Relation of Mitral Annular Dilation with Dynamic Mitral Regurgitation in Patients with Rheumatic Mitral Regurgitation

Introduction: Dynamic mitral regurgitation (MR) is frequently investigated in patients with left ventricular systolic dysfunction (LVSD). Data about the dynamic MR in patients with organic valve disease are limited. The aim of this study was to evaluate the alteration of MR by exercise in patients with rheumatic valve disease (RVD). Methods: Asymptomatic patients with rheumatic MR and normal left ventricular function had been included in our study. Transthoracic echocardiography and Doppler measurements were performed at rest and just after submaximal exercise test performed with treadmill. Severity of MR was evaluated quantitatively by measuring effective regurgitant orifice area (EROA) with flow convergence method. Results: A total of 34 patients with rheumatic MR had been included. Severity of MR increased in 10 patients with exercise (Group 1) and decreased in 24 of them (Group 2). When the variables of two groups were compared; diastolic blood pressure after exercise, EROA, left atrial volume, left ventricular diastolic volume and mitral annular area values were significantly higher in Group 1 patients. A linear regression model was constructed by considering change of EROA by exercise the dependent, and the variables showing significant differences as the independents. Mitral annular area was found to be independently associated with EROA increase with exercise (R²= 0.499; P < 0.001). Conclusion: Mitral annular dilation is independently associated with increase of MR with submaximal exercise in asymptomatic patients with MR due to RVD with normal left ventricular function.     

Diastolic Mitral Regurgitation

An 89-year-old female with a history of hypertension presented to the hospital with symptoms of fatigue. Her electrocardiogram (ECG) showed high-grade atrioventricular (AV) block, so a transthoracic echocardiogram was obtained to assess for structural heart abnormalities (Figure 1). Color Doppler showed mild mitral regurgitation (MR) extending into diastole. Temporal interrogation of the MR jet using continuous wave Doppler confirmed the diastolic component.Open in a separate windowFigure 1The hemodynamic elements of this mitral regurgitation (MR) are dissected and explained. MR: mitral regurgitation; LA: left atrial; LV: left ventricle; LVEDP: left ventricular end-diastolic pressure.Diastolic MR is generally described in the setting of AV dissociation. In patients with high-degree AV block and underlying sinus rhythm, the prolonged diastolic time with accompanying superimposed left atrial (LA) contractions will lead to a significant elevation in left ventricular end-diastolic pressure (LVEDP), creating a reverse gradient favoring flow from the left ventricle back into the LA during diastole. Diastolic MR also can occur with substantial elevations in LVEDP in restrictive cardiomyopathies and acute severe aortic regurgitation.     

Values for Mitral Valve Annulus Dimensions in Normals and Patients with Mitral Regurgitation

Objectives. The present study was designed to investigate the dimensions of mitral valve annulus in the presence of mitral regurgitation. Method. Fifty-four patients were examined. On transthoracic echocardiographic images, we performed linear measurements in the parasternal plane in order to define the size of the left ventricle, left atrium, and mitral valve annulus. We compared these findings with those obtained in 16 control subjects. Results. Twenty-one patients with mild or moderate mitral regurgitation demonstrated no significant change of the mitral valve annulus compared with the control group (P > 0.05). Seventeen patients with severe mitral regurgitation (grade of 4) had a significant increase of the dimensions of the mitral valve annulus, left ventricle, and left atrium (P < 0.05). The etiology of mitral regurgitation was degenerative in 32 patients, rheumatic in 2 patients, and mitral valve prolapse in 4 patients. All patients had normal left ventricular systolic function. Thirty-one patients were in normal sinus rhythm, and seven were in atrial fibrillation. Conclusions. The measurement of the diameter of the mitral valve annulus is feasible with transthoracic echo-cardiography. In addition to the evaluation of mitral valve leaflets and subvalvular apparatus, the measurement of the mitral valve annulus is important in the evaluation of mitral regurgitation, as its enlargement is indicative for severe mitral regurgitation .     

Severe Mitral Regurgitation after Radiotherapy

We present the case of a 69‐year‐old patient with a history of gynecological neoplasia and a pulmonary metastasis, who in 1996 underwent chemotherapy and mediastinal radiotherapy followed by cancer remission. Ten years later she presented with heart failure and her Doppler echocardiogram showed severe mitral regurgitation with pulmonary hypertension. In 2011, she underwent a mitral valve replacement with a biological prosthesis and the pathology exam revealed valve damage consistent with radiotherapy‐induced changes. This unusual mechanism of mitral regurgitation can be demonstrated clearly by echocardiography and should be disseminated among cardiology physicians and in patients who have survived for long periods after radiotherapy, it is important to remember that cardiac complications may indeed occur, and the treating physician is responsible for detecting them.     

