, respectively) and the number of patients who had abnormal HRT onset was significantly higher in the MVP group than in controls (15 vs. 8, P=0.011). In addition, HRV parameters were not statistically different between the two groups.

CONCLUSION

Although we found that the decrease in HRV parameters was not significantly different between MVP patients and controls, HRT variables (especially HRT onset) were significantly lower in MVP patients. Therefore, in our opinion, HRT is an attractive, easily applicable, and better way of non-invasive risk prediction compared with another non-invasive risk predictor, HRV.

Marfan syndrome and mitral valve prolapse

Mitral valve prolapse (MVP), an abnormal displacement into the left atrium of a thickened and redundant mitral valve during systole, is a relatively frequent abnormality in humans and may be associated with serious complications. A recent study implicates fibrillin-1, a component of extracellular matrix microfibrils, in the pathogenesis of a murine model of MVP. This investigation represents an initial step toward understanding the mechanisms involved in human MVP disease and the development of potential treatments.

Mitral valve prolapse

Mitral valve prolapse is a common valvular abnormality that is the most common cause of severe non-ischaemic mitral regurgitation in the USA. The overall prognosis of patients with mitral valve prolapse is excellent, but a small subset will develop serious complications, including infective endocarditis, sudden cardiac death, and severe mitral regurgitation. We present a comprehensive review of mitral valve prolapse, examining normal mitral anatomy, the clinical and echocardiographic features of mitral valve prolapse, and the pathophysiology and genetics of the disorder. We discuss the contemporary management of both asymptomatic and symptomatic prolapse, with particular attention to the timing and technique of surgical repair. We conclude that echocardiography is the method of choice for diagnosing mitral valve prolapse, that clinical and echocardiographic features can predict which patients with prolapse are at highest risk for complications, and that mitral valve repair is the treatment of choice for symptomatic prolapse.

Glycosaminoglycan profiles of myxomatous mitral leaflets and chordae parallel the severity of mechanical alterations

OBJECTIVES

This biochemical study compared the extracellular matrix of normal mitral valves and myxomatous mitral valves with either unileaflet prolapse (ULP) or bileaflet prolapse (BLP).

BACKGROUND

Myxomatous mitral valves are weaker and more extensible than normal valves, and myxomatous chordae are more mechanically compromised than leaflets. Despite histological evidence that glycosaminoglycans (GAGs) accumulate in myxomatous valves, previous biochemical analyses have not adequately examined the different GAG classes.

METHODS

Leaflets and chordae from myxomatous valves (n = 41 ULP, 31 BLP) and normal valves (n = 27) were dried, dissolved, and assayed for deoxyribonucleic acid, collagen, and total GAGs. Specific GAG classes were analyzed with selective enzyme digestions and fluorophore-assisted carbohydrate electrophoresis.

RESULTS

Biochemical changes were more pronounced in chordae than in leaflets. Myxomatous leaflets and chordae had 3% to 9% more water content and 30% to 150% higher GAG concentrations than normal. Collagen concentration was slightly elevated in the myxomatous valves. Chordae from ULP had 62% more GAGs than those from BLP, primarily from elevated levels of hyaluronan and chondroitin-6-sulfate.

CONCLUSIONS

The GAG classes elevated in the myxomatous chordae are associated with matrix microstructure and elastic fiber deficiencies and may influence the hydration-related "floppy" nature of these tissues. These abnormalities may be related to the reported mechanical weakness of myxomatous chordae. The biochemical differences between ULP and BLP confirm previous mechanical and echocardiographic distinctions.

[Physiopathology and etiology of mitral insufficiency]

Mitral regurgitation has a complex pathophysiology. It should be assessed from the study of factors influencing regurgitant volume and the evaluation of hemodynamics effects downstream (impact on left ventricular function) and upstream (level of left atrial compliance and pulmonary pressure). The regurgitant volume is larger when the regurgitation time is longer, the regurgitant orifice is bigger and the magnitude of the left ventrico-atrial systolic gradient higher. The study of left ventricular function is difficult, especially in chronic mitral regurgitation where the apparently normal left ventricular systolic function can hide a significant worsening in myocardiacs fibres contractile abilities. With the increase in life expectancy and with the decrease in the incidence of rheumatic fever, aetiologies of mitral regurgitation have changed in the past 30 years. They are now dominated by dystrophic mitral regurgitation and infective endocarditis while rheumatic fever becomes less frequent.

