Characterization of hypertrophic cardiomyopathy according to global, regional, and multi-layer longitudinal strain analysis, and prediction of sudden cardiac death

Endocardial versus whole-myocardial tracking global longitudinal strain analysis in patients with hypertrophic cardiomyopathy: A preliminary comparative study

BACKGROUND AND OBJECTIVES

We investigated whether the feasibility of left ventricular (LV) global longitudinal strain (GLS) in hypertrophic cardiomyopathy (HCM) varies according to the methodology (e.g. endocardial vs. whole myocardial tracking techniques).

METHODS

We retrospectively analyzed 111 consecutive patients with HCM (median age, 58 years; male, 68.5%) who underwent both transthoracic echocardiography (TTE) and cardiac magnetic resonance imaging (apical 29.7%, septal 33.3%, and diffuse or mixed 37.0%). TTE-whole myocardial and TTE-endocardial GLS were measured and compared in terms of association with late gadolinium enhancement (LGE) extent and discrimination performance for extensive LGE (>15% of the LV myocardium).

RESULTS

Although TTE-whole myocardial and TTE-endocardial GLS were significantly correlated, absolute TTE-endocardial GLS values (19.3 [16.2-21.9] %) were higher than TTE-whole myocardial GLS values (13.3[10.9-15.6] %, p<0.001). Both TTE-derived GLS parameters were significantly correlated with the LGE extent and independently associated with extensive LGE (odds ratio [OR] 1.30, p = 0.022; and OR 1.24, p = 0.013, respectively). Discrimination performance for extensive LGE was comparable between TTE-whole myocardial and TTE-endocardial GLS (area under the curve [AUC], 0.747 and 0.754, respectively, pdifference = 0.610). However, among patients with higher LV mass index (>70 g/m2), only TTE-whole myocardial GLS correlated with LGE extent and was independently associated with extensive LGE (OR 1.35, p = 0.042), while TTE-endocardial GLS did not. Additionally, TTE-whole myocardial GLS had better discrimination performance for extensive LGE than TTE-endocardial GLS (AUC, 0.705 and 0.668, respectively, pdifference = 0.006).

CONCLUSION

TTE-derived GLS using either the endocardial or whole myocardial tracking technique is feasible in patients with HCM. However, in those with severe hypertrophy, TTE-whole myocardial GLS is better than TTE-endocardial GLS.

Prognostic value of global longitudinal strain in hypertrophic cardiomyopathy: A systematic review and meta-analysis

BACKGROUND

As previously reported, impairment of left ventricular global longitudinal strain (LVGLS) is associated with myocardial fibrosis, arrhythmias, and heart failure in hypertrophic cardiomyopathy (HCM) patients.

HYPOTHESIS

This study aimed to estimate the association between LVGLS measured by echocardiography and major adverse cardiovascular events (MACE) in patients with HCM.

METHODS

Pubmed, Embase, Scopus, and Cochrane Library databases were systematically searched for evaluating the difference of LVGLS between MACE and non-MACE and the relevance of LVGLS and MACE in HCM patients, mean difference (MD), and pooled hazard ratios (HR) with 95% confidence interval (CI) were calculated. Publication bias was detected by funnel plots and Egger's test, and trim-and-fill analysis was employed when publication bias existed.

RESULTS

A total of 13 studies reporting 2441 HCM patients were included in this meta-analysis. Absolute value of LVGLS was lower in the group of HCM with MACE (MD = 2.74, 95% CI: 2.50-2.99, p < .001; I²  = 0, p = .48). In the pooled unadjusted model, LVGLS was related to MACE (HR = 1.14, 95% CI: 1.06-1.22, p < .05, I²  = 58.4%, p < .01) and there is a mild heterogeneity, and sensitivity analysis showed stable results. In the pooled adjusted model, LVGLS was related to MACE (HR = 1.12, 95% CI: 1.08-1.16, p < .05; I²  = 0%, p = .442). Egger's tests showed publication bias, and trim-and-fill analysis was applied, with final results similar to the previous and still statistically significant.

