Early marker of regional left ventricular deformation in patients with hypertrophic cardiomyopathy evaluated by MRI tissue tracking: The effects of myocardial hypertrophy and fibrosis

The Feasibility of Left Ventricular Strain and Strain Rate for Evaluating Hypertrophic Cardiomyopathy with Risk Factors of Sudden Cardiac Death by Feature-Tracking CMR

Sudden cardiac death (SCD) represents the most severe complication of hypertrophic cardiomyopathy (HCM). However, the relation between strain, strain rate (SR), and risk factors in SCD risk stratification remains elusive. The study aimed to assess the attenuation of strain and SR in HCM by feature tracking cardiac magnetic resonance. All strain and SRs were obtained automatically by feature tracking, with manual adjustment of endocardial and epicardial borders. Strain indicators included left ventricular global longitudinal, circumferential, global radial strain (GRS), peak diastolic-longitudinal, circumferential, and radial SR. Patients were categorized into high-risk and low-risk groups for SCD based on the 2020 American Heart Association/American College HCM risk-SCD model. The correlation between strain/SR and SCD risk factors was assessed through Spearman correlation analysis. Furthermore, a multivariate logistic regression analysis was conducted to explore the factors that influence SCD risk in HCM patients. A total of 105 HCM patients were analyzed in this study, including 38 patients in the high-risk group, and 67 patients in the low-risk group. Compared with the low-risk group, the high-risk group exhibited significantly worse strain and SR (p <0.001). Furthermore, both circumferential and GRS and SR exhibited meaningful associations with risk factors for SCD. Additionally, GRS emerged as an independent risk factor for predicting heightened SCD risk in HCM patients (p <0.001). In conclusion, left ventricular strain and SR based on feature tracking-cardiac magnetic resonance can be evaluated for SCD risk and are strongly associated with SCD risk factors.

Systolic anterior motion of the anterior mitral valve leaflet begins in subclinical hypertrophic cardiomyopathy

AIMS

Anterior mitral valve leaflet (AMVL) elongation is detectable in overt and subclinical hypertrophic cardiomyopathy (HCM). We sought to investigate the dynamic motion of the aorto-mitral apparatus to understand the behaviour of the AMVL and the mechanisms of left ventricular outflow tract obstruction (LVOTO) predisposition in HCM.

METHODS AND RESULTS

Cardiovascular magnetic resonance imaging using a 1.5 Tesla scanner was performed on 36 HCM sarcomere gene mutation carriers without left ventricular hypertrophy (G+LVH-), 31 HCM patients with preserved ejection fraction carrying a pathogenic sarcomere gene mutation (G+LVH+), and 53 age-, sex-, and body surface area-matched healthy volunteers. Dynamic excursion of the aorto-mitral apparatus was assessed semi-automatically on breath-held three-chamber cine steady-state free precession images. Four pre-defined regions of interest (ROIs) were tracked: ROIPMVL: hinge point of the posterior mitral valve leaflet; ROITRIG: intertrigonal mitral annulus; ROIAMVL: AMVL tip; and ROIAAO: anterior aortic annulus. Compared with controls, normalized two-dimensional displacement-vs.-time plots in G+LVH- revealed subtle but significant systolic anterior motion (SAM) of the AMVL (P < 0.0001) and reduced longitudinal excursion of ROIAAO (P = 0.014) and ROIPMVL (P = 0.048). In overt and subclinical HCM, excursion of the ROITRIG/AMVL/PMVL was positively associated with the burden of left ventricular fibrosis (P < 0.028). As expected, SAM was observed in G+LVH+ together with reduced longitudinal excursion of ROITRIG (P = 0.049) and ROIAAO (P = 0.008).

CONCLUSION

Dyskinesia of the aorto-mitral apparatus, including SAM of the elongated AMVL, is detectable in subclinical HCM before the development of LVH or left atrial enlargement. These data have the potential to improve our understanding of early phenotype development and LVOTO predisposition in HCM.

Functional significance of myocardial activity at 18F-FAPI PET/CT in hypertrophic cardiomyopathy identified by cardiac magnetic resonance feature-tracking strain analysis

PURPOSE

This study aimed to evaluate the functional significance of 18F-labeled fibroblast activation protein inhibitor (18F-FAPI) activity in hypertrophic cardiomyopathy (HCM) by comparison with cardiac magnetic resonance feature-tracking (CMR-FT) strain analysis.

METHODS

A total of 49 HCM patients were included in this study. Two independent control groups of healthy participants with a matched age and sex to the HCM patients were also enrolled. Left ventricular (LV) 18F-FAPI activity was analyzed for extent (FAPI%) and intensity (maximum target-to-background ratio, TBRmax). The CMR tissue characterization parameters of the LV included late gadolinium enhancement, native T1 value, and extracellular volume fraction. LV strain analysis was performed in radial, circumferential, and longitudinal peak strains (PS).

RESULTS

Intense LV myocardial 18F-FAPI uptake was observed in HCM patients, whereas no obvious uptake was detected in healthy participants (median TBRmax, 9.1 vs. 1.2, p < 0.001). The strain parameters of HCM patients, compared with healthy participants, were significantly impaired (mean radial PS, 23.5 vs. 36.0, mean circumferential PS, -14.5 vs. -20.0, and mean longitudinal PS, -9.9 vs. -16.0, all p < 0.001). At segmental levels, there was a moderate correlation between 18F-FAPI activity and strain parameters. The number of positive 18F-FAPI uptake segments (n = 653) was higher than that of hypertrophic segments (n = 190) and positive CMR tissue characterization segments (n = 525) (all p < 0.001). In segments with negative CMR tissue characterization findings, the strain capacity of positive 18F-FAPI uptake segments was lower than that of negative 18F-FAPI uptake segments (median radial PS, 30.5 vs. 36.1, p = 0.026 and median circumferential PS, -18.4 vs. -19.7, p = 0.041).

CONCLUSION

18F-FAPI imaging can partially reflect the potential strain reduction in HCM patients. 18F-FAPI imaging detects more involved myocardium than CMR tissue characterization techniques, and the additionally identified myocardium has impaired strain capacity.

Cardiac imaging and biomarkers for assessing myocardial fibrosis in children with hypertrophic cardiomyopathy

BACKGROUND

Myocardial fibrosis, as diagnosed on cardiac magnetic resonance imaging (cMRI) by late gadolinium enhancement (LGE), is associated with adverse outcomes in adults with hypertrophic cardiomyopathy (HCM), but its prevalence and magnitude in children with HCM have not been established. We investigated: (1) the prevalence and extent of myocardial fibrosis as detected by LGE cMRI; (2) the agreement between echocardiographic and cMRI measurements of cardiac structure; and (3) whether serum concentrations of N-terminal pro hormone B-type natriuretic peptide (NT-proBNP) and cardiac troponin-T are associated with cMRI measurements.

METHODS

A cross-section of children with HCM from 9 tertiary-care pediatric heart centers in the U.S. and Canada were enrolled in this prospective NHLBI study of cardiac biomarkers in pediatric cardiomyopathy (ClinicalTrials.gov Identifier: NCT01873976). The median age of the 67 participants was 13.8 years (range 1-18 years). Core laboratories analyzed echocardiographic and cMRI measurements, and serum biomarker concentrations.

