Evaluation of right and left ventricular function using speckle tracking echocardiography in patients with arrhythmogenic right ventricular cardiomyopathy and their first degree relatives

Value of cardiac magnetic resonance feature-tracking in Arrhythmogenic Cardiomyopathy (ACM): A systematic review and meta-analysis

We aimed to assess the diagnostic performance of Cardiac Magnetic Resonance (CMR) strain parameters in ACM patients to evaluate their diagnostic role. We systematically searched MEDLINE, EMBASE, Scopus, and Web of Science. Of the 146 records, 16 were included. All Right Ventricle (RV) global strains were significantly reduced in ACM patients compared to controls (Standardized Mean Difference (SMD)[95 % Confidence Interval (CI)]: Longitudinal 1.31[0.79,1.83]; Circumferential 0.88[0.34,1.42]; Radial -1.14[-1.78,-0.51]). Similarly, all Left Ventricle (LV) global strains were significantly impaired in ACM compared to healthy controls (SDM [95 %CI]: Longitudinal 0.88[0.48,12.28], Circumferential 0.97[0.72,1.22], Radial -1.24[-1.49,-1.00]). Regarding regional RV strains, longitudinal and circumferential strains were significantly reduced in basal and mid-wall regions, while they were comparable to controls in the apical regions. The RV radial strain was reduced only within the basal region in the ACM group compared to controls. ACM patients exhibited significant impairment of regional LV strains in all regions-basal, mid-wall, and apical-compared to control subjects. Ultimately, despite the limitations of CMR-FT in terms of reproducibility, it is superior to qualitative assessment in detecting wall motion abnormalities. Thus, integrating CMR-FT with ACM diagnostic criteria seems to enhance its diagnostic yield.

Arrhythmogenic Cardiomyopathy: Current Updates and Future Challenges

Arrhythmogenic cardiomyopathy (ACM) epitomises a genetic anomaly hallmarked by a relentless fibro-fatty transmogrification of cardiac myocytes. Initially typified as a right ventricular-centric disease, contemporary observations elucidate a frequent occurrence of biventricular and left-dominant presentations. The diagnostic labyrinth of ACM emerges from its clinical and imaging properties, often indistinguishable from other cardiomyopathies. Precision in diagnosis, however, is paramount and unlocks the potential for early therapeutic interventions and vital cascade screening for at-risk individuals. Adherence to the criteria established by the 2010 task force remains the cornerstone of ACM diagnosis, demanding a multifaceted assessment incorporating electrophysiological, imaging, genetic, and histological data. Reflecting the evolution of our understanding, these criteria have undergone several revisions to encapsulate the expanding spectrum of ACM phenotypes. This review seeks to crystallise the genetic foundation of ACM, delineate its clinical and radiographic manifestations, and offer an analytical perspective on the current diagnostic criteria. By synthesising these elements, we aim to furnish practitioners with a strategic, evidence-based algorithm to accurately diagnose ACM, thereby optimising patient management and mitigating the intricate challenges of this multifaceted disorder.

The Challenges of Diagnosis and Treatment of Arrhythmogenic Cardiomyopathy: Are We there yet?

Background

we sought to review the evolution in the diagnosis and treatment of Arrhythmogenic Cardiomyopathy (ACM), a clinically multifaceted entity beyond the observation of ventricular arrhythmias, and the outcome of therapies aiming at sudden death prevention in a single center experience.

Methods

retrospective analysis of the data of consecutive patients with an implanted cardioverter-defibrillator (ICD) and a confirmed diagnosis of ACM according to the proposed Padua Criteria, who were referred to our center from January 1992 to October 2021.

Results

we enrolled 72 patients (66% males, mean age at implant 46 ± 16 years), 63.9% implanted for primary prevention. At the time of ICD implant, 29 (40.3%) patients had a right ventricular involvement, 24 (33.3%) had a dominant LV involvement and 19 (26.4%) had a biventricular involvement. After a median follow-up of 6,1 years [IQR: 2.5-9.9], 34 patients (47.2%) had 919 sustained episodes of ventricular arrhythmias (VA). 27 patients (37.5%) had 314 episodes of life-threatening arrhythmias (LT-VA), defined as sustained ventricular tachycardia ≥ 200 beats/min. Considering only the patients with an ICD capable of delivering ATP, 80.4% of VA and 65% of LT-VA were successfully terminated with ATP. 16 (22.2%) patients had an inappropriate ICD activation, mostly caused by atrial fibrillation, while in 9 patients (12.5%) there was a complication needing reintervention (in 3 cases there was a loss of ventricular sensing dictating lead revision). During the follow-up 11 (15.3%) patients died, most of them due to heart failure, and 8 (11.1%) underwent heart transplantation.

