Echocardiographically documented mitral-valve prolapse. Long-term follow-up of 237 patients

Interactions between cardiovascular and cerebrovascular disease

OPININION STATEMENT: All patients with ischemic stroke should undergo a comprehensive assessment of cardiovascular risk. Patients with carotid artery disease, symptoms of cerebral ischemia and high cardiovascular risk profiles should be considered for noninvasive testing for coronary artery disease (CAD). Routine testing for CAD before carotid endarterctomy is not recommended. Patients with coexisting coronary and carotid artery disease should be more aggressively treated for reducing their "very high" risk of cardiovascular events. In patients candidates to carotid revascularization, a preoperative coronary angiography and coronary revascularization are not recommended. Warfarin is recommended in all patients with moderate to high risk of stroke. Novel oral anticoagulants represent an attractive alternative to warfarin. However, their place in therapy in clinical practice is not yet established. Percutaneous closure of the left atrial appendage for stroke prophylaxis may be considered in selected patients with atrial fibrillation and contraindications for oral anticoagulant therapy. Warfarin is not indicated in patients with heart failure who are in sinus rhythm. Percutaneous closure of patent foramen does not seem to be superior to medical therapy for the prevention of recurrences in patients with cryptogenic stroke.

Minimally invasive surgery for valvular heart disease

OPINION STATEMENT

Valvular heart disease imposes varying degrees of stress on the myocardium, which, untreated, leads to eventual ventricular dysfunction. The pathophysiologic mechanisms by which these lesions act depend not only on the affected valve, but also the degree to which they causes stenosis, regurgitation, or both. The goal of patient treatment is to identify and correct the defect before irreversible ventricular changes have occurred. Historically, the conventional surgical approach for valvular disease was via median sternotomy. Minimally invasive valve surgery (MIVS) refers to alternative surgical techniques, which avoid the trans-sternal approach. The objective is to (1) minimize surgical trauma, (2) reduce blood utilization, and (3) hasten postoperative convalesce. These goals are accomplished through the use of partial sternal, para-sternal, or thoracotomy incisions and can be adapted to robotic technologies. As with all evolving surgical techniques, the therapeutic aim of valve repair or replacement must be performed at or above the same standard of conventional surgery. Outcomes must not be sacrificed for the sake of better cosmesis. In addition, percutaneous catheter-based valvular interventions have seen rapid advances. These emerging technologies have dramatically broadened the therapeutic options, especially for an ever-increasing group of high-risk patients. As expected with all minimally invasive techniques, the major differences in the hard outcomes of mortality and major morbidity are seen in these highest risk groups. However, intermediate and low risk patients receive a tremendous benefit with regard to shortened hospital stay and quicker functional recovery. With the myriad of interventional options now available, the clinical challenge now is how best to individualize the treatment approach to a given patient providing the most durable result in order to alleviate symptoms and preserve myocardial function.

Relation of mitral valve morphology and motion to mitral regurgitation severity in patients with mitral valve prolapse

Background

Mitral valve thickness is used as a criterion to distinguish the classical from the non-classical form of mitral valve prolapse (MVP). Classical form of MVP has been associated with higher risk of mitral regurgitation (MR) and concomitant complications. We sought to determine the relation of mitral valve morphology and motion to mitral regurgitation severity in patients with MVP.

Methods

We prospectively analyzed transthoracic echocardiograms of 38 consecutive patients with MVP and various degrees of MR. In the parasternal long-axis view, leaflets length, diastolic leaflet thickness, prolapsing depth, billowing area and non-coaptation distance between both leaflets were measured.

Results

Twenty patients (53%) and 18 patients (47%) were identified as having moderate to severe and mild MR respectively (ERO = 45 ± 27 mm² vs. 5 ± 7 mm², p < 0.001). Diastolic leaflet thickness was similar in both groups (5.5 ± 0.9 mm vs. 5.3 ± 1 mm, p = 0.57). On multivariate analysis, the non-coaptation distance (OR 7.9 per 1 mm increase; 95% CI 1.72-37.2) was associated with significant MR. Thick mitral valve leaflet as traditionally reported (≥ 5 mm) was not associated with significant MR (OR 0.9; 95% CI 0.2-3.4).

Conclusions

In patients with MVP, thick mitral leaflet is not associated with significant MR. Leaflet thickness is probably not as important in risk stratification as previously reported in patients with MVP. Other anatomical and geometrical features of the mitral valve apparatus area appear to be much more closely related to MR severity.

Autonomic dysregulation as a novel underlying cause of mitral valve prolapse: a hypothesis

Mitral valve prolapse is a common valvular abnormality that is caused by myxomatous degeneration, characterized macroscopically by leaflet thickening and redundancy accompanied with histologically marked proliferation of the spongiosa and mucopolysaccharide acid replacement of leaflet collagen in the prolapse leaflets. Nevertheless, the discrepant natural history and various concomitant syndromes cannot be explained completely by the current genetic autosomal dominant inheritance theory. In addition, autonomic dysregulation has been commonly reported in mitral valve prolapse, but has never been indicated as a major underlying cause. This article attempts to interpret the occurrence of primary pathology and progression in mitral valve prolapse on a common basis of improper autonomic tone. The imbalanced background of autonomic nervous firing leads to disharmonized synthetic/catabolism balance in the extracellular matrix, disrupted transition in the interstitial cellular component and invalided anti-inflammatory pathway in the endothelium, which trigger and accelerate the progression of this condition. Such a hypothesis not only unifies the seemingly disparate syndromes and valvular disorder, but also has implications for future biopharmaceutical and mechanical treatment.

