Automatic echocardiographic evaluation of the probability of pulmonary hypertension using machine learning.

Echocardiography, a simple and noninvasive tool, is the first choice for screening pulmonary hypertension (PH). However, accurate assessment of PH, incorporating both the pulmonary artery pressures and additional signs for PH remained unsatisfied. Thus, this study aimed to develop a machine learning (ML) model that can automatically evaluate the probability of PH. This cohort included data from 346 (275 for training set and internal validation set and 71 for external validation set) patients with suspected PH patients and receiving right heart catheterization. Echocardiographic images on parasternal short axis-papillary muscle level (PSAX-PML) view from all patients were collected, labeled, and preprocessed. Local features from each image were extracted and subsequently integrated to build a ML model. By adjusting the parameters of the model, the model with the best prediction effect is finally constructed. We used receiver-operating characteristic analysis to evaluate model performance and compared the ML model with the traditional methods. The accuracy of the ML model for diagnosis of PH was significantly higher than the traditional method (0.945 vs. 0.892, p = 0.027 [area under the curve [AUC]]). Similar findings were observed in subgroup analysis and validated in the external validation set (AUC = 0.950 [95% CI: 0.897-1.000]). In summary, ML methods could automatically extract features from traditional PSAX-PML view and automatically assess the probability of PH, which were found to outperform traditional echocardiographic assessments.

Unileaflet mitral valve with one single papillary muscle: a rare congenital anomaly characterized by two- and three-dimensional echocardiography.

Heart failure with preserved ejection fraction assessed by cardiac magnetic resonance: From clinical uses to emerging techniques.

Patients with heart failure with preserved ejection fraction (HFpEF) account for approximately 50% of those with heart failure (HF) and have increased morbidity and mortality when compared to those with HF with reduced ejection fraction. Currently, the pathophysiology and diagnostic criteria for HFpEF remain unclear, contributing significantly to delays in creating a beneficial and tailored treatment that can improve the prognosis of HFpEF. A multitude of studies have exclusively tested and illustrated the diagnostic value of echocardiography imaging in HFpEF; however, a widely-accepted criterion to identify HFpEF using cardiovascular magnetic resonance (CMR) imaging has not been established. As the gold standard for cardiac structural, functional measurement, and tissue characterization, CMR holds great potential for the early discovery of the pathophysiology, diagnosis, and risk stratification of HFpEF. This review aims to comprehensively discuss the diagnostic and prognostic role of CMR parameters in the setting of HFpEF through validated routine and prospective emerging techniques, and provide clinical perspectives for CMR imaging application in HFpEF.

Early Outcomes of Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy in Children With Noonan Syndrome.

Noonan syndrome (NS) is a genetic syndrome causing obstructive hypertrophic cardiomyopathy (HCM) in infants. Studies of cardiac surgery in pediatric HCM patients with NS (NS-HCM) are lacking. We aim to characterize the early disease course of young NS-HCM patients before adolescence and assess their complications and survival condition after septal myectomy. Pediatric obstructive HCM patients who underwent septal myectomy at age 10 years or under were enrolled consecutively between 2009 and 2019. Ten patients with NS and 43 non-NS patients were enrolled in our study. NS-HCM patients were diagnosed at a younger age (5.00 ± 7.48 months vs. 18.73 ± 26.96 months) and more often had biventricular outflow tract obstruction (90.00% vs 30.23%). The surgical treatment can significantly reduce the pressure gradient of the outflow tract. More NS-HCM patients had biventricular reconstruction (70.00% vs 25.58%). The overall survival rates in all patients were 98.04% during 5-year follow-up, respectively. Complete heart block (CHB) was the most prevalent complication in patients with NS and tended to be more common than in non-NS patients (20% vs 7.32%). No sudden cardiac death (SCD) occurred in CHB patients who had pacemaker implantation. Biventricular reconstruction was the risk factor for CHB. Septal myectomy is safe and effective surgery to relieve obstruction in young age pediatric obstructive NS-HCM patients. Postoperative CHB is a common complication, especially in patients who underwent biventricular reconstruction. The implantation of pacemaker can protect CHB patients from SCD and improve their prognosis.