Conclusions

ACM is increasingly diagnosed owing to heightened suspicion at ECG examination and to improved imaging technology and availability, though the diagnostic workflow is particularly challenging in the earliest disease stages. ICD therapy is the cornerstone of sudden death prevention, albeit its efficacy is not based on controlled studies, and VT ablation/medical therapy are complementary to this strategy. The high burden of ATP-terminated VA makes shock-only devices debatable. The progressive nature of ACM leads to severe biventricular enlargement and refractory heart failure, which pose significant treatment issues when a predominant RV dysfunction occurs owing to the reduced possibility for mechanical circulatory assistance.

Echocardiographic Deformation Imaging for Early Detection of Genetic Cardiomyopathies: JACC Review Topic of the Week

Clinical screening of the relatives of patients with genetic cardiomyopathies is challenging, as they often lack detectable cardiac abnormalities at presentation. Life-threatening adverse events can already occur in these early stages of disease, so sensitive tools to reveal the earliest signs of disease are needed. The utility of echocardiographic deformation imaging for early detection has been explored for this population in multiple studies but has not been broadly implemented in clinical practice. The authors discuss contemporary evidence on the utility of deformation imaging in relatives of patients with genetic cardiomyopathies. The available body of data shows that deformation imaging reveals early disease-specific abnormalities in dilated cardiomyopathy, hypertrophic cardiomyopathy, and arrhythmogenic cardiomyopathy. Deformation imaging seems promising to enhance the screening and follow-up protocols in relatives, and the authors propose measures to accelerate its implementation in clinical care.

Assessment of right ventricular function using cardiovascular magnetic resonance in patients with type 2 diabetes mellitus

Background

Accurate evaluation of right ventricular (RV) function is always difficult due to its irregular shape and movement. Many indices have been proposed to assess RV function, but none have been universally accepted. This study evaluated RV function in type 2 diabetes mellitus (T2DM) patients using long-axis strain (LAS) and other traditional indices.

Methods

Fifty-seven patients with T2DM and 39 healthy controls were prospectively enrolled. Four-chamber cardiovascular magnetic resonance (CMR) and RV short-axis cine images were obtained from all participants to measure the tricuspid annular plane systolic excursion (TAPSE), RV ejection fraction (EF), peak longitudinal strain (PLS) and four LAS indices. The inter-and intraobserver variabilities were also calculated.

Results

Compared with healthy controls, T2DM was associated with a decreased LAS (apex/lateral wall) (-17.4%±4.2% vs. control, -19.7%±3.7%, P=0.008) and LAS (apex/middle point) (-17.5%±4.5% vs. control, -19.5%±3.9%, P=0.026), but both groups had a similar LAS (RV/lateral wall) and LAS (RV/middle point) (all P>0.05). After adjustments for age and body mass index, a significant difference was observed only for LAS (apex/lateral wall) (P=0.028). There were no significant differences in the TAPSE, RVEF and PLS (all P>0.05). LAS (apex/lateral wall) correlated with the TAPSE (r=-0.723, P<0.001), RVEF (r=-0.270, P=0.008) and PLS (r=0.210, P=0.040). The inter- and intraobserver variability of the LAS (apex/lateral wall) were lower than the other three LAS indices.

Conclusions

Compared with traditional RV function indices, such as the TAPSE, RVEF and PLS, LAS is easy to obtain and shows high repeatability. LAS (apex/lateral wall) may provide a more sensitive T2DM-related RV dysfunction index.

Clinical Diagnosis, Imaging, and Genetics of Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia: JACC State-of-the-Art Review

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is an inherited cardiomyopathy that can lead to sudden cardiac death and heart failure. Our understanding of its pathophysiology and clinical expressivity is continuously evolving. The diagnosis of ARVC/D remains particularly challenging due to the absence of specific unique diagnostic criteria, its variable expressivity, and incomplete penetrance. Advances in genetics have enlarged the clinical spectrum of the disease, highlighting possible phenotypes that overlap with arrhythmogenic dilated cardiomyopathy and channelopathies. The principal challenges for ARVC/D diagnosis include the following: earlier detection of the disease, particularly in cases of focal right ventricular involvement; differential diagnosis from other arrhythmogenic diseases affecting the right ventricle; and the development of new objective electrocardiographic and imaging criteria for diagnosis. This review provides an update on the diagnosis of ARVC/D, focusing on the contribution of emerging imaging techniques, such as echocardiogram/magnetic resonance imaging strain measurements or computed tomography scanning, new electrocardiographic parameters, and high-throughput sequencing.