Does the association between mitral valve prolapse and panic disorder really exist?

OBJECTIVE

Although the possible relationship between panic disorder and mitral valve prolapse (MVP) attracted considerable research interest in the 1980s and 1990s, the reported prevalence of MVP in these patients has been inconsistent and widely variable. Clinical and epidemiologic studies have produced controversial data on possible association or definite causal relationship between these 2 entities. The primary objective of the present review was to summarize the current state of knowledge on the association between panic disorder and MVP, including the influence of diagnostic criteria for MVP on the controversial results.

DATA SOURCES

We searched MEDLINE, LILACS, and EMBASE databases using the keywords panic and mitral. Inclusion criteria were articles concerning the reciprocal association of MVP and panic disorder, published from the earliest dates available through December 2006.

STUDY SELECTION

All relevant articles published in English, Spanish, or Portuguese and reporting original data related to the association of MVP and panic disorder were included. Forty articles fulfilling the criteria for inclusion in this review were identified.

DATA SYNTHESIS

Even though the reported prevalence of MVP in panic disorder varied from 0% to 57%, a significant association between the 2 disorders was documented in 17 of the 40 studies. Such inconsistent results were due to sampling biases in case or control groups, widely different diagnostic criteria for MVP, and lack of reliability of MVP diagnosis. None of the reviewed studies used the current state-of-the-art diagnostic criteria for MVP to evaluate the volunteers. Apparently, the more elaborate the study methodology, the lower the chance to observe a significant relationship between these 2 conditions.

CONCLUSIONS

Published results are insufficient to definitely establish or to exclude an association between MVP and panic disorder. If any relationship does actually exist, it could be said to be infrequent and mainly occur in subjects with minor variants of MVP. To clarify this intriguing issue, future studies should mainly focus on the observed methodological biases and particularly should use the current criteria for MVP as the standard for evaluation.

P-wave dispersion and heart rate variability in children with mitral valve prolapse

Previous studies have reported that patients with mitral valve prolapse (MVP) may display autonomic dysfunction. Measurement of heart rate variability (HRV) and P-wave dispersion (PWD) may provide insights into the functional state of the autonomic nervous system. Heart rate variability (HRV) has been used as a noninvasive marker of autonomic activity. However, to the authors' knowledge, PWD has not been studied in the context of MVP. This study aimed to examine HRV and PWD in patients with MVP and to determine whether differences exist between symptomatic and asymptomatic patients. The study population consisted of 54 healthy children (17 boys and 37 girls) ages 6-18 years and 76 patients with MVP (20 boys and 56 girls) ages 6-18 years. The duration and dispersion of the P-wave were measured by surface 12-lead electrocardiograms (ECGs). Heart rate variability was quantified using both time-domain and frequency-domain analyses of Holter ECGs. The minimum duration of the P-wave was significantly lower in the MVP patients (42.4 ± 10.0 ms) than in the control subjects (54.4 ± 12.8 ms) (p < 0.01), and the PWD was significantly increased in the MVP group (42.7 ± 10.8 ms) compared with the control subjects (31.8 ± 10.9 ms) (p < 0.01). However, no significant differences were found between the symptomatic and asymptomatic patients. In addition, the HRV parameters were not statistically different between the two groups. In conclusion, although HRV parameters were not significantly different between the MVP and control groups, the findings show that PWD was increased for the children with MVP. However, no relationship could be established between PWD and clinical symptoms.

CMR predictors of mitral regurgitation in mitral valve prolapse

OBJECTIVES

We sought to assess the correlation between mitral valve characteristics and severity of mitral regurgitation (MR) in subjects with mitral valve prolapse (MVP) undergoing cardiac magnetic resonance (CMR) imaging.

BACKGROUND

Compared with extensive echocardiographic studies, CMR predictors of MVP-related MR are unknown. The severity of MR at the time of diagnosis has prognostic implication for patients; therefore, the identification of determinants of MR and its progression may be important for risk stratification, follow-up recommendations, and surgical decision making.

METHODS

Seventy-one MVP patients (age 54 ± 11 years, 58% males, left ventricular [LV] ejection fraction 65 ± 5%) underwent cine CMR to assess annular dimensions, maximum systolic anterior and posterior leaflet displacement, papillary muscle (PM) distance to coaptation point and prolapsed leaflets, as well as diastolic anterior and posterior leaflet thickness and length, and LV volumes and mass. Velocity-encoded CMR was used to obtain aortic outflow and to quantify MR volume.