Left ventricular strain derived from cardiac magnetic resonance can predict outcomes of pulmonary valve replacement in patients with repaired tetralogy of Fallot.

Purpose:Several adults with repaired tetralogy of Fallot (rToF) undergo pulmonary valve replacement (PVR) to reduce the right ventricular volume and retain right ventricular function. However, there is currently no consensus on the ideal time for PVR surgery in asymptomatic patients with rTOF with pulmonary regurgitation (PR). Clinical outcomes after PVR are also indeterminate. Recently, myocardial strain and strain rate derived from cardiac magnetic resonance (CMR) feature tracking were found to be more sensitive to right ventricular dysfunction than conventional parameters and therefore may add prognostic value in patients with rToF. We aimed to analyze whether pre-PVR left ventricular (LV) strain and strain rate detected by CMR feature tracking are associated with midterm outcomes after PVR in patients with rToF.Methods:Seventy-eight asymptomatic patients with rToF who required PVR due to moderate or severe PR were prospectively enrolled between January 2014 and June 2020. CMR cine sequences were obtained, and feature tracking parameters were measured preoperatively. Adverse events were documented during the follow-up. Receiver operating characteristic analysis was performed to determine the cutoff value. Kaplan-Meier curves were drawn with log-rank statistics; moreover, univariate and multivariate Cox proportional hazards regression analyses and Harrel C-indices were analyzed.Results:During 3.6 ± 1.8 years of follow-up, 25 adverse events were recorded. Kaplan-Meier survival curves and univariate Cox analysis verified that patients with significantly reduced radial strain (RS), circumferential strain (CS), longitudinal strain (LS), RS rate at systole and diastole (RSRs and RSRe), and circumferential and LS rates at diastole (CSRe and LSRe) had worse event-free survival. After multivariate correction, only LS and LSRe remained significantly associated with adverse outcomes (hazard ratio = 1.243 [1.083-1.428] and 0.067 [0.017-0.258], respectively, all p < 0.05). The cutoff values of LS and LSRe were -12.30 (%) and 1.07 (s-1), respectively.Conclusion:The LV strain and strain rate prior to PVR are important prognostic factors for adverse events after PVR in rToF.

Cardiac Segmentation Method Based on Domain Knowledge.

Echocardiography plays an important role in the clinical diagnosis of cardiovascular diseases. Cardiac function assessment by echocardiography is a crucial process in daily cardiology. However, cardiac segmentation in echocardiography is a challenging task due to shadows and speckle noise. The traditional manual segmentation method is a time-consuming process and limited by inter-observer variability. In this paper, we present a fast and accurate echocardiographic automatic segmentation framework based on Convolutional neural networks (CNN). We propose FAUet, a segmentation method serially integrated U-Net with coordinate attention mechanism and domain feature loss from VGG19 pre-trained on the ImageNet dataset. The coordinate attention mechanism can capture long-range dependencies along one spatial direction and meanwhile preserve precise positional information along the other spatial direction. And the domain feature loss is more concerned with the topology of cardiac structures by exploiting their higher-level features. In this research, we use a two-dimensional echocardiogram (2DE) of 88 patients from two devices, Philips Epiq 7C and Mindray Resona 7T, to segment the left ventricle (LV), interventricular septal (IVS), and posterior left ventricular wall (PLVW). We also draw the gradient weighted class activation mapping (Grad-CAM) to improve the interpretability of the segmentation results. Compared with the traditional U-Net, the proposed segmentation method shows better performance. The mean Dice Score Coefficient (Dice) of LV, IVS, and PLVW of FAUet can achieve 0.932, 0.848, and 0.868, and the average Dice of the three objects can achieve 0.883. Statistical analysis showed that there is no significant difference between the segmentation results of the two devices. The proposed method can realize fast and accurate segmentation of 2DE with a low time cost. Combining coordinate attention module and feature loss with the original U-Net framework can significantly increase the performance of the algorithm.

