Clinical Utility of Cardiovascular Magnetic Resonance in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is characterized by substantial genetic and phenotypic heterogeneity, leading to considerable diversity in clinical course including the most common cause of sudden death in young people and a determinant of heart failure symptoms in patients of any age. Traditionally, two-dimensional echocardiography has been the most reliable method for establishing a clinical diagnosis of HCM. However, cardiovascular magnetic resonance (CMR), with its high spatial resolution and tomographic imaging capability, has emerged as a technique particularly well suited to characterize the diverse phenotypic expression of this complex disease. For example, CMR is often superior to echocardiography for HCM diagnosis, by identifying areas of segmental hypertrophy (ie., anterolateral wall or apex) not reliably visualized by echocardiography (or underestimated in terms of extent). High-risk HCM patient subgroups identified with CMR include those with thin-walled scarred LV apical aneurysms (which prior to CMR imaging in HCM remained largely undetected), end-stage systolic dysfunction, and massive LV hypertrophy. CMR observations also suggest that the cardiomyopathic process in HCM is more diffuse than previously regarded, extending beyond the LV myocardium to include thickening of the right ventricular wall as well as substantial morphologic diversity with regard to papillary muscles and mitral valve. These findings have implications for management strategies in patients undergoing invasive septal reduction therapy. Among HCM family members, CMR has identified unique phenotypic markers of affected genetic status in the absence of LV hypertrophy including: myocardial crypts, elongated mitral valve leaflets and late gadolinium enhancement. The unique capability of contrast-enhanced CMR with late gadolinium enhancement to identify myocardial fibrosis has raised the expectation that this may represent a novel marker, which may enhance risk stratification. At this time, late gadolinium enhancement appears to be an important determinant of adverse LV remodeling associated with systolic dysfunction. However, the predictive significance of LGE for sudden death is incompletely resolved and ultimately future large prospective studies may provide greater insights into this issue. These observations underscore an important role for CMR in the contemporary assessment of patients with HCM, providing important information impacting diagnosis and clinical management strategies.     

A novel and practical cardiovascular magnetic resonance method to quantify mitral annular excursion and recoil applied to hypertrophic cardiomyopathy

Background

We have developed a novel and practical cardiovascular magnetic resonance (CMR) technique to evaluate left ventricular (LV) mitral annular motion by tracking the atrioventricular junction (AVJ). To test AVJ motion analysis as a metric for LV function, we compared AVJ motion variables between patients with hypertrophic cardiomyopathy (HCM), a group with recognized systolic and diastolic dysfunction, and healthy volunteers.

Methods

We retrospectively evaluated 24 HCM patients with normal ejection fractions (EF) and 14 healthy volunteers. Using the 4-chamber view cine images, we tracked the longitudinal motion of the lateral and septal AVJ at 25 time points during the cardiac cycle. Based on AVJ displacement versus time, we calculated maximum AVJ displacement (MD) and velocity in early diastole (MVED), velocity in diastasis (VDS) and the composite index VDS/MVED.

Results

Patients with HCM showed significantly slower median lateral and septal AVJ recoil velocities during early diastole, but faster velocities in diastasis. We observed a 16-fold difference in VDS/MVED at the lateral AVJ [median 0.141, interquartile range (IQR) 0.073, 0.166 versus 0.009 IQR -0.006, 0.037, P < 0.001]. Patients with HCM also demonstrated significantly less mitral annular excursion at both the septal and lateral AVJ. Performed offline, AVJ motion analysis took approximately 10 minutes per subject.

Conclusions

Atrioventricular junction motion analysis provides a practical and novel CMR method to assess mitral annular motion. In this proof of concept study we found highly statistically significant differences in mitral annular excursion and recoil between HCM patients and healthy volunteers.     