RESULTS

Using multiple linear regression analysis including all variables, LV mass (p < 0.001), anterior leaflet length (p = 0.006), and posterior displacement (p = 0.01) were the best determinants of MR volume with a model-adjusted R(2) = 0.6. When the analysis was restricted to valvular characteristics, MR volume correlated with anterior mitral leaflet length (p < 0.001), posterior mitral leaflet displacement (p = 0.003), posterior leaflet thickness (p = 0.008), and the presence of flail (p = 0.005) with a model-adjusted R(2) = 0.5. We also demonstrated acceptable intraobserver and interobserver variability in these measurements.

CONCLUSIONS

Anterior leaflet length, posterior leaflet displacement, posterior leaflet thickness, and the presence of flail are the best CMR valvular determinants of MVP-related MR. The acceptable intraobserver and interobserver variability of our measurements confirms the role of CMR as an imaging modality for assessment of MVP patients with significant MR.

Predictors of outcome of mitral valve prolapse in patients with the Marfan syndrome

Mitral valve prolapse has a prevalence of 2% to 3% in the general population, with adverse outcomes such as mitral valve regurgitation (MVR), heart failure, and endocarditis. Predictors of outcomes are used in idiopathic mitral valve prolapse for the timing of surgery, but such predictors are unknown in Marfan syndrome. Therefore, a population-based cohort study of 112 patients (49 male, 63 female; mean age 34 ± 15 years) with classic Marfan syndrome and mitral valve prolapse with moderate or less MVR at baseline was conducted. During 4.6 ± 3.6 years of follow-up, progression of MVR was observed in 41 patients and valve-related events, which comprised mitral valve endocarditis (7 events), heart failure (5 events), and mitral valve surgery (25 events), were observed in 31 patients. Multivariate Cox proportional-hazards regression analysis identified a flail mitral leaflet (hazard ratio [HR] 3.262, 95% confidence interval [CI] 1.406 to 7.566, p = 0.006) and increased indexed end-systolic left ventricular diameters (HR 1.113, 95% CI 1.043 to 1.188, p = 0.001) as independent predictors of progression of MVR. Similarly, mitral valve-related events were independently predicted by a flail mitral leaflet (HR 5.343, 95% CI 2.229 to 12.808, p <0.001), and mild (HR 14.336, 95% CI 1.873 to 109.755, p = 0.01) or moderate (HR 16.849, 95% CI 2.205 to 128.76, p = 0.006) degree of MVR. Conversely, aortic dilatation, dural ectasia, and sporadic mode of inheritance were not associated with outcome. In conclusion, the same clinical determinants that predict outcomes in idiopathic mitral valve prolapse also predict outcomes in mitral valve prolapse associated with Marfan syndrome.

Cardiovascular involvement in patients with different causes of hyperthyroidism

Various clinical disorders can cause hyperthyroidism, the effects of which vary according to the patient's age, severity of clinical presentation and association with other comorbidities. Hyperthyroidism is associated with increased morbidity and mortality from cardiovascular disease, although whether the risk of specific cardiovascular complications is related to the etiology of hyperthyroidism is unknown. This article will focus on patients with Graves disease, toxic adenoma and toxic multinodular goiter, and will compare the cardiovascular risks associated with these diseases. Patients with toxic multinodular goiter have a higher cardiovascular risk than do patients with Graves disease, although cardiovascular complications in both groups are differentially influenced by the patient's age and the cause of hyperthyroidism. Atrial fibrillation, atrial enlargement and congestive heart failure are important cardiac complications of hyperthyroidism and are prevalent in patients aged > or = 60 years with toxic multinodular goiter, particularly in those with underlying cardiac disease. An increased risk of stroke is common in patients > 65 years of age with atrial fibrillation. Graves disease is linked with autoimmune complications, such as cardiac valve involvement, pulmonary arterial hypertension and specific cardiomyopathy. Consequently, the etiology of hyperthyroidism must be established to enable correct treatment of the disease and the cardiovascular complications.

Predictors of ventricular arrhythmias in patients with mitral valve prolapse

Arrhythmias have been reported to occur frequently in symptomatic patients with mitral valve prolapse (MVP). The mechanisms causing ventricular arrhythmias in patients with MVP have not been fully investigated. The purpose of this study was to determine the clinical, echocardiographic and heart rate variability parameters, and plasma concentrations of electrolytes and inflammatory markers in predicting ventricular arrhythmias in patients with MVP. A total of 58 consecutive patients with MVP were included in this study. We performed electrocardiography, echocardiography, holter analysis, routine biochemical tests including plasma concentrations of electrolytes and inflammatory markers, and evaluated the clinical characteristics. Ventricular arrhythmia defined as occurrence of any of the followings: ventricular premature contractions (VPCs), VPC couplets, and ventricular tachycardia documented by holter analysis, continuous monitoring or by electrocardiography. Twenty patients (34%) had ventricular arrhythmias, and 38 (66%) patients had no ventricular arrhythmias. Seventeen patients had VPC, 2 patients had VPC couplets and 1 patient had ventricular tachycardia. Univariable predictors of ventricular arrhythmias included isovolumetric relaxation time and the occurrence of moderate to severe mitral regurgitation. Multivariable logistic regression analysis showed that occurrence of moderate to severe mitral regurgitation was the only independent predictor of ventricular arrhythmias (relative risk: 8.42, 95% confidence interval: 1.49-47.64, p = 0.01). Present study showed that the only independent predictor of ventricular arrhythmias in patients with MVP is the occurrence of moderate to severe mitral regurgitation.

