Association between left atrial myopathy and sarcomere mutation in patients with hypertrophic cardiomyopathy: insights into left atrial strain by MRI feature tracking.

OBJECTIVES:Left atrial (LA) myopathy, characterized by LA enlargement and mechanical dysfunction, is associated with worse prognosis in hypertrophic cardiomyopathy (HCM) while the impact of sarcomere mutation on LA myopathy remains unclear. We aimed to assess the association between LA myopathy and sarcomere mutation and to explore the incremental utility of LA strain in mutation prediction.METHODS:A total of 105 consecutive HCM patients (mean age 47.8 ± 11.9 years, 71% male) who underwent HCM-related gene screening and cardiac MRI were retrospectively enrolled. LA volume, ejection fraction and strain indices in reservoir, conduit, and booster-pump phases were investigated respectively.RESULTS:Fifty mutation-positive patients showed higher LA maximal volume index (59.4 ± 28.2 vs 43.8 ± 18.1 mL/m2, p = 0.001), lower reservoir (21.3 ± 7.9 vs 26.2 ± 6.6%, p < 0.001), and booster-pump strain (12.1 ± 5.4 vs 17.1 ± 5.0%, p < 0.001) but similar conduit strain (9.2 ± 4.5 vs 9.1 ± 4.5%, p = 0.909) compared with mutation-negative patients. In multivariate logistic regression, LA booster-pump strain was associated with sarcomere mutation (odds ratio = 0.86, 95% confidence interval: 0.77-0.96, p = 0.010) independent of maximal wall thickness, late gadolinium enhancement, and LA volume. Furthermore, LA booster-pump strain showed incremental value for mutation prediction added to Mayo II score (AUC 0.798 vs 0.709, p = 0.024).CONCLUSIONS:In HCM, mutation-positive patients suffered worse LA enlargement and worse reservoir and booster-pump functions. LA booster-pump strain was a strong factor for sarcomere mutation prediction added to Mayo II score.CLINICAL RELEVANCE STATEMENT:The independent association between sarcomere mutation and left atrial mechanical dysfunction provide new insights into the pathogenesis of atrial myopathy and is helpful to understand the adverse prognosis regarding atrial fibrillation and stroke in mutation-positive patients.KEY POINTS:• In patients with hypertrophic cardiomyopathy, left atrial (LA) reservoir and booster-pump function, but not conduit function, were significantly impaired in mutation-positive patients compared with mutation-negative patients. • LA booster-pump strain measured by MRI-derived feature tracking is feasible to predict sarcomere mutation with high incremental value added to Mayo II score.

Incremental Diagnostic Value of Right Ventricular Strain Analysis in Arrhythmogenic Right Ventricular Cardiomyopathy.

BACKGROUND:Strain analysis is a sensitive method for the assessment of ventricular structural or functional alterations. The authors aimed to determine whether right ventricular (RV) strain parameters can discriminate patients with revised Task Force Criteria-diagnosed arrhythmogenic RV cardiomyopathy (ARVC) incremental to the existing cardiovascular magnetic resonance (CMR) criteria, thus improving the diagnostic yield of CMR in ARVC.METHODS AND RESULTS:A total of 74 patients with revised Task Force Criteria-diagnosed ARVC (37 borderline and 37 definite) and 37 controls were retrospectively enrolled for analysis. Using CMR feature tracking, RV global longitudinal (GLS), circumferential, and radial strain of all participants were evaluated. Compared with controls, the study patients demonstrated significantly impaired global biventricular strain in all 3 directions (all P<0.001). Receiver operating characteristic curve analysis indicated that RV GLS was the strongest discriminator among all RV strain parameters for the identification of patients with ARVC (area under the curve, 0.92). Using the Youden index, the authors determined RV GLS ≥-19.95% as the diagnostic criterion of ARVC. In patients diagnosed with borderline ARVC according to revised Task Force Criteria but with no or only minor CMR criteria, there were >50% presenting with impaired RV GLS. When both conventional criteria and RV GLS were considered together, this new diagnostic method demonstrated an overall diagnostic accuracy of 90%. The likelihood ratio test showed a significant incremental diagnostic value of RV GLS (P=0.02) over the existing CMR major criteria.CONCLUSIONS:The current study showed an improved diagnostic accuracy when both RV GLS and the existing CMR criteria were considered together, especially for patients with borderline diagnosis, suggesting the incremental value of strain analysis to the initial assessment of ARVC.

Radial and Circumferential CMR-Based RV Strain Predicts Low R Wave Amplitude after ICD Implantation in Patients with Arrhythmogenic Cardiomyopathy.