Two-dimensional Echocardiographic Assessment of Myocardial Strain: Important Echocardiographic Parameter Readily Useful in Clinical Field

Echocardiography is the first and is the most-available imaging modality for many cardiovascular diseases, and echocardiographic parameters can give much important information for diagnosis, treatment, and prognostic evaluations. Left ventricular ejection fraction (LVEF) is the most commonly used echocardiographic parameter for left ventricular (LV) systolic function. Although LVEF is used routinely in daily practice, it is calculated from volumetric change without representing true myocardial properties. Recently, strain echocardiography has been used to objectively measure myocardial deformation. Myocardial strain can give accurate information about intrinsic myocardial function, and it can be used to detect early-stage cardiovascular diseases, monitor myocardial changes with specific therapies, differentiate cardiomyopathies, and predict the prognosis of several cardiovascular diseases. Although strain echocardiography has been applied to measure the right ventricle and left atrium, in addition to analyzing the LV, many cardiologists who are not imaging specialists are unaware of its clinical use and importance. Therefore, this review describes the measurement and clinical utility of 2-dimensional strain analysis in various cardiovascular diseases.

Strain Analysis of the Right Ventricle Using Two-dimensional Echocardiography

Right ventricular (RV) systolic dysfunction has been identified as an independent prognostic marker of many cardiovascular diseases. However, there are problems in measuring RV systolic function objectively and identification of RV dysfunction using conventional echocardiography. Strain echocardiography is a new imaging modality to measure myocardial deformation. It can measure intrinsic myocardial function and has been used to measure regional and global left ventricular (LV) function. Although the RV has different morphologic characteristics than the LV, strain analysis of the RV is feasible. After strain echocardiography was introduced to measure RV systolic function, it became more popular and was incorporated into recent echocardiographic guidelines. Recent studies showed that RV global longitudinal strain (RVGLS) can be used as an objective index of RV systolic function with prognostic significance. In this review, we discuss RVGLS measurement, normal reference values, and the clinical importance of RVGLS.

Right ventricular systolic function and mechanical dispersion identify patients with arrhythmogenic right ventricular cardiomyopathy

PURPOSE

To assess right ventricular (RV) regional and global systolic function using feature tracking (FT) in patients with a definite diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC) and to investigate if changes in strain amplitude and mechanical dispersion indicate a propensity for arrhythmia.

MATERIALS AND METHODS

Twenty-seven patients fulfilling Task Force Criteria for ARVC and 24 healthy volunteers underwent MR at 1·5 Tesla. Steady-state free precession cine of long-axis slices and a short-axis stack of the RV was acquired. Segmental longitudinal systolic strain amplitude and time-to-peak (TTP) strain were measured in the four- and two-chamber views of the RV.

RESULTS

Compared to controls, patients with ARVC had lower RV ejection fraction (RVEF), (53% vs 57%, P = 0·012) and lower longitudinal strain amplitude in the RV free wall (-20·6 vs -26·3%, P = 0·014) and in the basal part of the RV (-22·8 vs -31·7%, P<0·001). Mechanical dispersion, defined as the standard deviation (SD) of TTP of RV segments, was larger in patients with ARVC (48 ms [21-74] vs 35 ms [13-66 ms], P = 0·02). Patients with ventricular tachycardia (VT) or non-sustained VT had lower RVEF (46% vs 55%, P = 0·008), but did not have significantly lower RV strain amplitude (-19·5% vs 21·0%, P = 0·073) and no signs of mechanical dispersion (49 ms vs 48 ms, P = 0·861) compared to patients without arrhythmia.

CONCLUSION

ARVC patients had lower longitudinal absolute strain amplitude in basal RV segments and increased mechanical dispersion compared to healthy volunteers, but the presence of mechanical dispersion was not predictive of ventricular arrhythmia.