High occurrence of mitral valve prolapse in cardiac catheterization patients with pure isolated mitral regurgitation

The aetiological spectrum of angiographically verified pure isolated mitral regurgitation (MR) was studied in 48 consecutive adult patients (35 males). Severe MR was found in 35 patients (73%) and moderate MR in 13 patients (27%). Mitral valve prolapse (MVP) syndrome was found in 21 patients (44%). These were younger than the rest of the study population (55 +/- 13 vs. 62 +/- 6 years, p less than 0.05) and 15 (71%) of them were men. Endocarditis and chordal rupture occurred in 19% and 43% of the MVP patients. Sixteen patients (33%) had MR secondary to myocardial infarction while only three patients (6%) had MR of rheumatic aetiology. Bacterial endocarditis, hypertensive heart disease, hypertrophic obstructive cardiomyopathy and mitral annulus calcification were less frequently found. Mitral valve replacement was done in 20 (57%) of the patients with severe MR and MVP was the underlying disease in 15 (75%) of these patients. In conclusion, MVP is a frequent cause of pure isolated MR and of mitral valve replacement. In contrast to the preponderance of young females amongst MVP patients in population surveys, most of the MVP patients with MR in this study are middle-aged and elderly men.

Cardiovascular magnetic resonance characterization of mitral valve prolapse

OBJECTIVES

This study sought to develop cardiovascular magnetic resonance (CMR) diagnostic criteria for mitral valve prolapse (MVP) using echocardiography as the gold standard and to characterize MVP using cine CMR and late gadolinium enhancement (LGE)-CMR.

BACKGROUND

Mitral valve prolapse is a common valvular heart disease with significant complications. Cardiovascular magnetic resonance is a valuable imaging tool for assessing ventricular function, quantifying regurgitant lesions, and identifying fibrosis, but its potential role in evaluating MVP has not been defined.

METHODS

To develop CMR diagnostic criteria for MVP, characterize mitral valve morphology, we analyzed transthoracic echocardiography and cine CMR images from 25 MVP patients and 25 control subjects. Leaflet thickness, length, mitral annular diameters, and prolapsed distance were measured. Two- and three-dimensional LGE-CMR images were obtained in 16 MVP and 10 control patients to identify myocardial regions of fibrosis in MVP.

RESULTS

We found that a 2-mm threshold for leaflet excursion into the left atrium in the left ventricular outflow tract long-axis view yielded 100% sensitivity and 100% specificity for CMR using transthoracic echocardiography as the clinical gold standard. Compared with control subjects, CMR identified MVP patients as having thicker (3.2 +/- 0.1 mm vs. 2.3 +/- 0.1 mm) and longer (10.5 +/- 0.5 mm/m(2) vs. 7.1 +/- 0.3 mm/m(2)) indexed posterior leaflets and larger indexed mitral annular diameters (27.8 +/- 0.7 mm/m(2) vs. 21.5 +/- 0.5 mm/m(2) for long axis and 22.9 +/-0.7 mm/m(2) vs. 17.8 +/- 0.6 mm/m(2) for short axis). In addition, we identified focal regions of LGE in the papillary muscles suggestive of fibrosis in 10 (63%) of 16 MVP patients and in 0 of 10 control subjects. Papillary muscle LGE was associated with the presence of complex ventricular arrhythmias in MVP patients.

CONCLUSIONS

Cardiovascular magnetic resonance image can identify MVP by the same echocardiographic criteria and can identify myocardial fibrosis involving the papillary muscle in MVP patients. Hyperenhancement of papillary muscles on LGE is often present in a subgroup of patients with complex ventricular arrhythmias.

Risk, determinants, and outcome implications of progression of mitral regurgitation after diagnosis of mitral valve prolapse in a single community

To analyze the evolution of mitral regurgitation (MR) after the diagnosis of mitral valve prolapse in community patients, 285 residents of Olmsted County, Minnesota, diagnosed with mitral valve prolapse without severe MR were studied. MR grade was assessed at diagnosis and at follow-up 1,663 +/- 1,079 days later using Doppler echocardiography. The progression of MR was defined as an increase of > or =1 MR grade. The patients' mean age was 56 +/- 22 years, 57% were women, and the mean ejection fraction was 60 +/- 9%. Between diagnostic and follow-up echocardiography, 108 patients showed progression of MR, 39 of whom had progression > or =1 grade. The mean overall MR grade increased from 0.4 +/- 0.7 to 0.9 +/- 1.1 (p <0.01). The progression of MR was observed in all subsets, irrespective of age, gender, prolapse localization, leaflet thickening, and initial MR grade. However, multivariate analysis identified age (p <0.01) and initial MR grade (p = 0.01) as independent predictors of progression. In addition, MR progression was associated with greater left atrial enlargement (p <0.001), ventricular dilatation (p = 0.02 for increase in end-diastolic and end-systolic diameters), and a worse outcome (adjusted p = 0.001). In conclusion, in patients with mitral valve prolapse, MR progression was observed over time in all clinical and anatomic subsets and was associated with more severe ventricular and atrial remodeling and worse outcome.

