Orthostatic hypotension,catecholamines, and alpha-adrenergic receptors in mitral valve prolapse.

The reported association of mitral valve prolapse with autonomic dysfunction and neuroendocrine abnormalities is derived from studies of patients selected because of symptoms or specifically referred for investigation. To determine whether such associations occur in nonreferred and unselected women with mitral valve prolapse, we measured blood pressure, heart rate, and norepinephrine response to standing in 13 volunteers with mitral valve prolapse and in 11 control subjects. Platelet alpha-adrenergic receptor quantity and affinity on standing also were determined in all persons. No significant differences were found between the groups in any of these measurements. Although small subsets of women with mitral valve prolapse may indeed have associated neuroendocrine epiphenomena and autonomic dysfunction, it is probably incorrect to generalize these findings to the vast spectrum of those with mitral valve prolapse.     

Programmed atrial and ventricular stimulation in patients with mitral valve prolapse--a personal experience]

Electrophysiological tests were performed in 60 patients aged between 18 and 63 years (mean age 38 years), and divided into two groups: with mitral valve leaves prolapse syndrome, and without this abnormality, in whom no other heart disease was diagnosed. Refraction of the right atrium, atrio-ventricular node, and right ventricle was evaluated together with cardiac response to different types of electrostimulation. A supraventricular dysrhythmia (most frequently atrial fibrillation) has been produced in 17 patients (42.5%) with mitral valve leaves prolapse syndrome whereas in the control group the same was produced in 2 patients (10%). Programmed stimulation of the ventricles did not produce ventricular tachycardia in none patient of both groups. Multiple ventricular beats have been produced in 3 patients with mitral valve prolapse syndrome and pairs of ventricular beats in other 3 patients of this group. Results suggest that "arrhythmogenic tendency", especially supraventricular dysrhythmia is more frequent in patients with mitral valve prolapse syndrome than in the general population.     

Mitral valve prolapse detected during hemodynamic studies

To estimate frequency of the posterior mitral valve leaflet prolapse in routinely performed left ventriculography, 1000 consecutive ventriculograms of the right anterior oblique projection were analyzed. A group of patients consisted of 511 women and 489 men at mean age 46,5 years. Clinical diagnosis of heart lesions, myocardial disease, pulmonary hypertension or arrhythmias were indications for hemodynamic studies. In the investigated group of patients, there were no patients with clinical diagnosis of the coronary artery disease. Prolapse of the posterior mitral valve leaflet was diagnosed in 59 patients. Idiopathic mitral valve prolapse was diagnosed in 10 patients. Prolapse of the posterior mitral valve leaflet was most frequent in atrial septal defect (16.6%), myocardial lesion (12.5%), and after mitral commissurotomy (8.9%). Posterior mitral valve leaflet prolapse is not a frequent anomaly in routinely performed left ventriculography. Relatively often occurrence of the mitral valve prolapse in atrial septal defect and only occasional in the aortic lesions and dilated cardiomyopathy seems to point out at a role of the left ventricle size in pathogenesis of this syndrome.     

Techniques of aortic valve repair

Similar to mitral repair, newer methods of aortic valve reconstruction are achieving excellent outcomes with an 85% to 90% freedom from valve-related complications at 10 years. The goal of this review is to illustrate these newer and more stable techniques of aortic valve repair. Most patients with aortic insufficiency from either trileaflet or bicuspid aortic valves are candidates for repair, in addition to selected patients with mixed aortic stenosis/insufficiency and aortic root aneurysms. Initially, aggressive commissural annuloplasty is performed to reduce measured valve diameter to 19 to 21 mm. Leaflet prolapse is corrected with plication stitches placed in the free edge of each leaflet adjacent to the Nodulus Arantius. In this regard, the leaflet free edge functions as the chorda tendinea of the aortic valve, and shortening with plication stitches raises the leaflet to a proper "effective height." Leaflet defects are augmented with gluteraldehyde-fixed autologous pericardium, and mild-to-moderate strategically placed spicules of calcium are removed with the cavitron ultrasonic surgical aspirator. Using these methods, most insufficient aortic valves, and many with mixed lesions, can be satisfactorily repaired. Six cases are illustrated in this review, spanning the spectrum of pathologies from annular dilatation without leaflet defects, to standard congenital bicuspid valve with prolapse, to trileaflet prolapse, to unusual bicuspid pathology with calcification, to a moderately calcified trileaflet valve with mixed lesions, and to aortic root aneurysms with severe aortic insufficiency. All valves were repaired using the techniques described above with trivial residual leak and minimal gradients. All repairs have been followed with yearly echocardiography, and valve reconstruction with these methods is now quite stable with excellent late outcomes. Most insufficient aortic valves now can undergo stable repair with minimal late valve-related complications. Greater application of aortic valve repair seems indicated.     