RESULTS

In 52 children with non-obstructive HCM undergoing cMRI, overall low levels of myocardial fibrosis with LGE >2% of left ventricular (LV) mass were detected in 37 (71%) (median %LGE, 9.0%; IQR: 6.0%, 13.0%; range, 0% to 57%). Echocardiographic and cMRI measurements of LV dimensions, LV mass, and interventricular septal thickness showed good agreement using the Bland-Altman method. NT-proBNP concentrations were strongly and positively associated with LV mass and interventricular septal thickness (P < .001), but not LGE.

CONCLUSIONS

Low levels of myocardial fibrosis are common in pediatric patients with HCM seen at referral centers. Longitudinal studies of myocardial fibrosis and serum biomarkers are warranted to determine their predictive value for adverse outcomes in pediatric patients with HCM.

Layer-specific strain in patients with cardiac amyloidosis using tissue tracking MR

Background

Cardiac infiltration is the major predictor of poor prognosis in patients with systemic amyloidosis, thus it becomes of great importance to evaluate cardiac involvement.

Purpose

We aimed to evaluate left ventricular myocardial deformation alteration in patients with cardiac amyloidosis (CA) using layer-specific tissue tracking MR.

Material and Methods

Thirty-nine patients with CA were enrolled. Thirty-nine normal controls were also recruited. Layer-specific tissue tracking analysis was done based on cine MR images.

Results

Compared with the control group, a significant reduction in LV whole layer strain values (GLS, GCS, and GRS) and layer-specific strain values was found in patients with CA (all P < 0.01). In addition, GRS and GLS, as well as subendocardial and subepicardial GLS, GRS, and GCS, were all diminished in patients with CA and reduced LVEF, when compared to those with preserved or mid-range LVEF (all P < 0.05). GCS showed the largest AUC (0.9952, P = 0.0001) with a sensitivity of 93.1% and specificity of 90% to predict reduced LVEF (<40%). Moreover, GCS was the only independent predictor of LV systolic dysfunction (Odds Ratio: 3.30, 95% CI:1.341-8.12, and P = 0.009).

Conclusion

Layer-specific tissue tracking MR could be a useful method to assess left ventricular myocardial deformation in patients with CA.

The prognostic role of right ventricular dysfunction in patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) primarily affects the left ventricle (LV) sparing the right ventricle (RV) in vast majority of cases. However, several studies employing CMR have revealed that myocardial hypertrophy may also involve the RV. To assess RV size and function in a large prospectively cohort of HCM patients and to evaluate whether these parameters in association with other MR findings can predict cardiac events. Two participating centers prospectively included patients with known or suspected HCM between 2011 and 2017. CMR studies were performed with three different scanners. Outcome measures were a composite of ventricular arrhythmias, hospitalization for HF and cardiac death. Of 607 consecutive patients with known or suspected HCM, 315 had complete follow-up information (mean 65 ± 20 months). Among them, 115 patients developed major cardiac events (MACE) during follow-up. At CMR evaluation, patients with events had higher left atrium (LA) diameter (41.5 ± 8 mm vs. 37.17 ± 7.6 mm, p < 0.0001), LV mass (156.7 vs. 144 g, p = 0.005) and myocardial LGE (4.3% vs. 1.9%, p = 0.001). Similarly, patients with events had lower RV stroke volume index (42.7 vs. 47.0, p = 0.0003) and higher prevalence of both RV hypertrophy (16.4% vs. 4.7%, p = 0.0005) and reduced RV ejection fraction (12.2% vs. 4.4%, p = 0.006). In the multivariate analysis, LA diameter and RV stroke volume index were the strongest predictors of events (p < 0.001 and p = 0.0006, respectively). Anatomic and functional RV anomalies detected and characterized with CMR may have may have a major role in predicting the prognosis of HCM patients.

Identification of fibrosis in hypertrophic cardiomyopathy: a radiomic study on cardiac magnetic resonance cine imaging

OBJECTIVES

Hypertrophic cardiomyopathy (HCM) often requires repeated enhanced cardiac magnetic resonance (CMR) imaging to detect fibrosis. We aimed to develop a practical model based on cine imaging to help identify patients with high risk of fibrosis and screen out patients without fibrosis to avoid unnecessary injection of contrast.

METHODS

A total of 273 patients with HCM were divided into training and test sets at a ratio of 7:3. Logistic regression analysis was used to find predictive image features to construct CMR model. Radiomic features were derived from the maximal wall thickness (MWT) slice and entire left ventricular (LV) myocardium. Extreme gradient boosting was used to build radiomic models. Integrated models were established by fusing image features and radiomic models. The model performance was validated in the test set and assessed by ROC and calibration curve and decision curve analysis (DCA).

RESULTS

We established five prediction models, including CMR, R1 (based on the MWT slice), R2 (based on the entire LV myocardium), and two integrated models (I_CMR+R1 and I_CMR+R2). In the test set, I_CMR+R2 model had an excellent AUC value (0.898), diagnostic accuracy (89.02%), sensitivity (92.54%), and F1 score (93.23%) in identifying patients with positive late gadolinium enhancement. The calibration plots and DCA indicated that I_CMR+R2 model was well-calibrated and presented a better net benefit than other models.

CONCLUSIONS

A predictive model that fused image and radiomic features from the entire LV myocardium had good diagnostic performance, robustness, and clinical utility.

KEY POINTS

• Hypertrophic cardiomyopathy is prone to fibrosis, requiring patients to undergo repeated enhanced cardiac magnetic resonance imaging to detect fibrosis over their lifetime follow-up. • A predictive model based on the entire left ventricular myocardium outperformed a model based on a slice of the maximal wall thickness. • A predictive model that fused image and radiomic features from the entire left ventricular myocardium had excellent diagnostic performance, robustness, and clinical utility.

Detecting Regional Fibrosis in Hypertrophic Cardiomyopathy: The Utility of Myocardial Strain Based on Cardiac Magnetic Resonance

RATIONALE AND OBJECTIVES

The value of myocardial strain for reflecting fibrosis in patients with hypertrophic cardiomyopathy (HCM) on cardiac magnetic resonance (CMR) has not been definite. We aim to explore whether there are underlying non-contrast parameters to evaluate myocardial fibrosis and screen which may be the best.

MATERIALS AND METHODS

We retrospectively included 127 HCM patients (89 men; average age 46.6 ± 15.6 years) and 30 healthy controls (20 men; average age 52.0 ± 13.2 years) who have undergone late gadolinium enhancement (LGE) CMR. Next, 127 HCM patients were divided randomly into two sets including training cohort and validation cohort. Strain and imaging parameters were measured and analyzed statistically.

RESULTS

Based on univariate and multivariate analysis, segmental circumferential strain (SCS) (p < 0.001) and maximal wall thickness (MWT) (p < 0.001) may differentiate myocardial segments with or without LGE as significant biomarkers for both sets. The area under the curve (AUC) was 0.803 (95% CI 0.785-0.820) for SCS and 0.777 (95% CI 0.759-0.795) for MWT to identify myocardial fibrosis. When combining SCS >-13.9% and MWT >16.4mm, the specificity of the model (AUC = 0.779; 95% CI 0.760-0.796) achieved the highest 93.9%, with a sensitivity of 61.8%.

CONCLUSION

Strain analysis in HCM holds promise for myocardial fibrosis detection and SCS is the best strain parameter based on CMR. Nevertheless, the model of combining SCS and MWT could achieve the highest specificity for fibrotic diagnosis.