Inadequate R wave amplitude (RWA) after implantable cardiac defibrillator (ICD) implantation in patients with arrhythmogenic cardiomyopathy (ACM) was suspected to relate to right ventricle impairment. However, little data-based evidence was provided to quantify the association. We retrospectively enrolled ACM patients receiving CMR examinations before transvenous ICD implantation from Fuwai Hospital. The RWA was obtained within 24 h and at 2-6-month follow-up after the operation. Structural, functional, as well as tissue characterization of the left ventricle (LV) and right ventricle (RV), were analyzed in relation to RWA. Among the 87 ACM patients (median RWA: 8.0 mV), 19 (21.8%) patients were found with low initial RWA (<5 mV) despite attempts in multiple positions. RV end diastolic diameter (RVEDD), (r = -0.44), RV ejection fraction (RVEF, r = 0.43), RV end diastolic volume index (RVEDVi, r = -0.49), RV end systolic volume index (RVESVi, r = -0.53), RV global circumferential (RVGCS, r = -0.64), and radial strain (RVGRS, r = 0.61, all p < 0.001) rather than LV metrics correlated strongly with initial RWA. RVGCS, RVESVi, and RVGRS were decent predictors of low RWA (areas under the curve AUC: 0.814, 0.769, 0.757, respectively) early after implantation and during 2-6-month follow-up. To summarize, low RWA of ICD lead in ACM patients was associated with RV abnormalities. The RVGCS, RVGRS, and RVESVi can be valuable predictors for identifying low RWA prior to ICD implantation.

Reverse remodeling of left atrium assessed by cardiovascular magnetic resonance feature tracking in hypertrophic obstructive cardiomyopathy after septal myectomy.

BACKGROUND:Assessing the structure and function of left atrium (LA) is crucial in hypertrophic obstructive cardiomyopathy (HOCM) because LA remodeling correlates with atrial fibrillation. However, few studies have investigated the potential effect of myomectomy on LA phasic remodeling in HOCM after myectomy using cardiovascular magnetic resonance (CMR) feature tracking (FT). This study aims to evaluate the LA structural and functional remodeling with HOCM after myectomy by CMR-FT and to further investigate the determinants of LA reverse remodeling.METHODS:In this single-center study, we retrospectively studied 88 patients with HOCM who received CMR before and after myectomy between January 2011 and June 2021. Preoperative and postoperative LA parameters derived from CMR-FT were compared, including LA reservoir function (total ejection fraction [EF], total strain [εs], peak positive strain rate [SRs]), conduit function (passive EF, passive strain [εe], peak early negative strain rate [SRe]) and booster function (booster EF, active strain [εa], late peak negative strain rate [SRa]). Eighty-six healthy participants were collected for comparison. Univariate and multivariate linear regression identified variables associated with the rate of change of εa.RESULTS:Compared with preoperative parameters, LA reservoir function (total EF, εs, SRs), booster function (booster EF, εa, SRa), and SRe were significantly improved after myectomy (all P < 0.05), while no significant differences were observed in passive EF and εe. Postoperative patients with HOCM still had larger LA and worse LA function than healthy controls (all P < 0.05). After analyzing the rates of change in LA parameters, LA boost function, especially εa, showed the most dramatic improvement beyond the improvements in reservoir function, conduit function, and volume. In multivariable regression analysis, minimum LA volume index (adjusted β = - 0.39, P < 0.001) and Δleft ventricular outflow tract (LVOT) pressure gradient (adjusted β = - 0.29, P = 0.003) were significantly related to the rate of change of εa.CONCLUSIONS:Patients with HOCM after septal myectomy showed LA reverse remodeling with a reduction in LA size and restoration in LA reservoir and booster function but unchanged LA conduit function. Among volumetric and functional changes, booster function had the greatest improvement postoperatively. Besides, preoperative LAVmin index and ΔLVOT might be potential factors associated with the degree of improvement in εa.

Cardiac magnetic resonance-derived myocardial scar is associated with echocardiographic response and clinical prognosis of left bundle branch area pacing for cardiac resynchronization therapy.

AIMS:Left bundle branch area pacing (LBBAP) is a novel approach for cardiac resynchronization therapy (CRT), but the impact of myocardial substrate on its effect is poorly understood. This study aims to assess the association of cardiac magnetic resonance (CMR)-derived scar burden and the response of CRT via LBBAP.METHODS AND RESULTS:Consecutive patients with CRT indications who underwent CMR examination and successful LBBAP-CRT were retrospectively analysed. Cardiac magnetic resonance late gadolinium enhancement was used for scar assessment. Echocardiographic reverse remodelling and composite outcomes (defined as all-cause death or heart failure hospitalization) were evaluated. The echocardiographic response was defined as a ≥15% reduction of left ventricular end-systolic volume. Among the 54 patients included, LBBAP-CRT resulted in a 74.1% response rate. The non-responders had higher global, septal, and lateral scar burden (all P < 0.001). Global, septal, and lateral scar percentage all predicted echocardiographic response [area under the curve (AUC): 0.857, 0.864, and 0.822; positive likelihood ratio (+LR): 9.859, 5.594, and 3.059; and negative likelihood ratio (-LR): 0.323, 0.233, and 0.175 respectively], which was superior to QRS morphology criteria (Strauss left bundle branch abnormality: AUC: 0.696, +LR 2.101, and -LR 0.389). After a median follow-up time of 20.3 (11.5-38.7) months, higher global, lateral and septal scar burdens were all predictive of the composite outcome (hazard ratios: 4.996, 7.019, and 4.741, respectively; P's < 0.05).CONCLUSION:Lower scar burden was associated with higher response rate of LBBAP-CRT. The pre-procedure CMR scar evaluation provides further useful information to identify potential responders and clinical outcomes.