Coexistence of von Willebrand's disease with mitral valve prolapse]

The authors present the case of mitral valve prolapse. In a young woman with three-year history of systematically treated epilepsia mitral valve prolapse with a spurious string within left ventricle has been diagnosed echocardiographically in coincidence with the symptoms of haemorrhagic diathesis of von Willebrand type in form of haemoptysis and or/massive haemorrhages in mouth occasionally being preceded by heart rhythm disturbances. No local changes have been observed in otorhinolaryngologic examination, bronchoscopy and gastroscopy. Possible mutual dependence of 3 above stated abnormalities is being discussed. It is not excluded, that mitral prolapse may constitute the primary entity and epilepsia is of secondary character as a result of cerebral ischaemic incidents or of cerebral embolism. It is also a matter of discussion to what extent abrupt haemodynamic disturbances connected with critical fall of systemic blood pressure due to mitral prolapse may influence the haemorrhagic episodes.     

Surgery Issue: Solving the Puzzle of Chronic Ischemic Mitral Regurgitation

Chronic ischemic mitral regurgitation is a prevalent problem among patients following a myocardial infarction. Until recently, the pathophysiology was poorly understood, resulting in surgical strategies with suboptimal results and limited durability. The surgical approach has evolved from revascularization alone to an additional mitral valve procedure, replacement, or repair. When the valve was repaired, isolated annuloplasty was performed. The dilemma that surgeons had when repairing a mitral valve was which type of ring to use and what size. In all series with annuloplasty alone, the results were poor with very high recurrence rates. The primary feature of ischemic mitral regurgitation is a prolapse of the anterior leaflet at A3 ± A2. This prolapse can be caused by fibrotic elongation of the papillary muscle supporting A3 ± A2 or tethering of P3 by a ballooning posterior left ventricular wall. Using a technique that corrects this prolapse with Gore-Tex neochords, we have achieved excellent results with effective and durable correction of the ischemic mitral regurgitation.     

Molecular and developmental mechanisms of congenital heart valve disease

Congenital heart disease occurs in approximately 1% of all live births and includes structural abnormalities of the heart valves. However, this statistic underestimates congenital valve lesions, such as bicuspic aortic valve (BAV) and mitral valve prolapse (MVP), that typically become apparent later in life as progressive valve dysfunction and disease. At present, the standard treatment for valve disease is replacement, and approximately 95,000 surgical procedures are performed each year in the United States. The most common forms of congenital valve disease include abnormal valve cusp morphogenesis, as in the case of BAV, or defects in extracellular matrix (ECM) organization and homeostasis, as occurs in MVP. The etiology of these common valve diseases is largely unknown. However, the study of murine and avian model systems, along with human genetic linkage studies, have led to the identification of genes and regulatory processes that contribute to valve structural malformations and disease. This review focuses on the current understanding and therapeutic implications of molecular regulatory pathways that control valve development and contribute to valve disease.     

Preventing complicated transseptal puncture with intracardiac echocardiography: case report

Supravalvular mitral stenosis is a rare condition characterized by an abnormal ridge, with one or two orifices, covering and obstructing the mitral valve. Preoperative diagnosis is difficult with transtoracic echo (TTE), angiography and magnetic resonance imaging (MRI). In this case, a 36-year-old male, was admitted to our Heart department: He experienced progressive dyspnea on effort and at rest. Diagnosis was made by transesophageal echocardiography which showed, on apical 4-chamber section, an anulare structure attached since a membrane to the atrial wall anterior mitral valve leaflet and just proximal to the posterior mitral leaflet. Pre-operative identification of the supravalvular mitral ring is the target for obtaining good surgical results. Cineangiography and MRI both failed in reaching this objective, whereas, transesophageal echocardiography is the best method to identify this congenital heart disease. Using TEE the identification is not only possible but also easier.     