Morphological and functional abnormalities pattern in hypertrophy-free HCM mutation carriers detected with echocardiography

To evaluate if morphological or functional abnormalities could be detected with echocardiography in hypertrophic myocardiopathy (HCM) mutation carriers without left ventricle (LV) hypertrophy has developed. HCM is caused by extensive genes mutations found in two-third of patients. Because screening for carriership of a large population is unreasonable, identification of asymptomatic subjects is confined to the use of imaging such as echocardiography, by which subtle abnormalities can be detected. Comprehensive echocardiographic studies including morphological and functional assessment were performed. Asymptomatic HCM mutation carriers without hypertrophy (Phe?/Gen+, n?=?14), and HCM patients (Phe+/Gen+, n?=?17) were compared with healthy control subjects (n?=?32) in a prospective design. Compared to controls, septum thickness was significantly higher with an elongated mitral valve in both groups. Thickened LV muscular band (LVMB) are more likely found in Phe?/Gen+ and Phe+/Gen+. The thickness of LVMB was higher in the Phe?/Gen+ versus controls. A LVMB thickness ≥3.6 mm was associated with HCM mutation carriership (sensitivity: 76.9?%, specificity: 94.1?%). The regional strain was significantly impaired in the basal segments of the septum in the Phe?/Gen+. The GLS was significantly impaired in the Phe+/Gen+ (?16.4?%?±?2.9 vs. ?21.4?%?±?2.3 in control subjects, p?=?0.01). Mitral A wave velocity, septal E/e′, averaged E/e′ were increased in both groups. E/A ratio was significantly lower in Phe+/Gen+. Morphological and functional abnormalities in hypertrophy-free HCM mutation carriers could be detected with echocardiography. Anomalous thickened LVMB could be representing a morphological marker for the HCM disease without overt hypertrophy has developed or in patients with an ambiguous diagnosis.     

The utility of global longitudinal strain in the identification of prior myocardial infarction in patients with preserved left ventricular ejection fraction

Prior myocardial infarction (MI) is associated with increased mortality and is prevalent in certain high risk patient groups. Electrocardiogram may be used in diagnosis, however, sensitivity is limited, thus non-invasive imaging techniques may improve diagnosis. We investigated whether global longitudinal strain (GLS) and longitudinal strain parameters are reduced in patients with prior MI but preserved left ventricular ejection fraction (LVEF). The study included 40 clinical patients with prior MI occurring >3 months previously (defined as subendocardial hyperenhancement on late Gadolinium enhancement imaging) with LVEF?≥?55% and 40 controls matched for age and LVEF. GLS, global longitudinal strain rate (GLSR) and early diastolic longitudinal strain rate (GLSRe) were measured from cine imaging feature tracking analysis. Presence of wall motion abnormality (WMA) and minimum systolic wall thickening (SWT) were calculated from cine imaging. GLS was ?17.3?±?3.7% in prior MI versus ?19.3?±?1.9% in controls (p?=?0.012). GLSR was ?88.0?±?33.7%/s in prior MI versus ?103.3?±?26.5%/s in controls (p?=?0.005). GLSRe was 76.4?±?28.4%/s in prior MI versus 95.5?±?26.0%/s in controls (p?=?0.001). GLS accurately identified prior MI [AUC 0.662 (95% CI 0.54–0.785) p?=?0.012] whereas WMA [AUC 0.500 (95% CI 0.386–0.614) p?=?1.0] and minimum SWT [AUC 0.609 (95% CI 0.483–0.735) p?=?0.093] did not. GLS, GLSR and GLSRe are reduced in prior MI with preserved LVEF. Normal LVEF and lack of WMA cannot exclude prior MI. Prior MI should be considered when reduced GLS, GLSR or GLSRe are detected by non-invasive imaging.     

全容积三维超声评价人工瓣、补片、封堵器及起搏电极的效果

目的　评价全容积三维超声 (FVTDE)对人工瓣、心内补片、封堵器及起搏电极成像效果。方法　经二维超声检查确定的 71例心内有人工瓣、补片、封堵器及起搏电极的患者接受了 FVTDE成像。结果　二维超声共发现了 88处人工瓣、心内补片、封堵器及起搏电极。 FVTDE可立体显示包括 1例瓣周漏的所有 31处二尖瓣位人工瓣环和瓣叶、 19处主动脉瓣位人工瓣叶和瓣环、 1处主动脉瓣位人工瓣仅人工瓣叶、所有 5处三尖瓣位人工瓣叶和瓣环、16处室间隔补片、 8处房间隔补片、 1处房间隔封堵器和 3处右心内起搏电极。仅 1处主动脉瓣位人工瓣环、 1处主动脉瓣位人工瓣叶和瓣环、 1处室间隔补片和 2处全置换的房间隔边缘显示不清。结论　 FVTDE可立体显示绝大部分人工瓣、心内补片、封堵器及起搏电极 ,但成像角度、观察方向等因素可能影响其显示效果     

实时三维超声心动图观察二尖瓣冗长影响左室流出道血流动力学的应用价值

目的 应用实时三维超声心动图(RT-3DE)观察二尖瓣冗长瓣膜立体形态及左室流出道血流动力学改变,分析二尖瓣前叶冗长致左室流出道梗阻的原因.方法 选取我院经超声心动图确诊的二尖瓣冗长患者18例(研究组)和正常健康成人23例(对照组),在常规二维超声心动图基础上,应用RT-3DE观察二尖瓣冗长瓣膜立体形态及左室血流动力学...     