CONCLUSION

The meta-analysis suggested that impaired LVGLS was associated with poor prognosis in HCM patients.

Echocardiographic and Cardiac Magnetic Resonance Imaging-Derived Strains in Relation to Late Gadolinium Enhancement in Hypertrophic Cardiomyopathy

We compared speckle tracking echocardiography (STE) and feature tracking cardiovascular magnetic resonance (FT-CMR) in patients with hypertrophic cardiomyopathy (HC) with a varying extent of fibrosis as defined by late gadolinium enhancement to look at the level of agreement between methods and their ability to relate those to myocardial fibrosis. At 2 reference centers, 79 patients with HC and 16 volunteers (the control group) underwent STE and CMR with late gadolinium enhancement and FT-CMR. Patients were classified into 3 categories: no detectable, limited, and extensive fibrosis. Global longitudinal strain (GLS) and global radial strain (GRS) were derived using FT-CMR and STE. STE-derived GRS was decreased in all HC categories compared with the control group (p <0.001), whereas FT-CMR GRS was reduced only in patients with HC with fibrosis (p <0.05). Reduced STE-derived GLS was associated with extensive fibrosis (p <0.05) and a value less than -15.2% identified those with extensive fibrosis (sensitivity 79%, specificity 92%, area under the curve 0.863, 95% confidence interval [CI] 0.76 to 0.97, p <0.001). Inter-modality agreement was moderate for STE versus CMR-GLS (overall population intra-class correlation coefficient = 0.615, 95% CI 0.42 to 0.75, p <0.001; patients with HC 0.63, 0.42 to 0.76, p <0.001) and GRS (overall population intra-class correlation coefficient = 0.601, 95% CI 0.397 to 0.735, p <0.001). A low level of agreement for GRS was seen between methods in patients with HC. In conclusion, strain indexes measured using echocardiography and CMR are reduced in patients with HC compared with the control group and correlate well with the burden of myocardial fibrosis. Reduced STE-GLS can identify patients with extensive fibrosis, but whether there is an added value for risk stratification for sudden cardiac death remains to be determined.

Vectorcardiography as a prognostic tool in hypertrophic cardiomyopathy

BACKGROUND

Vectorcardiography (VCG) has demonstrated diagnostic value in the assessment of hypertrophic cardiomyopathy (HCM), however, determining its prognostic value over time has not yet been investigated. This study sought to assess the correlation of VCG parameters with the progression of HCM.

METHODS

A retrospective chart review of 119 pediatric patients with diagnosis of HCM at the University of Minnesota. Eighty-three cases were excluded because of age, presence of congenital heart disease, not meeting criteria for HCM or negative phenotype. Sample was divided into 2 groups based on the presence or not of cardiac events (ventricular tachycardia, cardiac arrest, ventricular assist device, heart transplant). Derived vectorcardiography from standard 12‑lead ECG was obtained for the first ECG and last available or prior to sentinel event.

RESULTS

Of the 36 cases that met inclusion criteria, 9 (25%) developed a sentinel event. The median age for the event group was 10.1 ± 7.5 years and for the non-event group was 8.7 ± 6.35 years. There was no significant difference in age or sex between the groups. The T wave vector magnitude value was significantly smaller in the event group than in the non-event group (0.302 ± 0.146 mV Vs. 0.561 ± 0.305 mV, p 0.002), with a hazard ratio of 0.651 (95% CI 0.463 to 0.915). No other parameter showed significant difference between the two groups.

CONCLUSIONS

The T wave vector magnitude may predict sentinel events in HCM. Prospective studies are necessary to evaluate the utility of the evolution of VCG parameters.

