Left Ventricular Myocardial Fibrosis, Atrophy, and Impaired Contractility in Patients With Pulmonary Arterial Hypertension and a Preserved Left Ventricular Function: A Cardiac Magnetic Resonance Study

Right ventricular fibrosis in adults with uncorrected secundum atrial septal defect and pulmonary hypertension: a cardiovascular magnetic resonance study with late gadolinium enhancement, native T1 and extracellular volume

Introduction

Right ventricular (RV) fibrosis represents both adaptive and maladaptive responses to the overloaded RV condition. Its role in pulmonary hypertension (PH) associated with secundum atrial septal defect (ASD), which is the most common adult congenital heart disease (CHD), remains poorly understood.

Methods

We enrolled 65 participants aged ≥18 years old with uncorrected secundum ASD who had undergone clinically indicated right heart catheterization (RHC), divided into the non-PH group (n = 7), PH group (n = 42), and Eisenmenger syndrome (ES) group (n = 16). We conducted cardiovascular magnetic resonance (CMR) studies with late gadolinium enhancement (LGE) imaging, native T1 mapping, and extracellular volume (ECV) measurement to evaluate the extent and clinical correlates of RV fibrosis.

Results

LGE was present in 94% of the population and 86% of the non-PH group, mostly located at the right ventricular insertion point (RVIP) regions. LGE in the septal and inferior RV region was predominantly observed in the ES group compared to the other groups (p = 0.031 and p < 0.001, respectively). The mean LGE scores in the ES and PH groups were significantly higher than those in the non-PH group (3.38 ± 0.96 vs. 2.74 ± 1.04 vs. 1.57 ± 0.79; p = 0.001). The ES and PH groups had significantly higher degrees of interstitial RV fibrosis compared to those in the non-PH group, indicated by native T1 (1,199.9 ± 68.9 ms vs. 1,131.4 ± 47.8 ms vs. 1,105.4 ± 44.0 ms; p < 0.001) and ECV (43.6 ± 6.6% vs. 39.5 ± 4.9% vs. 39.4 ± 5.8%; p = 0.037). Additionally, native T1 significantly correlated with pulmonary vascular resistance (r = 0.708, p < 0.001), RV ejection fraction (r = -0.468, p < 0.001) and peripheral oxygen saturation (r = -0.410, p = 0.001).

Conclusion

In patients with uncorrected secundum ASD, RV fibrosis may occur before the development of PH and progressively intensify alongside the progression of PH severity. A higher degree of RV fibrosis, derived from CMR imaging, correlates with worse hemodynamics, RV dysfunction, and poorer clinical conditions.

Antifibrotic effects of sodium-glucose cotransporter-2 inhibitors: A comprehensive review

BACKGROUND AND AIMS

Scar tissue accumulation in organs is the underlying cause of many fibrotic diseases. Due to the extensive array of organs affected, the long-term nature of fibrotic processes and the large number of people who suffer from the negative impact of these diseases, they constitute a serious health problem for modern medicine and a huge economic burden on society. Sodium-glucose cotransporter-2 inhibitors (SGLT2is) are a relatively new class of anti-diabetic pharmaceuticals that offer additional benefits over and above their glucose-lowering properties; these medications modulate a variety of diseases, including fibrosis. Herein, we have collated and analyzed all available research on SGLT2is and their effects on organ fibrosis, together with providing a proposed explanation as to the underlying mechanisms.

METHODS

PubMed, ScienceDirect, Google Scholar and Scopus were searched spanning the period from 2012 until April 2023 to find relevant articles describing the antifibrotic effects of SGLT2is.

RESULTS

The majority of reports have shown that SGLT2is are protective against lung, liver, heart and kidney fibrosis as well as arterial stiffness. According to the results of clinical trials and animal studies, many SGLT2 inhibitors are promising candidates for the treatment of fibrosis. Recent studies have demonstrated that SGLT2is affect an array of cellular processes, including hypoxia, inflammation, oxidative stress, the renin-angiotensin system and metabolic activities, all of which have been linked to fibrosis.

CONCLUSION

Extensive evidence indicates that SGLT2is are promising treatments for fibrosis, demonstrating protective effects in various organs and influencing key cellular processes linked to fibrosis.

Myocardial strain parameters in pulmonary hypertension are determined by changes in volumetric function rather than by hemodynamic alterations

PURPOSE

To investigate associations of cardiac magnetic resonance feature-tracking-derived left (LV) and right ventricular (RV) global myocardial peak strains and strain rates with volumetric function and hemodynamic parameters to identify the major determinants of myocardial strain alterations in pulmonary hypertension (PH).

METHODS

Sixty-seven patients with PH or at risk of developing PH underwent right heart catheterization (RHC) and cine realtime imaging at 3 T. RHC parameters included mean pulmonary arterial pressure (mPAP), which was used for the diagnosis of PH. LV and RV volumetric function and feature-tracking-derived global radial, circumferential, and longitudinal (GLS) peak strains, together with their strain rates, were evaluated from cine images using routine software. Furthermore, myocardial strain parameters of 24 healthy subjects were evaluated as controls. Means were compared by t-test; relationships between parameters were investigated by correlation and regression analysis.

RESULTS

Compared to controls, RV-GLS, all RV systolic strain rates and the LV systolic longitudinal strain rate showed lower magnitudes in PH (RV-GLS: -21 ± 4% vs. -16 ± 5%, p < 0.0001); the strongest univariate correlate to mPAP was the RV-GLS (r = 0.59). All LV and RV strain parameters yielded stronger correlations with their respective ejection fractions. In bi-linear models using mPAP and ejection fraction as predictors, mPAP remained significant only for diastolic LV radial and circumferential strain rates.

CONCLUSION

Impairment of myocardial strains is more strongly associated with alterations in LV and RV volumetric function parameters than elevated mPAP, therefore limiting diagnostic information of myocardial strain parameters in PH.

Assessment of Right Ventricular Function-a State of the Art

PURPOSE OF REVIEW

The right ventricle (RV) has a complex geometry and physiology which is distinct from the left. RV dysfunction and failure can be the aftermath of volume- and/or pressure-loading conditions, as well as myocardial and pericardial diseases.

RECENT FINDINGS

Echocardiography, magnetic resonance imaging and right heart catheterisation can assess RV function by using several qualitative and quantitative parameters. In pulmonary hypertension (PH) in particular, RV function can be impaired and is related to survival. An accurate assessment of RV function is crucial for the early diagnosis and management of these patients. This review focuses on the different modalities and indices used for the evaluation of RV function with an emphasis on PH.