Assessment of late gadolinium enhancement in hypertrophic cardiomyopathy improves risk stratification based on current guidelines.

BACKGROUND AND AIMS:Identifying patients with hypertrophic cardiomyopathy (HCM) who are candidates for implantable cardioverter defibrillator (ICD) implantation in primary prevention for sudden cardiac death (SCD) is crucial. The aim of this study was to externally validate the 2022 European Society of Cardiology (ESC) model and other guideline-based ICD class of recommendation (ICD-COR) models and explore the utility of late gadolinium enhancement (LGE) in further risk stratification.METHODS:Seven hundred and seventy-four consecutive patients who underwent cardiac magnetic resonance imaging were retrospectively enrolled.RESULTS:Forty-six (5.9%) patients reached the SCD-related endpoint during 7.4 ± 2.5 years of follow-up. Patients suffering from SCD had higher ESC Risk-SCD score (4.3 ± 2.4% vs. 2.8 ± 2.1%, P < .001) and LGE extent (13.7 ± 9.4% vs. 4.9 ± 6.6%, P < .001). Compared with the 2014 ESC model, the 2022 ESC model showed increased area under the curve (.76 vs. .63), sensitivity (76.1% vs. 43.5%), positive predictive value (16.8% vs. 13.6%), and negative predictive value (98.1% vs. 95.9%). The C-statistics for SCD prediction of 2011 American College of Cardiology (ACC)/American Heart Association (AHA), 2014 ESC, 2020 AHA/ACC, and 2022 ESC models were .68, .64, .76 and .78, respectively. Furthermore, in patients without extensive LGE, LGE ≥5% was responsible for seven-fold SCD risk after multivariable adjustment. Whether in ICD-COR II or ICD-COR III, patients with LGE ≥5% and <15% showed significantly worse prognosis than those with LGE <5% (all P < .001).CONCLUSIONS:The 2022 ESC model performed better than the 2014 ESC model with especially improved sensitivity. LGE enabled further risk stratification based on current guidelines.

[Research status and progress of cardiovascular magnetic resonance molecular imaging].

Subendocardial Involvement as an Underrecognized LGE Subtype Related to Adverse Outcomes in Hypertrophic Cardiomyopathy.

BACKGROUND:Late gadolinium enhancement (LGE) has been established as an independent predictor for adverse outcomes in hypertrophic cardiomyopathy (HCM). However, the prevalence and clinical significance of some LGE subtypes have not been well demonstrated.OBJECTIVES:In this study, the authors sought to investigate the prognostic value of subendocardium-involved LGE pattern and location of right ventricle insertion points (RVIPs) with LGE in HCM patients.METHODS:In this single-center retrospective study, 497 consecutive HCM patients with LGE confirmed by cardiac magnetic resonance (CMR) were included. Subendocardium-involved LGE was defined as LGE involving subendocardium not corresponding to a coronary vascular distribution. Subjects with ischemic heart disease that would contribute to subendocardial LGE were excluded. Endpoints included a composite of heart failure-related events, arrhythmic events, and stroke.RESULTS:Of the 497 patients, subendocardium-involved LGE and RVIP LGE were observed in 184 (37.0%) and 414 (83.3%), respectively. Extensive LGE (≥15% of left ventricular mass) was detected in 135 patients. During a median follow-up of 57.9 months, 66 patients (13.3%) experienced composite endpoints. Patients with extensive LGE had a significantly higher annual incidence of adverse events (5.1% vs 1.9% per year; P < 0.001). However, spline analysis showed that the association between LGE extent and HRs for adverse outcomes tended to be nonlinear. The risk of composite endpoint increased with percentage increase in LGE extent in patients with extensive LGE, whereas a similar trend was not observed in patients with nonextensive LGE (<15%). In patients with extensive LGE, LGE extent significantly correlated with composite endpoints (HR: 1.05; P = 0.03) after adjusting for left ventricular ejection fraction <50%, atrial fibrillation, and nonsustained ventricular tachycardia, whereas in patients with nonextensive LGE, subendocardium-involved LGE rather than LGE extent was independently associated with adverse outcomes (HR: 2.12; P = 0.03). RVIP LGE was not significantly associated with poor outcomes.CONCLUSIONS:In HCM patients with nonextensive LGE, the presence of subendocardium-involved LGE rather than LGE extent is associated with unfavorable outcomes. Given that the prognostic value of extensive LGE has been broadly recognized, subendocardial involvement as an underrecognized LGE pattern shows the potential to improve risk stratification in HCM patients with nonextensive LGE.

