Deformation imaging of the atria using 2D strain: A noninvasive modality to characterize operating compliance?

This viewpoint with two illustrated case summaries of biventricular and biatrial mechanical function/dysfunction emphasizes the importance of continued research in deformation imaging beyond the left ventricle, as there are no Cinderellas in the heart and we just cannot afford to be nonchalant toward the atria, particularly the right atrium.     

Nonvolumetric echocardiographic indices of right ventricular systolic function: validation with cardiovascular magnetic resonance and relationship with functional capacity

Purpose: Right ventricular (RV) systolic function as measured by right ventricular ejection fraction (RVEF) has long been recognized as an important predictor of outcome in heart failure patients. The echocardiographic measurement of RV volumes and RVEF is challenging, however, owing to the unique geometry of the right ventricle. Several nonvolumetric echocardiographic indices of RV function have demonstrated prognostic value in heart failure. Comparison studies of these techniques with each other using RVEF as a benchmark are limited, however. Furthermore, the contribution of these various elements of RV function to patient functional status is uncertain. We therefore aimed to: (1) Determine which nonvolumetric echocardiographic index correlates best with RVEF as determined by cardiac magnetic resonance (CMR) imaging (the accepted gold standard measure of RV systolic function) and (2) Ascertain which echocardiographic index best predicts functional capacity. Methods: Eighty‐three subjects (66 with systolic heart failure and 17 healthy controls) underwent CMR, 2D echocardiography, and cardiopulmonary exercise testing for comparison of echocardiographic indices of RV function with CMR RVEF, 6‐minute walk distance and VO_{2 PEAK}. Results: Speckle tracking strain RV strain exhibited the closest association with CMR RV ejection fraction. Indices of RV function demonstrated weak correlation with 6‐minute walk distance, but basal RV strain rate by tissue velocity imaging had good correlation with VO_{2 PEAK}. Conclusion: Strain by speckle tracking echocardiography and strain rate by tissue velocity imaging may offer complementary information in the evaluation of RV contractility and its functional effects. (Echocardiography 2012;29:455‐463)     

Added clinical value of applying myocardial deformation imaging to assess right ventricular function

Right heart dysfunction has been found to be a strong prognostic factor predicting adverse outcome in various cardiopulmonary diseases. Conventional echocardiographic measurements can be limited by geometrical assumptions and impaired reproducibility. Speckle tracking–derived strain provides a robust quantification of right ventricular function. It explicitly evaluates myocardial deformation, as opposed to tissue Doppler–derived strain, which is computed from tissue velocity gradients. Right ventricular longitudinal strain provides a sensitive tool for detecting right ventricular dysfunction, even at subclinical levels. Moreover, the longitudinal strain can be applied for prognostic stratification of patients with pulmonary hypertension, pulmonary embolism, and congestive heart failure. Speckle tracking–derived right atrial strain, right ventricular longitudinal strain–derived mechanical dyssynchrony, and three‐dimensional echocardiography–derived strain are emerging imaging parameters and methods. Their application in research is paving the way for their clinical use.     

Comparison of Right Ventricular Systolic Function in Patients with Low Risk and Intermediate‐to‐High Risk Pulmonary Embolism: A Two‐Dimensional Strain Imaging Study

Aim: Right ventricular (RV) dysfunction is key for risk stratification in pulmonary embolism (PE). The goal of this study was to compare RV strain values between low and intermediate‐to‐high risk PE patients assessed by two‐dimensional (2D) strain imaging. Methods: The inclusion criterion was a diagnosis of PE confirmed by thoracic computed tomography scan with contrast medium, or by scintigraphy perfusion lung scan. Risk stratification of PE was defined as high when there was hemodynamic instability; intermediate when there were signs of RV dysfunction on echocardiography; and/or elevated troponin I and/or brain natriuretic peptide and low when none of these criteria were present. All patients underwent echocardiography at admission. Apical four‐chamber images were analyzed off line using both conventional and 2D strain imaging. Results: Sixty‐two patients (mean age 66 years) were prospectively recruited: 33 with low risk PE, 29 with intermediate‐to‐high risk PE. Global 2D RV strain differed significantly between groups (?13.1% vs. ?18.7%, P < 0.01), as did free wall (?12.7% vs. ?20.2%, P < 0.016) and septal wall (?13.5% vs. ?17.2%, P < 0.01). When the RV was divided into segments, we observed a similar reduction in absolute strain value in the mid and apical free wall segments and in the apical septal wall (?20.3 ± ?7.6 vs. ?11.8 ± 8.9%; P < 0.01 and ?19.6 ± 6.9 vs. ?7.4 ± 9.1%; P < 0.01, and ?17.7 ± 7.0 vs. 9.9 ± 8.0; P < 0.01, respectively). 2D strain and tricuspid annular plane systolic excursion were significantly related (r² = 0.35, P < 0.01). Conclusions: Peak RV longitudinal 2D strain is reduced in patients with intermediate‐to‐high risk PE, especially in the apical and mid segments of the free wall. Global and regional RV longitudinal 2D strain is altered in patients with intermediate‐to‐high risk PE as compared with low risk PE.     

Subclinical right ventricular dysfunction in diabetes mellitus--an ultrasonic strain/strain rate study.

