Asymmetry of Systolic Anterior Motion of the Mitral Valve in Patients with Hypertrophic Obstructive Cardiomyopathy: A Real-time Three-dimensional Echocardiographic Study

A Case Report of Asymmetry of Systolic Anterior Motion of the Mitral Valve, a Not Widely Well-Known but Practically Important Echocardiographic Presentation in Hypertrophic Cardiomyopathy

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Echocardiography is useful for evaluating LVOT obstruction in patients with HCM.

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Asymmetry of SAM in patients with HCM is not a well-known presentation.

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This patient had asymmetry of SAM, resulting in a narrow laterally located LVOT.

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In a patient with asymmetry of SAM, LVOT gradient should be estimated carefully.

The influence of aortoseptal angulation on provocable left ventricular outflow tract obstruction in hypertrophic cardiomyopathy

Objectives

Aortoseptal angulation (AoSA) can predict provocable left ventricular outflow tract obstruction (LVOTO) in patients with symptomatic hypertrophic cardiomyopathy (HCM). Lack of a standardised measurement technique in HCM without the need for complex three-dimensional (3D) imaging limits its usefulness in routine clinical practice. This study aimed to validate a simple measurement of AoSA using 2D echocardiography and cardiac MR (CMR) imaging as a predictor of LVOTO.

Methods

We retrospectively assessed 160 patients with non-obstructive HCM, referred for exercise stress echocardiography. AoSA was measured using resting 2D echocardiography in all patients, and CMR in 29. Twenty-five controls with normal echocardiograms were used for comparison.

Results

Patients with HCM had a reduced AoSA compared with controls (113°±12 vs 126°±6), p<0.0001. Sixty (38%) patients had provocable LVOTO, with smaller angles than non-obstructive patients (108°±12 vs 116°±12, p<0.0001). AoSA, degree of mitral valvular regurgitation and incomplete systolic anterior motion (SAM) were associated with peak left ventricular outflow tract gradient (r=0.508, p<0.0001). An angle ≤100° had 27% sensitivity, 91% specificity and 59% positive predictive value for predicting provocable LVOTO. When combined with SAM, specificity was 99% and positive predictive value 88%. Intraclass correlation coefficient of AoSA measured by two observers was 0.901 (p<0.0001). Bland-Altman analysis of echocardiographic AoSA showed good agreement with the CMR-derived angle.

Conclusions

Measurement of AoSA using echocardiography in HCM is easy, reproducible and comparable to CMR. Patients with provocable LVOTO have reduced angles compared with non-obstructive patients. AoSA is highly specific for provocable LVOTO and should prompt further evaluation in symptomatic patients without resting obstruction.

In vivo measurement of mitral leaflet surface area and subvalvular geometry in patients with asymmetrical septal hypertrophy: insights into the mechanism of outflow tract obstruction

BACKGROUND

Analyzing the determinants of systolic anterior motion of the mitral valve and consequent left ventricular outflow tract (LVOT) obstruction in patients with asymmetrical septal hypertrophy requires a comprehensive 3-dimensional analysis of mitral leaflet (ML) area, papillary muscle (PM) geometry, and the distribution of left ventricular hypertrophy.

METHODS AND RESULTS

Real-time 3-dimensional echocardiography was performed in 47 patients with asymmetrical septal hypertrophy and 32 normal controls. Patients included 20 with resting LVOT obstruction (group I) and 27 without (group II). Customized software (Omni 4D) provided a validated measure of ML surface area, LVOT area, mitral annular area and nonplanarity, LVOT hypertrophy index by topography (percent area with wall thickness >16 mm), and 3-dimensional PM positions relative to annulus. ML area was more than twice as large in group I than normal and 1.4 times normal in group II (P<0.001). Group I patients were also characterized by higher LVOT hypertrophy index and medial and anterior displacements of both PMs, resulting in a shorter inter-PM distance. Independent determinants of LVOT obstruction were indexed total ML area (adjusted odds ratio, 5.651; 95% confidence interval, 1.573 to 20.304; P=0.008) and inter-PM distance (adjusted odds ratio, 0.416; 95% confidence interval, 0.203 to 0.854; P=0.0169). Minimal LVOT area during systole correlated well with peak LVOT pressure gradient (R(2)=0.83, P<0.001); its independent determinants were left ventricular end-systolic volume (P=0.0183), indexed total ML area (P=0.0108), inter-PM distance (P=0.0378), annular height (P=0.0047), and LVOT hypertrophy index (P=0.0098).

CONCLUSIONS

Myocardium is not the only tissue affected in patients with asymmetrical septal hypertrophy, and primary changes of the mitral apparatus, including ML area increase and PM displacement, are independent determinants of LVOT obstruction and provide a comprehensive mechanism that determines leaflet slack and anteriorly directed motion. Abnormal PM-mitral valve geometry assessed by real-time 3-dimensional echocardiography can provide reasonable new targets for individualized intervention.

[Evaluation of the mitral valve by transthoracic real-time three-dimensional echocardiography]

Recently, echocardiography is the most widely used routine non-invasive diagnostic method, with which morphology and function of the mitral valve can be characterized. The aim of this review is to demonstrate the role of one of the newest echocardiographic developments, the transthoracic real-time three-dimensional echocardiography in the evaluation of mitral valve.