Qualification of Ventricular Flow in Patients With Precapillary Pulmonary Hypertension With 4-dimensional Flow Magnetic Resonance Imaging

PURPOSE

Our goal was to study both right and left ventricular blood flow in patients with precapillary pulmonary hypertension (pre-PH) with 4-dimensional (4D) flow magnetic resonance imaging (MRI) and to analyze their correlation with cardiac functional metrics on cardiovascular magnetic resonance (CMR) and hemodynamics from right heart catheterization (RHC).

MATERIALS AND METHODS

129 patients (64 females, mean age 47 ± 13 y) including 105 patients with pre-PH (54 females, mean age 49 ± 13 y) and 24 patients without PH (10 females, mean age 40 ± 12 y) were retrospectively included. All patients underwent CMR and RHC within 48 hours. 4D flow MRI was acquired using a 3-dimensional retrospectively electrocardiograph-triggered, navigator-gated phase contrast sequence. Right and left ventricular flow components including the percentages of direct flow (PDF), retained inflow (PRI), delayed ejection flow (PDE), and residual volume (PRVo) were respectively quantified. The ventricular flow components between patients with pre-PH and non-PH were compared and correlations of flow components with CMR functional metrics and hemodynamics measured with RHC were analyzed. Biventricular flow components were compared between survivors and deceased patients during the perioperative period.

RESULTS

Right ventricular (RV) PDF and PDE significantly correlated with RVEDV and RV ejection fraction. RV PDF negatively correlated with pulmonary arterial pressure (PAP) and pulmonary vascular resistance. When the RV PDF was <11%, the sensitivity and specificity of RV PDF for predicting mean PAP ≥25 mm Hg were 88.6% and 98.7%, respectively, with an area under the curve value of 0.95 ± 0.02. When RV PRVo was more than 42%, the sensitivity and specificity of RV PRVo for predicting mean PAP ≥25 mm Hg were 85.7% and 98.5%, respectively, with an area under the curve value of 0.95 ± 0.01. Nine patients died during the perioperative period. Biventricular PDF, RV PDE, and PRI of survivors were higher than nonsurvivors whereas RV PRVo increased in deceased patients.

CONCLUSIONS

Biventricular flow analysis with 4D flow MRI provides comprehensive information about the severity and cardiac remodeling of PH and may be a predictor of perioperative death of patients with pre-PH.

Distinct cardiovascular phenotypes are associated with prognosis in systemic sclerosis: a cardiovascular magnetic resonance study

AIMS

Cardiovascular involvement in systemic sclerosis (SSc) is heterogeneous and ill-defined. This study aimed to: (i) discover cardiac phenotypes in SSc by cardiovascular magnetic resonance (CMR); (ii) provide a CMR-based algorithm for phenotypic classification; and (iii) examine for associations between phenotypes and mortality.

METHODS AND RESULTS

A retrospective, single-centre, observational study of 260 SSc patients who underwent clinically indicated CMR including native myocardial T1 and T2 mapping from 2016 to 2019 was performed. Agglomerative hierarchical clustering using only CMR variables revealed five clusters of SSc patients with shared CMR characteristics: dilated right hearts with right ventricular failure (RVF); biventricular failure dilatation and dysfunction (BVF); and normal function with average cavity (NF-AC), normal function with small cavity (NF-SC), and normal function with large cavity (NF-LC) sizes. Phenotypes did not co-segregate with clinical or antibody classifications. A CMR-based decision tree for phenotype classification was created. Sixty-three (24%) patients died during a median follow-up period of 3.4 years. After adjustment for age and presence of pulmonary hypertension (PH), independent CMR predictors of all-cause mortality were native T1 (P < 0.001) and right ventricular ejection fraction (RVEF) (P = 0.0032). NF-SC and NF-AC groups had more favourable prognoses (P≤0.036) than the other three groups which had no differences in prognoses between them (P > 0.14). Hazard ratios (HR) were statistically significant for RVF (HR = 8.9, P < 0.001), BVF (HR = 5.2, P = 0.006), and NF-LC (HR = 4.9, P = 0.002) groups. The NF-LC group remained significantly predictive of mortality after adjusting for RVEF, native T1, and PH diagnosis (P = 0.0046).

CONCLUSION

We identified five CMR-defined cardiac SSc phenotypes that did not co-segregate with clinical data and had distinct outcomes, offering opportunities for a more precision-medicine based management approach.

Cardiac inflammation and fibrosis patterns in systemic sclerosis, evaluated by magnetic resonance imaging: An update

Systemic sclerosis (SSc) presents high morbidity/mortality, due to internal organ fibrosis, including the heart. Cardiac magnetic resonance (CMR) can perform myocardial function and tissue characterization in the same examination. The Lake Louise criteria (LLC) can identify recent myocardial inflammation using CMR. Abnormal values include: (a) myocardial over skeletal muscle ratio in STIRT2-W images >2, (b) early gadolinium enhancement values >4, (c) epicardial/intramyocardial late gadolinium enhancement (LGE). The diagnosis of myocarditis using LLC is considered if 2/3 criteria are positive. Parametric imaging including T2, native T1 mapping and extracellular volume fraction (ECV) has been recently used to diagnose inflammatory cardiomyopathy. According to expert recommendations, myocarditis should be considered if at least 2 indices, one T2 and one T1 parameter are positive, whereas native T1 mapping and ECV assess diffuse fibrosis or oedema, even in the absence of LGE. Moreover, transmural/subendocardial fibrosis following the distribution of coronary arteries and diffuse subendocardial fibrosis not related with epicardial coronary arteries are indicative of epicardial and micro-vascular coronary artery disease, respectively. To conclude, CMR can identify acute/active myocardial inflammation and myocardial infarction using classic and parametric indices in parallel with ventricular function evaluation.

Novel Hybrid Treatment for Pulmonary Arterial Hypertension with or without Eisenmenger Syndrome: Double Lung Transplantation with Simultaneous Endovascular or Classic Surgical Closure of the Patent Ductus Arteriosus (PDA)

Patients with pulmonary arterial hypertension (PAH) become candidates for lung or lung and heart transplantation when the maximum specific therapy is no longer effective. The most difficult challenge is choosing one of the above options in the event of symptoms of right ventricular failure. Here, we present two female patients with PAH: (1) a 21-year-old patient with Eisenmenger syndrome, caused by a congenital defect-patent ductus arteriosus (PDA); and (2) a 39-year-old patient with idiopathic PAH and coexistent PDA. Their common denominator is PDA and the hybrid surgery performed: double lung transplantation with simultaneous PDA closure. The operation was performed after pharmacological bridging (conditioning) to transplantation that lasted for 33 and 70 days, respectively. In both cases, PDA closure effectiveness was 100%. Both patients survived the operation (100%); however, patient no. 1 died on the 2nd postoperative day due to multi-organ failure; while patient no. 2 was discharged home in full health. The authors did not find a similar description of the operation in the available literature and PubMed database. Hence, we propose this new treatment method for its effectiveness and applicability proven in our practice.