AIMS: While left ventricular dysfunction has been recognized to be a common complication of diabetes mellitus, data regarding right ventricular (RV) performance in patients with diabetes are incomplete. The aim of the study was to determine the preclinical effects of diabetes on regional RV systolic and diastolic function in asymptomatic persons with diabetes using the echocardiographic strain/strain rate technique. METHODS: Groups studied consisted of 33 subjects with diabetes only (DM; aged 57.3 +/- 12.9 years) and 40 subjects with coexisting diabetes and hypertension (DMHT; aged 57.5 +/- 10.5 years). In all patients with diabetes, coronary artery disease and pulmonary hypertension were excluded. Thirty-six healthy age-matched persons served as control subjects. In each patient an echocardiographic study with strain/strain rate imaging was performed. Analysis of RV deformation data included assessment of systolic strain, peak systolic strain rate (SRs) and peak early diastolic strain rate (SRe) obtained from the basal and apical segments of the RV free wall. RESULTS: Significantly lower values of systolic strain and SRs in the basal and apical segment of the RV free wall in the DM and DMHT groups as compared with control subjects indicated impairment of RV systolic function. Similarly, decreased SRe in patients with diabetes in both RV segments examined reflected abnormalities of RV diastolic performance. The systolic defects were more pronounced in the apical than in the basal segment. All measured parameters were similar in the two groups with diabetes. CONCLUSION: Diabetes mellitus is associated with subclinical RV systolic and diastolic dysfunction, regardless of coexisting hypertension.     

Impaired biventricular deformation in Marfan syndrome: a strain and strain rate study in adult unoperated patients

Objective: To investigate the presence of any regional myocardial deformation abnormalities in Marfan syndrome (MFS) and determine the benefits of using advanced echocardiography compared to conventional techniques. Background: Myocardial dysfunction in MFS may be caused by extracellular matrix remodeling thus, resulting in uniform reduced functionality. However, increased aortic stiffness may cause segmental ventricular abnormalities. Strain rate imaging (SRI) constitutes a validated technique to assess regional deformation in various clinical conditions. With this in mind, we aimed to investigate biventricular function in MFS using SRI. Methods: Forty‐four MFS patients (mean age 30 ± 12 years, 26 men) and 49 controls without valvular disease were examined using SRI. Ejection fraction (EF) was calculated by the Simpson's biplane method. Biventricular deformation was assessed by measuring strain/strain rate. Strain values were divided by left ventricular (LV) end‐diastolic volume to adjust LV deformation for geometry changes providing a strain index (SI). Aortic stiffness was evaluated using the β‐stiffness index. Results: EF (%) was reduced in MFS patients (59 ± 5 vs 72 ± 4, P < 0.001), whereas β‐stiffness was increased (P < 0.001). LV radial and LV and right ventricular (RV) long‐axis strain values (%) were reduced in the patient group (70 ± 17 vs 93 ± 10; 19 ± 2 vs 25 ± 2; 30 ± 9 vs 36 ± 8, respectively, P < 0.001). Strain rate measurements were also reduced (P < 0.001). In a multiple regression analysis, MFS diagnosis was negatively associated with LV SI (?0.262 [?0.306, ?0.219], P < 0.001). β‐Stiffness was negatively associated with SI obtained from the septum, inferior and anterior walls. ROC analyses demonstrated that SRI, when compared with conventional echocardiography, had higher sensitivity and specificity in predicting biventricular dysfunction in MFS. Conclusions: Our study showed a uniform reduction in biventricular deformation in MFS. These findings suggest that assessment of myocardial function using advanced echocardiographic techniques could be more accurate in MFS patient evaluation than conventional echocardiography alone. (Echocardiography 2011;28:416‐430)     

Right ventricular longitudinal strain: a tool for diagnosis and prognosis in light-chain amyloidosis

Objectives: Light-chain (AL) amyloidosis can lead to an infiltrative cardiomyopathy with increased wall thickness (IWT) of very poor prognosis. Our primary aim was to analyse the right ventricle (RV) in patients with IWT to discriminate AL amyloidosis from IWT due to hypertrophic cardiomyopathy (HCM) or to arterial hypertension (HTN). Our secondary aim was to assess if RV dysfunction predicts overall mortality in cardiac AL amyloidosis.

Methods: We retrospectively and consecutively compared clinical, biological and echocardiographic data of 315 patients with IWT: 105 biopsy-proven AL amyloidosis patients, 105 patients with HCM and 105 patients with HTN. The prognostic value of these parameters was analysed in the AL amyloidosis group.

Results: Free-wall right ventricular longitudinal strain (FWRVLS) worse than ?21.2% discriminates AL amyloidosis [area under the curve (AUC)?=?0.744)] from patients with IWT due to other aetiologies. In AL amyloidosis, FWRVLS is the strongest echocardiographic prognostic marker with AUC =0.722 and ?16.5% as the optimal cut-off value, beyond which overall mortality increases significantly. It is also the only independent echocardiographic predictor of overall mortality (HR =1.113; 95%CI 1.029–1.204; p?=?.007), even when adjusted to the Mayo stage and global left ventricular longitudinal strain.

Conclusions: FWRVLS should be considered in the diagnostic and prognostic workup in light-chain amyloidosis.