Mitral valve regurgitation and 3D echocardiography

The mitral valve is a complex, dynamic and functional apparatus that can be altered by a wide range of disorders leading to stenosis or regurgitation. Surgical management of mitral valve disease may be difficult. Planned intervention may not always be feasible when the surgeon is faced with complex pathology that cannot be assessed fully by conventional 2D echocardiography. Transthoracic and transesophageal 3D echocardiography can provide a more reliable functional and anatomical assessment of the different valve components and evaluation of its geometry, which can aid the surgeon in planning a more suitable surgical intervention and improve outcomes. Although 3D echocardiography is a new technology, it has proven to be an important modality for the accurate assessment of valvular heart disease and in the future, it promises to be an essential part in the routine assessment of cardiovascular patients.

Echocardiographic assessment of left ventricular geometry and the mitral valve apparatus in cats with hypertrophic cardiomyopathy

OBJECTIVES

This retrospective study addressed the general hypothesis that abnormalities of the mitral valve apparatus are common in cats with idiopathic hypertrophic cardiomyopathy (HCM) and contribute to dynamic obstruction of the left ventricular outflow tract (LVOT).

ANIMALS, MATERIALS AND METHODS

106 cats (28 controls and 78 with HCM) had transthoracic two-dimensional and Doppler echocardiography performed with quantification of 33 variables. Three groups of cats (control [Group-1], HCM without obstruction [Group-2], and HCM with obstruction [Group-3]) were identified and compared by analysis of variance, chi(2) analysis, and correlation analysis.

RESULTS

Cats in Group-3 had more LV and papillary muscle hypertrophy, increased length of the anterior mitral valve leaflet, and a higher prevalence of false tendons in the LVOT compared to cats in Group-2 (P < or = 0.05). The length of the anterior mitral valve leaflet was correlated to the severity of dynamic obstruction (P < or = 0.05) and the magnitude of LV hypertrophy (P < or = 0.001). Systolic anterior motion of chordae tendineae (CAM) was observed in 16% of control cats and >50% of cats with HCM (P < or = 0.05).

CONCLUSIONS

Abnormalities of the mitral valve are common in cats with HCM suggesting a possible role in the pathogenesis of dynamic outflow tract obstruction.

[The role of real-time three-dimensional echocardiography in the evaluation of hypertrophic cardiomyopathy]

Hypertrophic cardiomyopathy is a relatively common hereditary disorder, which is associated with cardiac morphologic and functional alterations. Echocardiography is a non-invasive, simple and easy-to-learn method to evaluate patients with cardiomyopathy. The aim of this review paper is to demonstrate the possible diagnostic role of one of the newest echocardiographic development, the real-time 3-dimensional echocardiography in the evaluation of hypertrophic cardiomyopathy.

Echocardiography in hypertrophic cardiomyopathy: the role of conventional and emerging technologies

Hypertrophic cardiomyopathy is a relatively common inherited cardiomyopathy that is occasionally challenging to differentiate from hypertensive heart disease and athlete hearts on the basis of morphologic or functional abnormalities alone. Echocardiography has traditionally played a preeminent role in the diagnosis, formulation of management strategies, and the prognostication of this complex disease. In this review, we briefly profile the utility and pitfalls of established echocardiographic modalities and discuss the evolving role of novel echocardiographic imaging modalities such as tissue Doppler, Doppler-based strain, 2-dimensional strain (speckle tracking imaging), and 3-dimensional imaging in the assessment of hypertrophic cardiomyopathy.

Three-dimensional ultrasonography of shoulders with rotator cuff tears

BACKGROUND

It is possible to evaluate the size of rotator cuff tears by ultrasonography (US) or magnetic resonance imaging. However, there are only a few reports on the imaging assessment of the configuration of cuff tears, which could provide important preoperative information that assists performing an optimal anatomical repair. The purpose of this study was to determine quantitatively the reproducibility of three-dimensional US in the assessment of rotator cuff tear configuration.

METHODS

Ten embalmed cadaveric shoulders with rotator cuff tears were examined. After resecting the proximal humerus with the rotator cuff, we put it in water and scanned it using high-resolution US with a three-dimensional linear probe. Actual tear lengths and widths were compared with sonographic measurements (Pearson correlation coefficient). By superimposing the real photographic image on the reconstructed three-dimensional image, we calculated the concordance rate (ratio of the concordance area to the tear area).

RESULTS

The actual tear length (16.6 +/- 7.1 mm; mean +/- SD) and width (8.4 +/- 4.4 mm) were correlated with the tear length (16.4 +/- 7.5 mm) and width (8.2 +/- 4.4 mm) measured from reconstructed three-dimensional ultrasonograms (r = 0.998 and 0.994, respectively). The mean concordance rate was 91.4%, indicating that almost exactly the same configuration was reconstructed by US.

CONCLUSIONS

Three-dimensional US is useful for evaluating the configuration of rotator cuff tears. This is the first report to quantify the similarity between the configuration evaluated by US and the actual configuration. Using this method, we can visualize the configuration of rotator cuff tears preoperatively, facilitating optimal repair design.

Three-Dimensional Echocardiographic Technology

This article addresses the current state of the art of technology in three-dimensional echocardiography as it applies to transducer design, beam forming, display, and quantification. Because three-dimensional echocardiography encompasses many technical and clinical areas, this article reviews its strengths and limitations and concludes with an analysis of what to use when.