Left atrial dysfunction may precede left atrial enlargement and abnormal left ventricular longitudinal function: a cardiac MR feature tracking study.

BACKGROUND:The role of the dysfunction of left atrium in the occurrence and development of cardiovascular disease has been gradually recognized. We aim to compare the impact on left atrial (LA) function between patients with hypertrophic cardiomyopathy (HCM) and hypertension (HTN) without LA enlargement using cardiovascular magnetic resonance feature tracking (CMR-FT), and if possible, explore the capability of LA function for providing clinical implication and predicting clinical adverse events in the early stage of cardiovascular disease.METHODS:Consecutive 60 HCM patients and 60 HTN patients with normal LA size among 1413 patients who underwent CMR were retrospectively analyzed as well as 60 controls. Left atrial and ventricular functions were quantified by volumetric and CMR-FT derived strain analysis from long and short left ventricular view cines. The primary endpoint was a composite of all-cause death, stroke, new-onset or worsening heart failure to hospitalization, and paroxysmal or persistent atrial fibrillation.RESULTS:Compared to the controls, both HTN and HCM participants had impaired LA reservoir function (εs) and conduit function (εe) with the different stage of LA booster pump dysfunction (εa). LA strain was more sensitive than LV longitudinal strain (GLS) for evaluate primary endpoint (εs: 33.9% ± 7.5 vs. 41.2% ± 14.3, p = 0.02; εe: 13.6% ± 6.2 vs. 17.4% ± 10.4, p = 0.03; εa: 20.2% ± 6.0 vs. 23.7% ± 8.8, p = 0.07; GLS: -19.4% ± 6.4 vs. -20.0% ± 6.8, p = 0.70, respectively). After a mean follow-up of 6.8 years, 23 patients reached primary endpoint. Cox regression analyses indicated impaired LA reservoir and booster pump strain were associated with clinical outcomes in patients at the early stage of HTN and HCM (p < 0.05).CONCLUSIONS:CMR-FT-derived strain is a potential and robust tool in demonstrating impaired LA mechanics, quantifying LA dynamics and underlining the impacts on LA-LV coupling in patients with HTN and HCM without LA enlargement. The corresponding LA dysfunction is a promising metric to assess clinical implication and predict prognosis at the early stage, superior to GLS.

The Role of Sorting Nexin 17 in Cardiac Development.

Sorting nexin 17 (SNX17), a member of sorting nexin (SNX) family, acts as a modulator for endocytic recycling of membrane proteins. Results from our previous study demonstrated the embryonic lethality of homozygous defect of SNX17. In this study, we investigated the role of SNX17 in rat fetal development. Specifically, we analyzed patterns of SNX17 messenger RNA (mRNA) expression in multiple rat tissues and found high expression in the cardiac outflow tract (OFT). This expression was gradually elevated during the cardiac OFT morphogenesis. Homozygous deletion of the SNX17 gene in rats resulted in mid-gestational embryonic lethality, which was accompanied by congenital heart defects, including the double-outlet right ventricle and atrioventricular and ventricular septal defects, whereas heterozygotes exhibited normal fetal development. Moreover, we found normal migration distance and the number of cardiac neural crest cells during the OFT morphogenesis. Although cellular proliferation in the cardiac OFT endocardial cushion was not affected, cellular apoptosis was significantly suppressed. Transcriptomic profiles and quantitative real-time PCR data in the cardiac OFT showed that SNX17 deletion resulted in abnormal expression of genes associated with cardiac development. Overall, these findings suggest that SNX17 plays a crucial role in cardiac development.