Mechanics of the mitral valve

Alterations in mitral valve mechanics are classical indicators of valvular heart disease, such as mitral valve prolapse, mitral regurgitation, and mitral stenosis. Computational modeling is a powerful technique to quantify these alterations, to explore mitral valve physiology and pathology, and to classify the impact of novel treatment strategies. The selection of the appropriate constitutive model and the choice of its material parameters are paramount to the success of these models. However, the in vivo parameters values for these models are unknown. Here, we identify the in vivo material parameters for three common hyperelastic models for mitral valve tissue, an isotropic one and two anisotropic ones, using an inverse finite element approach. We demonstrate that the two anisotropic models provide an excellent fit to the in vivo data, with local displacement errors in the sub-millimeter range. In a complementary sensitivity analysis, we show that the identified parameter values are highly sensitive to prestrain, with some parameters varying up to four orders of magnitude. For the coupled anisotropic model, the stiffness varied from 119,021 kPa at 0 % prestrain via 36 kPa at 30 % prestrain to 9 kPa at 60 % prestrain. These results may, at least in part, explain the discrepancy between previously reported ex vivo and in vivo measurements of mitral leaflet stiffness. We believe that our study provides valuable guidelines for modeling mitral valve mechanics, selecting appropriate constitutive models, and choosing physiologically meaningful parameter values. Future studies will be necessary to experimentally and computationally investigate prestrain, to verify its existence, to quantify its magnitude, and to clarify its role in mitral valve mechanics.     

Arrhythmia in patients with mitral valve prolapse]

An incidence of cardiac arrhythmias was evaluated in 119 patients with mitral valve prolapse. The disease was made basing on the results of clinical symptoms, echo-, angio- and phonocardiography. Electrocardiograms were recorded from the standard 12 lead and Holter technique for 24 hours in each patient to assess present arrhythmias. It was found that the most frequent cardiac arrhythmias accompanying mitral valve prolapse are ventricular extrasystolic contractions of Lown's class 1a and 1b. Only examination of strictly selected groups of patients (age groups with or without co-existing mitral valve insufficiency for adequate period of time) will facilitate precise evaluation of an incidence of different cardiac arrhythmias accompanying the underlying disease.     

Robotic artificial chordal replacement for repair of mitral valve prolapse

Artificial chordal replacement (ACR) has emerged as a superior method of mitral valve repair with excellent early and late efficacy. It is also ideal to combine with robotic techniques for correction of mitral prolapse, and this article presents a current method of robotic Gore-Tex ACR. Patients with isolated posterior leaflet prolapse are approached with the fourth-generation DaVinci robotic system and endoaortic balloon occlusion. A pledgetted anchor stitch is placed in a papillary muscle, and a 2-o Gore-Tex suture is passed through the anchor pledget. After full annuloplasty ring placement, the Gore-Tex suture is woven into the prolapsing segment and positioned temporarily with robotic forceps. Chordal length is then "adjusted" by lengthening or shortening the temporary knot over 1-cm increments as the valve is tested by injection of cold saline into the ventricle. After achieving good leaflet position and valve competence, the chord is tied permanently. The "adjustable" ACR procedure preserves leaflet surface area and produces a competent valve in the majority of patients. Postoperative transesophageal echo shows a large surface area of coaptation. Patient recovery is facilitated by the minimally invasive approach, while long-term stability of similar open ACR techniques have been excellent with a 2% to 3% failure rate over 10 years of follow-up. Robotic Gore-Tex ACR without leaflet resection is a reproducible procedure that simplifies mitral repair for prolapse. The outcomes observed in early robotic applications have been excellent. It is suggested that most patients with simple prolapse might validly be approached in this manner.     