Incremental prognostic value of left atrial and biventricular feature tracking in dilated cardiomyopathy: a long-term study.

BACKGROUND:Despite the use of cardiovascular magnetic resonance (CMR) feature tracking (FT) imaging to detect myocardial deformation, the optimal strain index in dilated cardiomyopathy (DCM) is unclear. This study aimed to determine whether atrial and biventricular strains can provide the greatest or joint incremental prognostic value in patients with DCM over a long follow-up period.METHODS:Four hundred-twelve DCM patients were included retrospectively. Comprehensive clinical evaluation and imaging investigations were obtained, including measurements of CMR-FT derived left atrial (LA) reservoir, conduit, booster strain (εs, εe, εa); left ventricular (LV) and right ventricular (RV) global longitudinal, radial, circumferential strain (GLS, GRS, GCS). All patients were followed up for major adverse cardiac events (MACE) including all-cause mortality, heart transplantation, and implantable cardioverter defibrillator discharge. The predictors of MACE were examined with univariable and multivariable Cox regression analysis. Subsequently, nested Cox regression models were built to evaluate the incremental prognostic value of strain parameters. The incremental predictive power of strain parameters was assessed by Omnibus tests, and the model performance and discrimination were evaluated by Harrell C-index and integrated discrimination improvement (IDI) analysis. Patient survival was illustrated by Kaplan-Meier curves and differences were evaluated by log-rank test.RESULTS:During a median follow-up of 5.0 years, MACE were identified in 149 (36%) patients. LAεe, LVGLS, and RVGLS were the most predictive strain parameters for MACE (AUC: 0.854, 0.733, 0.733, respectively). Cox regression models showed that the predictive value of LAεe was independent from and incremental to LVGLS, RVGLS, and baseline variables (HR 0.74, 95% CI 0.68-0.81, P < 0.001). In reclassification analysis, the addition of LAεe provided the best discrimination of the model (χ2 223.34, P < 0.001; C-index 0.833; IDI 0.090, P < 0.001) compared with LVGLS and RVGLS models. Moreover, LAεe with a cutoff of 5.3% further discriminated the survival probability in subgroups of patients with positive LGE or reduced LVEF (all log-rank P < 0.001).CONCLUSION:LAεe provided the best prognostic value over biventricular strains and added incremental value to conventional clinical predictors for patients with DCM.

[The value of cardiac MRI in the risk stratification in patients with hypertrophic cardiomyopathy].

Objective: To explore the value of cardiac magnetic resonance imaging (CMR) in the risk stratification of hypertrophic cardiomyopathy (HCM). Methods: HCM patients who underwent CMR examination in Fuwai Hospital between March 2012 and May 2013 were retrospectively enrolled. Baseline clinical and CMR data were collected and patient follow-up was performed using telephone contact and medical record. The primary composite endpoint was sudden cardiac death (SCD) or and equivalent event. The secondary composite endpoint was all-cause death and heart transplant. Patients were divided into SCD and non-SCD groups. Cox regression was used to explore risk factors of adverse events. Receiver operating characteristic (ROC) curve analysis was used to assess the performance and the optimal cut-off of late gadolinium enhancement percentage (LGE%) for the prediction of endpoints. Kaplan-Meier and log-rank tests were used to compare survival differences between groups. Results: A total of 442 patients were enrolled. Mean age was (48.5±12.4) years and 143(32.4%) were female. At (7.6±2.5) years of follow-up, 30 (6.8%) patients met the primary endpoint including 23 SCD and 7 SCD equivalent events, and 36 (8.1%) patients met the secondary endpoint including 33 all-cause death and 3 heart transplant. In multivariate Cox regression, syncope(HR=4.531, 95%CI 2.033-10.099, P<0.001), LGE% (HR=1.075, 95%CI 1.032-1.120, P=0.001) and left ventricular ejection fraction (LVEF) (HR=0.956, 95%CI 0.923-0.991, P=0.013) were independent risk factors for primary endpoint; Age (HR=1.032, 95%CI 1.001-1.064, P=0.046), atrial fibrillation (HR=2.977, 95%CI 1.446-6.131, P=0.003),LGE% (HR=1.075, 95%CI 1.035-1.116, P<0.001) and LVEF (HR=0.968, 95%CI 0.937-1.000, P=0.047) were independent risk factors for secondary endpoint. ROC curve showed the optimal LGE% cut-offs were 5.1% and 5.8% for the prediction of primary and secondary endpoint, respectively. Patients were further divided into LGE%=0, 0

Association between left atrial myopathy and sarcomere mutation in patients with hypertrophic cardiomyopathy: insights into left atrial strain by MRI feature tracking.