QT dispersion and diastolic functions in differential diagnosis of primary mitral valve prolapse and rheumatic mitral valve prolapse

There is no specific criteria established to guide physicians in the differential diagnosis of primary mitral valve prolapse (MVP) and rheumatic MVP. Previous studies suggested that history and pathology of mitral valve could be helpful in differential diagnosis of MVP. The aim of this study was to evaluate the value of QT interval, QT dispersion, and diastolic function in differential diagnosis of MVP. We examined electrocardiographies and echocardiographies of 24 primary MVP patients, 20 rheumatic MVP patients, and 21 healthy subjects. MVP was defined as superior displacement of the mitral leaflets more than 2 mm into the left atrium during systole. QT dispersion was significantly higher in primary MVP patients (71 +/- 13.5 ms, p < 0.01). Maximum QT dispersion value in rheumatic MVP patients was 55 ms. E and A velocity values which show ventricular early and late diastolic filling, were lower in primary MVP patients (p < 0.01). There was no difference in the heart rate corrected QT interval values between the primary MVP patients (397 +/- 28.1), rheumatic MVP patients (403 +/- 23.8) and healthy children (404 +/- 15.8; p > 0.05). Our findings may indicate that QT dispersion can be used as a parameter for differential diagnosis of primary MVP and rheumatic MVP. Further studies are needed to identify a cut-off point of QT dispersion.

Mitral valve prolapse syndrome as cause of sudden death in young adults

Mitral valve prolapse syndrome (MVPS) is a relatively common disorder of the mitral valve and most cases take a benign clinical course. Only a subset of patients develop severe clinical symptoms such as arrhythmia, insufficiency of the mitral valve or infective endocarditis. As a consequence, sudden death might occur in these patients, thought to be caused by an arrhythmogenic event. By presenting six cases of sudden unexpected death in young female adults, we point at clinical and pathological data from the literature, which are of interest from the viewpoint of legal medicine. The incidence of MVPS in autopsy series has been reported to be about 4-5%, while clinical data hint at an incidence of about 2.5%. The presented cases suggest that even clinically benign cases of MVPS in young adults might result in sudden unexpected death. Such cases are not included in hospital based studies on the topic. This might lead to an underestimation of the fatal risk associated with the disease, even if sudden death might be a rare event in MVPS.

The Crossed Swords Sign: Insights into the Dilemma of Repair in Bileaflet Mitral Valve Prolapse

BACKGROUND

The need for bileaflet repair in bileaflet mitral valve prolapse (MVP) remains controversial. Will anterior leaflet prolapse resolve with posterior leaflet repair or should both leaflets be addressed? Single-leaflet MVP produces oppositely directed mitral regurgitant jets. Some patients show two crossed jets oppositely directed from the coaptation zone. We hypothesized that these indicate bileaflet lesions requiring complex repair.

METHODS

Echocardiograms and surgical reports of 52 consecutive patients with MVP undergoing surgery were reviewed.

RESULTS

First, all 14 patients with two oppositely directed jets had prolapse of more than one leaflet. Each jet was related to discrete leaflet distortions causing malcoaptation. Six underwent valve replacement. Seven had both leaflets repaired. One had posterior leaflet repair and annuloplasty, with persistent mitral regurgitation requiring valve replacement. Second, 36 of 38 patients with single jets had single-leaflet MVP. One underwent replacement; all others did well with single-leaflet repair. Two patients with bileaflet MVP but only one jet did well with single-leaflet repair or annuloplasty.

CONCLUSION

This crossed swords sign is an important clue to bileaflet mechanism of mitral regurgitation in MVP, associated with complex repair procedures. Thus, it provides a clue in the dilemma of bileaflet versus single-leaflet repair.

Prevalence and clinical correlates of isolated mitral, isolated aortic regurgitation, and both in adults aged 21 to 35 years (from the CARDIA study)

Aortic regurgitation (AR) and mitral regurgitation (MR) can result in serious clinical complications and death. The physiologic and clinical correlates of AR and MR in a free-living young adult population, however, have not been well defined. The prevalence and correlates of AR and MR were investigated in Coronary Artery Risk Development in Young Adults (CARDIA), a multicenter National Heart, Lung, and Blood Institute study of 4,352 men and women aged 21 to 35 years who had 2-dimensionally directed M-mode echocardiographic and spectral and color Doppler examinations. Isolated MR by color Doppler was detected in 10.4% (90.4% with trivial or mild severity). Isolated AR by color Doppler was present in 0.8% (37.7% with mild severity). Combined AR and MR occurred in 0.5%. There was no association between body mass index and the prevalence or severity of MR or AR. Left ventricular mass was greater in subjects with isolated AR (mean +/- SD 172 +/- 49 g) than in those with MR (155 +/- 48 g) and greater in both groups than in subjects without MR and AR (148 +/- 44 g). AR was associated with increased aortic root diameter, whereas subjects with isolated MR and those with AR and MR had increased left atrial dimensions and greater left ventricular internal dimensions. In conclusion, MR and AR detected by color Doppler echocardiography are relatively uncommon in a healthy young adult population, but both are associated with evidence of increased left ventricular dimensions and mass.