Comprehensive Echocardiography of Left Atrium and Left Ventricle Using Modern Techniques Helps in Better Revealing Atrial Fibrillation in Patients with Hypertrophic Cardiomyopathy

Atrial fibrillation (AF) is an important arrhythmia in hypertrophic cardiomyopathy (HCM). We aimed to explore whether a complex evaluation of the left ventricle (LV) using modern echocardiography techniques, additionally to the left atrium (LA) boosts the probability of AF diagnosis. Standard echocardiography, 2D and 3D speckle tracking, were performed for LA and LV evaluation in HCM patients and healthy volunteers. Of 128 initially qualified HCM patients, 60 fulfilled included criteria, from which 43 had a history of AF, and 17 were without AF. LA volume index and peak strain, LV ejection fraction, and strains were significant predictors of AF. In addition, 2D global longitudinal strain (GLS) for LV at cut off -16% turned out to be the most accurate predictor of AF (OR 48.00 [95% CI 2.68-859.36], p = 0.001), whereas the combination of LA peak strain ≤ 22% and LV GLS ≥ -16% had the highest discriminatory power (OR 76.36 [95% CI 4.13-1411.36], p = 0.001). AF in HCM patients seems to be LA as well as LV disease. Revealing lower strain for LV, in addition to lower LA strain, may have an important impact on accurate characteristics of HCM patients with AF history.

Usefulness of Global Longitudinal Strain to Predict Heart Failure Progression in Patients With Nonobstructive Hypertrophic Cardiomyopathy

While predicting prognosis to anticipate adverse disease course has long been an aspiration in hypertrophic cardiomyopathy (HC), reliable markers of progressive and unrelenting heart failure symptoms in the absence of obstruction are not well characterized. We sought to evaluate markers of systolic function, including the role of global longitudinal strain (GLS), to identify nonobstructive HC patients at risk for future heart failure. A cohort of 296 consecutive nonobstructive HC patients (42 ± 18years; 75% male) with NYHA class I/II symptoms and preserved systolic function at study entry (EF: 65 ± 6%), were followed for progressive heart failure symptoms (increase in ≥ 1 NYHA functional class) and/or development of systolic dysfunction (EF < 50%). Over median follow-up of 4 ± 3 years, 35 study patients (10%) experienced new heart failure events, including 31 with progressive symptoms and 4 who developed systolic dysfunction. Abnormal GLS < 16% was associated with a 5-fold increase in risk for heart failure compared to GLS > 18% (p < 0.001). GLS remained an independent predictor of heart failure even after adjustment for other relevant disease variables including EF (OR 1.23, p = 0.005). However, notably, when GLS and EF were combined, the prediction of heart failure for individual patients was enhanced (net reclassification improvement 0.55; p = 0.002). Together, GLS < 16% and EF 50% to 59% were associated with a 12.5-fold greater risk for heart failure versus patients with GLS > 18% and EF ≥ 60%, who were at the lowest risk. In conclusion, in nonobstructive HC with no or mild symptoms and preserved EF, abnormal GLS is a strong independent predictor for subsequent development of progressive heart failure symptoms and/or systolic dysfunction. Furthermore, the greatest power in predicting outcome in nonobstructive HC is achieved by combining GLS with EF to identify HC patients at the highest risk for heart failure progression and systolic dysfunction.

3D speckle tracking echocardiographic strain pattern in Hypertrophic Cardiomyopathy and its relation with Sudden Cardiac Death risk markers

CONTEXT

Sudden cardiac death (SCD) predictability for assessing the need for primary insertion of Implantable Cardioverter Defibrillator (ICD) in patients with Hypertrophic cardiomyopathy (HCM) is difficult though there are several conventional risk markers. The role of deformation indices in predicting SCD in HCM is less addressed.

OBJECTIVES

To analyse the 3D speckle tracking echocardiographic strain parameters of HCM patients and its relation with SCD risk markers.

DESIGN AND STUDY METHODOLOGY

It was a cross-sectional observation study done over a period of one year with a follow up period of one year. Fifty HCM patients were included after screening eighty-two patients. Their global LV strain parameters, Global Longitudinal Strain (GLS), Global Circumferential Strain (GCS), Global Radial Strain (GRS) and Global area strain (GAS) were analysed with respect to their age and gender-matched controls. The various strain parameters were correlated with the conventional SCD risk markers and the ESC SCD risk score among these HCM patients.