Echocardiographic spectrum of posterior systolic motion of the mitral valve in the general population.

The prevalence of mitral valve prolapse has been established in selected groups of patients but not in the general population. The present study was designed to define the echocardiographic spectrum of mitral valve motion in a population of young individuals without clinical evidence of significant cardiac disease or hypertension. Echocardiograms were performed on 136 normal volunteers. Six subjects (4.4 per cent) had mitral valve prolapse. Eighteen subjects (13.2 per cent) had a lesser degree of posterior systolic motion of the mitral valve leaflets which was suggestive but not diagnostic of prolapse. Minor degrees of posterior systolic mitral valve motion may represent a variant of normal. Caution should be exercised in making the echocardiographic diagnosis of mitral prolapse until this question is settled.     

Double-orifice mitral valve with intact atrioventricular septum: an echocardiographic study with anatomic and functional considerations.

We identified 18 patients with double-orifice mitral valve (DOMV) and intact atrioventricular (AV) septum out of 40,179 echocardiographic studies performed between 1997 and 2002 at Children's Hospital, Denver, CO. In this study we describe (1) the anatomic characteristics of the DOMV in the absence of AV septal defect, (2) the function of the mitral valve by spectral and color Doppler flow mapping, and (3) associated lesions. The topographic location of the orifices in the leaflets suggests possible embryologic mechanisms of DOMV. In this series, DOMV was most commonly associated with left-sided obstructive lesions (in 39% of patients). Spectral and color Doppler interrogation demonstrated a normal flow profile in most cases; only 2 patients had significant mitral regurgitation or stenosis. Therefore, due to the uncertain natural history of this lesion and the potential need for endocarditis prophylaxis, careful imaging of the mitral valve is recommended, particularly in the presence of left-sided obstructive lesions.     

动态三维超声心动图对正常和病变二尖瓣器的临床研究

目的探讨动态三维超声心动图对二尖瓣器评分的价值。方法通过多平面经食管三维超声心动图容积提取显示法（３ＤＶ）对２０例正常二尖瓣、８例二尖瓣狭窄、１２例二尖瓣关闭不全和１０例二尖瓣位人工机械瓣患者的二尖瓣器进行了评分,并与取自三维数据集的任意切面超声心动图（ＡＰＥ）和多平面经食管二维超声心动图（ＴＥＥ）对照。结果３ＤＶ对正常和病变二尖瓣的活动度、连合部、瓣口面积和与毗邻结构的空间关系的评分显著高于ＴＥＥ和ＡＰＥ（Ｐ＜０．０１和Ｐ＜０．０５）。３ＤＶ对病变二尖瓣的诊断价值更优于正常二尖瓣。它对瓣叶厚度、瓣环和瓣下结构的评分低于ＴＥＥ和ＡＰＥ（Ｐ＜０．０１）。三种检查方法对二尖瓣位人工机械瓣的评分无显著性差异（Ｐ＞０．０５）。结论３ＤＶ对评价正常和病变二尖瓣器提供了一种有特殊价值的新方法。     

Accuracy of electrocardiographic criteria for atrial enlargement: validation with cardiovascular magnetic resonance

Purpose

In mitral valve prolapse, determining whether the valve is suitable for surgical repair depends on the location and mechanism of regurgitation. We assessed whether cardiovascular magnetic resonance (CMR) could accurately identify prolapsing or flail mitral valve leaflets and regurgitant jet direction in patients with known moderate or severe mitral regurgitation.

Methods

CMR of the mitral valve was compared with trans-thoracic echocardiography (TTE) in 27 patients with chronic moderate to severe mitral regurgitation due to mitral valve prolapse. Contiguous long-axis high temporal resolution CMR cines perpendicular to the valve commissures were obtained across the mitral valve from the medial to lateral annulus. This technique allowed systematic valve inspection and mapping of leaflet prolapse using a 6 segment model. CMR mapping was compared with trans-oesophageal echocardiography (TOE) or surgical inspection in 10 patients.