Feature tracking CMR reveals abnormal strain in preclinical arrhythmogenic right ventricular dysplasia/ cardiomyopathy: a multisoftware feasibility and clinical implementation study

BACKGROUND

Regional right ventricular (RV) dysfunction is the hallmark of Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C), but is currently only qualitatively evaluated in the clinical setting. Feature Tracking Cardiovascular Magnetic Resonance (FT-CMR) is a novel quantitative method that uses cine CMR to calculate strain values. However, most prior FT-CMR studies in ARVD/C have focused on global RV strain using different software methods, complicating implementation of FT-CMR in clinical practice. We aimed to assess the clinical value of global and regional strain using FT-CMR in ARVD/C and to determine differences between commercially available FT-CMR software packages.

METHODS

We analyzed cine CMR images of 110 subjects (39 overt ARVD/C [mutation+/phenotype+], 40 preclinical ARVD/C [mutation+/phenotype-] and 31 control) for global and regional (subtricuspid, anterior, apical) RV strain in the horizontal longitudinal axis using four FT-CMR software methods (Multimodality Tissue Tracking, TomTec, Medis and Circle Cardiovascular Imaging). Intersoftware agreement was assessed using Bland Altman plots.

RESULTS

For global strain, all methods showed reduced strain in overt ARVD/C patients compared to control subjects (p < 0.041), whereas none distinguished preclinical from control subjects (p > 0.275). For regional strain, overt ARVD/C patients showed reduced strain compared to control subjects in all segments which reached statistical significance in the subtricuspid region for all software methods (p < 0.037), in the anterior wall for two methods (p < 0.005) and in the apex for one method (p = 0.012). Preclinical subjects showed abnormal subtricuspid strain compared to control subjects using one of the software methods (p = 0.009). Agreement between software methods for absolute strain values was low (Intraclass Correlation Coefficient = 0.373).

CONCLUSIONS

Despite large intersoftware variability of FT-CMR derived strain values, all four software methods distinguished overt ARVD/C patients from control subjects by both global and subtricuspid strain values. In the subtricuspid region, one software package distinguished preclinical from control subjects, suggesting the potential to identify early ARVD/C prior to overt disease expression.

Role of Two-Dimensional Speckle-Tracking Echocardiography Strain in the Assessment of Right Ventricular Systolic Function and Comparison with Conventional Parameters

Despite the already well-known role the right side of the heart plays in many diseases, right ventricular (RV) function has only recently been carefully considered. Echocardiography is the first-line diagnostic technique for the assessment of the right ventricle and right atrium, whereas cardiac magnetic resonance is considered the gold standard but is limited by cost and availability. According to the current guidelines, systolic RV function should be assessed by several conventional measurements, but the efficacy of these parameters as diagnostic and prognostic tools has been questioned by many authors. The development in recent years of myocardial deformation imaging techniques and their application to the right heart chambers has allowed deeper evaluation of the importance of RV function in the pathophysiology of a large number of cardiovascular conditions, but the real value of this new tool has not been completely clarified. The aim of this review is to provide a wide and careful analysis of findings available in the literature about the assessment of RV systolic function by strain measurements, comparing them with conventional parameters and evaluating their role in several clinical settings.

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.

Left Ventricular Function in Children and Adolescents With Arrhythmogenic Right Ventricular Cardiomyopathy

The aim of this study was to determine if left ventricular (LV) contractility is reduced in children with arrhythmogenic right ventricular cardiomyopathy (ARVC). For this retrospective study, children and adolescents undergoing a workup for ARVC were characterized according to the revised Task Force Criteria (rTFC). LV strain, rotation, and torsion were measured by feature-tracking cardiovascular magnetic resonance imaging (CMR). Of 142 pediatric patients, 41% had no, 23% possible, 20% borderline, and 16% definite ARVC. LV ejection fraction (EF) did not differ between rTFC categories. Patients in higher rTFC categories had lower right ventricular (RV) EF z-scores (Z-), higher Z-RV end-diastolic volumes (EDVs) and larger Z-LVEDVs (p <0.001, p = 0.002 and 0.013, respectively). LV global circumferential strain was lower in higher rTFC categories (p = 0.018). Z-LVEDV correlated with Z-RVEDV, and Z-LVEF correlated with Z-RVEF (r = 0.69 and r = 0.55, both p <0.001). Z-LVEF and Z-RVEF correlated with LV global circumferential strain (r = 0.48 and r = 0.46, both p <0.001). Forty-eight patients (34%) underwent follow-up CMR investigations after a mean of 3.2 ± 1.9 (0.4 to 8.4) years. A decrease of Z-LVEF over time correlated with that of Z-RVEF (r = 0.35), and Z-LVEDV increase correlated with Z-RVEDV increase (r = 0.57). In conclusion, LV myocardial dysfunction is present in young patients with suspected ARVC. Progressive LV dysfunction assessed by conventional CMR and feature-tracking and enlargement over time parallel adverse remodeling of the RV.