OBJECTIVES:Left atrial (LA) myopathy, characterized by LA enlargement and mechanical dysfunction, is associated with worse prognosis in hypertrophic cardiomyopathy (HCM) while the impact of sarcomere mutation on LA myopathy remains unclear. We aimed to assess the association between LA myopathy and sarcomere mutation and to explore the incremental utility of LA strain in mutation prediction.METHODS:A total of 105 consecutive HCM patients (mean age 47.8 ± 11.9 years, 71% male) who underwent HCM-related gene screening and cardiac MRI were retrospectively enrolled. LA volume, ejection fraction and strain indices in reservoir, conduit, and booster-pump phases were investigated respectively.RESULTS:Fifty mutation-positive patients showed higher LA maximal volume index (59.4 ± 28.2 vs 43.8 ± 18.1 mL/m2, p = 0.001), lower reservoir (21.3 ± 7.9 vs 26.2 ± 6.6%, p < 0.001), and booster-pump strain (12.1 ± 5.4 vs 17.1 ± 5.0%, p < 0.001) but similar conduit strain (9.2 ± 4.5 vs 9.1 ± 4.5%, p = 0.909) compared with mutation-negative patients. In multivariate logistic regression, LA booster-pump strain was associated with sarcomere mutation (odds ratio = 0.86, 95% confidence interval: 0.77-0.96, p = 0.010) independent of maximal wall thickness, late gadolinium enhancement, and LA volume. Furthermore, LA booster-pump strain showed incremental value for mutation prediction added to Mayo II score (AUC 0.798 vs 0.709, p = 0.024).CONCLUSIONS:In HCM, mutation-positive patients suffered worse LA enlargement and worse reservoir and booster-pump functions. LA booster-pump strain was a strong factor for sarcomere mutation prediction added to Mayo II score.CLINICAL RELEVANCE STATEMENT:The independent association between sarcomere mutation and left atrial mechanical dysfunction provide new insights into the pathogenesis of atrial myopathy and is helpful to understand the adverse prognosis regarding atrial fibrillation and stroke in mutation-positive patients.KEY POINTS:• In patients with hypertrophic cardiomyopathy, left atrial (LA) reservoir and booster-pump function, but not conduit function, were significantly impaired in mutation-positive patients compared with mutation-negative patients. • LA booster-pump strain measured by MRI-derived feature tracking is feasible to predict sarcomere mutation with high incremental value added to Mayo II score.

Incremental Diagnostic Value of Right Ventricular Strain Analysis in Arrhythmogenic Right Ventricular Cardiomyopathy.

BACKGROUND:Strain analysis is a sensitive method for the assessment of ventricular structural or functional alterations. The authors aimed to determine whether right ventricular (RV) strain parameters can discriminate patients with revised Task Force Criteria-diagnosed arrhythmogenic RV cardiomyopathy (ARVC) incremental to the existing cardiovascular magnetic resonance (CMR) criteria, thus improving the diagnostic yield of CMR in ARVC.METHODS AND RESULTS:A total of 74 patients with revised Task Force Criteria-diagnosed ARVC (37 borderline and 37 definite) and 37 controls were retrospectively enrolled for analysis. Using CMR feature tracking, RV global longitudinal (GLS), circumferential, and radial strain of all participants were evaluated. Compared with controls, the study patients demonstrated significantly impaired global biventricular strain in all 3 directions (all P<0.001). Receiver operating characteristic curve analysis indicated that RV GLS was the strongest discriminator among all RV strain parameters for the identification of patients with ARVC (area under the curve, 0.92). Using the Youden index, the authors determined RV GLS ≥-19.95% as the diagnostic criterion of ARVC. In patients diagnosed with borderline ARVC according to revised Task Force Criteria but with no or only minor CMR criteria, there were >50% presenting with impaired RV GLS. When both conventional criteria and RV GLS were considered together, this new diagnostic method demonstrated an overall diagnostic accuracy of 90%. The likelihood ratio test showed a significant incremental diagnostic value of RV GLS (P=0.02) over the existing CMR major criteria.CONCLUSIONS:The current study showed an improved diagnostic accuracy when both RV GLS and the existing CMR criteria were considered together, especially for patients with borderline diagnosis, suggesting the incremental value of strain analysis to the initial assessment of ARVC.

Radial and Circumferential CMR-Based RV Strain Predicts Low R Wave Amplitude after ICD Implantation in Patients with Arrhythmogenic Cardiomyopathy.