Clinically Suspected Severe Ischaemia-induced Mitral Regurgitation

Abstract Eighteen patients with clinical signs suggesting severe mitral regurgitation secondary to ischaemic heart disease were assessed by echocardiography. Non-ischaemic diseases needing specific therapy were revealed in six patients. In the other 12 patients echocardiography demonstrated myocardial lesions explaining the mitral regurgitation. Apart from the distinction between non-ischaemic conditions and lesions induced by ischaemia, echocardiography seems to be helpful in the demonstration of severe yet operable mitral valve regurgitation due to a small ischaemic lesion. Such cases are opposed to functional mitral regurgitation caused by extensive myocardial injury as demonstrated by two-dimensional echocardiography and reflected by a minimum mitral valve/septum separation of more than 2 1/2 cm on the M-mode echocardiogram. These conditions make symptomatic improvement by mitral valve surgery unlikely and carry an extremely high operative mortality. A more precise definition by heart catheterization is required when serious clinical heart failure is not explained by the echocardiographic finding of severe global myocardial impairment.     

Impact of TAVI on Mitral Regurgitation: A Prospective Echocardiographic Study

Objective: This study aims to assess changes in mitral regurgitation (MR) severity after transcatheter aortic valve implantation (TAVI). Background: Existing data on MR after TAVI are contradictory. Methods: Thirty‐five patients with MR graded ≥ 2+ were followed after undergoing TAVI with either the Edwards Sapien or CoreValve device. Echocardiography was performed the week before and 3 months after the procedure. MR was graded on a scale of 0 to 4+, classified as organic or functional, and the effective regurgitant orifice area (EROA) and MR index were calculated. Results: At baseline, MR was graded 4+ in 4 (11.4%) patients, 3+  in 10 (28.6%), and 2+ in 21 (60%). At follow‐up, MR was graded at 3+ in 4 (11.4%) patients, 2+ in 8 (22.9%), and 1+ in 19 (54.3%); 4 (11.4%) exhibited no MR. EROA (24.4 ± 11.5 mm² pre‐TAVI vs. 11.2 ± 10.3 mm² post‐TAVI, P < 0.001) and MR index (1.9 ± 0.3 pre‐TAVI vs. 1.3 ± 0.7 post‐TAVI, P < 0.001) were reduced with TAVI, independent of the etiology. MR decreased by at least 1 grade in 28 (80%) patients, with a reduction ≥2 grades in 10 (28.6%) patients; no patient showed a worsened condition. Subgroup analyses showed that the reduction in MR was significant in patients treated with the Edwards Sapien device but not in patients treated with the CoreValve device. Conclusions: This multiparametric echocardiographic evaluation showed that MR improved significantly after TAVI and that this result may be related to the type of valve implanted.     

Gargantuan Left Atrium: A Sequela of Mitral Regurgitation and Mitral Stenosis

Cardiac magnetic resonance imaging and echocardiography revealed a gargantuan left atrium measuring 18.9 cm × 15.7 cm × 11.3 cm in a 56‐year‐old patient diagnosed with severe rheumatic mitral stenosis, severe pulmonary hypertension, and permanent atrial fibrillation. A chest x‐ray also revealed a cardiothoracic ratio approaching 1.0 and a transthoracic echocardiogram measured diameters as large as 19.2 cm. The patient then underwent mitral valve replacement and left atrial reduction surgery and has had no further admissions or complications.     

Impact of Preserved Myocardial Contractile Function in the Segments Attached to the Papillary Muscles on Reduction in Functional Mitral Regurgitation

Background: Effectiveness of functional mitral regurgitation (FMR) in heart failure patients is of growing importance for patient prognosis. The purpose of this study was to investigate whether regional myocardial contractile function as assessed by tissue Doppler strain rate imaging can predict reduction in FMR caused by dobutamine. Methods: Fifty‐one patients with depressed left ventricular (LV) ejection fraction (32 ± 9%) secondary to dilated cardiomyopathy and FMR underwent evaluation of effective regurgitant orifice (ERO) of FMR, mitral valve deformation, global LV remodeling, and regional myocardial contractile function assessed by longitudinal peak systolic strain rate (Ssr) in 6 mid‐LV segments from standard apical views. We also determined the average Ssr of segments attached to the papillary muscles, that is, the inferior, inferolateral, and anterolateral segments (PM segments Ssr). Low‐dose (10 μg/kg per minute) dobutamine‐induced reduction in ERO was compared with baseline variables. Results: Baseline valve tenting was associated with dobutamine‐induced reduction in ERO (r = ?0.30, P < 0.05). Receiver operating characteristic curve analysis showed that baseline valve tenting, LV sphericity index, inferior Ssr, inferolateral Ssr, and PM segments Ssr were predictors of dobutamine‐induced ≥30% reduction in ERO. Importantly, only PM segments Ssr predicted dobutamine‐induced ≥20% reduction in valve tenting with area under the curve of 0.67 (P < 0.05). Conclusions: Preserved myocardial contractile function in the segments attached to the PMs was associated with dobutamine‐induced reduction in mitral valve tenting and FMR, suggesting that our findings are important for improvement in cardiac function and FMR with medical treatment.     