Phenotypic expression of ARVC: How 12 lead ECG can predict left or right ventricle involvement. A familiar case series and a review of literature

AIMS

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart-muscle disease primarily affecting the right ventricle (RV) and potentially causing sudden death in young people. The natural history of the disease is firstly characterized by a concealed form progressing over a biventricular involvement. Three different cases coming from the same family are presented together with a review of the literature.

METHODS AND RESULTS

Multi-parameter analysis including imaging and electrocardiographic analysis is presented since the first medical referral with follow-up ranging from 11 to 38years. Case 1 presented a typical RV involvement in agreement with the ECG pattern. Case 2 presented a prevalent left ventricular involvement leading from the beginning to a pattern of dilated cardiomyopathy in agreement with his ECG evolution over the years. On the other side, Case 3 came to observation with a typical RV involvement (similar to Case 1) but with ECG evolution of typical left ventricle involvement (similar to Case 2). The genetic analysis showed a mutation in desmoglein-2 (DSG2) gene: p. Arg49His. Comparison between size and localization of ventricular dyskinesia at cardiovascular imaging and the surface 12 lead electrocardiography are proposed.

CONCLUSIONS

ARVC may lead to an extreme phenotypic variability in clinical manifestations even within patients coming from the same family in which ARVC is caused by the same genetic mutation. ECG progression over time reflects disease evolution and in particular cases may anticipate wall motion abnormalities by years.

A meta-analysis for echocardiographic assessment of right ventricular structure and function in ARVC

INTRODUCTION

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is an inherited pathology that can increase the risk of sudden death. Current Task Force Criteria for echocardiographic diagnosis do not include new, regional assessment tools which may be relevant in a phenotypically diverse disease. We adopted a systematic review and meta-analysis approach to highlight echocardiographic indices that differentiated ARVC patients and healthy controls.

METHODS

Data was extracted and analysed from prospective trials that employed a case-control design meeting strict inclusion and exclusion as well as a-priori quality criteria. Structural indices included proximal RV outflow tract(RVOT1) and RV diastolic area(RVDarea). Functional indices included RV fractional area change (RVFAC), Tricuspid Annular Systolic Excursion(TAPSE), peak systolic and early diastolic myocardial velocities (S' and E' respectively) and myocardial strain.

RESULTS

Patients with ARVC had larger RVOT1 (mean  SD; 34 vs. 28 mm P<0.001) and RVDarea (23 vs. 18 cm2 P<0.001) compared to healthy controls. ARVC patients also had lower RVFAC (38 vs. 46 % P<0.001), TAPSE(17 vs. 23 mm P<0.001), S' (9 vs. 12 cm.s-1 P<0.001), E' (9 vs. 13 cm.s-1 P<0.001) and myocardial strain (-17 vs. -30% P<0.001).

CONCLUSION

The data from this meta-analysis support current Task Force criteria for the diagnosis of ARVC. In addition, other RV measures that reflect the complex geometry and function in ARVC clearly differentiated between ARVC and healthy controls and may provide additional diagnostic and management value. We recommend that future working groups consider this data when proposing new / revised criteria for the echocardiographic diagnosis of ARVC.

Utility of speckle tracking echocardiography imaging in patients with asymptomatic and symptomatic arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

Arrhythmogenic right ventricular dysplasia (ARVD) is characterized by the progressive replacement of ventricular myocytes with variable amounts of fibrous and adipose tissue. Several studies have suggested that speckle tracking echocardiographic (STE) parameters such as strain (S) and strain rate (SR) may prove useful in the early detection of right ventricular (RV) dysfunction. Therefore, the aim of this study was to evaluate RV myocardial function using the STE method in both asymptomatic and symptomatic patients with ARVD and to assess its potential role in the differential diagnosis of these two presentations.

METHODS

We recruited 34 patients with ARVD. Seventeen patients were symptomatic, and seventeen were asymptomatic.