Inadequate R wave amplitude (RWA) after implantable cardiac defibrillator (ICD) implantation in patients with arrhythmogenic cardiomyopathy (ACM) was suspected to relate to right ventricle impairment. However, little data-based evidence was provided to quantify the association. We retrospectively enrolled ACM patients receiving CMR examinations before transvenous ICD implantation from Fuwai Hospital. The RWA was obtained within 24 h and at 2-6-month follow-up after the operation. Structural, functional, as well as tissue characterization of the left ventricle (LV) and right ventricle (RV), were analyzed in relation to RWA. Among the 87 ACM patients (median RWA: 8.0 mV), 19 (21.8%) patients were found with low initial RWA (<5 mV) despite attempts in multiple positions. RV end diastolic diameter (RVEDD), (r = -0.44), RV ejection fraction (RVEF, r = 0.43), RV end diastolic volume index (RVEDVi, r = -0.49), RV end systolic volume index (RVESVi, r = -0.53), RV global circumferential (RVGCS, r = -0.64), and radial strain (RVGRS, r = 0.61, all p < 0.001) rather than LV metrics correlated strongly with initial RWA. RVGCS, RVESVi, and RVGRS were decent predictors of low RWA (areas under the curve AUC: 0.814, 0.769, 0.757, respectively) early after implantation and during 2-6-month follow-up. To summarize, low RWA of ICD lead in ACM patients was associated with RV abnormalities. The RVGCS, RVGRS, and RVESVi can be valuable predictors for identifying low RWA prior to ICD implantation.

Reverse remodeling of left atrium assessed by cardiovascular magnetic resonance feature tracking in hypertrophic obstructive cardiomyopathy after septal myectomy.

BACKGROUND:Assessing the structure and function of left atrium (LA) is crucial in hypertrophic obstructive cardiomyopathy (HOCM) because LA remodeling correlates with atrial fibrillation. However, few studies have investigated the potential effect of myomectomy on LA phasic remodeling in HOCM after myectomy using cardiovascular magnetic resonance (CMR) feature tracking (FT). This study aims to evaluate the LA structural and functional remodeling with HOCM after myectomy by CMR-FT and to further investigate the determinants of LA reverse remodeling.METHODS:In this single-center study, we retrospectively studied 88 patients with HOCM who received CMR before and after myectomy between January 2011 and June 2021. Preoperative and postoperative LA parameters derived from CMR-FT were compared, including LA reservoir function (total ejection fraction [EF], total strain [εs], peak positive strain rate [SRs]), conduit function (passive EF, passive strain [εe], peak early negative strain rate [SRe]) and booster function (booster EF, active strain [εa], late peak negative strain rate [SRa]). Eighty-six healthy participants were collected for comparison. Univariate and multivariate linear regression identified variables associated with the rate of change of εa.RESULTS:Compared with preoperative parameters, LA reservoir function (total EF, εs, SRs), booster function (booster EF, εa, SRa), and SRe were significantly improved after myectomy (all P < 0.05), while no significant differences were observed in passive EF and εe. Postoperative patients with HOCM still had larger LA and worse LA function than healthy controls (all P < 0.05). After analyzing the rates of change in LA parameters, LA boost function, especially εa, showed the most dramatic improvement beyond the improvements in reservoir function, conduit function, and volume. In multivariable regression analysis, minimum LA volume index (adjusted β = - 0.39, P < 0.001) and Δleft ventricular outflow tract (LVOT) pressure gradient (adjusted β = - 0.29, P = 0.003) were significantly related to the rate of change of εa.CONCLUSIONS:Patients with HOCM after septal myectomy showed LA reverse remodeling with a reduction in LA size and restoration in LA reservoir and booster function but unchanged LA conduit function. Among volumetric and functional changes, booster function had the greatest improvement postoperatively. Besides, preoperative LAVmin index and ΔLVOT might be potential factors associated with the degree of improvement in εa.

Cardiac magnetic resonance-derived myocardial scar is associated with echocardiographic response and clinical prognosis of left bundle branch area pacing for cardiac resynchronization therapy.

AIMS:Left bundle branch area pacing (LBBAP) is a novel approach for cardiac resynchronization therapy (CRT), but the impact of myocardial substrate on its effect is poorly understood. This study aims to assess the association of cardiac magnetic resonance (CMR)-derived scar burden and the response of CRT via LBBAP.METHODS AND RESULTS:Consecutive patients with CRT indications who underwent CMR examination and successful LBBAP-CRT were retrospectively analysed. Cardiac magnetic resonance late gadolinium enhancement was used for scar assessment. Echocardiographic reverse remodelling and composite outcomes (defined as all-cause death or heart failure hospitalization) were evaluated. The echocardiographic response was defined as a ≥15% reduction of left ventricular end-systolic volume. Among the 54 patients included, LBBAP-CRT resulted in a 74.1% response rate. The non-responders had higher global, septal, and lateral scar burden (all P < 0.001). Global, septal, and lateral scar percentage all predicted echocardiographic response [area under the curve (AUC): 0.857, 0.864, and 0.822; positive likelihood ratio (+LR): 9.859, 5.594, and 3.059; and negative likelihood ratio (-LR): 0.323, 0.233, and 0.175 respectively], which was superior to QRS morphology criteria (Strauss left bundle branch abnormality: AUC: 0.696, +LR 2.101, and -LR 0.389). After a median follow-up time of 20.3 (11.5-38.7) months, higher global, lateral and septal scar burdens were all predictive of the composite outcome (hazard ratios: 4.996, 7.019, and 4.741, respectively; P's < 0.05).CONCLUSION:Lower scar burden was associated with higher response rate of LBBAP-CRT. The pre-procedure CMR scar evaluation provides further useful information to identify potential responders and clinical outcomes.