经食道超声心动图在二尖瓣关闭不全瓣膜修补术中的应用

对严重的二尖瓣关闭不全病人进行二尖瓣修补术与置换相比，有着明显的利益，然而，部分病例修补术后可能持续存在二尖瓣返流，且传统的术中评价二尖瓣修补术效果的方法往往不可靠。本组术中经食道超声心动图（TEE）发现二尖瓣修补术后仍有22％（2／9）的病例存在严重的二失瓣返流，根据这一信息．这2例病人当即进行了二尖瓣置换术。随访16～24个月，7例二尖瓣修补术的病人心功能一级，无需再次手术。因此，术中TEE技术是快速准确的评价瓣膜修补术效果的方法，保证了手术的成功，能使更多更复杂的病例进行二尖瓣修补术。     

Dynamic Ischaemic Mitral Regurgitation and the Role of Stress Echocardiography

Objective:

This paper aims to explain the main mechanisms that cause ischaemic mitral regurgitation (MR), the pathophysiology, and the role played by stress echocardiography in the evaluation of the dynamic component of MR.

Introduction:

Chronic ischaemic MR is a frequent complication of myocardial infarction (MI), and is associated with a poor prognosis and outcome. The more the severity of ischaemic MR, the lower is the survival rate. In recent times, improvements in the management of the acute phase of MI, has increased the survival rate after MI. This, combined with an increase in the incidence of MI, will probably lead to a higher prevalence of ischemic MR in the next decades. As a consequence, ischaemic MR should be thoroughly understood and promptly identified. Furthermore, it is well recognized that ischaemic MR is dynamic. The best way to explore the dynamic nature of ischaemic MR is exercise stress echocardiography, and this test should probably be integrated in the evaluation and the management of patients with chronic ischaemic MR.

Conclusion:

Based on our experience, exercise stress echocardiography might be of interest in the following subsets of patients: 1) in patients with left ventricular (LV) dysfunction who present exertional dyspnea out of proportion to the severity of resting LV dysfunction or MR severity, 2) in patients in whom acute pulmonary oedema occurs without any obvious cause; 3) to unmask patients at high risk of mortality and heart failure 4) before surgical revascularization in patients with moderate ischaemic MR and, 5) following surgery, to identify persistence of pulmonary hypertension and explain the absence of functional class improvement.     

缺血性二尖瓣反流的机制、诊断和治疗研究进展

缺血性二尖瓣反流是心肌梗死所致心室结构及功能的改变引起二尖瓣关闭不全,是冠心病常见的并发症。左室重构基础上发生的瓣叶栓拉与关闭动力失衡,瓣环形变等多种因素参与缺血性二尖瓣反流的发生。心脏超声不仅可评估二尖瓣反流严重程度,还能明确瓣叶、瓣环、腱索、乳头肌和左室壁结构功能改变,有助于确诊和指导治疗。     

Quantification of Mitral and Tricuspid Regurgitation Using Jet Centerline Velocities: An In Vitro Study of Jets in an Ambient Counterflow

A method for quantifying mitral and tricuspid regurgitant volume that utilizes a measure of jet orifice velocity U(0) - m/sec), a distal centerline velocity (U(m) - m/sec), and the intervening distance (X - cm) was recently developed; where jet flow rate (Q(cal) - L/min) is calculated as Q(cal) = (U(m)X)(2)/(26.46U(o)). This method, however, modeled the regurgitant jet as a free jet, whereas many atrial jets are counterflowing jets because of jet opposing intra-atrial flow fields (counterflows). This study concentrated on the feasibility of using the free jet quantification equation in the atrium where ambient flow fields may alter jet centerline velocities and reduce the accuracy of jet flow rate calculations. A 4-cm wide chamber was used to pump counterflows of 0, 4, and 22 cm/sec against jets of 2.3, 4.8, and 6.4 m/sec originating from a 2-mm diameter orifice. For each counterflow-jet combination, jet centerline velocities were measured using laser Doppler anemometry. For free jets (no counterflow), flow rate was calculated with 98% mean accuracy. For all jets in counterflow, the calculation was less accurate as: (i) the ratio of jet orifice velocity to counterflow velocity decreased (U(o)/U(c), where U(c) is counterflow velocity), i.e., the counterflow was relatively more intense, and (ii) centerline measurements were made further from the orifice. But although counterflow lowered jet centerline velocities beneath free jet values, it did so only significantly in the jet's distal portion (X/D > 16, i.e., >16 orifice diameters from the origin of the jet). Thus, the initial portion (X/D < 16) of a jet in counterflow behaved essentially as a free jet. As a result, even in significant counterflow, jet flow rate was calculated with >93% accuracy and >85% for jets typical of mitral and tricuspid regurgitation, respectively. Counterflow lowers jet centerline velocities beneath equivalent free jet values. This effect, however, is most significant in the distal portion of the jet. Therefore, regurgitant jets, although not classically free because of systolic atrial inflow or jet-induced intra-atrial swirling flows, will decay in their initial portions as free jets and thus are candidates for quantification with the centerline technique. (ECHOCARDIOGRAPHY, Volume 13, July 1996)