Cardiovascular magnetic resonance myocardial feature tracking for the determination of left atrial strain in hypertensive left ventricular hypertrophy and hypertrophic cardiomyopathy

AIM

To measure the left atrial (LA) function in patients with hypertrophic cardiomyopathy (HCM; with [OHCM] and without obstruction [NOHCM]) and hypertension-related left ventricular hypertrophy (H-LVH) using cardiovascular magnetic resonance imaging feature tracking (CMR-FT).

MATERIALS AND METHODS

Patients who met the criteria for HCM (n=68), H-LVH (n=46), and 30 healthy controls participated. Left atrial strain was analysed using CMR-FT in cine images with two and four chambers.

RESULTS

The strain rate and LA strain measurements showed that patients with HCM, and H-LVH had impaired conduit and reservoir functions (versus controls). These capacities were more severely impaired in OHCM than those seen in NOHCM and H-LVH. The LA volume parameters (LAVIpac, LAVImin and LAVImax) from the OHCM group were higher than both the NOHCM and H-LVH groups (all p<0.05). There were differences between the OHCM and H-LVH groups in terms of the parameters for LA reservoir function (εs), booster pump function (SRa), and conduit function (SRe, LA passive EF, εe; p<0.05). The strongest correlations included the associations between LA total EF and εs, εe and LA passive EF, and SRe and LA passive EF.

CONCLUSION

CMR-FT can reliably identify LA dysfunction and deformation in the early stages of HCM and H-LVH.

Diastolic dysfunction assessed by cardiac magnetic resonance imaging tissue tracking on normal-thickness wall segments in hypertrophic cardiomyopathy

OBJECTIVES

Myocardial strain is reported to be a sensitive indicator of myocardial mechanical changes in patients with hypertrophic cardiomyopathy (HCM). The changes in the mechanics of the myocardium of normal wall thickness (< 12 mm) have yet to be well studied. This study aimed to evaluate the function of myocardial segments of normal thickness in patients with HCM.

METHODS

Sixty-three patients with HCM and 30 controls were retrospectively enrolled in this retrospective study. Cine imaging, native and post-contrast T1 maps, T2 maps, and late gadolinium enhancement were performed. In addition, regional myocardial strain was assessed by cardiac magnetic resonance-tissue tracking. Strain parameters were compared between the controls and HCM patients with segments of the myocardium of normal thickness. Subgroup analysis was conducted in obstructive and non-obstructive HCM. Lastly, p < 0.05 was considered statistically significant.

RESULTS

In normal-thickness myocardial segments of HCM (n = 716), diastolic peak strain rates (PSRs) were significantly lower than in the control group (n = 480) (radial, - 2.43 [- 3.36, - 1.78] vs. - 2.67 [- 3.58, - 1.96], p = 0.002; circumferential, 1.28 [1.01,1.60] vs. 1.39 [1.14, 1.78], p < 0.001; and longitudinal, 1.16 [0.75,1.51] vs. 1.28 [0.90, 1.71], p < 0.001). The normal-thickness segments showed no significant difference in systolic PSRs between HCM and the controls. In the subgroup analysis, significantly decreased diastolic PSRs were noted in both obstructive and non-obstructive HCM, compared with the controls (p < 0.05).

CONCLUSIONS

Diastolic changes in myocardial mechanics were observed in normal-thickness segments of HCM, occurring before morphological remodeling and systolic dysfunction developed. This finding contributed to a better understanding of the mechanical pathophysiology of HCM with preserved left ventricular ejection fraction. It may potentially aid in predicting disease progression and risk stratification.

Association of sodium intake with adverse left atrial function and left atrioventricular coupling in Chinese

OBJECTIVES

High sodium intake is strongly associated with hypertension and obesity. This study aims to investigate the relationship between 24-h urinary sodium (a surrogate measure of sodium intake), ambulatory blood pressure parameters, left atrial function, and left atrioventricular coupling. Further, we intend to examine whether blood pressure and BMI might be mediators of the relationship between 24-h urinary sodium and subclinical cardiac function.

METHODS

Our study had 398 participants, all of whom were subjected to 24-h urine collection, 24-h ambulatory blood pressure measurement, and cardiac magnetic resonance imaging.

RESULTS

The average age of the participants was 55.70 ± 11.30 years old. The mean urinary sodium of the participants was 172.01 ± 80.24 mmol/24 h. After adjusting for age, sex, history of diabetes, smoking status, alcohol consumption, and use of diuretics, 24-h urinary sodium was correlated with multiple ambulatory blood pressure parameters, BMI, left atrial function, and the left atrioventricular coupling index (LACI) (P < 0.05). Mediation analysis showed that BMI explained 16% of the indirect effect of 24-h urinary sodium and left atrial function and 30% of the indirect effect of LACI. Independent of the mediator, 24-h urinary sodium had a significant direct effect on left atrial function and left atrioventricular coupling.

CONCLUSIONS

Higher 24-h urinary sodium was associated with a greater BMI as well as poor left atrial function and left atrioventricular coupling, and the BMI mediated the relationship between 24-h urinary sodium and subclinical left cardiac function. Furthermore, and more importantly, 24-h urinary sodium may have directly affected the left atrial function and left atrioventricular coupling independent of intermediary factors.

Feasibility of one breath-hold cardiovascular magnetic resonance compressed sensing cine for left ventricular strain analysis

Objective

To investigate the feasibility of 3D left ventricular global and regional strain by using one breath-hold (BH) compressed sensing cine (CSC) protocol and determine the agreement between CSC and conventional cine (CC) protocols.

Methods

A total of 30 volunteers were enrolled in this study. Cardiovascular magnetic resonance (CMR) images were acquired using a 1.436 T magnetic resonance imaging (MRI) system. The CSC protocols included one BH CSC and the shortest BH CSC protocols with different parameters and were only performed in short-axis (SA) view following CC protocols. Left ventricular (LV) end-diastole volume (EDV), end-systole volume (ESV), stroke volume (SV), and ejection fraction (EF) global and regional strain were calculated by CC, one BH CSC, and shortest BH CSC protocols. The intraclass correlation coefficient (ICC) and coefficient of variance (CV) of these parameters were used to determine the agreement between different acquisitions.

Results

The agreement of all volumetric variables and EF between the CC protocol and one BH CSC protocol was excellent (ICC &gt; 0.9). EDV, ESV, and SV between CC and shortest BH CSC protocols also had a remarkable coherence (ICC &gt; 0.9). The agreement of 3D LV global strain assessment between CC protocol and one BH CSC protocol was good (ICC &gt; 0.8). Most CVs of variables were also good (CV &lt; 15%). ICCs of all variables were lower than 0.8. CVs of all parameters were higher than 15% except global longitudinal strain (GLS) between CC and shortest BH CSC protocols. The agreement of regional strain between CC and BH CSC protocols was heterogeneous (-0.2 &lt; ICC &lt; 0.7). Many variables of CVs were poor.

Conclusion

Notably, one BH CSC protocol can be used for 3D global strain analysis, along with a good correlation with the CC protocol. The regional strain should continue to be computed by the CC protocol due to poor agreement and a remarkable variation between the protocols. The shortest BH CSC protocol was insufficient to replace the CC protocol for 3D global and regional strain.