Assessment of late gadolinium enhancement in hypertrophic cardiomyopathy improves risk stratification based on current guidelines.

BACKGROUND AND AIMS:Identifying patients with hypertrophic cardiomyopathy (HCM) who are candidates for implantable cardioverter defibrillator (ICD) implantation in primary prevention for sudden cardiac death (SCD) is crucial. The aim of this study was to externally validate the 2022 European Society of Cardiology (ESC) model and other guideline-based ICD class of recommendation (ICD-COR) models and explore the utility of late gadolinium enhancement (LGE) in further risk stratification.METHODS:Seven hundred and seventy-four consecutive patients who underwent cardiac magnetic resonance imaging were retrospectively enrolled.RESULTS:Forty-six (5.9%) patients reached the SCD-related endpoint during 7.4 ± 2.5 years of follow-up. Patients suffering from SCD had higher ESC Risk-SCD score (4.3 ± 2.4% vs. 2.8 ± 2.1%, P < .001) and LGE extent (13.7 ± 9.4% vs. 4.9 ± 6.6%, P < .001). Compared with the 2014 ESC model, the 2022 ESC model showed increased area under the curve (.76 vs. .63), sensitivity (76.1% vs. 43.5%), positive predictive value (16.8% vs. 13.6%), and negative predictive value (98.1% vs. 95.9%). The C-statistics for SCD prediction of 2011 American College of Cardiology (ACC)/American Heart Association (AHA), 2014 ESC, 2020 AHA/ACC, and 2022 ESC models were .68, .64, .76 and .78, respectively. Furthermore, in patients without extensive LGE, LGE ≥5% was responsible for seven-fold SCD risk after multivariable adjustment. Whether in ICD-COR II or ICD-COR III, patients with LGE ≥5% and <15% showed significantly worse prognosis than those with LGE <5% (all P < .001).CONCLUSIONS:The 2022 ESC model performed better than the 2014 ESC model with especially improved sensitivity. LGE enabled further risk stratification based on current guidelines.

[Research status and progress of cardiovascular magnetic resonance molecular imaging].

Subendocardial Involvement as an Underrecognized LGE Subtype Related to Adverse Outcomes in Hypertrophic Cardiomyopathy.

BACKGROUND:Late gadolinium enhancement (LGE) has been established as an independent predictor for adverse outcomes in hypertrophic cardiomyopathy (HCM). However, the prevalence and clinical significance of some LGE subtypes have not been well demonstrated.OBJECTIVES:In this study, the authors sought to investigate the prognostic value of subendocardium-involved LGE pattern and location of right ventricle insertion points (RVIPs) with LGE in HCM patients.METHODS:In this single-center retrospective study, 497 consecutive HCM patients with LGE confirmed by cardiac magnetic resonance (CMR) were included. Subendocardium-involved LGE was defined as LGE involving subendocardium not corresponding to a coronary vascular distribution. Subjects with ischemic heart disease that would contribute to subendocardial LGE were excluded. Endpoints included a composite of heart failure-related events, arrhythmic events, and stroke.RESULTS:Of the 497 patients, subendocardium-involved LGE and RVIP LGE were observed in 184 (37.0%) and 414 (83.3%), respectively. Extensive LGE (≥15% of left ventricular mass) was detected in 135 patients. During a median follow-up of 57.9 months, 66 patients (13.3%) experienced composite endpoints. Patients with extensive LGE had a significantly higher annual incidence of adverse events (5.1% vs 1.9% per year; P < 0.001). However, spline analysis showed that the association between LGE extent and HRs for adverse outcomes tended to be nonlinear. The risk of composite endpoint increased with percentage increase in LGE extent in patients with extensive LGE, whereas a similar trend was not observed in patients with nonextensive LGE (<15%). In patients with extensive LGE, LGE extent significantly correlated with composite endpoints (HR: 1.05; P = 0.03) after adjusting for left ventricular ejection fraction <50%, atrial fibrillation, and nonsustained ventricular tachycardia, whereas in patients with nonextensive LGE, subendocardium-involved LGE rather than LGE extent was independently associated with adverse outcomes (HR: 2.12; P = 0.03). RVIP LGE was not significantly associated with poor outcomes.CONCLUSIONS:In HCM patients with nonextensive LGE, the presence of subendocardium-involved LGE rather than LGE extent is associated with unfavorable outcomes. Given that the prognostic value of extensive LGE has been broadly recognized, subendocardial involvement as an underrecognized LGE pattern shows the potential to improve risk stratification in HCM patients with nonextensive LGE.