RESULTS

The RV free wall global longitudinal S and SR were significantly lower in symptomatic patients with ARVD than in asymptomatic patients. According to a cutoff value of 1.35 per seconds for RV global SR, the sensitivity and specificity for predicting ARVD were 88% and 77%, respectively. According to a cutoff value of 17.3% for RV S, the sensitivity and specificity for predicting ARVD were 82% and 77%, respectively.

CONCLUSION

In conclusion, we present strong evidence that STE-derived global S and SR in the RV free wall are decreased in symptomatic patients with ARVD compared with asymptomatic patients.

Right ventricular strain by MR quantitatively identifies regional dysfunction in patients with arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

Analysis of regional wall motion of the right ventricle (RV) is primarily qualitative with large interobserver variation in clinical practice. Thus, the purpose of this study was to use feature tracking to analyze regional wall motion abnormalities in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC).

METHODS

We enrolled 110 subjects (39 overt ARVC [mutation+/phenotype+] (35.5%), 40 preclinical ARVC [mutation+/phenotype-] (36.3%), and 31 control subjects (28.2%)). Cine steady state free precession cardiac MR was performed with temporal resolution ≤40 ms in the horizontal long axis (HLA), axial, and short axis directions. Regional strain was analyzed using feature tracking software and reproducibility was assessed by means of intraclass correlation coefficient. Dunnett's test was used in univariate analysis for comparisons to control subjects; cumulative odds logistic regression was used for minimally and fully adjusted multivariate models.

RESULTS

Strain was significantly impaired in overt ARVC compared with control subjects both globally (P < 0.01) and regionally (all segments of HLA view, P < 0.01). In the HLA view, regional reproducibility was excellent within (intraclass correlation coefficient [ICC] = 0.81) and moderate between (ICC = 0.62) observers. Using a threshold of -31% subtricuspid strain in the HLA view, the sensitivity and specificity for overt ARVC were 75.0% and 78.2%, respectively. In multivariable analysis involving all three groups, subtricuspid strain less than -31% (beta = 1.38; P = 0.014) and RV end diastolic volume index (beta = 0.06; P = 0.001) were significant predictors of disease presence.

CONCLUSION

RV strain can be reproducibly assessed with MR feature tracking, and regional strain is abnormal in overt ARVC compared with control subjects.

Biventricular myocardial strain analysis in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) using cardiovascular magnetic resonance feature tracking

BACKGROUND

Fibrofatty degeneration of myocardium in ARVC is associated with wall motion abnormalities. The aim of this study was to examine whether Cardiovascular Magnetic Resonance (CMR) based strain analysis using feature tracking (FT) can serve as a quantifiable measure to confirm global and regional ventricular dysfunction in ARVC patients and support the early detection of ARVC.

METHODS

We enrolled 20 patients with ARVC, 30 with borderline ARVC and 22 subjects with a positive family history but no clinical signs of a manifest ARVC. 10 healthy volunteers (HV) served as controls. 15 ARVC patients received genotyping for Plakophilin-2 mutation (PKP-2), of which 7 were found to be positive. Cine MR datasets of all subjects were assessed for myocardial strain using FT (TomTec Diogenes Software). Global strain and strain rate in radial, circumferential and longitudinal mode were assessed for the right and left ventricle. In addition strain analysis at a segmental level was performed for the right ventricular free wall.

RESULTS

RV global longitudinal strain rates in ARVC (-0.68 ± 0.36 sec⁻¹) and borderline ARVC (-0.85 ± 0.36 sec⁻¹) were significantly reduced in comparison with HV (-1.38 ± 0.52 sec⁻¹, p ≤ 0.05). Furthermore, in ARVC patients RV global circumferential strain and strain rates at the basal level were significantly reduced compared with HV (strain: -5.1 ± 2.7 vs. -9.2 ± 3.6%; strain rate: -0.31 ± 0.13 sec(-1) vs. -0.61 ± 0.21 sec⁻¹). Even for patients with ARVC or borderline ARVC and normal RV ejection fraction (n=30) global longitudinal strain rate proved to be significantly reduced compared with HV (-0.9 ± 0.3 vs. -1.4 ± 0.5 sec(-1); p < 0.005). In ARVC patients with PKP-2 mutation there was a clear trend towards a more pronounced impairment in RV global longitudinal strain rate. On ROC analysis RV global longitudinal strain rate and circumferential strain rate at the basal level proved to be the best discriminators between ARVC patients and HV (AUC: 0.9 and 0.92, respectively).