Usefulness of Tissue Tracking by Cardiac Magnetic Resonance to Predict Events in Patients With Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HC) is the most common cardiovascular inherited disease, and it is associated with arrhythmic events, heart failure, and death. Strain analysis by tissue tracking (TT) techniques on cardiac magnetic resonance (CMR) is a novel noninvasive diagnostic tool. However, the usefulness of CMR-TT to identify patients with HC at risk of adverse outcomes remains unknown. CMR strain parameters by CMR-TT were prospectively measured in a cohort of 136 consecutive patients with HC. Clinical (death or readmission for heart failure) and arrhythmic (any ventricular tachycardia) events during follow-up were prospectively recorded. Global radial systolic strain rate and global radial diastolic strain rate showed the best area under the receiver operating characteristic curve (ROC curve) to predict adverse clinical events. On Cox multivariate regression models, a global radial systolic strain rate value <1.4/s and a global radial diastolic strain rate value ≥ -1.38/s were independently associated with clinical events at follow-up (adjusted hazard ratio 6.57, 95% confidence interval [CI] 2.01 to 21.49, p = 0.002; adjusted hazard ratio 5.96, 95% CI 1.79 to 19.89, p = 0.004, respectively). Regarding arrhythmic events, global radial peak strain <27% showed the best area under the ROC curve and remained independently associated with ventricular tachycardia after adjustment for confounders (odds ratio 7.33, 95% CI 1.07 to 50.41, p = 0.043). CMR strain parameters by TT predict clinical and arrhythmic events in patients with HC.

Using multi-parametric quantitative MRI to screen for cardiac involvement in patients with idiopathic inflammatory myopathy

Idiopathic inflammatory myopathies (IIM) is a group of heterogeneous autoimmune systemic diseases, which not only involve skeletal muscle but also myocardium. Cardiac involvement in IIM, which eventually develops into heart failure, is difficult to identify by conventional examinations at early stage. The aim of this study was to investigate if multi-parametric cardiac magnetic resonance (CMR) imaging can screen for early cardiac involvement in IIM, compared with clinical score (Myositis Disease Activity Assessment Tool, MDAAT). Forty-nine patients of IIM, and 25 healthy control subjects with comparable age-range and sex-ratio were enrolled in this study. All subjects underwent CMR examination, and multi-slice short-axis and 4-chamber cine MRI were acquired to evaluate biventricular global circumferential strain (GCS) and global longitudinal strain (GLS). Native T1 and T2 mapping were performed, and post-contrast T1 mapping and LGE were acquired after administration of contrast. A CMR score was developed from native T1 mean and T2 mean for the identification of cardiac involvement in the IIM cohort. Using contingency tables MDAAT and CMR were compared and statistically analyzed using McNemar test. McNemar's test revealed no significant difference between CMR score and MDAAT (p = 0.454). CMR score had potential to screen for early cardiac involvement in IIM patients, compared to MDAAT.

Prognostic value of regional strain by cardiovascular magnetic resonance feature tracking in hypertrophic cardiomyopathy

BACKGROUND

Few studies have demonstrated the performance of regional strain by cardiovascular magnetic resonance (CMR) feature tracking in hypertrophic cardiomyopathy (HCM) patients, and the prognostic value of segmental strain remains unknown. This study aimed to explore the prognostic implications of strain parameters generated by CMR feature tracking analysis in HCM patients.

METHODS

In total, 104 clinically diagnosed HCM patients and 30 healthy volunteers were enrolled in this study, and all patients underwent a standard CMR examination. Global and regional strain was computed by short axis, 2-, 3-, and 4-chamber view cine MR imaging using specialized software. Cardiac structure, function, and myocardial strain were compared between the control group and HCM patients, and the event and event-free groups. Univariate and multivariate Cox regression analyses were performed to evaluate the correlations between clinical and CMR parameters and poor prognosis.

RESULTS

During the follow-up time, 8 patients reached the primary end points and 14 patients reached secondary end points. Regional radial strain of hypertrophic segments (RRS) and regional circumferential strain of hypertrophic segments (RCS) were worse in HCM patients with primary and secondary end points. In univariate Cox regression analysis of RRS, RCS were associated with primary and secondary end points. Regional radial strain of hypertrophic segments [hazard ratio (HR) 1.64, 95% confidence interval (CI): 1.13-2.38] and RCS (HR 2.35, 95% CI: 1.20-4.59) were independent predictors of primary end points, and RRS (HR 1.71, 95% CI: 1.09-2.66) and RCS (HR 2.63, 95% CI: 1.20-5.75) remained independent predictors of secondary end points in multivariate analysis. Kaplan-Meier survival curves indicated patients with RRS <10.0% and RCS ≥-8.5% had a higher rate of primary end points, and patients with RRS <17.9% and RCS ≥-12.1% experienced a higher rate of secondary end points.

CONCLUSIONS

In HCM patients, RRS and RCS were associated with primary and secondary end points and remained independent predictors in multivariate analysis. Impaired regional strain may potentially predict poor prognosis in HCM patients.

KEYWORDS

Prognosis; hypertrophic cardiomyopathy (HCM); cardiovascular magnetic resonance (CMR); regional strain.

Association of left ventricular systolic dysfunction with coronary artery dilation in Kawasaki disease patients: Assessment with cardiovascular magnetic resonance

PURPOSE

To quantify global and regional left ventricular (LV) strain parameters in patients with Kawasaki disease (KD) using cardiovascular magnetic resonance (CMR) tissue tracking and assess the association of coronary artery dilation (CA dilation) with LV systolic dysfunction.

METHODS

Thirty-one KD patients with CA dilation, 22 patients without CA dilation and 27 age- and sex-matched normal controls underwent 3.0 T CMR examination. Z score of >2 was defined as CA dilation. Global LV strain parameters and regional LV strain parameters in 16 American Heart Association segmentation, including radial, circumferential and longitudinal peak strain (PS) and LV function were measured and compared among groups.

RESULTS

No significant difference in LV ejection fraction has been observed among controls, KD patients with CA dilation and without CA dilation (all p > 0.05). However, global longitudinal PS (GLPS) was lower in groups with CA dilation than those without CA dilation (-12.6 ± 4.1% vs -14.9 ± 2.6%, p < 0.05). For regional strain parameters, the segments with CA dilation (n = 301) were lower than those in both normal controls (n = 416) and segments without CA dilation (n = 547) in regional radial, circumferential and longitudinal PS (all p < 0.05). The severity of CA dilation was positively correlated to GLPS and regional longitudinal PS (r = 0.388 and r = 0.222; both p < 0.05) in KD patients. After adjusting for clinical characteristics, the multivariate analysis demonstrated that Z score was independently associated with GLPS in KD patients (β = 0.469, p = 0.000, model R² = 0.355).

CONCLUSIONS

CMR tissue tracking could sensitively identify subclinical LV dysfunction in KD patients with CA dilation. LV systolic dysfunction occurs particularly in the myocardium dominated by the dilated coronary artery. CA dilation is an independent predictor of LV systolic dysfunction.

Global Circumferential Strain by Cardiac Magnetic Resonance Tissue Tracking Associated With Ventricular Arrhythmias in Hypertrophic Cardiomyopathy Patients

Background: Hypertrophic cardiomyopathy (HCM) is prone to myocardial heterogeneity and fibrosis, which are the substrates of ventricular arrhythmias (VAs). Cardiac magnetic resonance tissue tracking (CMR-TT) can quantitatively reflect global and regional left ventricular strain from different directions. It is uncertain whether the change of myocardial strain detected by CMR-TT is associated with VAs. The aim of the study is to explore the differential diagnostic value of VAs in HCM by CMR-TT.