Results

CMR and TTE agreed on the presence/absence of leaflet abnormality in 53 of 54 (98%) leaflets. Prolapse or flail was seen in 36 of 54 mitral valve leaflets examined on TTE. CMR and TTE agreed on the discrimination of prolapse from flail in 33 of 36 (92%) leaflets and on the predominant regurgitant jet direction in 26 of the 27 (96%) patients. In the 10 patients with TOE or surgical operative findings available, CMR correctly classified presence/absence of segmental abnormality in 49 of 60 (82%) leaflet segments.

Conclusion

Systematic mitral valve assessment using a simple protocol is feasible and could easily be incorporated into CMR studies in patients with mitral regurgitation due to mitral valve prolapse.     

Mapping of mitral regurgitant defects by cardiovascular magnetic resonance in moderate or severe mitral regurgitation secondary to mitral valve prolapse

Purpose

In mitral valve prolapse, determining whether the valve is suitable for surgical repair depends on the location and mechanism of regurgitation. We assessed whether cardiovascular magnetic resonance (CMR) could accurately identify prolapsing or flail mitral valve leaflets and regurgitant jet direction in patients with known moderate or severe mitral regurgitation.

Methods

CMR of the mitral valve was compared with trans-thoracic echocardiography (TTE) in 27 patients with chronic moderate to severe mitral regurgitation due to mitral valve prolapse. Contiguous long-axis high temporal resolution CMR cines perpendicular to the valve commissures were obtained across the mitral valve from the medial to lateral annulus. This technique allowed systematic valve inspection and mapping of leaflet prolapse using a 6 segment model. CMR mapping was compared with trans-oesophageal echocardiography (TOE) or surgical inspection in 10 patients.

Results

CMR and TTE agreed on the presence/absence of leaflet abnormality in 53 of 54 (98%) leaflets. Prolapse or flail was seen in 36 of 54 mitral valve leaflets examined on TTE. CMR and TTE agreed on the discrimination of prolapse from flail in 33 of 36 (92%) leaflets and on the predominant regurgitant jet direction in 26 of the 27 (96%) patients. In the 10 patients with TOE or surgical operative findings available, CMR correctly classified presence/absence of segmental abnormality in 49 of 60 (82%) leaflet segments.

Conclusion

Systematic mitral valve assessment using a simple protocol is feasible and could easily be incorporated into CMR studies in patients with mitral regurgitation due to mitral valve prolapse.     

Left ventricular function in patients with hypertrophic cardiomyopathy and its relation to myocardial fibrosis and exercise tolerance

We sought to determine the relation between myocardial extracellular volume (ECV), left ventricular (LV) diastolic function, and exercise tolerance in patients with hypertrophic cardiomyopathy (HCM). Forty five HCM patients with an ejection fraction >50% and no previous septal reduction therapy underwent imaging by CMR and transthoracic echocardiography. CMR was used to quantify LV volumes, mass, EF, LA volumes, scar burden, pre and post contrast T1 relaxation times and ECV. Echocardiography was used to measure outflow tract gradients, mitral inflow and annular velocities, circumferential strain, systolic, early and late diastolic strain rates. Exercise duration and peak oxygen consumption were noted. HCM patients had increased native T1 relaxation time and ECV vs. controls [ECV controls: 24.7 (23.2–26.4) vs. HCM: 26.8 (24.6–31.3)%, P?=?0.014]. Both parameters were significantly associated with LV diastolic dysfunction, circumferential strain, diastolic strain rate and peak oxygen consumption (r?=??0.73, P?<?0.001). Compared to controls, HCM patients have significantly longer native T1 relaxation time and higher ECV. These structural changes lead to worse LV global and segmental diastolic function and in turn reduced exercise tolerance.     