The crosstalk among autophagy, apoptosis, and pyroptosis in cardiovascular disease

In recent years, the mechanism of cell death has become a hotspot in research on the pathogenesis and treatment of cardiovascular disease (CVD). Different cell death modes, including autophagy, apoptosis, and pyroptosis, are mosaic with each other and collaboratively regulate the process of CVD. This review summarizes the interaction and crosstalk of key pathways or proteins which play a critical role in the entire process of CVD and explores the specific mechanisms. Furthermore, this paper assesses the interrelationships among these three cell deaths and reviews how they regulate the pathogenesis of CVD. By understanding how these three cell death modes go together we can learn about the pathogenesis of CVD, which will enable us to identify new targets for preventing, controlling, and treating CVD. It will not only reduce mortality but also improve the quality of life.

The Balance between the Left and Right Ventricular Deformation Evaluated by Speckle Tracking Echocardiography Is a Great Predictor of the Major Adverse Cardiac Event in Patients with Pulmonary Hypertension

Cardiovascular failure is one of the most relevant causes of death in pulmonary hypertension (PH). With progressive increases of right ventricular (RV) afterload in PH patients, both RV and left ventricular (LV) function impair and RV–LV dyssynchrony develop in parallel. We aimed to analyze the balance between the left and right ventricular deformation to assess the outcome of patients with pulmonary hypertension by means of speckle tracking echocardiography. In this prospective study, 54 patients with invasively diagnosed pulmonary hypertension, and 26 healthy volunteers were included and underwent a broad panel of noninvasive assessment including 2D-echocardiography, 2D speckle tracking, 6-minute walking test and BNP. Patients were followed up for 338.7 ± 131.1 (range 60 to 572) days. There were significant differences in |LVGLS/RVFLS-1| and |LASc/RASc-1| between PH patients and the control group. During the follow up, 13 patients experienced MACEs, which included 7 patients with cardiac death and 6 patients with re-admitted hospital due to right ventricular dysfunction. In the multivariate Cox model analysis, |LVGLS/RVFLS-1| remained independent prognosis of markers (HR = 4.03). Our study findings show that |LVGLS/RVFLS-1| is of high clinical and prognostic relevance in pulmonary hypertension patients and reveal the importance of the balance between the left and right ventricular deformation.

Multifunctional biomaterial platforms for blocking the fibrosis process and promoting cellular restoring effects in myocardial fibrosis therapy

Myocardial fibrosis is the result of abnormal healing after acute and chronic myocardial damage and is a direct cause of heart failure and cardiac insufficiency. The clinical approach is to preserve cardiac function and inhibit fibrosis through surgery aimed at dredging blood vessels. However, this strategy does not adequately address the deterioration of fibrosis and cardiac function recovery. Therefore, numerous biomaterial platforms have been developed to address the above issues. In this review, we summarize the existing biomaterial delivery and restoring platforms, In addition, we also clarify the therapeutic strategies based on biomaterial platforms, including general strategies to block the fibrosis process and new strategies to promote cellular restoring effects. The development of structures with the ability to block further fibrosis progression as well as to promote cardiomyocytes viability should be the main research interests in myocardial fibrosis, and the reestablishment of structures necessary for normal cardiac function is central to the treatment of myocardial fibrosis. Finally, the future application of biomaterials for myocardial fibrosis is also highlighted.

Myocardial Strain Evaluation with Cardiovascular MRI: Physics, Principles, and Clinical Applications

Myocardial strain is a measure of myocardial deformation, which is a more sensitive imaging biomarker of myocardial disease than the commonly used ventricular ejection fraction. Although myocardial strain is commonly evaluated by using speckle-tracking echocardiography, cardiovascular MRI (CMR) is increasingly performed for this purpose. The most common CMR technique is feature tracking (FT), which involves postprocessing of routinely acquired cine MR images. Other CMR strain techniques require dedicated sequences, including myocardial tagging, strain-encoded imaging, displacement encoding with stimulated echoes, and tissue phase mapping. The complex systolic motion of the heart can be resolved into longitudinal strain, circumferential strain, radial strain, and torsion. Myocardial strain metrics include strain, strain rate, displacement, velocity, torsion, and torsion rate. Wide variability exists in the reference ranges for strain dependent on the imaging technique, analysis software, operator, patient demographics, and hemodynamic factors. In anticancer therapy cardiotoxicity, CMR myocardial strain can help identify left ventricular dysfunction before the decline of ejection fraction. CMR myocardial strain is also valuable for identifying patients with left ventricle dyssynchrony who will benefit from cardiac resynchronization therapy. CMR myocardial strain is also useful in ischemic heart disease, cardiomyopathies, pulmonary hypertension, and congenital heart disease. The authors review the physics, principles, and clinical applications of CMR strain techniques. Online supplemental material is available for this article. ^©RSNA, 2022.

Myocardial extracellular volume quantification by cardiac CT in pulmonary hypertension: Comparison with cardiac MRI

PURPOSE

Myocardial extracellular volume (ECV) measured by cardiac magnetic resonance imaging (MRI) has been suggested as a marker of disease severity in pulmonary hypertension (PH). However, consistency between ECVs quantified by computed tomography (CT) and MRI has not been sufficiently investigated in (PH). We investigated the utility of CT-ECV in PH, using MRI-ECV as a reference standard.

METHOD

We evaluated 20 patients with known or suspected PH who underwent dual-energy CT, cardiac MRI, and right heart catheterization. We used Pearson correlation analysis to investigate correlations between CT-ECV and MRI-ECV. We also assessed correlations between ECV and mean pulmonary artery pressure (mPAP).

RESULTS

CT-ECV showed a very strong correlation with MRI-ECV at the anterior (r = 0.83) and posterior right ventricular insertion points (RVIPs) (r = 0.84). CT-ECV and MRI-ECV were strongly correlated in the septum and left ventricular free wall (r = 0.79-0.73) but weakly correlated in the right ventricular free wall (r = 0.26). CT-ECV showed a strong correlation with mPAP in the anterior RVIP (r = 0.64) and a moderate correlation in the posterior RVIP and septum (r = 0.50-0.42). Compared with CT-ECV, MRI-ECV had a higher correlation with mPAP; however, the difference was not significant (anterior RVIP, r = 0.72 [MRI-ECV] vs. 0.64 [CT-ECV], p = 0.663; posterior RVIP, r = 0.67 vs. 0.50, p = 0.446).