Materials and Methods: We retrospectively included 93 HCM patients (38 with VAs and 55 without VAs) and 30 healthy cases. Left ventricular function, myocardial strain parameters and percentage of late gadolinium enhancement (%LGE) were evaluated.

Results: Global circumferential strain (GCS) and %LGE correlated moderately (r = 0.51, P < 0.001). HCM patients with VAs had lower left ventricular ejection fraction (LVEF), global radial strain (GRS), GCS, and global longitudinal strain (GLS), but increased %LGE compared with those without VAs (P < 0.01 for all). %LGE and GCS were indicators of VAs in HCM patients by multivariate logistic regression analysis. HCM patients with %LGE >5.35% (AUC 0.81, 95% CI 0.70–0.91, P < 0.001) or GCS >-14.73% (AUC 0.79, 95% CI 0.70–0.89, P < 0.001) on CMR more frequently had VAs. %LGE + GCS were able to better identify HCM patients with VAs (AUC 0.87, 95% CI 0.79–0.95, P < 0.001).

Conclusion: GCS and %LGE were independent risk indicators of VAs in HCM. GCS is expected to be a good potential predictor in identifying HCM patients with VAs, which may provide important values to improve risk stratification in HCM in clinical practice.

Predictive values of multiple non-invasive markers for myocardial fibrosis in hypertrophic cardiomyopathy patients with preserved ejection fraction

Myocardial fibrosis assessed by late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR) is associated with cardiovascular outcomes in hypertrophic cardiomyopathy (HCM) patients, but little is known about the utility of non-invasive markers for detecting LGE. This study aims to explore the association between cardiac-specific biomarkers, CMR myocardial strain, left ventricular (LV) hypertrophy and LGE in HCM patients with preserved ejection fraction (EF) and investigate the predictive values of these indexes for LGE. We recruited 33 healthy volunteers and 86 HCM patients with preserved EF to undergo contrast-enhanced CMR examinations. In total, 48 of 86 HCM patients had the presence of LGE. The LGE-positive patients had significant higher serum high-sensitivity cardiac troponin I (hs-cTnI) and N-terminal pro b-type natriuretic peptide (Nt-proBNP) levels and lower global longitudinal (GLS) and circumferential (GCS) strains than the LGE-negative group. The LGE% was independently associated with the Nt-proBNP levels, GCS, LV end-diastolic maximum wall thickness (MWT) and beta-blocker treatment. In the receiver operating characteristic curve analysis, the combined parameters of Nt-proBNP ≥ 108.00 pg/mL and MWT ≥ 17.30 mm had good diagnostic performance for LGE, with a specificity of 81.25% and sensitivity of 70.00%. These data indicate that serum Nt-proBNP is a potential biomarker associated with LGE% and, combined with MWT, were useful for identifying myocardial fibrosis in HCM patients with preserved EF. Additionally, LV GCS may be a more sensitive indicator for reflecting the presence of myocardial fibrosis than GLS.

Defining the Reference Range for Left Ventricular Strain in Healthy Patients by Cardiac MRI Measurement Techniques: Systematic Review and Meta-Analysis

BACKGROUND. Echocardiography is the primary noninvasive technique for left ventricular (LV) strain measurement. MRI has potential advantages, although reference ranges and thresholds to differentiate normal from abnormal left ventricular global longitudinal strain (LVGLS), left ventricular global circumferential strain (LVGCS), and left ventricular global radial strain (LVGRS) are not yet established. OBJECTIVE. The purpose of our study was to determine the mean and lower limit of normal (LLN) of MRI-derived LV strain measurements in healthy patients and explore factors potentially influencing these measurements. EVIDENCE ACQUISITION. PubMed, Embase, and Cochrane Library databases were searched for studies published through January 1, 2020, that reported MRI-derived LV strain measurements in at least 30 healthy individuals. Mean and LLN measurements of LV strain were pooled using random-effects models overall and for studies stratified by measurement method (feature tracking [FT] or tagging). Additional subgroup and meta-regression analyses were performed. EVIDENCE SYNTHESIS. Twenty-three studies with a total of 1782 healthy subjects were included. Pooled means and LLNs for all studies were -18.6% (95% CI, -19.5% to -17.6%) and -13.3% (-13.9% to 12.7%) for LVGLS, -21.0% (-22.4% to -19.6%) and -15.6% (-17.0% to -14.3%) for LVGCS, and 38.7% (30.5-46.9%) and 20.6% (15.1-26.1%) for LVGRS. Pooled means and LLNs for LVGLS by strain measurement method were -19.4% (95% CI, -20.6% to -18.1%) and -13.1% (-14.2% to -12.0%) for FT and -15.6% (-16.2% to -15.1%) and -13.1% (-14.1% to -12.2%) for tagging. A later year of study publication, increasing patient age, and increasing body mass index were associated with more negative mean LVGLS values. An increasing LV end-diastolic volume index was associated with less negative mean LVGLS values. No factor was associated with LLN of LVGLS. CONCLUSION. We determined the pooled means and LLNs, with associated 95% CIs, for LV strain by cardiac MRI to define thresholds for normal, abnormal, and borderline strain in healthy patients. The method of strain measurement by MRI affected the mean LVGLS. No factor affected the LLN of LVGLS. CLINICAL IMPACT. This meta-analysis lays a foundation for clinical adoption of MRI-derived LV strain measurements, with management implications in both healthy patients and patients with various disease states.

Prognostic value of multiple cardiac magnetic resonance imaging parameters in patients with idiopathic dilated cardiomyopathy

PURPOSE

Our study aimed to comprehensively explore efficient prognostic indicators in idiopathic dilated cardiomyopathy (IDCM) patients with reduced left ventricular ejection fraction (LVEF<40%).

BACKGROUND

Prognostic value of cardiac magnetic resonance(CMR) parameters for IDCM have been inconsistent.

METHODS

126 IDCM patients with reduced LVEF (<40%) were retrospectively enrolled. Cardiac function parameters, myocardial strain indices and myocardial fibrosis were evaluated. Laboratory data also were analyzed. The endpoint was a combination of major adverse cardiac events (MACEs), including cardiac death, heart transplantation, and rehospitalization. Prognostic value was evaluated by the Kaplan-Meier method and Cox regression.

RESULTS

During a median follow-up of 31 months, 44 patients experienced MACEs, including 9 deaths, 1 heart transplantation, and 34 rehospitalizations due to heart failure. Univariate and multivariate Cox analyses showed that cardiac function and myocardial strain indexes were not associated with the prognosis of IDCM (all p>0.05). NT-proBNP (HR 1.5, 95%CI: 1.053 to 2.137), Late‑gadolinium enhancement(LGE) mass (HR 1.022, 95%CI: 1.005 to 1.038), and LGE mass/left ventricle mass were significant predictors (HR 1.027, 95%CI: 1.007 to 1.046) for MACEs, all p < 0.05. Besides, poorest prognosis was observed in IDCM patients with positive LGE combined with NT-proBNP (log-rank = 27.261, p ≤ 0.001).

CONCLUSION

NT-proBNP and extent of LGE were reliable predictors in IDCM patients with reduced LVEF. Additionally, presence of LGE combined with NT-proBNP showed the strongest prognostic value in IDCM with reduced LVEF. Myocardial strain parameters seemed to have no prognostic value in IDCM patients with reduced LVEF.