Antithrombotic and interventional treatment options in cardioembolic transient ischaemic attack and ischaemic stroke

Peer-reviewed data pertaining to anti-thrombotic and interventional therapy for transient ischaemic attack (TIA) or ischaemic stroke patients with non-valvular atrial fibrillation, atrial flutter, interatrial septal abnormalities, or left ventricular thrombus were reviewed. Long-term oral anticoagulant therapy with warfarin is the treatment of choice for secondary stroke prevention following TIA or minor ischaemic stroke in association with persistent or paroxysmal non-valvular atrial fibrillation or atrial flutter. If warfarin is contraindicated, long-term aspirin is a safe, but much less effective alternative treatment option in this subgroup of patients with cerebrovascular disease. Management of young patients with TIA or stroke in association with an interatrial septal defect is controversial. Various treatment options are outlined, but readers are encouraged to include these patients in one of the ongoing randomised clinical trials in this area. It is reasonable to consider empirical anticoagulation in patients with TIA or ischaemic stroke in association with left ventricular thrombus formation following myocardial infarction or in association with idiopathic dilated cardiomyopathy. If warfarin is prescribed, one should aim for a target international normalised ratio of 2.5 (range 2-3) to achieve the best balance between adequate secondary prevention of cardioembolic events and the risk of major haemorrhagic complications.

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.

Tissue Doppler echocardiography reveals insufficient contractile reserve recruitment during effort in subjects with mitral valve prolapse and those with thick mitral valve

OBJECTIVE

To assess by tissue Doppler echocardiography (TDE), the tissue velocities, both at rest and after exercise stress testing, in subjects with mitral valve prolapse (MVP) and those with thick mitral valve (TMV).

METHODS

Twenty individuals with typical MVP, 30 with TMV, and 30 healthy controls were enrolled. TDE was performed at the basal-inferior wall and the parameters evaluated were the S, Em, and Am velocities, as well as the Em/Am ratio.

RESULTS

The mean S-wave at rest was higher in subjects with MVP compared to that of the TMV (P < 0.01) and the control groups (P = 0.00005), whereas after exercise it was higher in the control group compared to either MVP (P = 0.013) or TMV group (P = 0.00002). The mean Em wave at rest was higher in the control individuals both at rest (P = 0.007 compared with MVP group and P = 0.013 compared with TMV group), and after exercise (P = 0.0002 and 0.0009, respectively). The Am wave in the MVP group was higher compared with TMV and control subjects at rest (P = 0.022 and 0.00001, respectively) but it was not after exercise (P = ns for both comparisons). The Em/Am ratio of the control group at rest was higher than that of the MVP (P = 0.0000) and TMV (P = 0.00028) groups. However, after exercise, it was higher only when compared with the MVP group (P = 0.016).

CONCLUSIONS

Subjects with MVP and those with TMV exhibit a less effective contractile response to exercise compared to healthy individuals. Some degree of diastolic dysfunction, particularly after exercise, was also detected in the individuals with MVP.

New locus for autosomal dominant mitral valve prolapse on chromosome 13: clinical insights from genetic studies

BACKGROUND

Mitral valve prolapse (MVP) is a common disorder associated with mitral regurgitation, endocarditis, heart failure, and sudden death. To date, 2 MVP loci have been described, but the defective genes have yet to be discovered. In the present study, we analyzed a large family segregating MVP, and identified a new locus, MMVP3. This study and others have enabled us to explore mitral valve morphological variations of currently uncertain clinical significance.

METHODS AND RESULTS

Echocardiograms and blood samples were obtained from 43 individuals who were classified by the extent and pattern of displacement. Genotypic analyses were performed with polymorphic microsatellite markers. Evidence of linkage was obtained on chromosome 13q31.3-q32.1, with a peak nonparametric linkage score of 18.41 (P<0.0007). Multipoint parametric analysis gave a logarithm of odds score of 3.17 at marker D13S132. Of the 6 related individuals with mitral valve morphologies not meeting diagnostic criteria but resembling fully developed forms, 5 carried all or part of the haplotype linked to MVP.

CONCLUSIONS

The mapping of a new MVP locus to chromosome 13 confirms the observed genetic heterogeneity and represents an important step toward gene identification. Furthermore, the genetic analysis provides clinical lessons with regard to previously nondiagnostic morphologies. In the familial context, these may represent early expression in gene carriers. Early recognition of gene carriers could potentially enhance the clinical evaluation of patients at risk of full expression, with the ultimate aim of developing interventions to reduce progression.