Mitral valve prolapse in the general population: the benign nature of echocardiographic features in the Framingham Heart Study

OBJECTIVE

The aim of this study was to examine the echocardiographic features and associations of mitral valve prolapse (MVP) diagnosed by current two-dimensional echocardiographic criteria in an unselected outpatient sample.

BACKGROUND

Previous studies of patients with MVP have emphasized the frequent occurrence of echocardiographic abnormalities such as significant mitral regurgitation (MR) and left atrial (LA) enlargement that are associated with clinical complications. These studies, however, have been limited by the use of hospital-based or referral series.

METHODS

We quantitatively studied all 150 subjects with possible MVP by echocardiography and 150 age- and gender-matched subjects without MVP from the 3,491 subjects in the Framingham Heart Study. Based on leaflet morphology, subjects were classified as having classic (n = 46), nonclassic (n = 37), or no MVP.

RESULTS

Leaflet length, MR degree, and LA and left ventricular size were significantly but mildly increased in MVP (p < 0.0001 to 0.004), with mean values typically within normal range. Average MR jet area was 15.1 +/- 1.4% (mild) in classic MVP and 8.9 +/- 1.5% (trace) in nonclassic MVP; MR was severe in only 3 of 46 (6.5%) subjects with classic MVP, and LA volume was increased in only 8.7% of those with classic MVP and 2.7% of those with nonclassic MVP.

CONCLUSIONS

Although the echocardiographic characteristics of subjects with MVP in the Framingham Heart Study differ from those without MVP, they display a far more benign profile of associated valvular, atrial, and ventricular abnormalities than previously reported in hospital- or referral-based series. Therefore, these findings may influence the perception of and approach to the outpatient with MVP.

Clinical, echocardiographic, and biomechanical differences in mitral valve prolapse affecting one or both leaflets

Mitral valve prolapse (MVP) is the most common cause of severe mitral regurgitation necessitating surgical correction. Unileaflet prolapse (ULP), usually involving the posterior leaflet, is more common than bileaflet prolapse (BLP), which is more difficult to repair. Little is known about clinical, echocardiographic, and biomechanical differences between ULP and BLP. In this study, biomechanical testing was performed on mitral valve leaflets and chordae obtained at operation for severe mitral regurgitation. Preoperative clinical characteristics and echocardiographic measurements were obtained on surgical patients (ULP = 88, BLP = 37). Men outnumbered women by a factor of 4:1 in ULP, and by 3:1 in BLP. Patients with BLP were younger (53.2 +/- 1.7 vs 59.5 +/- 1.1 years) than those with ULP, and this difference was greater in women (48.9 +/- 2.5 vs 62.9 +/- 2.2 years). BLP patients were less likely to be hypertensive, and more likely to undergo valve replacement rather than repair. Echocardiography showed that BLP leaflets were longer and thicker than ULP leaflets. The severity of mitral regurgitation was similar in both groups, although ULP patients had a much higher incidence of flail leaflets (45% vs 5% in BLP). Mechanical strength of chordae was greater in BLP than in ULP, although leaflet strength was similar. The increased chordal strength in BLP may be responsible for less flail. In patients with MVP and severe mitral regurgitation requiring surgery, ULP and BLP are distinct entities with substantial differences in the population affected, in echocardiographic manifestations including prevalence of flail, in chordal mechanics, and in the likelihood of surgical repair.