Phenotyping of hypertensive heart disease and hypertrophic cardiomyopathy using personalized 3D modelling and cardiac cine MRI

Differential diagnosis of hypertensive heart disease (HHD) and hypertrophic cardiomyopathy (HCM) is clinically challenging but important for treatment management. This study aims to phenotype HHD and HCM in 3D + time domain by using a multiparametric motion-corrected personalized modeling algorithm and cardiac magnetic resonance (CMR). 44 CMR data, including 12 healthy, 16 HHD and 16 HCM cases, were examined. Multiple CMR phenotype data consisting of geometric and dynamic variables were extracted globally and regionally from the models over a full cardiac cycle for comparison against healthy models and clinical reports. Statistical classifications were used to identify the distinctive characteristics and disease subtypes with overlapping functional data, providing insights into the challenges for differential diagnosis of both types of disease. While HCM is characterized by localized extreme hypertrophy of the LV, wall thickening/contraction/strain was found to be normal and in sync, though it was occasionally exaggerated at normotrophic/less severely hypertrophic regions during systole to preserve the overall ejection fraction (EF) and systolic functionality. Additionally, we observed that hypertrophy in HHD could also be localized, although at less extreme conditions (i.e. more concentric). While fibrosis occurs mostly in those HCM cases with aortic obstruction, only minority of HHD patients were found affected by fibrosis. We demonstrate that subgroups of HHD (i.e. preserved and reduced EF: HHDpEF & HHDrEF) have different 3D + time CMR characteristics. While HHDpEF has cardiac functions in normal range, dilation and heart failure are indicated in HHDrEF as reflected by low LV wall thickening/contraction/strain and synchrony, as well as much reduced EF.

Are all left bundle branch blocks the same? Myocardial mechanical implications by cardiovascular magnetic resonance

AIMS

Left bundle branch block (LBBB) is usually associated with structural myocardial diseases progressively leading to left ventricular (LV) dysfunction. We sought to determine the mechanical implications of LBBB (as defined based on Strauss' criteria) by Cardiovascular Magnetic Resonance (CMR).

METHOD AND RESULTS

We included consecutive patients referred to CMR to assess the structural cause of LBBB. CMR scans consisted of cine, stress perfusion, and late gadolinium enhancement (LGE) sequences. Myocardial deformation was assessed by tissue tracking analysis; LGE was quantified using the full width at half maximum method. We included 86 patients [63% male, 70 years (60-72)] with mean QRS duration 150 ± 13 msec. A structural disease was identified on CMR in 53% of patients (ischemic heart disease, IHD, 31%; non-ischemic heart disease, NIHD, 22%), while LBBB-related septal dyssynchrony (SD) was the only abnormality in 47%. LGE was found in 42% of patients. LVEF and myocardial deformation were impaired. Despite similar ECG characteristics, myocardial strain differed significantly between IHD, NIHD and SD patients, and patients with SD showed less impaired myocardial deformation. Indexed LV end-systolic volume and LGE extent were independently associated with impaired strain.

CONCLUSIONS

Patients with LBBB show different structural and mechanical properties, and LGE extent has an unfavourable effect on myocardial mechanics.

Left Ventricular Outflow Tract Obstruction in Hypertrophic Cardiomyopathy: The Utility of Myocardial Strain Based on Cardiac MR Tissue Tracking

BACKGROUND

Myocardial strain for assessment of hypertrophic cardiomyopathy (HCM) is of importance and may play a role in identifying obstruction in HCM patients.

PURPOSE

To evaluate the utility of myocardial strain for detecting left ventricular (LV) outflow tract (LVOT) obstruction in HCM patients based on magnetic resonance tissue tracking.

STUDY TYPE

Retrospective.

POPULATION

In all, 44 adult HCM patients with LVOT obstruction and 108 adult HCM patients without LVOT obstruction.

FIELD STRENGTH/SEQUENCE

1.5 T; Steady-state free-precession cine sequence; phase-sensitive inversion-prepared segmented gradient echo sequence for late gadolinium enhancement (LGE) imaging.

ASSESSMENT

Strain parameters including the local and global levels of LV myocardium and the subtraction (Sub) of myocardial strain variables between interventricular septal segments (IVSS) and noninterventricular septal segments (NIVSS) were measured for differentiating HCM with obstruction from nonobstruction. Average and maximum LV wall thickness (Average and Maximum LVWT) were also analyzed.

STATISTICAL TESTS

Univariate and multivariate logistic regression analysis, area under the receiver operating characteristic (ROC) curve (AUC), intraclass correlation coefficient.

RESULTS

In multivariate analysis, Average LVWT, Maximum LVWT, and the subtraction of radial peak strain (Sub Radial PS) between NIVSS and IVSS were independently associated with LVOT obstruction. The AUCs were 0.731, 0.840, and 0.890 for Average LVWT, Maximum LVWT, and Sub Radial PS, respectively. Sub Radial PS (cutoff value: 8.1%) demonstrated the highest sensitivity of 75.0% and a high specificity of 87.9% for identifying LVOT; Maximum LVWT (cutoff value: 22.9 mm) showed good sensitivity (72.7%) and specificity (83.3%). Combining Maximum LVWT >22.9 mm and Sub Radial PS > 8.1% achieved a better diagnostic performance (specificity 95.4%, sensitivity 70.5%).

DATA CONCLUSION

Combining Maximum LVWT >22.9 mm and Sub Radial PS >8.1% holds promise for objectively evaluating LVOT obstruction in HCM patients with very high specificity and acceptable sensitivity.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY STAGE: 2.

Assessment of left ventricular deformation in patients with type 2 diabetes mellitus by cardiac magnetic resonance tissue tracking

To quantify the global and regional left ventricular (LV) myocardial strain in type 2 diabetes mellitus (T2DM) patients using cardiac magnetic resonance (CMR) tissue-tracking techniques and to determine the ability of myocardial strain parameters to assessment the LV deformation. Our study included 98 adult T2DM patients (preserved LV ejection fraction [LVEF], 72; reduced LVEF, 26) and 35 healthy controls. Conventional LV function, volume-time curve parameters and LV remodeling index were measured using CMR. Global and regional LV myocardial strain parameters were measured using CMR tissue tracking and compared between the different sub-groups. Receiver operating characteristic analysis was used to assess the diagnostic accuracy. Regression analyses were conducted to determine the relationship between strain parameters and the LV remodeling index. The results show that global radial peak strain (PS) and circumferential PS were not significantly different between the preserved-LVEF group and control group (P > 0.05). However, longitudinal PS was significantly lower in the preserved-LVEF group than in the control group (P = 0.005). Multivariate linear and logistic regression analyses showed that global longitudinal PS was independently associated (β = 0.385, P < 0.001) with the LV remodeling index. In conclusion, early quantitative evaluation of cardiac deformation can be successfully performed using CMR tissue tracking in T2DM patients. In addition, global longitudinal PS can complement LVEF in the assessment of cardiac function.