Three-dimensional transesophageal echocardiography measurement of mitral valve area in patients with rheumatic mitral stenosis: multiplanar reconstruction or 3D direct planimetry?

3D direct planimetry is increasingly used in clinical practice as a rapid way to measure the mitral valve area (MVA) in patients with rheumatic mitral stenosis (MS) who underwent three-dimensional transesophageal echocardiography (3D-TEE). However, data on its accuracy and reliability are scarce. This study aimed to compare the MVA measurements obtained by 3D direct planimetry to the conventional technique multiplanar reconstruction (MPR) in MS patients using 3D-TEE. We retrospectively included 49 patients with rheumatic MS undergoing clinically-indicated 3D-TEE in the study. We determined the 3D direct planimetry measurements of MVA from the left atria aspect (MVALA) and the left ventricle aspect (MVALV), and compared those with the MPR method (MVAMPR). We also assessed the major and minor diameters of the mitral valve orifice using MPR and 3D direct planimetry. We found an excellent agreement between the MVA measurements obtained by the MPR method and 3D direct planimetry (MVALA and MVALV) [intraclass correlation coefficients (ICC) = 0.951 and 0.950, respectively]. However, the MVAMPR measurements were significantly larger than the MVALA and MVALV (p < 0.001; mean difference: 0.12 ± 0.15 cm2 and 0.11 ± 0.16 cm2, respectively).The inter-observer and intra-observer variability ICC were 0.875 and 0.856 for MVAMPR, 0.982 and 0.984 for MVALA, and 0.988 and 0.986 for MVALV, respectively. The major diameter measured by MPR (1.90 ± 0.42 cm) was significantly larger than that obtained by 3D direct planimetry (1.72 ± 0.35 cm for the LA aspect, p < 0.001; 1.73 ± 0.36 cm for the LV aspect, p < 0.001). The minor diameter measured by MPR (0.96 ± 0.25 cm) did not differ from that derived by 3D direct planimetry (0.94 ± 0.25 cm for the LA aspect, p = 0.07; 0.95 ± 0.27 cm for the LV aspect, p = 0.32). 3D direct planimetry provides highly reproducible measurements of MVA and yields data in excellent agreement with those obtained by the MPR method. The discrepancy between the two techniques may be due to differences in major diameter measurements of the mitral valve orifice.

MRI Characteristics, Prevalence, and Outcomes of Hypertrophic Cardiomyopathy with Restrictive Phenotype.

PURPOSE:To investigate the MRI characteristics, prevalence, and outcomes of hypertrophic cardiomyopathy (HCM) with restrictive phenotype.MATERIALS AND METHODS:A total of 2592 consecutive patients with HCM were evaluated to identify individuals who fulfilled the diagnostic criteria of restrictive phenotype. Thirty-four patients with HCM (mean age, 41 years ± 16 [standard deviation]; range, 21-62 years, 16 men) with restrictive phenotype were retrospectively identified. Thirty-four patients with HCM with the same age and sex distributions were randomly selected as a control group. Kaplan-Meier survival curves were compared using log-rank statistics for survival analysis.RESULTS:The anteroposterior diameters of the left and right atria were 55 mm ± 5 and 61 mm ± 9, respectively, which were larger than those of the control group (P < .001). The maximum wall thickness in the restrictive group was lower than that in the control group (16 mm ± 2 vs 19 mm ± 3, P < .001). No significant difference was found in late gadolinium enhancement fraction between the restricted phenotype and the control group (15% ± 8 vs 13% ± 7, P = .376). The 5-year event-free survival from any cause of death and cardiac transplantation was 81% in the restrictive group, compared with 94% in the control group (log-rank P = .018).CONCLUSION:Restrictive phenotype is a rare subtype of HCM and is associated with severe clinical symptoms and poor prognosis. The MRI features of this phenotype include mild to moderate left ventricular hypertrophy, markedly enlarged atria, moderate myocardial fibrosis, and pericardial effusion.© RSNA, 2020.