Thyroid hormone action in the heart

The heart is a major target organ for thyroid hormone action, and marked changes occur in cardiac function in patients with hypo- or hyperthyroidism. T(3)-induced changes in cardiac function can result from direct or indirect T(3) effects. Direct effects result from T(3) action in the heart itself and are mediated by nuclear or extranuclear mechanisms. Extranuclear T(3) effects, which occur independent of nuclear T(3) receptor binding and increases in protein synthesis, influence primarily the transport of amino acids, sugars, and calcium across the cell membrane. Nuclear T(3) effects are mediated by the binding of T(3) to specific nuclear receptor proteins, which results in increased transcription of T(3)-responsive cardiac genes. The T(3) receptor is a member of the ligand-activated transcription factor family and is encoded by cellular erythroblastosis A (c-erb A) genes. T(3) also leads to an increase in the speed of diastolic relaxation, which is caused by the more efficient pumping of the calcium ATPase of the sarcoplasmic reticulum. This T(3) effect results from T(3)-induced increases in the level of the mRNA coding for the sarcoplasmic reticulum calcium ATPase protein, leading to an increased number of calcium ATPase pump units in the sarcoplasmic reticulum.

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.

Antithrombotic Therapy in Valvular Heart Disease—Native and Prosthetic

This chapter about antithrombotic therapy in native and prosthetic valvular heart disease is part of the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following: For patients with rheumatic mitral valve disease and atrial fibrillation (AF), or a history of previous systemic embolism, we recommend long-term oral anticoagulant (OAC) therapy (target international normalized ratio [INR], 2.5; range, 2.0 to 3.0) [Grade 1C+]. For patients with rheumatic mitral valve disease with AF or a history of systemic embolism who suffer systemic embolism while receiving OACs at a therapeutic INR, we recommend adding aspirin, 75 to 100 mg/d (Grade 1C). For those patients unable to take aspirin, we recommend adding dipyridamole, 400 mg/d, or clopidogrel (Grade 1C). In people with mitral valve prolapse (MVP) without history of systemic embolism, unexplained transient ischemic attacks (TIAs), or AF, we recommended against any antithrombotic therapy (Grade 1C). In patients with MVP and documented but unexplained TIAs, we recommend long-term aspirin therapy, 50 to 162 mg/d (Grade 1A). For all patients with mechanical prosthetic heart valves, we recommend vitamin K antagonists (Grade 1C+). For patients with a St. Jude Medical (St. Paul, MN) bileaflet valve in the aortic position, we recommend a target INR of 2.5 (range, 2.0 to 3.0) [Grade 1A]. For patients with tilting disk valves and bileaflet mechanical valves in the mitral position, we recommend a target INR of 3.0 (range, 2.5 to 3.5) [Grade 1C+]. For patients with caged ball or caged disk valves, we suggest a target INR of 3.0 (range, 2.5 to 3.5) in combination with aspirin, 75 to 100 mg/d (Grade 2A). For patients with bioprosthetic valves, we recommend vitamin K antagonists with a target INR of 2.5 (range, 2.0 to 3.0) for the first 3 months after valve insertion in the mitral position (Grade 1C+) and in the aortic position (Grade 2C). For patients with bioprosthetic valves who are in sinus rhythm and do not have AF, we recommend long-term (> 3 months) therapy with aspirin, 75 to 100 mg/d (Grade 1C+).

The Use of Stress Echocardiography in the Assessment of Mitral Valvular Disease

Stress echocardiography plays an important role in evaluating asymptomatic patients with significant mitral stenosis and symptomatic patients with only mild disease at rest, as it correlates the exercise-induced symptoms with changes in transmitral gradients, pulmonary pressures, and mitral valve area. In patients with mitral regurgitation (MR), exercise or dobutamine protocols assess for the change in the degree of regurgitation and the pulmonary artery pressure (PAP) in response to high flow states, and detect underlying left ventricular (LV) dysfunction prior to valvular surgery. Exercise echocardiography also helps in the prognostic assessment of patients with mitral valve prolapse as new MR, or latent LV dysfunction may be provoked to identify a group of high risk individuals with normal resting echocardiographic parameters. Finally, it evaluates the proper functioning of prosthetic mitral valves and helps on the monitoring of transmitral gradients and PAPs after mitral valve surgery.

Biomechanical and echocardiographic characterization of flail mitral leaflet due to myxomatous disease: further evidence for early surgical intervention

BACKGROUND

Flail mitral leaflet (FML) is a common complication of mitral valve prolapse, often leading to severe mitral regurgitation (MR) and left ventricular dysfunction. In the absence of timely surgical correction, survival is significantly impaired. Early recognition of FML and identification of risk factors is important because early intervention increases the chances of survival.

METHODS

We studied 123 patients undergoing mitral valve surgery for severe MR caused by myxomatous disease. Chart review, echocardiography, and tensile testing were performed.

RESULTS

Thirty-eight patients had FML, and 85 patients had non-flail mitral leaflet (non-FML). Patients with FML were younger (53.7 +/- 1.8 vs 59.3 +/- 1.4 years, P =.02), had more severe MR (3.89 +/- 0.04 vs 3.76 +/- 0.04, P =.02), were less likely to be in New York Heart Association class III or IV heart failure (5% vs 20%, P =.037), and were less likely to have bileaflet mitral valve prolapse (5% vs 38%, P <.001) than non-FML patients. Valve tissue from patients with FML had less stiff chordae (23.5 +/- 3.6 vs 59.1 +/- 11.7 Mpa, P =.006) that tended to have a lower failure stress (3.8 +/- 0.9 vs 9.6 +/- 2.2 Mpa, P =.07) and had more extensible leaflets (56.4% +/- 7.9% vs 42.9% +/- 2.7% strain, P =.04) compared with that of non-FML patients.