Evaluation of left ventricular strain in patients with arrhythmia based on the 3T MR temporal parallel acquisition technique

Most of the current studies on myocardial strain are mainly applied in patients with sinus rhythm because the image quality of arrhythmias obtained with conventional scanning sequences does not meet diagnostic needs. Here, we intend to assess left ventricular (LV) global myocardial strain in patients with arrhythmias with 3 Tesla magnetic resonance (MR) and a new cine sequence. Thirty-three patients with arrhythmia and forty-eight subjects with sinus rhythm were enrolled in the study. LV myocardial thickness, cardiac function, myocardial strain and the apparent contrast-to-noise ratio (CNR) were all measured and compared using images generated by the real-time temporal parallel acquisition technique (TPAT) and the conventional cine sequence. In the arrhythmia group, the image quality of real-time TPAT was significantly better than that of the conventional cine sequence. In the arrhythmia group, the LV global peak radial strain and global peak circumferential strain values of real-time TPAT were significantly different from those of the conventional technique (radial strain, conventional: 20.27 ± 15.39 vs. TPAT: 24.14 ± 15.85, p = 0.007; circumferential strain, conventional:-12.06 ± 6.60 vs. TPAT: -13.71 ± 6.31, p = 0.015). There was no significant difference in global peak longitudinal strain between real-time TPAT and the conventional technique (-10.94 ± 4.66 vs. -10.70 ± 5.96, p = 0.771). There was no significant difference in the cardiac function parameters between the two techniques (p > 0.05), but there was a significant difference in 12 segments of the LV wall thickness between the two sequences (p < 0.05). In the sinus rhythm group, image quality using real-time TPAT was comparable to that using the conventional technique, and there was no significant difference in any of the indices (p > 0.05). Real-time TPAT is an effective method for detection of left ventricular myocardial deformation in patients with arrhythmia.

Assessing right ventricular deformation in hypertrophic cardiomyopathy patients with preserved right ventricular ejection fraction: a 3.0-T cardiovascular magnetic resonance study

To assess the global and regional right ventricular (RV) deformation in hypertrophic cardiomyopathy (HCM) patients with preserved right ventricular ejection fraction (RVEF) using 3.0-T cardiovascular magnetic resonance tissue tracking (CMR-TT). Eighty-two HCM patients and 32 age- and sex-matched healthy controls were enrolled. HCM patients were divided into groups depending on the presence or absence of right ventricular hypertrophy (RVH), RV late gadolinium enhancement (RV-LGE), and left ventricular outflow tract obstruction (LVOTO), respectively. The RV global and apical longitudinal peak strain (LPS) in HCM patients with RVH were significantly lower than that in HCM patients without RVH and controls (P < 0.05). The global, apical and mid-ventricular LPS in HCM patients with RV-LGE were significantly lower than that in HCM patients without RV-LGE and controls (P < 0.05). Lower LPS was demonstrated in HCM patients without RV-LGE compared with controls in apical and mid-ventricular levels (P < 0.05). No significant difference was found regarding global and regional LPS in HCM patients with LVOTO compared without LVOTO (all P > 0.05). CMR-TT was able to detect subclinical RV myocardial deformation prior to RVEF impairment, which was more severe in the presence of RVH and RV-LGE.

Left Ventricular Deformation in Patients with Connective Tissue Disease: Evaluated by 3.0T Cardiac Magnetic Resonance Tissue Tracking

The aim of this study was to assess left ventricular (LV) myocardial strain in patients with connective tissue disease (CTD) and compare LV deformation between subgroups of idiopathic inflammatory myopathy (IIM) and non-IIM. Ninety-eight patients with CTD, comprising 56 with IIM and 42 with non-IIM, and 30 healthy subjects were enrolled and underwent 3.0T cardiac magnetic resonance imaging (MRI) scanning. The LV function and strain parameters were measured and assessed. Our result revealed that CTD patients had preserved LV ejection fraction (60.85%) and had significantly decreased global and regional peak strain (PS) in radial, circumferential, and longitudinal directions (all p < 0.05). IIM patients showed significantly reduced global longitudinal PS (GLPS) and longitudinal PS at apical slice, whereas all strain parameters decreased in non-IIM patients. Except GLPS and longitudinal PS at apical slice, all strain parameters in non-IIM patients were lower than those in IIM patients. By Pearson’s correlation analysis, the LV global radial and circumferential PS were correlated to N-terminal pro-brain natriuretic peptide level and LV ejection fraction in both IIM and non-IIM patients. This study indicated that CTD patients showed abnormal LV deformation despite with preserved LVEF. The impairment of LV deformation differed between IIM and non-IIM patients.

Regional Strain by Cardiac Magnetic Resonance Imaging Improves Detection of Right Ventricular Scar Compared With Late Gadolinium Enhancement on a Multimodality Scar Evaluation in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy is an inherited cardiomyopathy characterized by fibrofatty replacement of right ventricular myocardium resulting in reentrant ventricular tachycardia (VT). Cardiac magnetic resonance imaging (CMR) can noninvasively measure regional abnormalities using tissue-tracking strain as well as late gadolinium enhancement (LGE). In this study, we examine arrhythmogenic substrate using regional CMR strain, LGE, and electroanatomic mapping (EAM) in arrhythmogenic right ventricular cardiomyopathy patients presenting for VT ablation.

METHODS AND RESULTS

Twenty-one patients underwent right ventricular endocardial EAM, whereas 17 underwent epicardial EAM, to detect dense scar (<0.5 mV) as well as CMR study within 12 months. Quantitative regional strain analysis was performed in all 21 patients, although the presence of LGE was visually examined in 17 patients. Strain was lower in segments with dense scar on endocardial and epicardial EAM (-9.7±4.1 versus -7.3±4.0, and -9.8±2.8 versus -7.6±3.8; P<0.05), in segments with LGE scar (-9.9±4.4 versus -6.0±3.6; P=0.001), and at VT culprit sites (-7.4±3.7 versus -10.1±4.1; P<0.001), compared with the rest of right ventricular. On patient-clustered analysis, a unit increase in strain was associated with 21% and 18% decreased odds of scar on endocardial and epicardial EAM, respectively, 17% decreased odds of colocalizing VT culprit site, and 43% decreased odds of scar on LGE-CMR ( P<0.05 for all). LGE and EAM demonstrated poor agreement with κ=0.18 (endocardial, n=17) and κ=0.06 (epicardial, n=13). Only 8 (15%) VT termination sites exhibited LGE.

CONCLUSIONS

Regional myocardial strain on cine CMR improves detection of arrhythmogenic VT substrate compared with LGE. This may enhance diagnostic accuracy of CMR in arrhythmogenic right ventricular cardiomyopathy without the need for invasive procedures and facilitate the planning of VT ablation procedures.

Early Left Ventricular Involvement Detected by Cardiovascular Magnetic Resonance Feature Tracking in Arrhythmogenic Right Ventricular Cardiomyopathy: The Effects of Left Ventricular Late Gadolinium Enhancement and Right Ventricular Dysfunction

Background

Left ventricular (LV) involvement is common in arrhythmogenic right ventricular cardiomyopathy (ARVC). We aim to evaluate LV involvement in ARVC patients by cardiovascular magnetic resonance feature tracking.