Noninvasive assessment of the stenotic mitral valve orifice by two-dimensional echocardiography

Two-dimensional echocardiographic imaging of the mitral valve orifice was attempted in 26 patients with isolated mitral stenosis. The intention was to examine further the clinical usefulness and limitations of this technique for estimating the severity of mitral stenosis. Technically adequate recordings of the mitral orifice were obtained in 20 patients (77%). Mitral valve area calculated from echocardiography compared favorably to the valve area derived from cardiac catheterization with the use of the Gorlin formula (r = 0.95). The average difference between the two methods was 0.109 cm(2). Two-dimensional echocardiography does provide clinically useful data for predicting the degree of mitral stenosis in the majority of patients provided that critical technical limitations are recognized.     

ARRHYTHMIA WITH MITRAL VALVE PROLAPSE: RESULTS OF ANNULOPLASTY IN TWO PATIENTS

The effectiveness of posterior annuloplasty in two patients who failed to respond to medical treatment for atrial and ventricular arrhythmias related to mitral valve prolapse (MVP) is reported. Although the etiology of arrhythmia in MVP remains mostly speculative, anatomic correction of prolapse or billowing of the mitral leaflets appears to reverse the anatomic and pathologic conditions that cause the arrhythmia.     

Arrhythmia in patients with mitral valve prolapse syndrome and the status of the sympathetic nervous system]

The study aimed at evaluating a possible relationship between the adrenergic system tone determined with the excretion of catecholamines with the urine and an incidence of the ventricular arrhythmias in patients with the mitral valve prolapse. The study included 20 patients (13 women and 7 men aged between 20 and 50 years; mean = 31.6 years) with the mitral valve prolapse syndrome diagnosed with the aid of the patients' history, physical examinations and echocardiography. Echocardiograms have shown anterior mitral leaflet prolapse in 7 patients, posterior mitral leaflet prolapse in 8 patients, and both mitral leaflets prolapse in the remaining 5 patients. Daily excretion of adrenaline and noradrenaline was measured with Van Euler and Lishajko's fluorimetric technique. Cardiac arrhythmias were determined with a 24-hour ECG monitoring and classified according to Lown. Premature ventricular contractions of class I were seen in 1 patient, of class II in 5, class III in 1, class IV in 2, and class V in 3 patients. Holter monitoring technique did not show the arrhythmias in 8 patients. Daily adrenaline and noradrenaline excretion with the urine was within the normal values (3.2-30.8 ug and 0.2-16.2 ug, respectively) in all examined patients. Daily urine noradrenaline was higher in patients with serious ventricular arrhythmias (Lown's class V) than mean values in the whole examined group.     

Sex differences in birth defects: a study of opposite-sex twins

BACKGROUND: Sex differences in structural birth defects are often confounded by environmental risk factors. Opposite-sex twins provide a unique model for detecting sex differences in birth defects while maximally controlling environmental risk factors in a natural setting. METHODS: Population data from the Florida Birth Defects Registry were analyzed. A total of 4,768 pairs of twins who were discordant for sex and born between 1996 and 2001 were analyzed. The McNemar test was used to compare the differences between a male twin and his twin sister for the risk of developing specific defects and organ-system defects. RESULTS: Of 4,768 twin pairs, 225 males (4.72%) and 175 females (3.67%) had birth defects. Among opposite-sex twin pairs, males had a 29% higher risk for birth defects than their twin sisters. Compared to their twin sisters, males had a 5.4 times higher risk for pyloric stenosis and a 2.4 times higher risk for obstructive genitourinary defect, but only one-tenth the risk for congenital hip dislocation. CONCLUSIONS: Sex differences in birth defects exist between opposite-sex twins.     

Modeling mitral valve stenosis: A parametric study on the stenosis severity level