CONCLUSION

Dual-energy CT can quantify myocardial ECV and yield results comparable to those obtained using cardiac MRI. CT-ECV in the anterior RVIP could be a noninvasive surrogate marker of disease severity in PH.

Empagliflozin reduces diffuse myocardial fibrosis by extracellular volume mapping: A meta-analysis of clinical studies

OBJECTIVE

The aim of the study was to evaluate the effect of empagliflozin on diffuse myocardial fibrosis by cardiac magnetic resonance (CMR) T1 mapping.

RESEARCH METHODS AND PROCEDURES

Databases including PubMed, Cochrane library, Embase, and Sinomed for clinical studies of empagliflozin on myocardial fibrosis were searched. Two authors extracted the data and evaluated study quality independently. Weighted mean difference (WMD) and 95% confidence intervals (CI) were used for continuous variables. Review Manager 5.3 was used to performed the analysis.

RESULTS

Six studies were included in this meta-analysis. One of the six studies was assessed as poor quality by the assessment of methodological quality; however, the remaining five studies were considered good. The WMD value of △extracellular volume (ECV) was merged by the fixed-effect model, and the pooled effect size was -1.48 (95% CI -1.76 to -1.21, P < 0.00001), which means in favor of empagliflozin. Heterogeneity analysis did not find any heterogeneity (chi² = 0.39, P = 0.82, I ² = 0%). In addition, empagliflozin had a tendency to reduce ECV compared to treatment before with no statistical significance (WMD = -0.29, 95% CI -1.26 to 0.67, P = 0.55; heterozygosity test, chi² = 2.66, P = 0.45, I ² = 0%). The WMD value of △native T1 was also merged by the fixed-effect model, but the pooled effect size showed neither statistical difference between empagliflozin and placebo treatment (WMD = -5.40, 95% CI -21.63 to 10.83, P = 0.51) nor heterogeneity (chi² = 0.05, P = 0.83, I ² = 0%).

CONCLUSIONS

Empagliflozin has cardiovascular benefits by reducing diffuse myocardial fibrosis. ECV could act as a non-invasive imaging tool to assess diffuse myocardial fibrosis and monitor disease progression.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=324804, identifier: CRD42022324804.

Extracellular Vesicle TGF-β1 Is Linked to Cardiopulmonary Dysfunction in Human Immunodeficiency Virus

Extracellular vesicles (EVs) have emerged as important mediators in cell-cell communication; however, their relevance in pulmonary hypertension (PH) secondary to human immunodeficiency virus (HIV) infection is yet to be explored. Considering that circulating monocytes are the source of the increased number of perivascular macrophages surrounding the remodeled vessels in PH, this study aimed to identify the role of circulating small EVs and EVs released by HIV-infected human monocyte-derived macrophages in the development of PH. We report significantly higher numbers of plasma-derived EVs carrying higher levels of TGF-β1 (transforming growth factor-β1) in HIV-positive individuals with PH compared with individuals without PH. Importantly, levels of these TGF-β1-loaded, plasma-derived EVs correlated with pulmonary arterial systolic pressures and CD4 counts but did not correlate with the Dl CO or viral load. Correspondingly, enhanced TGF-β1-dependent pulmonary endothelial injury and smooth muscle hyperplasia were observed. HIV-1 infection of monocyte-derived macrophages in the presence of cocaine resulted in an increased number of TGF-β1-high EVs, and intravenous injection of these EVs in rats led to increased right ventricle systolic pressure accompanied by myocardial injury and increased levels of serum ET-1 (endothelin-1), TNF-α, and cardiac troponin-I. Conversely, pretreatment of rats with TGF-β receptor 1 inhibitor prevented these EV-mediated changes. Findings define the ability of macrophage-derived small EVs to cause pulmonary vascular modeling and PH via modulation of TGF-β signaling and suggest clinical implications of circulating TGF-β-high EVs as a potential biomarker of HIV-associated PH.

Diverse Right Ventricular Remodeling Evaluated by MRI and Prognosis in Eisenmenger Syndrome With Different Shunt Locations

BACKGROUND

Congenital shunt location is related to Eisenmenger syndrome (ES) survival. Moreover, right ventricular (RV) remodeling is associated with poor survival in pulmonary hypertension.

PURPOSE

To investigate RV remodeling using comprehensive magnetic resonance imaging (MRI) techniques and identify its relationship with prognosis in ES subgroups classified by shunt location.

STUDY TYPE

Prospective observational study.

POPULATION

Fifty-four adults with ES (16 with pre-tricuspid shunt and 38 with post-tricuspid shunt).

FIELD STRENGTH/SEQUENCE

3.0 T/cine MRI with balanced steady-state free precession sequence, late gadolinium enhancement with inversion recovery segmented gradient echo sequence and phase-sensitive reconstruction, and T1 mapping with modified Look-Locker inversion recovery sequence.

ASSESSMENT

Demographics, clinical characteristics, hemodynamics, RV remodeling features (morphology, systolic function, RV-pulmonary artery (PA) coupling and myocardial fibrosis), and prognosis were compared between ES subgroups. The adverse endpoint was all-cause mortality or readmission for heart failure.

STATISTICAL TESTS

The independent samples t-test, Fisher's exact test or Chi-squared test, and the Kaplan-Meier method were used. P < 0.05 was considered significant.

RESULTS

Compared to patients with post-tricuspid shunt, patients with pre-tricuspid shunt were significantly older and had higher N-terminal pro-B-type natriuretic peptide concentrations and poorer exercise tolerance. Pre-tricuspid shunt showed significantly larger RV dimensions (end-diastolic volume index: 185.81 ± 37.49 vs. 98.20 ± 36.26 mL/m² ), worse RV ejection fraction (23.54% ± 12.35% vs. 40.82% ± 10.77%), and RV-PA decoupling (0.35 ± 0.31 vs. 0.72 ± 0.29). Biventricular myocardial fibrosis was significantly more severe in pre-tricuspid shunt than post-tricuspid shunt (extracellular volume, left ventricle: 35.85% ± 2.58% vs. 29.10% ± 5.20%; RV free wall: 30.93% ± 5.65% vs. 26.75% ± 5.15%). In addition, pre-tricuspid shunt demonstrated a significantly increased risk of adverse endpoint (hazard ratio: 2.938, 95% confidence interval: 1.204-7.172).

DATA CONCLUSION

ES with pre-tricuspid shunt might be a unique subtype with worse clinically decompensated RV remodeling and poor prognosis.

LEVEL OF EVIDENCE

2 Technical Efficacy Stage: 5.

Cardiac Magnetic Resonance Imaging in Pulmonary Arterial Hypertension: Ready for Clinical Practice and Guidelines?