Automatic echocardiographic evaluation of the probability of pulmonary hypertension using machine learning.

Echocardiography, a simple and noninvasive tool, is the first choice for screening pulmonary hypertension (PH). However, accurate assessment of PH, incorporating both the pulmonary artery pressures and additional signs for PH remained unsatisfied. Thus, this study aimed to develop a machine learning (ML) model that can automatically evaluate the probability of PH. This cohort included data from 346 (275 for training set and internal validation set and 71 for external validation set) patients with suspected PH patients and receiving right heart catheterization. Echocardiographic images on parasternal short axis-papillary muscle level (PSAX-PML) view from all patients were collected, labeled, and preprocessed. Local features from each image were extracted and subsequently integrated to build a ML model. By adjusting the parameters of the model, the model with the best prediction effect is finally constructed. We used receiver-operating characteristic analysis to evaluate model performance and compared the ML model with the traditional methods. The accuracy of the ML model for diagnosis of PH was significantly higher than the traditional method (0.945 vs. 0.892, p = 0.027 [area under the curve [AUC]]). Similar findings were observed in subgroup analysis and validated in the external validation set (AUC = 0.950 [95% CI: 0.897-1.000]). In summary, ML methods could automatically extract features from traditional PSAX-PML view and automatically assess the probability of PH, which were found to outperform traditional echocardiographic assessments.

Unileaflet mitral valve with one single papillary muscle: a rare congenital anomaly characterized by two- and three-dimensional echocardiography.

Heart failure with preserved ejection fraction assessed by cardiac magnetic resonance: From clinical uses to emerging techniques.

Patients with heart failure with preserved ejection fraction (HFpEF) account for approximately 50% of those with heart failure (HF) and have increased morbidity and mortality when compared to those with HF with reduced ejection fraction. Currently, the pathophysiology and diagnostic criteria for HFpEF remain unclear, contributing significantly to delays in creating a beneficial and tailored treatment that can improve the prognosis of HFpEF. A multitude of studies have exclusively tested and illustrated the diagnostic value of echocardiography imaging in HFpEF; however, a widely-accepted criterion to identify HFpEF using cardiovascular magnetic resonance (CMR) imaging has not been established. As the gold standard for cardiac structural, functional measurement, and tissue characterization, CMR holds great potential for the early discovery of the pathophysiology, diagnosis, and risk stratification of HFpEF. This review aims to comprehensively discuss the diagnostic and prognostic role of CMR parameters in the setting of HFpEF through validated routine and prospective emerging techniques, and provide clinical perspectives for CMR imaging application in HFpEF.

Early Outcomes of Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy in Children With Noonan Syndrome.

Noonan syndrome (NS) is a genetic syndrome causing obstructive hypertrophic cardiomyopathy (HCM) in infants. Studies of cardiac surgery in pediatric HCM patients with NS (NS-HCM) are lacking. We aim to characterize the early disease course of young NS-HCM patients before adolescence and assess their complications and survival condition after septal myectomy. Pediatric obstructive HCM patients who underwent septal myectomy at age 10 years or under were enrolled consecutively between 2009 and 2019. Ten patients with NS and 43 non-NS patients were enrolled in our study. NS-HCM patients were diagnosed at a younger age (5.00 ± 7.48 months vs. 18.73 ± 26.96 months) and more often had biventricular outflow tract obstruction (90.00% vs 30.23%). The surgical treatment can significantly reduce the pressure gradient of the outflow tract. More NS-HCM patients had biventricular reconstruction (70.00% vs 25.58%). The overall survival rates in all patients were 98.04% during 5-year follow-up, respectively. Complete heart block (CHB) was the most prevalent complication in patients with NS and tended to be more common than in non-NS patients (20% vs 7.32%). No sudden cardiac death (SCD) occurred in CHB patients who had pacemaker implantation. Biventricular reconstruction was the risk factor for CHB. Septal myectomy is safe and effective surgery to relieve obstruction in young age pediatric obstructive NS-HCM patients. Postoperative CHB is a common complication, especially in patients who underwent biventricular reconstruction. The implantation of pacemaker can protect CHB patients from SCD and improve their prognosis.