The long-term outcome of mitral valve repair for mitral valve prolapse

The rationale of early surgery for severe chronic mitral regurgitation (MR) due to mitral valve prolapse (MVP) has been developed over the past decade on the basis of the understanding of the natural history of this disease and the predictors of outcomes after surgical correction of MR. The important decrease in operative mortality associated with the advancements in myocardial preservation, and more importantly the improved reparability of the myxomatous mitral valve, were an additional incentive to develop the concept of early surgery. Previous studies showed that mitral valve repair offers a survival advantage at short- and 10-year follow-up, and therefore suggested that it should be the treatment of choice for severe MR due to MVP. Moreover, very recent data provided new insight on the very long-term follow up, ie, beyond the usual first 10 years in which the initial survival benefit of repair may be negated by a late deterioration.

Prevalence and correlates of mitral valve prolapse in a population-based sample of American Indians: the Strong Heart Study

PURPOSE

Mitral valve prolapse is heritable and occurs frequently in the general population despite associations with mitral regurgitation and infective endocarditis, suggesting that selective advantages might be associated with mitral valve prolapse.

SUBJECTS AND METHODS

Clinical examination and 2-dimensional and color Doppler echocardiography were performed in 3340 American Indian participants in the Strong Heart Study.

RESULTS

Mitral valve prolapse (clear-cut billowing of one or both mitral leaflets across the mitral anular plane in 2-dimensional parasternal long-axis recordings or >2-mm late systolic posterior displacement of mitral leaflets by M mode) occurred in 37 (1.8%) of 2077 women and 20 (1.6%) of 1263 men (P = 0.88); 32 (3.5%) of 907 patients with normal glucose tolerance, 11 (2.3%) of 486 patients with impaired glucose tolerance, and 13 (0.7%) of 1735 patients with diabetes (P <0.0001). Participants with mitral valve prolapse had lower mean (+/- SD) body mass index (28 +/- 5 kg/m(2) vs. 31 +/- 6 kg/m(2), P = 0.001) and blood pressure (124/71 +/- 19/10 mm Hg vs. 130/75 +/- 21/10 mm Hg, P <0.05), as well as lower levels of fasting glucose, triglycerides, serum creatinine, and log urine albumin/creatinine ratio (all P <0.001), than did those without mitral valve prolapse, although all subjects were similar in age (60 +/- 8 years). Participants with mitral valve prolapse had lower ventricular septal (0.87 +/- 0.08 cm vs. 0.93 +/- 0.13 cm) and posterior wall thicknesses (0.82 +/- 0.08 cm vs. 0.87 +/- 0.10 cm), mass (38 +/- 7 g/m(2.7) vs. 42 +/- 11 g/m(2.7)), and relative wall thickness (0.33 +/- 0.04 vs. 0.35 +/- 0.05), and increased stress-corrected midwall shortening (all P <0.01). Mitral valve prolapse was associated with a higher prevalence of mild (16 of 57 [28%] vs. 614 of 3283 [19%]) and more severe mitral regurgitation (5 of 57 [9%] vs. 48 of 3283 [1%], P <0.0001). Regression analyses showed prolapse was associated with low ventricular relative wall thickness, high midwall function, and low urine albumin/creatinine ratio, independent of age, sex, body mass index, and diabetes.

CONCLUSIONS

Mitral valve prolapse is fairly common and is strongly associated with mitral regurgitation in the general population. However, it is also associated with lower body weight, blood pressure, and prevalence of diabetes; a more favorable metabolic profile and ventricular geometry; and better myocardial and renal function.

Transesophageal echocardiographic (TEE) evaluation of the mitral and tricuspid valves

In skilled hands, multiplane TEE provides a comprehensive assessment of the anatomy and function of the mitral and tricuspid valves. TEE is uniquely effective in the evaluation of the diverse pathophysiologic processes that cause valvular heart disease.

Surgical timing for mitral valve regurgitation

Advances in diagnostic and surgical techniques in the management of mitral regurgitation have resulted in improved survival rates and clinical outcomes. Echocardiography is a valuable noninvasive diagnostic tool in the determination of the timing of surgical correction of mitral regurgitation. Improved surgical techniques, the growing role of mitral valve repair, low operative mortality rates, and improved long-term survival rates are important considerations for earlier surgical intervention in symptomatic patients and in asymptomatic patients with echocardiographic criteria of left ventricular dilatation. Intraoperative transesophageal echocardiography is very useful in mitral valve repair and valve replacement with preservation of chordal structures.