Purpose of Review

Pulmonary arterial hypertension (PAH) is a progressive disease with high mortality. A greater understanding of the physiology and function of the cardiovascular system in PAH will help improve survival. This review covers the latest advances within cardiovascular magnetic resonance imaging (CMR) regarding diagnosis, evaluation of treatment, and prognostication of patients with PAH.

Recent Findings

New CMR measures that have been proven relevant in PAH include measures of ventricular and atrial volumes and function, tissue characterization, pulmonary artery velocities, and arterio-ventricular coupling.

Summary

CMR markers carry prognostic information relevant for clinical care such as treatment response and thereby can affect survival. Future research should investigate if CMR, as a non-invasive method, can improve existing measures or even provide new and better measures in the diagnosis, evaluation of treatment, and determination of prognosis of PAH.

Myocardial T1-mapping and extracellular volume in pulmonary arterial hypertension: A systematic review and meta-analysis

INTRODUCTION

Elevated myocardial T₁-mapping and extracellular volume (ECV) measured on cardiac MR (CMR) imaging is associated with myocardial abnormalities such as oedema or fibrosis. This meta-analysis aims to provide a summary of T₁-mapping and ECV values in pulmonary arterial hypertension (PAH) and compare their values with controls.

METHODS

We searched CENTRAL, MEDLINE, Embase, and Web of Science in August 2020. We included CMR studies reporting T₁-mapping or ECV values in adults with any type of PAH. We calculated the mean difference of T₁-values and ECV between PAH and controls.

RESULTS

We included 12 studies with 674 participants. T₁-values were significantly higher in PAH with the highest mean difference (MD) recorded at the RV insertion points (RVIP) (108 milliseconds (ms), 95% confidence intervals (CI) 89 to 128), followed by the RV free wall (MD 91 ms, 95% CI 56 to 126). The pooled mean T₁-value in PAH at the RVIP was 1084, 95% CI (1071 to 1097) measured using 1.5 Tesla Siemens systems. ECV was also higher in PAH with an MD of 7.5%, 95% CI (5.9 to 9.1) at the RV free wall.

CONCLUSION

T₁ mapping values in PAH patients are on average 9% higher than healthy controls when assessed under the same conditions including the same MRI system, magnetic field strength or sequence used for acquisition. The highest T₁ and ECV values are at the RVIP. T₁ mapping and ECV values in PH are higher than the values reported in cardiomyopathies and were associated with poor RV function and RV dilatation.

Diffuse myocardial fibrosis: mechanisms, diagnosis and therapeutic approaches

Diffuse myocardial fibrosis resulting from the excessive deposition of collagen fibres through the entire myocardium is encountered in a number of chronic cardiac diseases. This lesion results from alterations in the regulation of fibrillary collagen turnover by fibroblasts, facilitating the excessive deposition of type I and type III collagen fibres within the myocardial interstitium and around intramyocardial vessels. The available evidence suggests that, beyond the extent of fibrous deposits, collagen composition and the physicochemical properties of the fibres are also relevant in the detrimental effects of diffuse myocardial fibrosis on cardiac function and clinical outcomes in patients with heart failure. In this regard, findings from the past 20 years suggest that various clinicopathological phenotypes of diffuse myocardial fibrosis exist in patients with heart failure. In this Review, we summarize the current knowledge on the mechanisms and detrimental consequences of diffuse myocardial fibrosis in heart failure. Furthermore, we discuss the validity and usefulness of available imaging techniques and circulating biomarkers to assess the clinicopathological variation in this lesion and to track its clinical evolution. Finally, we highlight the currently available and potential future therapeutic strategies aimed at personalizing the prevention and reversal of diffuse myocardial fibrosis in patients with heart failure.

Underfilling decreases left ventricular function in pulmonary arterial hypertension

To evaluate the association between impaired left ventricular (LV) longitudinal function and LV underfilling in patients with pulmonary arterial hypertension (PAH). Thirty-nine patients with PAH and 18 age and sex-matched healthy controls were included. LV volume and left atrial volume (LAV) were delineated in short-axis cardiac magnetic resonance (CMR) cine images. LV longitudinal function was assessed from atrio-ventricular plane displacement (AVPD) and global longitudinal strain (GLS) was assessed using feature tracking in three long-axis views. LV filling was assessed by LAV and by pulmonary artery wedge pressure (PAWP) using right heart catheterisation. Patients had a smaller LAV, LV volume and stroke volume as well as a lower LV-AVPD and LV-GLS than controls. PAWP was 6 [IQR 5––9] mmHg in patients. LV ejection fraction did not differ between groups. LV stroke volume correlated with LV-AVPD (r = 0.445, p = .001), LV-GLS (r = − 0.549, p < 0.0001) and LAVmax (r = .585, p < 0.0001). Furthermore, LV-AVPD (r = .598) and LV-GLS (r = − 0.675) correlated with LAVmax (p < 0.0001 for both). Neither LV-AVPD, LV-GLS, LAVmax nor stroke volume correlated with PAWP. Impaired LV longitudinal function was associated with low stroke volume, low PAWP and a small LAV in PAH. Small stroke volumes and LAV, together with normal LA pressure, implies that the mechanism causing reduced LV longitudinal function is underfilling rather than an intrinsic LV dysfunction in PAH.

Right Ventricular Extracellular Volume with Dual-Layer Spectral Detector CT: Value in Chronic Thromboembolic Pulmonary Hypertension

Background Right ventricular (RV) extracellular volumes (ECVs), as a surrogate for histologic fibrosis, have not been sufficiently investigated. Purpose To evaluate and compare RV and left ventricular (LV) ECVs obtained with dual-layer spectral detector CT (DLCT) in chronic thromboembolic pulmonary hypertension (CTEPH) and investigate the clinical importance of RV ECV. Materials and Methods Retrospective analysis was performed on data from 31 patients with CTEPH (17 were not treated with pulmonary endarterectomy [PEA] or balloon pulmonary angioplasty [BPA] and 14 were) and eight control subjects who underwent myocardial delayed enhancement (MDE) DLCT from January 2019 to June 2020. The ECVs in the RV and LV walls were calculated by using iodine density as derived from spectral data pertaining to MDE. Statistical analyses were performed with one-way repeated analysis of variance with the Tukey post hoc test or the Kruskal-Wallis test with the Steel-Dwass test and linear regression analysis. Results The PEA- and BPA-naive group showed significantly higher ECVs than the PEA- or BPA-treated group and control group in the septum (28.2% ± 2.9 vs 24.3% ± 3.6, P = .005), anterior right ventricular insertion point (RVIP) (32.9% ± 4.6 vs 25.3% ± 3.6, P < .001), posterior RVIP (35.2% ± 5.2 vs 27.3% ± 4.2, P < .001), mean RVIP (34.0% ± 4.2 vs 26.3% ± 3.4, P < .001), RV free wall (29.5% ± 3.3 vs 25.9% ± 4.1, P = .036), and mean RV wall (29.1% ± 3.0 vs 26.1% ± 3.1, P = .029). There were no significant differences between the PEA- or BPA-treated group and control subjects in these segments (septum, P = .93; anterior RVIP, P = .38; posterior RVIP, P = .52; mean RVIP, P = .36; RV free wall, P = .97; and mean RV, P = .33). There were significant correlations between ECV and mean pulmonary artery pressure (PAP) or brain natriuretic peptide (BNP) in the mean RVIP (mean PAP: R = 0.66, P < .001; BNP: R = 0.44, P = .014) and the mean RV (mean PAP: R = 0.49, P = .005; BNP: R = 0.44, P = .013). Conclusion Right ventricular and right ventricular insertion point extracellular volumes could be noninvasive surrogate markers of disease severity and reverse tissue remodeling in chronic thromboembolic pulmonary hypertension. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Sandfort and Bluemke in this issue.