CONCLUSIONS

The development of FML may result from intrinsic tissue abnormalities and is associated with a distinct subset of the myxomatous population. Identification of such clinical characteristics in this population and knowledge of an implicit mechanical abnormality of valve tissue may further the argument for early surgical correction.

Cerebral ischemic events after diagnosis of mitral valve prolapse: a community-based study of incidence and predictive factors

BACKGROUND AND PURPOSE

Association of mitral valve prolapse (MVP) with ischemic neurological events (INEs) is uncertain.

METHODS

In the community of Olmsted County (Minn), we identified all MVP diagnosed (1989 to 1998) in patients in sinus rhythm with no prior history of INE. We measured INE rates and compared them with expected rates in our community to define the excess risk of INE.

RESULTS

Among 777 eligible subjects (age, 49+/-20 years; 66% female; follow-up, 5.5+/-3.0 years), 30 patients had at least 1 INE during follow-up (at 10 years, 7+/-1%). Compared with expected INEs in the same community, subjects with MVP showed excess risk of lifetime INE (relative risk [RR], 2.2; 95% CI, 1.5 to 3.2; P<0.001) and during follow-up under purely medical management (RR, 1.8; 95% CI, 1.1 to 2.8; P=0.009). Independent determinants of INE were older age (RR, 1.08 per year; 95% CI, 1.04 to 1.11; P<0.001), mitral thickening (RR, 3.2; 95% CI, 1.4 to 7.4; P=0.008), atrial fibrillation (AFib) during follow-up (RR, 4.3; 95% CI, 1.9 to 10.0; P<0.001), and need for cardiac surgery (RR, 2.5; 95% CI, 1.1 to 5.8; P=0.03). INE 10-year rates were low in patients <50 years of age (0.4+/-0.4%, P=0.60 versus expected) but were excessive in patients >50 years of age (16+/-3%, P<0.001 versus expected) or with thickened leaflets (7+/-2%, P<0.001 versus expected). Predictors of follow-up AFib were age, mitral regurgitation, and left atrium diameter (all P<0.01).

CONCLUSIONS

In the community, subjects with MVP display a lifetime excess rate of INE compared with expected. Clinical (older age) and echocardiographic (leaflets thickening) characteristics define patients with MVP at high risk for INE, and subsequent AFib or need for cardiac surgery, both related to the degree of mitral regurgitation, increase the risk of INE.

JS, Dai D, Leyne M, Marshall JE, Nesta F, Levine RA, Slaugenhaupt SA. A locus for autosomal dominant mitral valve prolapse on chromosome 11p15.4

Mitral valve prolapse (MVP) is a common cardiovascular abnormality in the United States, occurring in approximately 2.4% of the general population. Clinically, patients with MVP exhibit fibromyxomatous changes in one or both of the mitral leaflets that result in superior displacement of the leaflets into the left atrium. Although often clinically benign, MVP can be associated with important accompanying sequelae, including mitral regurgitation, bacterial endocarditis, congestive heart failure, atrial fibrillation, and even sudden death. MVP is genetically heterogeneous and is inherited as an autosomal dominant trait that exhibits both sex- and age-dependent penetrance. In this report, we describe the results of a genome scan and show that a locus for MVP maps to chromosome 11p15.4. Multipoint parametric analysis performed by use of GENEHUNTER gave a maximum LOD score of 3.12 for the chromosomal region immediately surrounding the four-marker haplotype D11S4124-D11S2349-D11S1338-D11S1323, and multipoint nonparametric analysis (NPL) confirms this finding (NPL=38.59; P=.000397). Haplotype analysis across this region defines a 4.3-cM region between the markers D11S1923 and D11S1331 as the location of a new MVP locus, MMVP2, and confirms the genetic heterogeneity of this disorder. The discovery of genes involved in the pathogenesis of this common disease is crucial to understanding the marked variability in disease expression and mortality seen in MVP.

Progress toward a global understanding of infective endocarditis. Lessons from the International Collaboration on Endocarditis

In the century and a quarter since William Osler delivered his famed Gulstonian lectures on endocarditis, continual advancements have been made in understanding and treating this disease. Here we have reviewed some key aspects of current knowledge in the areas of population epidemiology, host factors, microorganisms, and diagnosis. The advent of the ICE investigation provides the opportunity to further expand our understanding of IE by developing a very large, global database of IE patients whose clinical, echocardiographic, and microbiologic findings have been characterized with standard methodology. Further, ICE may serve as a rich source of material for investigators seeking to perform specific studies. Finally, the ICE infrastructure creates the opportunity for performing randomized trials to test therapeutic strategies. Although many obstacles remain to be overcome, ICE has created the opportunity for a quantum leap in our knowledge of IE over the next 25 years.