Methods and Results

Sixty‐eight patients with ARVC and 30 controls were prospectively enrolled. ARVC patients were divided into 2 subgroups: the preserved LV ejection fraction (LVEF) group (LVEF ≥55%, n=27) and the reduced LVEF group (LVEF <55%, n=41). Cardiovascular magnetic resonance with late gadolinium enhancement (LGE) and cardiovascular magnetic resonance feature tracking were performed in all subjects. LV global and regional (basal, mid, apical) peak strain (PS) in radial, circumferential and longitudinal directions were assessed, respectively. Right ventricular global PS in three directions were also analyzed. Compared with the controls, LV global and regional PS were all significantly impaired in the reduced LVEF group (all P<0.05). However, only LV global longitudinal PS as well as mid and apical longitudinal PS were impaired in the preserved LVEF group (all P<0.05), and all these parameters were significantly associated with right ventricular global radial PS (r=−0.47, −0.47, and −0.49, respectively, all P<0.001). The reduced LVEF group showed significantly higher prevalence of LGE (95.10% versus 63.00%, P=0.002) than the preserved LVEF group. Moreover, LV radial PS was significantly reduced in LV segments with LGE (33.15±20.42%, n=46) than those without LGE (41.25±15.98%, n=386) in the preserved LVEF group (P=0.016).

Conclusions

In patients with ARVC, cardiovascular magnetic resonance feature tracking could detect early LV dysfunction, which was associated with LV myocardial LGE and right ventricular dysfunction.

Correlation between left ventricular myocardial strain and left ventricular geometry in healthy adults: a cardiovascular magnetic resonance-feature tracking study

This study was aimed to investigate the correlation between left ventricular (LV) myocardial strain and LV geometry in healthy adults using cardiovascular magnetic resonance-feature tracking (CMR-FT). 124 gender-matched healthy adults who underwent healthy checkup using CMR cine imaging were retrospectively analyzed. Peak global radial, circumferential, longitudinal strain (GRS, GCS and GLS) for left ventricle were measured. LV geometry was assessed by the ratio of LV mass (LVM) and end-diastolic volume (EDV). GRS, GCS and GLS were 34.18 ± 6.71%, - 22.17 ± 2.28%, - 14.76 ± 2.39% for men, and 33.40 ± 6.95%, - 22.49 ± 2.27%, - 15.72 ± 2.36% for women. Multiple linear regression showed that LVM/EDV was associated with decreased GLS (β = - 0.297, p = 0.005), but was not significantly associated with GRS and GCS (both p > 0.05). There was an increase in the magnitude of GRS, GCS and GLS with advancing age (β = 0.254, β = 0.466 and β = 0.313, all p < 0.05). Greater BMI was associated with decreased GRS, GCS and GLS (β = - 0.232, β = - 0. 249 and β = - 0.279, all p < 0.05). In conclusion, compared with GRS and GCS, GLS is more sensitive to assess LV concentric remodeling in healthy adults. GRS, GCS and GLS are all independently positively associated with age and negatively associated with BMI. Sex-based LV strain reference values for healthy Chinese adults are established.

Cardiac magnetic resonance feature tracking for quantifying right ventricular deformation in type 2 diabetes mellitus patients

To determine the feasibility of deformation analysis in the right ventricle (RV) using cardiovascular magnetic resonance myocardial feature tracking (CMR-FT) in type 2 diabetes mellitus (T2DM) patients. We enrolled 104 T2DM patients, including 14 with impaired right ventricular ejection fraction (RVEF) and 90 with preserved RVEF, and 26 healthy controls in this prospective study. CMR was used to determine RV feature-tracking parameters. RV strain parameters were compared among the controls, patients with preserved and reduced RVEF. Binary logistic regression was used to predict RV dysfunction. Receiver operating characteristic analysis was used to assess the diagnostic accuracy. The agreement was tested by Bland-Altman analysis. Compared with controls, longitudinal and circumferential global peak strain (PS) and PS at mid-ventricular, apical slices were significantly decreased in T2DM patients with or without reduced RVEF (p < 0.05). Within the T2DM patients, the global longitudinal PS (GLPS) and the longitudinal PS at mid-ventricular segments were significantly reduced in the reduced RVEF group than in preserved RVEF groups (p < 0.05). GLPS was an independent predictor of RV dysfunction (odds ratio: 1.246, 95% CI: 1.037-1.496; p = 0.019). The GLPS demonstrated greater diagnostic accuracy (area under curve: 0.716) to predict RV dysfunction. On Bland-Altman analysis, global circumferential PS and GLPS had the best intra- and inter-observer agreement, respectively. In T2DM patients, CMR-FT could quantify RV deformation and identify subclinical RV dysfunction in those with normal RVEF. Further, RV strain parameters are potential predictors for RV dysfunction in T2DM patients.

Evaluation of hemodynamics in patients with hypertrophic cardiomyopathy by vector flow mapping: Comparison with healthy subjects

The present study investigated the role of energy loss assessed by vector flow mapping (VFM) in patients with hypertrophic cardiomyopathy (HCM). VFM analysis was performed in 42 patients with HCM and in 40 control subjects, which were matched for age, sex and left ventricular (LV) ejection fraction. The intra-LV and left atrial blood flow were obtained from the apical 3-chamber view, and the energy loss (EL) during the systolic and diastolic phases was calculated. The measurements were averaged over three cardiac cycles and indexed to body surface area. Compared with the controls, the left ventricular energy loss (LVEL)-total value was significantly decreased in patients with HCM during the diastolic phase (P1, P2 and P3; all P<0.05). A tendency for increased systolic LVEL-total values was observed in the patients with HCM compared with the controls (P>0.05). LVEL-base values were decreased in the patients with HCM during P1 and P2 (slow filling time). Compared with the controls, patients with HCM had lower LVEL-mid values during the diastolic phases (P0, P1, P2 and P3; all P<0.05). However, the LVEL-mid value of patients with HCM was higher compared with that of the controls during systolic P5 (P<0.05). LVEL-apex was decreased in patients with HCM during P0, P2 and P3. Compared with the controls, the left atrial energy loss (LAEL) of all three phases in patients with HCM were lower (each P<0.01). The diastolic LVEL values were significantly lower in patients with HCM compared with the controls; however, the systolic LVEL levels tended to be higher in HCM. The LAEL of the reservoir phase, conduit phase and atrial systolic phase were decreased in HCM compared with controls. The present study demonstrated that measurement of EL by VFM is a sensitive method of determining subclinical LV dysfunction in patients with HCM. The value of EL has been considered to be a quantitative parameter for the estimation of the efficiency of intraventricular blood flow.

High T2-weighted signal intensity is associated with myocardial deformation in hypertrophic cardiomyopathy

The association between global and segmental myocardial strain impairment and fibrosis extent in hypertrophic cardiomyopathy (HCM) is widely verified. The aim of this study was to investigate the contribution of high T2-weighted signal intensity (HighT2) to myocardial deformation in HCM. We prospectively recruited 57 patients with HCM examined by a 3.0 Tesla magnetic resonance scanner with cine, T2-weighted imaging with fat saturation and phase-sensitive inversion recovery. Global and segmental radial, circumferential and longitudinal strains were included for analysis. The extent of HighT2 was negatively correlated with global radial strain (ρ = −0.275, p = 0.038) and positively correlated with global circumferential strain (ρ = 0.308, p = 0.02) and global longitudinal strain (ρ = 0.422, p = 0.001). Radial, circumferential and longitudinal strains were all significantly associated with segment thickness. Regarding circumferential strain, segments at the mid-ventricular level with LGE and HighT2 showed more impairment than segments with only LGE. For longitudinal strain, the influence of HighT2 appeared only at the mid-ventricular level. The HighT2 extent in HCM was observed to contribute to global and segmental strain parameters. At the segmental level, HighT2 indeed affects left ventricular deformation, and follow-up studies are still warranted.