RESULTS

All the global strain parameters were significantly low in HCM patients compared to their controls {GLS -7.30 ± 3.424 vs -18.78 ± 2.342, p < 001; GCS -11.26 ± 2.754 vs -25.08 ± 3.542, p < 001; GRS 20.56 ± 8.929 vs 39.70 ± 7.546, p < 001}. On subgroup analysis of HCM patients with LV thickness >30 mm, abnormal exercise test, family history of SCD, LVOT gradients >30mmHgand more than one SCD risk marker had significantly low values for all global deformation parameters, when compared with their control HCM cohort. The ESC risk score also had significant inverse correlation with all deformation parameters (GLS 0.496, p < 0.001; GCS 0.491, p < 0.001; GRS -0.529, p < 0.001; GAS 0.519, p < 0.001). On follow up, only one event was recorded in this cohort.

CONCLUSION

There exists a possible linear correlation between conventional SCD risk markers and 3D deformation parameters, which may be utilized for risk stratification and SCD predictability in HCM patients after confirmation with further large prospective studies.

Fibrosis in hypertrophic cardiomyopathy: role of novel echo techniques and multi-modality imaging assessment

Hypertrophic cardiomyopathy (HCM) represents one of the primary cardiomyopathies and may lead to heart failure and sudden cardiac death. Among various histologic features of the disease examined, assessment of myocardial fibrosis may offer valuable information, since it may be considered the common nominator for all HCM connected complications. Late gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) has emerged as the reference noninvasive method for visualizing and quantifying myocardial fibrosis in patients with HCM. T1 mapping, a promising new CMR technique, may provide an advantage over conventional LGE-CMR, by permitting a more valid quantification of diffuse fibrosis. On the other hand, echocardiography offers a significantly more portable, affordable, and easily accessible solution for the study of fibrosis. Various echocardiographic techniques ranging from integrated backscatter and contrast-enhanced ultrasound to two- (2D) or three-dimensional (3D) deformation and shear wave imaging may offer new insights into substrate characterization in HCM. The aim of this review is to describe thoroughly all different modalities that may be used in everyday clinical practice for HCM fibrosis evaluation (with special focus on echocardiographic techniques), to concisely present available evidence and to argue in favor of multi-modality imaging application. It is essential to understand that the role of various imaging modalities is not competitive but complementary, since the information provided by each one is necessary to illuminate the complex pathophysiologic pathways of HCM, offering a personalized approach and treatment in every patient.

Multimodality imaging predictors of sudden cardiac death

Sudden cardiac death (SCD) is the worst clinical event occurring in the clinical context of cardiomyopathies. Current guidelines recommend using LV ejection fraction as the only imaging-derived parameter to identify patients who may benefit from ICD implantation in cardiomyopathies with reduced ejection fraction; however, a relevant proportion of high-risk population is left with unmet therapeutic goal. In case of dilated, hypertrophic, or arrhythmogenic cardiomyopathies, there is still a room for more sensitive and specific risk markers for identifying a cluster at higher risk of SCD. In this paper, we reviewed the evidence supporting the use of advanced echocardiography, CMR, and nuclear cardiology for SCD stratification in patients with the most common cardiomyopathies. The added value of these modalities may be explained on the basis of tissue characterization, especially scar detection, a central player in the pathogenesis of arrhythmias. Therefore, integration of these modalities to our everyday clinical practice may help in dealing with the gray zones where current guidelines are still ineffective for patient selection.

Prognostic significance of cardiac magnetic resonance-based markers in patients with hypertrophic cardiomyopathy