Left ventricular strain derived from cardiac magnetic resonance can predict outcomes of pulmonary valve replacement in patients with repaired tetralogy of Fallot.

Purpose:Several adults with repaired tetralogy of Fallot (rToF) undergo pulmonary valve replacement (PVR) to reduce the right ventricular volume and retain right ventricular function. However, there is currently no consensus on the ideal time for PVR surgery in asymptomatic patients with rTOF with pulmonary regurgitation (PR). Clinical outcomes after PVR are also indeterminate. Recently, myocardial strain and strain rate derived from cardiac magnetic resonance (CMR) feature tracking were found to be more sensitive to right ventricular dysfunction than conventional parameters and therefore may add prognostic value in patients with rToF. We aimed to analyze whether pre-PVR left ventricular (LV) strain and strain rate detected by CMR feature tracking are associated with midterm outcomes after PVR in patients with rToF.Methods:Seventy-eight asymptomatic patients with rToF who required PVR due to moderate or severe PR were prospectively enrolled between January 2014 and June 2020. CMR cine sequences were obtained, and feature tracking parameters were measured preoperatively. Adverse events were documented during the follow-up. Receiver operating characteristic analysis was performed to determine the cutoff value. Kaplan-Meier curves were drawn with log-rank statistics; moreover, univariate and multivariate Cox proportional hazards regression analyses and Harrel C-indices were analyzed.Results:During 3.6 ± 1.8 years of follow-up, 25 adverse events were recorded. Kaplan-Meier survival curves and univariate Cox analysis verified that patients with significantly reduced radial strain (RS), circumferential strain (CS), longitudinal strain (LS), RS rate at systole and diastole (RSRs and RSRe), and circumferential and LS rates at diastole (CSRe and LSRe) had worse event-free survival. After multivariate correction, only LS and LSRe remained significantly associated with adverse outcomes (hazard ratio = 1.243 [1.083-1.428] and 0.067 [0.017-0.258], respectively, all p < 0.05). The cutoff values of LS and LSRe were -12.30 (%) and 1.07 (s-1), respectively.Conclusion:The LV strain and strain rate prior to PVR are important prognostic factors for adverse events after PVR in rToF.

Cardiac Segmentation Method Based on Domain Knowledge.

Echocardiography plays an important role in the clinical diagnosis of cardiovascular diseases. Cardiac function assessment by echocardiography is a crucial process in daily cardiology. However, cardiac segmentation in echocardiography is a challenging task due to shadows and speckle noise. The traditional manual segmentation method is a time-consuming process and limited by inter-observer variability. In this paper, we present a fast and accurate echocardiographic automatic segmentation framework based on Convolutional neural networks (CNN). We propose FAUet, a segmentation method serially integrated U-Net with coordinate attention mechanism and domain feature loss from VGG19 pre-trained on the ImageNet dataset. The coordinate attention mechanism can capture long-range dependencies along one spatial direction and meanwhile preserve precise positional information along the other spatial direction. And the domain feature loss is more concerned with the topology of cardiac structures by exploiting their higher-level features. In this research, we use a two-dimensional echocardiogram (2DE) of 88 patients from two devices, Philips Epiq 7C and Mindray Resona 7T, to segment the left ventricle (LV), interventricular septal (IVS), and posterior left ventricular wall (PLVW). We also draw the gradient weighted class activation mapping (Grad-CAM) to improve the interpretability of the segmentation results. Compared with the traditional U-Net, the proposed segmentation method shows better performance. The mean Dice Score Coefficient (Dice) of LV, IVS, and PLVW of FAUet can achieve 0.932, 0.848, and 0.868, and the average Dice of the three objects can achieve 0.883. Statistical analysis showed that there is no significant difference between the segmentation results of the two devices. The proposed method can realize fast and accurate segmentation of 2DE with a low time cost. Combining coordinate attention module and feature loss with the original U-Net framework can significantly increase the performance of the algorithm.