Severe mitral regurgitation due to mitral valve prolapse: risk factors for development, progression, and need for mitral valve surgery

Patients with mitral valve prolapse (MVP) may develop severe mitral regurgitation (MR) and require valve surgery. Preliminary data suggest that high body weight and blood pressure might add to the irreversible factors of older age and male gender in increasing risk of these complications. Fifty-four patients with severe MR due to MVP were compared with 117 control subjects with uncomplicated MVP to elucidate factors independently associated with severe MR: the need for valve surgery and the cumulative risk of requiring mitral valve surgery. Patients with severe MR were older (p<0.00005), more overweight (p = 0.002), had higher systolic (p = 0.0003) and diastolic (p = 0.007) blood pressures, and were more likely to have hypertension (p = 0.0001) and to be men (p<0.001). In both groups, men had higher blood pressure and relative body weight than women. In multivariate analysis, older age was most strongly associated with MR; higher body mass index, hypertension, and gender were independent predictors of severe MR in analyses that excluded age. Among the 54 patients with severe MR, the 32 (59%) who underwent mitral valve surgery during 11 years of follow-up were older, more overweight, and more likely to be hypertensive than those not requiring surgery. Among patients undergoing mitral valve surgery in 3 centers, mitral prolapse was the etiology in 25%, 67% of whom were men. Using these data and national statistics, we estimate that the gender-specific cumulative risk for requiring valvular surgery for severe MR in subjects with MVP is 0.8% in women and 2.6% in men before age 65, and 1.4% and 5.5% by age 75. Thus, subjects with MVP who are older, more overweight, and hypertensive are at greater risk for severe MR and valve surgery. Higher blood pressure and relative weight in men with MVP appear to contribute to the gender difference in risk for severe MR.

Prevalence and clinical outcome of mitral-valve prolapse

BACKGROUND

Mitral-valve prolapse has been described as a common disease with frequent complications. To determine the prevalence of mitral-valve prolapse in the general population, as diagnosed with the use of current two-dimensional echocardiographic criteria, we examined the echocardiograms of 1845 women and 1646 men (mean [+/-SD] age, 54.7+/-10.0 years) who participated in the fifth examination of the offspring cohort of the Framingham Heart Study.

METHODS

Classic mitral-valve prolapse was defined as superior displacement of the mitral leaflets of more than 2 mm during systole and as a maximal leaflet thickness of at least 5 mm during diastasis, and nonclassic prolapse was defined as displacement of more than 2 mm, with a maximal thickness of less than 5 mm.

RESULTS

A total of 84 subjects (2.4 percent) had mitral-valve prolapse: 47 (1.3 percent) had classic prolapse, and 37 (1.1 percent) had nonclassic prolapse. Their age and sex distributions were similar to those of the subjects without prolapse. None of the subjects with prolapse had a history of heart failure, one (1.2 percent) had atrial fibrillation, one (1.2 percent) had cerebrovascular disease, and three (3.6 percent) had syncope, as compared with unadjusted prevalences of these findings in the subjects without prolapse of 0.7, 1.7, 1.5, and 3.0 percent, respectively. The frequencies of chest pain, dyspnea, and electrocardiographic abnormalities were similar among subjects with prolapse and those without prolapse. The subjects with prolapse were leaner (P<0.001) and had a greater degree of mitral regurgitation than those without prolapse, but on average the regurgitation was classified as trace or mild.

CONCLUSIONS

In a community based sample of the population, the prevalence of mitral-valve prolapse was lower than previously reported. The prevalence of adverse sequelae commonly associated with mitral-valve prolapse in studies of patients referred for that diagnosis was also low.