Naturally Occurring Shear Waves in Healthy Volunteers and Hypertrophic Cardiomyopathy Patients

We apply a high frame rate (over 500 Hz) tissue Doppler method to measure the propagation velocity of naturally occurring shear waves (SW) generated by aortic and mitral valves closure. The aim of this work is to demonstrate clinical relevance. We included 45 healthy volunteers and 43 patients with hypertrophic cardiomyopathy (HCM). The mitral SW (4.68 ± 0.66 m/s) was consistently faster than the aortic (3.51 ± 0.38 m/s) in all volunteers (p < 0.0001). In HCM patients, SW velocity correlated with E/e’ ratio (r = 0.346, p = 0.04 for aortic SW and r = 0.667, p = 0.04 for mitral SW). A subgroup of 20 volunteers were matched for age and gender to 20 HCM patients. In HCM, the mean velocity of 5.1 ± 0.7 m/s for the aortic SW (3.61 ± 0.46 m/s in matched volunteers, p < 0.0001) and 6.88 ± 1.12 m/s for the mitral SW(4.65 ± 0.77 m/s in matched volunteers, p < 0.0001). A threshold of 4 m/s for the aortic SW correctly classified pathologic myocardium with a sensitivity of 95% and specificity of 90%. Naturally occurring SW can be used to assess differences between normal and pathologic myocardium.     

A successful percutaneous closure of ventricular septal defect following septal myectomy in patients with hypertrophic obstructive cardiomyopathy

Postoperative ventricular septal defect (post-op VSD) after septal myectomy in patients with hypertrophic obstructive cardiomyopathy is a rare and unexpected complication. We report a case of successful percutaneous closure of VSD following septal myectomy and mitral valve replacement in a patient with intrinsic mitral valve disease and severe mitral valve regurgitation together with hypertrophic obstructive cardiomyopathy.     

经胸超声心动图详细定位二尖瓣脱垂部位在二尖瓣成形术中的应用价值

目的尝试运用经胸二维超声心动图对二尖瓣脱垂的具体部位及病因进行详细区分和准确判断。方法39例二尖瓣脱垂患者，于二尖瓣成形或置换术前进行经胸超声心动图检查，初步判断脱垂瓣叶的准确部位及病因，外科术中直视下诊断。结果根据外科二尖瓣结构修正命名，术前二尖瓣水平短轴观及其衍生的非标准切面诊断出脱垂的局部瓣体44处，共涉及65个分区，15例患者发现断裂的腱索；术中证实分别为51处瓣体、78个分区，20例检出断裂腱索，符合率86％、83％和75％；5例患者脱垂瓣叶及腱索上发现赘生物并均在术中证实。结论经胸二维超声心动图能对大多数二尖瓣脱垂的具体部位及病因作出准确判断。二尖瓣水平短轴观及其衍生的非标准切面具有重要价值。     

Preprocedural imaging for transcatheter mitral valve‐in‐valve replacement: Planning makes perfect

Transcatheter mitral valve‐in‐valve replacement (TMViVR) in degenerated bioprostheses or valvular rings shows promise as an alternative to surgical MVR in selected high‐risk patients. However, these procedures are particularly challenging given the complex anatomy of the mitral valve apparatus and the surrounding structures, potentially causing LV outflow tract obstruction (LVOTO). Preprocedural planning with virtual implantation and planimetric estimation of the neo‐LVOT at end‐systole is crucial for improving procedural results. In this case, we also include a dynamic evaluation of the neo‐LVOT and implement virtual reality imaging for immersive assessment of the implanted valve.     

Helical distribution of hypertrophy in patients with hypertrophic cardiomyopathy: prevalence and clinical implications

Recently a novel pattern of helical distribution of hypertrophy has been described in patients with hypertrophic cardiomyopathy (HCM). Our aim was to determine its prevalence and potential implications in an unselected cohort. One-hundred- and eight consecutive patients diagnosed with HCM by cardiac magnetic resonance (CMR) were included (median clinical follow up of 1718 days). All clinical and complementary test information was prospectively collected. The presence of a helical pattern was assessed by a simple measurement of the maximal left ventricle (LV) wall thickness (LVWT) for each of the 17 classical LV segments and it was classified in one of three types according to its extension. A helical distribution was detected in 58% of patients, and was associated to a higher incidence of left ventricular outflow tract obstruction (LVOT; 35% vs. 10%; p?=?0.005) and systolic anterior motion of the mitral valve (SAM; 30% vs. 13%, p = 0.053). No significant difference in the maximal LVWT was observed. However, the presence of a helical pattern showed a significant association with non sustained ventricular tachycardia (NSVT; 22% vs. 7%; p?=?0.029) and was associated to a higher risk of sudden cardiac death (SCD) calculated with the European society of cardiology (ESC) calculator (p = 0.006). Notably, patients with a more extense spiral had a higher incidence of heart failure (75% vs. 34%, p = 0.012) and all-cause death (21 vs. 3%, p?=?0.049). A helical pattern is frequent in HCM and can be readily assessed on CMR standard cine sequences. In conclusion, a helical pattern carries negative clinical implications and is associated to a higher estimated risk of SCD.     