Left atrial dysfunction may precede left atrial enlargement and abnormal left ventricular longitudinal function: a cardiac MR feature tracking study.

BACKGROUND:The role of the dysfunction of left atrium in the occurrence and development of cardiovascular disease has been gradually recognized. We aim to compare the impact on left atrial (LA) function between patients with hypertrophic cardiomyopathy (HCM) and hypertension (HTN) without LA enlargement using cardiovascular magnetic resonance feature tracking (CMR-FT), and if possible, explore the capability of LA function for providing clinical implication and predicting clinical adverse events in the early stage of cardiovascular disease.METHODS:Consecutive 60 HCM patients and 60 HTN patients with normal LA size among 1413 patients who underwent CMR were retrospectively analyzed as well as 60 controls. Left atrial and ventricular functions were quantified by volumetric and CMR-FT derived strain analysis from long and short left ventricular view cines. The primary endpoint was a composite of all-cause death, stroke, new-onset or worsening heart failure to hospitalization, and paroxysmal or persistent atrial fibrillation.RESULTS:Compared to the controls, both HTN and HCM participants had impaired LA reservoir function (εs) and conduit function (εe) with the different stage of LA booster pump dysfunction (εa). LA strain was more sensitive than LV longitudinal strain (GLS) for evaluate primary endpoint (εs: 33.9% ± 7.5 vs. 41.2% ± 14.3, p = 0.02; εe: 13.6% ± 6.2 vs. 17.4% ± 10.4, p = 0.03; εa: 20.2% ± 6.0 vs. 23.7% ± 8.8, p = 0.07; GLS: -19.4% ± 6.4 vs. -20.0% ± 6.8, p = 0.70, respectively). After a mean follow-up of 6.8 years, 23 patients reached primary endpoint. Cox regression analyses indicated impaired LA reservoir and booster pump strain were associated with clinical outcomes in patients at the early stage of HTN and HCM (p < 0.05).CONCLUSIONS:CMR-FT-derived strain is a potential and robust tool in demonstrating impaired LA mechanics, quantifying LA dynamics and underlining the impacts on LA-LV coupling in patients with HTN and HCM without LA enlargement. The corresponding LA dysfunction is a promising metric to assess clinical implication and predict prognosis at the early stage, superior to GLS.

The Role of Sorting Nexin 17 in Cardiac Development.

Sorting nexin 17 (SNX17), a member of sorting nexin (SNX) family, acts as a modulator for endocytic recycling of membrane proteins. Results from our previous study demonstrated the embryonic lethality of homozygous defect of SNX17. In this study, we investigated the role of SNX17 in rat fetal development. Specifically, we analyzed patterns of SNX17 messenger RNA (mRNA) expression in multiple rat tissues and found high expression in the cardiac outflow tract (OFT). This expression was gradually elevated during the cardiac OFT morphogenesis. Homozygous deletion of the SNX17 gene in rats resulted in mid-gestational embryonic lethality, which was accompanied by congenital heart defects, including the double-outlet right ventricle and atrioventricular and ventricular septal defects, whereas heterozygotes exhibited normal fetal development. Moreover, we found normal migration distance and the number of cardiac neural crest cells during the OFT morphogenesis. Although cellular proliferation in the cardiac OFT endocardial cushion was not affected, cellular apoptosis was significantly suppressed. Transcriptomic profiles and quantitative real-time PCR data in the cardiac OFT showed that SNX17 deletion resulted in abnormal expression of genes associated with cardiac development. Overall, these findings suggest that SNX17 plays a crucial role in cardiac development.