Cardiac Magnetic Resonance in Pulmonary Hypertension-an Update

PURPOSE OF REVIEW

This article reviews advances over the past 3 years in cardiac magnetic resonance (CMR) imaging in pulmonary hypertension (PH). We aim to bring the reader up-to-date with CMR applications in diagnosis, prognosis, 4D flow, strain analysis, T1 mapping, machine learning and ongoing research.

RECENT FINDINGS

CMR volumetric and functional metrics are now established as valuable prognostic markers in PH. This imaging modality is increasingly used to assess treatment response and improves risk stratification when incorporated into PH risk scores. Emerging techniques such as myocardial T1 mapping may play a role in the follow-up of selected patients. Myocardial strain may be used as an early marker for right and left ventricular dysfunction and a predictor for mortality. Machine learning has offered a glimpse into future possibilities. Ongoing research of new PH therapies is increasingly using CMR as a clinical endpoint.

SUMMARY

The last 3 years have seen several large studies establishing CMR as a valuable diagnostic and prognostic tool in patients with PH, with CMR increasingly considered as an endpoint in clinical trials of PH therapies. Machine learning approaches to improve automation and accuracy of CMR metrics and identify imaging features of PH is an area of active research interest with promising clinical utility.

Left ventricular ischemia in pre-capillary pulmonary hypertension: a cardiovascular magnetic resonance study

Background

Prognosis in pulmonary arterial hypertension (PAH) is largely dependent on right ventricular (RV) function. However, recent studies have suggested the presence of left ventricular (LV) dysfunction in PAH patients. The potential role of LV ischemia, as a contributor to progressive LV dysfunction, has not been systematically studied in PAH. We aim to assess the presence and extent of LV myocardial ischemia in patients with known PH and without obstructive coronary artery disease (CAD), using oxygen-sensitive (OS) cardiovascular magnetic resonance (CMR) and stress/rest CMR T1 mapping.

Methods

We prospectively recruited 28 patients with right heart catheter-proven PH and no significant CAD, 8 patients with known CAD and 11 normal age-matched controls (NC). OS-CMR images were acquired using a T2* sequence and T1 maps were acquired using Shortened Modified Look-Locker Inversion recovery (ShMOLLI) at rest and adenosine-induced stress vasodilatation; ΔOS-CMR signal intensity (SI) index (stress/rest SI) and ΔT1 reactivity (stress-rest/rest T1 mapping) were calculated.

Results

Global LV ΔOS SI index was significantly lower in PH patients compared with controls (11.1%±6.7% vs. 20.5%±10.5%, P=0.016), as was ΔT1 reactivity (5.2%±4.5% vs. 8.0%±2.9%, P=0.047). The ischemic segments of CAD patients had comparable ΔOS SI (10.3%±6.4% vs. 11.1%±6.7%, P=0.773) to PH patients, but lower ΔT1 reactivity (1.1%±4.2% vs. 5.2%±4.5%, P=0.036).

Conclusions

Decreased OS-CMR SI and T1 reactivity signify the presence of impaired myocardial oxygenation and vasodilatory response in PH patients. Given their unobstructed epicardial coronary arteries, this is likely secondary to coronary microvascular dysfunction (CMD).

Cardiac MRI in Pulmonary Hypertension: From Magnet to Bedside

Pulmonary hypertension (PH) is a disease characterized by progressive rise of pulmonary artery (PA) pressure, which can lead to right ventricular (RV) failure. It is usually diagnosed late because of the nonspecificity of its symptoms. RV performance and adaptation to an increased afterload, reflecting the interaction of the PA and RV as a morphofunctional unit, constitute a critical determinant of morbidity and mortality in these patients. Therefore, early detection of dysfunction may prevent treatment failure. Cardiac MRI constitutes one of the most complete diagnostic modalities for diagnosing PH. It allows evaluation of the morphology and hemodynamics of the PA and RV. Several cine steady-state free-precession (SSFP)-derived parameters (indexed RV end-diastolic volume or RV systolic volume) and phase-contrast regional area change have been suggested as powerful biomarkers for prognosis and treatment. Recently, new cardiac MRI sequences have been added to clinical protocols for PH evaluation, providing brand-new information. Strain analysis with myocardial feature tracking can help detect early RV dysfunction, even with preserved ejection fraction. Four-dimensional flow cardiac MRI can enhance assessment of advanced RV and PA hemodynamics. Late gadolinium enhancement (LGE) imaging may allow detection of replacement fibrosis in PH patients, which is associated with poor outcome. T1 mapping may help detect interstitial fibrosis, even with normal LGE imaging results. The authors analyze the imaging workup of PH with a focus on the role of morphologic and functional cardiac MRI in diagnosis and management of PH, including some of the newer techniques. Online supplemental material is available for this article. ^©RSNA, 2020.

Icariside II improves myocardial fibrosis in spontaneously hypertensive rats by inhibiting collagen synthesis

OBJECTIVES

We aimed to investigate the effects of icariside II (ICS II) on myocardial fibrosis in spontaneously hypertensive rats (SHRs) and to explore the possible mechanisms.

METHODS

We used SHRs as animal models, and we administered ICS II (4, 8 or 16 mg/kg) orally by gavage for 12 consecutive weeks (Fu et al., Biomed Pharmacother 2018; 100: 64). The left ventricular morphology of the rats was observed using haematoxylin-eosin (HE) staining. The occurrence of myocardial interstitial fibrosis was detected by Masson's trichrome staining. The protein levels of alpha smooth muscle actin (α-SMA), Collagen I, III, matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9, respectively), tissue inhibitor of metalloproteinase 1 (TIMP-1), transforming growth factor-β1 (TGF-β1), phospho-Smad2 (p-Smad2), phospho-Smad3 (p-Smad3) and phospho-p38 (p-p38) were examined by Western blotting.