Incremental prognostic value of left atrial and biventricular feature tracking in dilated cardiomyopathy: a long-term study.

BACKGROUND:Despite the use of cardiovascular magnetic resonance (CMR) feature tracking (FT) imaging to detect myocardial deformation, the optimal strain index in dilated cardiomyopathy (DCM) is unclear. This study aimed to determine whether atrial and biventricular strains can provide the greatest or joint incremental prognostic value in patients with DCM over a long follow-up period.METHODS:Four hundred-twelve DCM patients were included retrospectively. Comprehensive clinical evaluation and imaging investigations were obtained, including measurements of CMR-FT derived left atrial (LA) reservoir, conduit, booster strain (εs, εe, εa); left ventricular (LV) and right ventricular (RV) global longitudinal, radial, circumferential strain (GLS, GRS, GCS). All patients were followed up for major adverse cardiac events (MACE) including all-cause mortality, heart transplantation, and implantable cardioverter defibrillator discharge. The predictors of MACE were examined with univariable and multivariable Cox regression analysis. Subsequently, nested Cox regression models were built to evaluate the incremental prognostic value of strain parameters. The incremental predictive power of strain parameters was assessed by Omnibus tests, and the model performance and discrimination were evaluated by Harrell C-index and integrated discrimination improvement (IDI) analysis. Patient survival was illustrated by Kaplan-Meier curves and differences were evaluated by log-rank test.RESULTS:During a median follow-up of 5.0 years, MACE were identified in 149 (36%) patients. LAεe, LVGLS, and RVGLS were the most predictive strain parameters for MACE (AUC: 0.854, 0.733, 0.733, respectively). Cox regression models showed that the predictive value of LAεe was independent from and incremental to LVGLS, RVGLS, and baseline variables (HR 0.74, 95% CI 0.68-0.81, P < 0.001). In reclassification analysis, the addition of LAεe provided the best discrimination of the model (χ2 223.34, P < 0.001; C-index 0.833; IDI 0.090, P < 0.001) compared with LVGLS and RVGLS models. Moreover, LAεe with a cutoff of 5.3% further discriminated the survival probability in subgroups of patients with positive LGE or reduced LVEF (all log-rank P < 0.001).CONCLUSION:LAεe provided the best prognostic value over biventricular strains and added incremental value to conventional clinical predictors for patients with DCM.

[The value of cardiac MRI in the risk stratification in patients with hypertrophic cardiomyopathy].

Objective: To explore the value of cardiac magnetic resonance imaging (CMR) in the risk stratification of hypertrophic cardiomyopathy (HCM). Methods: HCM patients who underwent CMR examination in Fuwai Hospital between March 2012 and May 2013 were retrospectively enrolled. Baseline clinical and CMR data were collected and patient follow-up was performed using telephone contact and medical record. The primary composite endpoint was sudden cardiac death (SCD) or and equivalent event. The secondary composite endpoint was all-cause death and heart transplant. Patients were divided into SCD and non-SCD groups. Cox regression was used to explore risk factors of adverse events. Receiver operating characteristic (ROC) curve analysis was used to assess the performance and the optimal cut-off of late gadolinium enhancement percentage (LGE%) for the prediction of endpoints. Kaplan-Meier and log-rank tests were used to compare survival differences between groups. Results: A total of 442 patients were enrolled. Mean age was (48.5±12.4) years and 143(32.4%) were female. At (7.6±2.5) years of follow-up, 30 (6.8%) patients met the primary endpoint including 23 SCD and 7 SCD equivalent events, and 36 (8.1%) patients met the secondary endpoint including 33 all-cause death and 3 heart transplant. In multivariate Cox regression, syncope(HR=4.531, 95%CI 2.033-10.099, P<0.001), LGE% (HR=1.075, 95%CI 1.032-1.120, P=0.001) and left ventricular ejection fraction (LVEF) (HR=0.956, 95%CI 0.923-0.991, P=0.013) were independent risk factors for primary endpoint; Age (HR=1.032, 95%CI 1.001-1.064, P=0.046), atrial fibrillation (HR=2.977, 95%CI 1.446-6.131, P=0.003),LGE% (HR=1.075, 95%CI 1.035-1.116, P<0.001) and LVEF (HR=0.968, 95%CI 0.937-1.000, P=0.047) were independent risk factors for secondary endpoint. ROC curve showed the optimal LGE% cut-offs were 5.1% and 5.8% for the prediction of primary and secondary endpoint, respectively. Patients were further divided into LGE%=0, 0