Three-dimensional transesophageal echocardiography measurement of mitral valve area in patients with rheumatic mitral stenosis: multiplanar reconstruction or 3D direct planimetry?

3D direct planimetry is increasingly used in clinical practice as a rapid way to measure the mitral valve area (MVA) in patients with rheumatic mitral stenosis (MS) who underwent three-dimensional transesophageal echocardiography (3D-TEE). However, data on its accuracy and reliability are scarce. This study aimed to compare the MVA measurements obtained by 3D direct planimetry to the conventional technique multiplanar reconstruction (MPR) in MS patients using 3D-TEE. We retrospectively included 49 patients with rheumatic MS undergoing clinically-indicated 3D-TEE in the study. We determined the 3D direct planimetry measurements of MVA from the left atria aspect (MVALA) and the left ventricle aspect (MVALV), and compared those with the MPR method (MVAMPR). We also assessed the major and minor diameters of the mitral valve orifice using MPR and 3D direct planimetry. We found an excellent agreement between the MVA measurements obtained by the MPR method and 3D direct planimetry (MVALA and MVALV) [intraclass correlation coefficients (ICC) = 0.951 and 0.950, respectively]. However, the MVAMPR measurements were significantly larger than the MVALA and MVALV (p < 0.001; mean difference: 0.12 ± 0.15 cm2 and 0.11 ± 0.16 cm2, respectively).The inter-observer and intra-observer variability ICC were 0.875 and 0.856 for MVAMPR, 0.982 and 0.984 for MVALA, and 0.988 and 0.986 for MVALV, respectively. The major diameter measured by MPR (1.90 ± 0.42 cm) was significantly larger than that obtained by 3D direct planimetry (1.72 ± 0.35 cm for the LA aspect, p < 0.001; 1.73 ± 0.36 cm for the LV aspect, p < 0.001). The minor diameter measured by MPR (0.96 ± 0.25 cm) did not differ from that derived by 3D direct planimetry (0.94 ± 0.25 cm for the LA aspect, p = 0.07; 0.95 ± 0.27 cm for the LV aspect, p = 0.32). 3D direct planimetry provides highly reproducible measurements of MVA and yields data in excellent agreement with those obtained by the MPR method. The discrepancy between the two techniques may be due to differences in major diameter measurements of the mitral valve orifice.

MRI Characteristics, Prevalence, and Outcomes of Hypertrophic Cardiomyopathy with Restrictive Phenotype.

PURPOSE:To investigate the MRI characteristics, prevalence, and outcomes of hypertrophic cardiomyopathy (HCM) with restrictive phenotype.MATERIALS AND METHODS:A total of 2592 consecutive patients with HCM were evaluated to identify individuals who fulfilled the diagnostic criteria of restrictive phenotype. Thirty-four patients with HCM (mean age, 41 years ± 16 [standard deviation]; range, 21-62 years, 16 men) with restrictive phenotype were retrospectively identified. Thirty-four patients with HCM with the same age and sex distributions were randomly selected as a control group. Kaplan-Meier survival curves were compared using log-rank statistics for survival analysis.RESULTS:The anteroposterior diameters of the left and right atria were 55 mm ± 5 and 61 mm ± 9, respectively, which were larger than those of the control group (P < .001). The maximum wall thickness in the restrictive group was lower than that in the control group (16 mm ± 2 vs 19 mm ± 3, P < .001). No significant difference was found in late gadolinium enhancement fraction between the restricted phenotype and the control group (15% ± 8 vs 13% ± 7, P = .376). The 5-year event-free survival from any cause of death and cardiac transplantation was 81% in the restrictive group, compared with 94% in the control group (log-rank P = .018).CONCLUSION:Restrictive phenotype is a rare subtype of HCM and is associated with severe clinical symptoms and poor prognosis. The MRI features of this phenotype include mild to moderate left ventricular hypertrophy, markedly enlarged atria, moderate myocardial fibrosis, and pericardial effusion.© RSNA, 2020.