Valvular disease in the elderly

As the incidence of valvular disease in the elderly is increasing, understanding of its pathogenesis and natural progression as well as surgical approaches and device technologies are improving. Future studies are needed to develop medical interventions that slow or halt the degenerative valvular processes associated with aging. In addition, mechanical approaches with lower operative risks should be explored and the search should continue for a valve substitute that is durable, hemodynamically efficient, easy to implant, and does not require anticoagulation. Hopefully, future intervention trials will include quality of life assessments such as symptoms, functional capacity and perceptions of well being. At present, the degenerative valvular processes must be followed closely by the clinician, and individual management decisions for the elderly based on the type and severity of valve disease, comorbid medical conditions, and the risks and benefits of intervention, along with patient preferences, rather than on the chronologic age of the patient. It is becoming clear that both survival and quality of life outcomes can improve by consideration of surgery at the onset of indications, before further deterioration eliminates the opportunity to provide benefit for the elderly patient with valvular disease.

A family study of anterior mitral leaflet thickness and mitral valve prolapse

To determine whether mitral valve prolapse (MVP) with or without mitral leaflet thickening (> or =5 mm) represents distinct heritable conditions, 13 patients with MVP with leaflet thickening and their relatives were compared with 67 patients with MVP with normal leaflets and their relatives. The 2 groups of relatives had similar mitral leaflet thicknesses and similar long-term outcome, arguing against the existence of a distinctive subtype of MVP characterized by increased mitral leaflet thickness.

Management of mitral regurgitation. Optimal timing for surgery

Chronic mitral regurgitation is a progressive disorder that can produce myocardial dysfunction in the absence of symptoms. Improvements in surgical techniques have resulted in earlier intervention, at times in asymptomatic patients. This article discusses the factors that influence prognosis, reviews the evidence supporting earlier intervention and provides guidelines for the management of patients with this lesion.

Platelet and blood clotting activation in patients with mitral valve prolapse

In patients with mitral valve prolapse (MVP) a high incidence of valvular abnormalities with a history of previous cerebrovascular disease has been reported and an embolic mechanism has been proposed. Aim of this study is the study of platelet and coagulation activation in patients with MVP. Fifty-four patients affected by MVP (mean age 46 +/- 15 yrs, 22 males, 32 females) and 50 control subjects, age- and sex-matched, were tested for platelet activation [P-selectin and GpIIb-IIIa platelet surface expression at rest and after stimuli by flow cytometric analysis, Beta-Thromboglobulin (TG) and Platelet Factor 4 (PF4) plasma levels by ELISA, platelet-rich-plasma (PRP) and whole blood spontaneous platelet aggregation (SPA)] and for activation of blood coagulation (Prothrombin activation fragment F1+2 plasma levels by ELISA). P-selectin, GpIIb-IIIa expression, Beta-TG, PF4 and SPA were found similar in MVP patients and in controls. However, in patients with severe mitral regurgitation (MR) the percentage of activated platelets which express P-selectin after stimuli was slightly but significantly (p < 0.05) lower in comparison to MVP patients without or with mild to moderate MR and to controls. Moreover, in patients with severe MR F1+2 levels (median 1.6 nmol/L, range 0.6-2.6 nmol/L) were significantly higher (p < 0.001) than both in controls (median 0.95 nmol/L, range 0.2-1.4 nmol/L) and in patients without or with mild to moderate MR (median 1.0 nmol/L, range 0.4-2.3 nmol/L). Our findings suggest that MVP is not responsible per se for blood clotting activation, but in patients with severe mitral insufficiency an increase in thrombin generation can occur. These alterations in hemostatic system may represent a mechanism by which MR increases the risk of thromboembolic events in patients with MVP.