CONCLUSION

CMR based strain analysis using FT is an objective and useful measure for quantification of wall motion abnormalities in ARVC. It allows differentiation between manifest or borderline ARVC and HV, even if ejection fraction is still normal.

Right ventricular function quantification in Takotsubo cardiomyopathy using two-dimensional strain echocardiography

Aims

This study sought to characterize global and regional right ventricular (RV) myocardial function in patients with Takotsubo cardiomyopathy (TC) using 2D strain imaging.

Methods

We compared various parameters of RV and left ventricular (LV) systolic function between 2 groups of consecutive patients with TC at initial presentation and upon follow-up. Group 1 had RV involvement and group 2 did not have RV involvement.

Results

At initial presentation, RV peak systolic longitudinal strain (RVPSS) and RV fractional area change (RVFAC) were significantly lower in group 1 (−13.2±8.6% vs. −21.8±5.4%, p = 0.001; 30.7±9.3% vs. 43.5±6.3%, p = 0.001) and improved significantly upon follow-up. Tricuspid annular plane systolic excursion (TAPSE) did not differ significantly at initial presentation between both groups (14.8±4.1 mm vs. 17.9±3.5 mm, p = 0.050). Differences in regional systolic RV strain were only observed in the mid and apical segments. LV ejection fraction (LVEF) and LV global strain were significantly lower in group 1 (36±8% vs. 46±10%, p = 0.006 and −5.5±4.8% vs. −10.2±6.2%, p = 0.040) at initial presentation. None of the parameters were significantly different between the 2 groups upon follow-up. A RVPSS cut-off value of >−19.1% had a sensitivity of 85% and a specificity of 71% to discriminate between the 2 groups.

Conclusion

In TC, RVFAC, RVPSS, LVEF and LV global strain differed significantly between patients with and without RV dysfunction, whereas TAPSE did not. 2 D strain imaging was feasible for the assessment of RV dysfunction in TC and could discriminate between patients with and without RV involvement in a clinically meaningful way.

Layer-specific radiofrequency ultrasound-based strain analysis in a porcine model of ischemic cardiomyopathy validated by a geometric model

Local layer-specific myocardial deformation after myocardial infarction (MI) has not been studied extensively although the sub-endocardium is more vulnerable to ischemia and interstitial fibrosis deposition. Radiofrequency (RF) ultrasound-based analysis could provide superior layer-specific radial strain estimation compared with clinically available deformation imaging techniques. In this study, we used RF-based myocardial deformation measurements to investigate layer-specific differences between healthy and damaged myocardium in a porcine model of chronic MI. RF data were acquired epicardially in healthy (n = 21) and infarcted (n = 5) regions of a porcine chronic MI model 12 wk post-MI. Radial and longitudinal strains were estimated in the sub-endocardial, mid-wall and sub-epicardial layers of the left ventricle. Collagen content was quantified in three layers of healthy and infarcted regions in five pigs. An analytical geometric model of the left ventricle was used to theoretically underpin the radial deformation estimated in different myocardial layers. Means ± standard errors of the peak radial and longitudinal strain estimates of the sub-endocardial, mid-wall and sub-epicardial layers of the healthy and infarcted tissue were: 82.7 ± 5.2% versus 39.9 ± 10.8% (p = 0.002), 63.6 ± 3.3% versus 38.8 ± 7.7% (p = 0.004) and 34.3 ± 3.0% versus 35.1 ± 5.2% (p = 0.9), respectively. The radial strain gradient between the sub-endocardium and the sub-epicardium had decreased 12 wk after MI, and histologic examination revealed the greatest increases in collagen in the sub-endocardial and mid-wall layers. Comparable normal peak radial strain values were found by geometric modeling when input values were derived from the in vivo measurements and literature. In conclusion, the estimated strain values are realistic and indicate that sub-endocardial radial strain in healthy tissue can amount to 80%. This high value can be explained by the cardiac geometry, as was illustrated by geometric modeling. After MI, strain values were decreased and collagen content was increased in the sub-endocardial and mid-wall layers. Layer-specific peak radial strain can be assessed by RF strain estimation and clearly differs between healthy and infarcted tissue. Although the relationship between tissue stiffness and tissue strain is not strictly local, this novel technique provides a valuable way to assess layer-specific regional cardiac function in a variety of myocardial diseases.