KEY FINDINGS

The results suggested that ICS II improved myocardial interstitial and perivascular collagen deposition and decreased Collagen I/III and α-SMA expression. ICS II (8 and 16 mg/kg) downregulated the expression of MMP-2 and MMP9 and upregulated the expression of TIMP1. In addition, the protein levels of p-Smad2/3, TGF-β1 and p-p38 were decreased by ICS II treatment.

CONCLUSIONS

The results suggest that ICS II can inhibit the expression of Collagen I and Collagen III through the MMP/TIMP-1 and TGF-β1/Smad2,3/p-p38 signalling pathways and that it has therapeutic effects on myocardial fibrosis.

Right Ventricular Fibrosis

The role of right ventricular (RV) fibrosis in pulmonary hypertension (PH) remains a subject of ongoing discussion. Alterations of the collagen network of the extracellular matrix may help prevent ventricular dilatation in the pressure-overloaded RV. At the same time, fibrosis impairs cardiac function, and a growing body of experimental data suggests that fibrosis plays a crucial role in the development of RV failure. In idiopathic pulmonary arterial hypertension and chronic thromboembolic PH, the RV is exposed to a ≈5 times increased afterload, which makes these conditions excellent models for studying the impact of pressure overload on RV structure. With this review, we present clinical evidence of RV fibrosis in idiopathic pulmonary arterial hypertension and chronic thromboembolic PH, explore the correlation between fibrosis and RV function, and discuss the clinical relevance of RV fibrosis in patients with PH. We postulate that RV fibrosis has a dual role in patients with pressure-overloaded RVs of idiopathic pulmonary arterial hypertension and chronic thromboembolic PH: as part of an adaptive response to prevent cardiomyocyte overstretch and to maintain RV shape for optimal function, and as part of a maladaptive response that increases diastolic stiffness, perturbs cardiomyocyte excitation-contraction coupling, and disrupts the coordination of myocardial contraction. Finally, we discuss potential novel therapeutic strategies and describe more sensitive techniques to quantify RV fibrosis, which may be used to clarify the causal relation between RV fibrosis and RV function in future research.

Pressure overload induced right ventricular remodeling is not attenuated by the anti-fibrotic agent pirfenidone

Cardiac fibrosis contributes to the development of heart failure in pulmonary hypertension. We aimed to assess the development of fibrosis and the effects of treatment with the anti-fibrotic agent pirfenidone in pressure overload induced right ventricular (RV) failure. Wistar rat weanlings were randomized to pulmonary trunk banding (PTB) or sham surgery. One week after the procedure, PTB rats were randomized into two groups with either six weeks on standard chow or treatment with pirfenidone mixed in chow (700 mg/kg/day). RV hemodynamic effects were evaluated by echocardiography, cardiac magnetic resonance imaging (MRI), and pressure-volume measurements. Sections from the isolated RV, left ventricle, and septum were sampled systematically; stereological point grids and the nucleator were used to estimate volume of fibrosis and cardiac hypertrophy, respectively. PTB caused RV failure in all rats subjected to the procedure. The volume fraction of fibrosis in the RV increased threefold in PTB rats corresponding to a sixfold increase in total volume of RV fibrosis. Volume fraction of fibrosis and total volume of fibrosis also increased in the septum and in the left ventricle. Pirfenidone reduced body weight but did not improve RV hemodynamics or reduce cardiac fibrosis. RV cardiomyocyte profile area was increased twofold in PTB rats without any effect of pirfenidone. RV pressure overload after PTB induced not only RV but also septal and left ventricular fibrosis assessed by stereology. Treatment with pirfenidone reduced body weight but did not reduce the development of cardiac fibrosis or delay the progression of RV failure.

Cardiac magnetic resonance T1 mapping. Part 2: Diagnostic potential and applications

Non-invasive identification and differentiation of myocardial diseases represents the primary objectives of cardiac magnetic resonance (CMR) longitudinal relaxation time (T1) and extracellular volume (ECV) mapping. Given the fact that myocardial T1 and ECV values overlap throughout and within left ventricular phenotypes, a central issue to be addressed is whether and to what extent myocardial T1 and ECV mapping provides additional or superior diagnostic information to standard CMR imaging, and whether native T1 mapping could be employed as a non-contrast alternative to late gadolinium enhancement (LE) imaging. The present review aims to summarize physiological and pathophysiological alterations in native T1 and ECV values and summarized myocardial T1 and ECV alterations associated with cardiac diseases to support the translation of research findings into routine CMR imaging.

A Computational Cardiac Model for the Adaptation to Pulmonary Arterial Hypertension in the Rat

Pulmonary arterial hypertension (PAH) imposes pressure overload on the right ventricle (RV), leading to RV enlargement via the growth of cardiac myocytes and remodeling of the collagen fiber architecture. The effects of these alterations on the functional behavior of the right ventricular free wall (RVFW) and organ-level cardiac function remain largely unexplored. Computational heart models in the rat (RHMs) of the normal and hypertensive states can be quite valuable in simulating the effects of PAH on cardiac function to gain insights into the pathophysiology of underlying myocardium remodeling. We thus developed high-fidelity biventricular finite element RHMs for the normal and post-PAH hypertensive states using extensive experimental data collected from rat hearts. We then applied the RHM to investigate the transmural nature of RVFW remodeling and its connection to wall stress elevation under PAH. We found a strong correlation between the longitudinally-dominated fiber-level adaptation of the RVFW and the transmural alterations of relevant wall stress components. We further conducted several numerical experiments to gain new insights on how the RV responds both normally and in the post-PAH state. We found that the effect of pressure overload alone on the increased contractility of the RV is comparable to the effects of changes in the RV geometry and stiffness. Furthermore, our RHMs provided fresh perspectives on long-standing questions of the functional role of the interventricular septum in RV function. Specifically, we demonstrated that an inaccurate identification of the mechanical adaptation of the septum can lead to a significant underestimation of RVFW contractility in the post-PAH state. These findings show how integrated experimental-computational models can facilitate a more comprehensive understanding of the cardiac remodeling events during PAH.

Left Atrial Epicardial Fat Volume Is Associated With Atrial Fibrillation: A Prospective Cardiovascular Magnetic Resonance 3D Dixon Study

BACKGROUND

Recent studies demonstrated a strong association between atrial fibrillation (AF) and epicardial fat around the left atrium (LA). We sought to assess whether epicardial fat volume around the LA is associated with AF, and to determine the additive value of LA-epicardial fat measurements to LA structural remodeling for identifying patients with AF using 3-dimensional multi-echo Dixon fat-water separated cardiovascular magnetic resonance.