Relationship between severity of mitral regurgitation and prognosis of mitral valve prolapse: echocardiographic follow-up study

We investigated the relation between the severity of mitral regurgitation and the development of complications and cardiac events by using two-dimensional and color Doppler echocardiography in 229 consecutive patients with mitral valve prolapse. The frequency of moderate and severe mitral regurgitation was significantly higher in patients with a prolapsed posterior leaflet (61%) than in patients with a prolapsed anterior leaflet (25%), and the older the patient, the greater the severity of mitral regurgitation. The occurrence of complications, such as atrial fibrillation, congestive heart failure, and chordal rupture, was significantly greater in prolapsed posterior leaflet cases than in prolapsed anterior leaflet cases, and the occurrence was closely associated with the degree of severity of mitral regurgitation. Multiple logistic regression analysis showed that the severity of mitral regurgitation is a strong prognostic indicator for developing complications. Furthermore in a subgroup of 49 patients tracked for a mean of 4.8 years, the new development of complications was significantly higher in patients who showed a progression in the severity of mitral regurgitation (52%) that in patients without progression in severity (8%). The initial severity of mitral regurgitation was related to the occurrence of cardiac events (mitral valve replacement, infective endocarditis, cerebral embolism and death). The data indicated that the progression of mitral regurgitation is closely associated with the development of complications and cardiac events and suggest that the severity of mitral regurgitation is an important prognostic indicator for the development of complications and cardiac events in patients with mitral valve prolapse.

Maternal congenital heart disease and pregnancy outcome

OBJECTIVE

To study the obstetrics and neonatal outcome of women with congenital heart disease.

METHOD

This is a retrospective study of 85 women with congenital cardiac disease. Data collected include maternal characteristics, New York Heart Association Class, cardiac complications and obstetric and neonatal outcome.

RESULTS

The maternal and neonatal outcomes were excellent with no maternal and perinatal mortality. The main cardiac lesions were mitral valve prolapse (60.8%), atrial septal defect (8.6%), ventricle septal defect (6.5%) and aortic regurgitation (4.3%) and 2.1% each of tricuspid regurgitation, pulmonary regurgitation, Ebstein's anomaly, coarctation of aorta, patent ductus arteriosus, and Eisenmenger's syndrome. Six deliveries were associated with New York Heart Association deterioration. Compared to the general obstetric population, more women in the study group were primigravida, had pregnancy induced hypertension, underwent instrumental vaginal deliveries and caesarean sections and had more babies with lower birth weights.

CONCLUSION

Despite potential difficulties and complications associated with congenital heart disease, careful cardiac and obstetric management in a tertiary referal centre resulted in good maternal and fetal outcomes.

Predisposing factors for severe mitral regurgitation in idiopathic mitral valve prolapse

To elucidate predisposing factors for severe mitral regurgitation (MR) in idiopathic mitral valve prolapse (MVP), 124 MVP patients were classified into the following categories: 55 with isolated clicks (click group), 35 with a late-systolic murmur (late-SM group), and 34 with a holosystolic murmur (holo-SM group). Their clinical and echocardiographic findings were compared with those of 26 patients with spontaneous chordal rupture (rupture group). In 22 patients in the click group, 24 in the late-SM group, and 22 in the holo-SM group, follow-up studies were performed for a mean of 4.5 years (range 1 to 13.5). The mean age was youngest in the click group and oldest in the rupture group. The click and late-SM groups showed a female predominance, but the holo-SM and rupture groups showed a male predominance. There was no difference in the incidence of systemic hypertension among the 4 groups. Most patients in the click and late-SM groups had anterior leaflet prolapse. In the holo-SM and rupture groups, however, the incidence of posterior leaflet involvement was significantly increased. The incidence of thickened mitral valve increased in order of the click (8%), late-SM (21%), holo-SM (38%), and rupture (50%) groups. Six patients in the holo-SM group developed chordal rupture with severe MR during the follow-up period. In the click and late-SM groups, however, there were no complications and no development into a holo-SM. Thus, aging, male sex, posterior leaflet prolapse, thickened mitral valve, and holo-SM were found to be important predisposing factors for severe MR in idiopathic MVP.