超声检测二尖瓣对合指数可行性研究及初步结果

目的 探讨采用经食管实时三维超声心动图检测心房颤动患者二尖瓣对合面积及对合指数的可行性.方法 对15例心房颤动患者均行经食管实时三维超声心动图检查,并用Qlab软件对原始数据进行后处理分析.选取舒张早期及收缩末期两个时相,分别手动标记瓣环及瓣叶.计算对合面积和对合指数公式分别为：舒张早期二尖瓣面积-收缩末期二尖瓣面积;[（舒张早期二尖瓣面积-收缩末期二尖瓣面积）/舒张早期二尖瓣面积]×100%.结果 所有15例患者均能成功得到二尖瓣对合面积并可以计算出对合指数这一参数.对合面积范围从119.8～514.5 mm2,平均（293.4±114.0）mm2;对合指数范围16%～42%,平均（23.0±7.0）%.结论 通过Q-lab软件得到二尖瓣对合指数这种方法是可行的.     

动态三维超声心动图评价二尖瓣关闭不全

本文采取经胸壁及经食道旋转扫描方法获取二维数据，利用总体重建法（ＶｏｌｕｍｉｃＲｅｎｄｅｒｉｎｇＤｉｓｐｌａｙ）对１２例正常人二尖瓣，１４例风心病二尖瓣关闭不全，２０例二尖瓣脱垂患者的二尖瓣解剖结构及二尖瓣返流束进行了动态三维超声心动图重建。重建图像能从左室或左房侧显示二尖瓣装置的整体三维空间结构及动态变化。正常二尖瓣叶光滑平软，舒张期瓣口充分开放，收缩期前后叶对合良好。风心病二尖瓣关闭不全患者瓣叶增厚，收缩期前后叶之间出现裂缝。二尖瓣脱垂时瓣叶某一部分呈“瓢匙”样向左房侧脱出。动态三维超声心动图还能显示二尖瓣关闭不全血液返流束的立体形态及在左房内的空间走向。初步经验表明动态三维超声心动图对二尖瓣关闭不全的诊断有重要临床价值     

经食管实时三维超声心动图对二尖瓣立体结构的定量研究

目的 探讨经食管实时三维超声心动图二尖瓣立体结构定量分析(MVQ)软件的临床价值,筛选出对诊断二尖瓣脱垂和分析二尖瓣反流机制有意义的参数.方法 对18例无二尖瓣反流、瓣膜结构功能正常患者(对照组)和13例二尖瓣脱垂引起大量二尖瓣反流患者(脱垂组),分别行经食管实时三维超声检查,应用MVQ进行后处理,测量收缩期关于二尖瓣立体结构的18个参数.统计两组中有统计学意义的参数.结果 脱垂组的二尖瓣瓣环参数均较对照组增大,差异有统计学意义(P＜0.05).瓣叶的参数关闭时前叶瓣体与瓣环最高平面的夹角(θant)、关闭时后叶瓣体与瓣环最高平面的夹角(θpost)、关闭时前叶与后叶瓣体对合时形成的夹角(θNPA)、瓣叶关闭时穹隆高度(Htent)、瓣叶穹隆的容积(Vtent)、前后叶关闭时对合线的长度(L2DALPm)、主动脉瓣环与二尖瓣环平面夹角(OAv-Mv)两组间比较差异无统计学意义(P＞0.05).前叶自瓣根至对合线的长度(L3Dant)、后叶从瓣根至对合线的长度(L3Dpost)、脱垂瓣叶向左房侧隆起的高度(Hprol)、脱垂部分的容积(Vprol)、后叶瓣体的面积(A3Dpost)、前叶瓣体的面积(A3Dant)脱垂组均大于对照组,差异有统计学意义(P＜0.05).结论 MVQ分析软件可以定量测量二尖瓣的立体结构,使超声心动图对瓣膜病变的诊断更加详细量化,对外科制定精确的手术方案具有重要的指导意义.