New computational techniques providing more accurate representation of human heart pathologies could help uncovering relevant physical phenomena and improve the outcome of medical therapies. In this framework, the present work describes an efficient computational model for the evaluation of the ventricular flow alteration in presence of mitral valve stenosis. The model is based on the direct numerical simulation of the Navier–Stokes equations two-way coupled with a structural solver for the left ventricle and mitral valve dynamics. The presence of mitral valve stenosis is mimicked by a single-parameter constraint acting on the kinematics of the mitral leaflets.Four different degrees of mitral valve stenosis are considered focusing on the hemodynamic alterations occurring in pathologic conditions. The mitral jet, generated during diastole, is seen to shrink and strengthen when the stenosis gets more severe. As a consequence, the kinetic energy of the flow, the tissues shear stresses, the transvalvular pressure drop and mitral regurgitation increase. It results that, as the stenosis severity level increases, the geometric and effective orifice areas decrease up to 50% with respect the normal case due to the reduced leaflets mobility and stronger blood acceleration during the diastolic phase. The modified intraventricular hemodynamics is also related to a stronger pressure gradient that, for severe stenosis, can be more than ten times larger than the healthy valve case. These computational results are fully consistent with the available clinical literature and open the way to the virtual assessment of surgical procedures and to the evaluation of prosthetic devices.     

Indication and timing of percutaneous mitral balloon valvotomy and the role of atrial fibrillation

Percutaneous transvenous mitral balloon valvotomy (PTMV) has been proven to be an effective and safe method for treatment of patients with severe mitral valve stenosis. This technique has become an accepted alternative for surgical commissurotomy, not only in young patients with pliable valves, but also in selected older patients with extensive valvular pathology. This review highlights the significance of coexisting atrial fibrillation, patient selection and timing of PTMV in patients with mitral valve stenosis.     

123例二尖瓣狭窄患者经皮二尖瓣球囊扩张术治疗的疗效分析

目的：探讨经皮二尖瓣球囊扩张术（PBMv）治疗二尖瓣狭窄（Ms）的效果。方法：123例患者采用经皮经房间隔穿刺球囊扩张治疗二尖瓣狭窄。手术前后分别记录左心房压（LAP）、二尖瓣跨瓣压差（MPG）,二尖瓣口面积（MVA）,并进行术后1年随防。结果：术后即刻患者左心房压、二尖瓣跨瓣压差下降,二尖瓣口面积增加,术后1年,患者二尖瓣跨瓣压差、二尖瓣口面积与术后即刻对比无明显变化,患者心功能和生活质量明显改善。结论：经皮二尖瓣球囊扩张术能明显改善风心病二尖瓣狭窄患者心功能。     

Pregnancy in women with prosthetic heart valves

Pregnancy in women with mechanical valve prostheses has a high maternal complication rate including valve thrombosis and death. Coumarin derivatives are relatively safe for the mother with a lower incidence of valve thrombosis than un-fractionated and low-molecular-weight heparin, but carry the risk of embryopathy, which is probably dose-dependent. The different anticoagulation regimens are discussed in this review. When valve thrombosis occurs during pregnancy, thrombolysis is the preferable therapeutic option. Bioprostheses have a more favourable pregnancy outcome than mechanical prostheses but due to the high re-operation rate in young women they do not constitute the ideal alternative. When women with native valve stenosis need pre-pregnancy intervention, mitral balloon valvuloplasty is the best option in mitral stenosis, while the Ross operation or homograft implantation may be the preferable surgical regimen in aortic stenosis. (Neth Heart J 2008;16:406-11.)     

Cardiac valve replacement in elderly patients.

Cardiac valve replacement in 65 consecutive elderly patients (aged 65 years and older) revealed that the indications for cardiac valve replacement in the elderly should be the same as those in the general population. These 65 patients represented 16% of the patients undergoing valve replacement. The mortality in the first 30 days after operation was 4.6% in the elderly group, compared with 0.9% in the group under 65 years of age. There were 26 significant but nonfatal early complications in the elderly patients, but their long-term functional status was excellent, most of the survivors ending up in either class I or class II of the New York Heart Association functional classification. The late mortality was 3.9% per patient year for aortic valve replacement and 15.1% for mitral with or without aortic valve replacement. The actuarial survival rates were 88% at 24 months and 55% at 54 months for the total elderly group, 86% at 36 months for those with aortic valve replacement, 85% at 24 months and 64% at 36 months for those with mitral valve replacement, 90% at 24 months and 77% at 42 months for the men, and 82% at 24 months and 68% at 42 months for the women. Aortic valve replacement was more common in the elderly than in the younger group because of the higher prevalence of congenital calcific aortic stenosis in the former, and this operation provided more gratifying results than mitral valve replacement in the elderly patients.