Natural history of mitral valve prolapse

To assess the rate and predictors of complications in patients with mitral valve prolapse (MVP), 316 subjects (mean age 42 +/- 15 years) with echocardiographic MVP were followed prospectively for a mean of 102 months: 220 (70%) were women, 225 (71%) had clinically recognized MVP, and 91 (29%) were detected in family studies. During follow-up, 11 patients (0.4/100 subject-years) required mitral valve surgery, 6 died of cardiac causes (0.2/100 subject-years), 7 developed cerebral ischemia (0.3/100 subject-years), and 2 developed active infective endocarditis (0.1/100 subject-years). The overall rate of fatal and nonfatal complications (1/100 patient-years) was higher in men than in women (odds ratio [OR] 3.2, p < 0.003), in subjects aged > 45 than < or = 45 years (OR 3.4, p = 0.002), in clinically recognized patients than in affected family members (OR 3.8, p < 0.02), and in those with a holosystolic murmur (OR 26.9, p < 0.00005); the overall rate was lower in those with a midsystolic click (OR 0.3, p < 0.002). Echocardiographic left ventricular or atrial diameter > or = 6.0 or > or = 4.0 cm, respectively, was associated with a 16.7- and 15.1-fold higher likelihood, respectively, of subsequent complications.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Pregnancy outcome and mitral valve prolapse

Mitral valve prolapse (MVP) comprises a large proportion of obstetric cardiac problems and has a general prevalence of 4%. We examined the obstetric outcome of patients with MVP delivered between 1988-1991 at the National University Hospital, Singapore. During this interval, deliveries totalled 16,755 of which 85 (0.51%) had maternal cardiac disease. Of these, 28 (32.9%) had echocardiographic evidence of non-myxomatous MVP. Ten patients (37.5%) had demonstrable mitral regurgitation and 4 (14.3%) had benign ventricular ectopics. All patients remained well throughout pregnancy. Gestation at delivery and use of analgesia did not differ significantly from non-cardiac patients. However, the labour induction rate was twice the department average at 17.9%. Twenty-four (85.7%) patients achieved vaginal delivery and 4 (14.3%) patients were delivered abdominally. All babies were liveborn. Eight patients (28.6%) did not receive antibiotic prophylaxis during labour and postpartum period and remained afebrile. The role of antibiotics in this category of patients is discussed. Patients with MVP without myxomatous valve changes may expect excellent pregnancy outcome.

Arrhythmias in mitral valve prolapse: relation to anterior mitral leaflet thickening, clinical variables, and color Doppler echocardiographic parameters

Atrial and ventricular arrhythmias have been reported with variable incidence in symptomatic patients with mitral valve prolapse (MVP). The role of clinical and echocardiographic parameters as predictors for arrhythmias still needs to be clarified. One hundred nineteen consecutive patients (56 women and 63 men, mean age 40 +/- 17 years) with echocardiographically diagnosed MVP were examined. A complete echocardiographic study (M-mode, two-dimensional, and Doppler) and 24-hour electrocardiographic monitoring were performed in all patients. Complex atrial arrhythmias (CAAs) included atrial couplets, atrial tachycardia, and paroxysmal or sustained atrial flutter or fibrillation. Complex ventricular arrhythmias (CVAs) included multiform ventricular premature contractions (VPCs), VPC couplets, and runs of three or more sequential VPCs (salvos of ventricular tachycardia). The relation between complex arrhythmias and clinical parameters (age and gender) and echocardiographic parameters (left atrial and left ventricular dimensions, anterior mitral leaflet thickness [AMLT], and presence and severity of mitral regurgitation) was evaluated by multiple logistic regression analysis. CAA were present in 14% of patients and CVA in 30%. According to multiple logistic modeling, CAA correlated separately in the univariate analysis with age, presence of MR, and left ventricular and left atrial diameters; age was the only independent predictor (p < 0.001). CVA, in the univariate analysis, correlated with age, female gender, left ventricular end-diastolic diameter, and AMLT; only female gender and AMLT were independent predictors in the multivariate analysis (p < 0.01). The incidence of mitral regurgitation (59%) was higher than expected in a general population of MVP patients.(ABSTRACT TRUNCATED AT 250 WORDS)