METHODS AND RESULTS

A total of 105 subjects were studied: 53 patients with a history of AF and 52 age-matched patients with other cardiovascular diseases but no history of AF. The 3-dimensional multi-echo Dixon fat-water separated sequence was performed for LA-epicardial fat measurements. AF patients had significantly greater LA-epicardial fat (28.9±12.3 and 14.2±7.3 mL for AF and non-AF, respectively; P<0.001) and LA volume (110.8±38.2 and 89.7±30.3 mL for AF and non-AF, respectively; P=0.002). LA-epicardial fat adjusted for LA volume was still higher in patients with AF compared with those without AF (P<0.001). LA-epicardial fat and hypertension were independently associated with the risk of AF (odds ratio, 1.17; 95% confidence interval, 1.10%-1.25%, P<0.001, and odds ratio, 3.29; 95% confidence interval, 1.17%-9.27%, P=0.03, respectively). In multivariable logistic regression analysis adjusted for body surface area, LA-epicardial fat remained significant and an increase per mL was associated with a 42% increase in the odds of AF presence (odds ratio, 1.42; 95% confidence interval, 1.23%-1.62%, P<0.001). Combined assessment of LA-epicardial fat and LA volume provided greater discriminatory performance for detecting AF than LA volume alone (c-statistic=0.88 and 0.74, respectively, DeLong test; P<0.001).

CONCLUSIONS

Cardiovascular magnetic resonance 3-dimensional Dixon-based LA-epicardial fat volume is significantly increased in AF patients. LA-epicardial fat measured by 3-dimensional Dixon provides greater performance for detecting AF beyond LA structural remodeling.

Baicalin inhibits pressure overload-induced cardiac fibrosis through regulating AMPK/TGF-β/Smads signaling pathway

AMP-activated protein kinase (AMPK) is a central regulator of multiple metabolic pathways. It has been shown that activation of AMPK could inhibit fibroblast proliferation and extracellular matrix (ECM) accumulation, thereby suppressing cardiac fibrosis. Baicalin, the major component found in skullcap, possesses multiple protective effects on the cardiovascular system. However, little is known about the effect of baicalin on cardiac fibrosis and the molecular mechanism by which baicalin exerts its anti-fibrotic effects has not been investigated. In this study, we revealed that baicalin could inhibit cell proliferation, collagen synthesis, fibronectin (FN) and Connective tissue growth factor (CTGF) protein expression in cardiac fibroblasts induced by angiotensin Ⅱ (Ang Ⅱ). It also ameliorated cardiac fibrosis in rats submitted to abdominal aortic constriction (AAC). Moreover, baicalin inhibited transforming growth factor-β (TGF-β)/Smads signaling pathway stimulated with Ang Ⅱ through activating AMPK. Subsequently, we also demonstrated that baicalin attenuated Ang Ⅱ-induced Smad3 nuclear translocation, and interaction with transcriptional coactivator p300, but promoted the interaction of p300 and AMPK. Taken together, these results provide the first evidence that the effect of baicalin against cardiac fibrosis may be attributed to its regulation on AMPK/TGF-β/Smads signaling, suggesting the therapeutic potential of baicalin on the prevention of cardiac fibrosis and heart failure.

Non-invasive imaging of global and regional cardiac function in pulmonary hypertension

Pulmonary hypertension (PH) is a progressive illness characterized by elevated pulmonary artery pressure; however, the main cause of mortality in PH patients is right ventricular (RV) failure. Historically, improving the hemodynamics of pulmonary circulation was the focus of treatment; however, it is now evident that cardiac response to a given level of pulmonary hemodynamic overload is variable but plays an important role in the subsequent prognosis. Non-invasive tests of RV function to determine prognosis and response to treatment in patients with PH is essential. Although the right ventricle is the focus of attention, it is clear that cardiac interaction can cause left ventricular dysfunction, thus biventricular assessment is paramount. There is also focus on the atrial chambers in their contribution to cardiac function in PH. Furthermore, there is evidence of regional dysfunction of the two ventricles in PH, so it would be useful to understand both global and regional components of dysfunction. In order to understand global and regional cardiac function in PH, the most obvious non-invasive imaging techniques are echocardiography and cardiac magnetic resonance imaging (CMRI). Both techniques have their advantages and disadvantages. Echocardiography is widely available, relatively inexpensive, provides information regarding RV function, and can be used to estimate RV pressures. CMRI, although expensive and less accessible, is the gold standard of biventricular functional measurements. The advent of 3D echocardiography and techniques including strain analysis and stress echocardiography have improved the usefulness of echocardiography while new CMRI technology allows the measurement of strain and measuring cardiac function during stress including exercise. In this review, we have analyzed the advantages and disadvantages of the two techniques and discuss pre-existing and novel forms of analysis where echocardiography and CMRI can be used to examine atrial, ventricular, and interventricular function in patients with PH at rest and under stress.

Association of native T1 times with biventricular function and hemodynamics in precapillary pulmonary hypertension

In precapillary pulmonary hypertension (PH) patients, we sought to (1) investigate the relationship between ventricular insertion point (VIP) T1 times, hemodynamic parameters, and biventricular function, and (2) determine the predictors of anterior and inferior VIP T1 time. Twenty-two patients with precapillary PH underwent 1.5-T cardiac MR, right heart catheterization (RHC), and echocardiography. A group of 10 healthy age- and sex-matched volunteers served as controls. Biventricular function, morphology and mass were obtained from short-axis cine images. Native T1 times at anterior, inferior VIP, septum and LV lateral wall were respectively derived from all subjects. Mixed venous oxygen saturation (SvO₂) was the strongest hemodynamic parameters correlating with anterior (r_p = -0.67, P = 0.001) and inferior VIP T1 time (r_p = -0.81, P < 0.001). Elevated VIP T1 times were associated with reduced right ventricular (RV) ejection fraction, RV longitudinal and transverse motion, and increased RV end-diastolic and end-systolic volume index. LV diastolic function, quantified as mitral E velocity, was negatively correlated with anterior, inferior VIP (r_p = -0.55, P = 0.01) and septal T1 times (r_p = -0.50, P = 0.02), and positively correlated with RV systolic function and wall motion. In multivariate linear regression analyses, systolic eccentricity index (sEI) was the independent predictor of average VIPs T1 time (β= 0.47, P < 0.01), and remained significant correlation after adjustment of RHC and demographic parameters. In patients with precapillary PH, VIP T1 times are associated with biventricular function and hemodynamic parameters. Among all the parameters, sEI acts as a determinant of average VIPs T1 time.