The prognosis of patients with hypertrophic cardiomyopathy (HCM) varies greatly. Cardiac magnetic resonance (CMR) is the gold standard method for assessing left ventricular (LV) mass and volumes. Myocardial fibrosis can be noninvasively detected using CMR. Moreover, feature-tracking (FT) strain analysis provides information about LV deformation. We aimed to investigate the prognostic significance of standard CMR parameters, myocardial fibrosis, and LV strain parameters in HCM patients. We investigated 187 HCM patients who underwent CMR with late gadolinium enhancement and were followed up. LV mass (LVM) was evaluated with the exclusion and inclusion of the trabeculae and papillary muscles (TPM). Global LV strain parameters and mechanical dispersion (MD) were calculated. Myocardial fibrosis was quantified. The combined endpoint of our study was all-cause mortality, heart transplantation, malignant ventricular arrhythmias and appropriate implantable cardioverter defibrillator (ICD) therapy. The arrhythmia endpoint was malignant ventricular arrhythmias and appropriate ICD therapy. The LVM index (LVMi) was an independent CMR predictor of the combined endpoint independent of the quantification method (p < 0.01). The univariate predictors of the combined endpoint were LVMi, global longitudinal (GLS) and radial strain and longitudinal MD (MDL). The univariate predictors of arrhythmia events included LVMi and myocardial fibrosis. More pronounced LV hypertrophy was associated with impaired GLS and increased MDL. More extensive myocardial fibrosis correlated with impaired GLS (p < 0.001). LVMi was an independent CMR predictor of major events, and myocardial fibrosis predicted arrhythmia events in HCM patients. FT strain analysis provided additional information for risk stratification in HCM patients.

Advanced myocardial characterization in hypertrophic cardiomyopathy: feasibility of CMR-based feature tracking strain analysis in a case-control study

OBJECTIVES

This study aimed to evaluate the feasibility and reproducibility of using cardiovascular magnetic resonance feature tracking (CMR-FT) for analysis of bi-ventricular strain and strain rate (SR) in hypertrophic cardiomyopathy (HCM) patients as well as to explore the correlation between right ventricular (RV) and left ventricular (LV) deformation.

METHODS

A total of 60 HCM patients and 48 controls were studied. Global and segmental peak values of bi-ventricular longitudinal, circumferential, radial strain, and systolic SR were analyzed. Pearson analysis was performed to investigate the correlation of RV and LV deformation. Intra-observer and inter-observer reproducibility were also assessed.

RESULTS

LV mass in the HCM group was significantly higher than that in the control group. LV end-systolic and end-diastolic volume and RV end-systolic and end-diastolic volume in the HCM group were all significantly lower than the correlated parameters in the control group (p < 0.001, respectively), whereas no statistical difference was found in ejection fraction (p > 0.05). Global longitudinal strain (GLS), global longitudinal strain rate (GLSR), global circumferential strain (GCS), global circumferential strain rate (GCSR), global radial strain (GRS), and global radial strain rate (GRSR) of the LV and RV were all significantly lower than the control group, and segmental strain and SR were also true (p < 0.001, respectively). Bi-ventricular strain and SR measurements were highly reproducible at both intra- and inter-observer levels. Additionally, Pearson analysis showed RV GCS, GLS, and GRS positively correlated with LV GCS, GLS, and GRS (r = 0.713, p < 0.001; r = 0.728, p < 0.001; r = 0.730, p < 0.001, respectively).

CONCLUSIONS

CMR-FT is a promising approach to analyze impairment of global and segmental myocardium deformation in HCM patients non-invasively and quantitatively.

KEY POINTS

• CMR-FT allows for advanced myocardial characterization with high reproducibility. • As compared with controls, HCM patients have significant differences in CMR-FT strain analysis while ejection fraction was similar. • CMR-FT may serve as an early biomarker of HCM in subjects at risk.

The prognostic role of speckle tracking echocardiography in clinical practice: evidence and reference values from the literature

Speckle tracking echocardiography (STE) is a second-level echocardiographic technique which has gradually gained relevance in the last years. It allows semi-automatic quantification of myocardial deformation and function, overcoming most of the limitations characterizing basic echocardiography and providing an early detection of cardiac impairment. Today, its feasibility and usefulness are highly supported by literature. In particular, several studies demonstrated that STE could provide additional prognostic information beyond conventional echocardiographic and traditional clinical parameters. Moreover, a recent standardization of speckle tracking analysis regarding all cardiac chambers paved the way for the integration of STE in diagnostic and prognostic protocols for particular clinical settings. The aim of this review is to describe the prognostic role of STE in different clinical scenarios basing on currently available evidence.