Autophagy and ubiquitin-dependent proteolysis processes in left ventricular mass loss in pulmonary arterial hypertension.

The goal of this study was to evaluate the intensity of autophagy and ubiquitin-dependent proteolysis processes occurring in myocardium of left ventricle (LV) in subsequent stages of pulmonary arterial hypertension (PAH) to determine mechanisms responsible for LV mass loss in a monocrotaline-induced PAH rat model. LV myocardium samples collected from 32 Wistar rats were analyzed in an early PAH group (n = 8), controls time-paired (n = 8), an end-stage PAH group (n = 8), and their controls (n = 8). Samples were subjected to histological analyses with immunofluorescence staining, autophagy assessment by western blotting, and evaluation of ubiquitin-dependent proteolysis in the LV by immunoprecipitation of ubiquitinated proteins. Echocardiographic, hemodynamic, and heart morphometric parameters were assessed regularly throughout the experiment. Considerable morphological and hemodynamic remodeling of the LV was observed over the course of PAH. The end-stage PAH was associated with significantly impaired LV systolic function and a decrease in LV mass. The LC3B-II expression in the LV was significantly higher in the end-stage PAH group compared to the early PAH group (p = 0.040). The measured LC3B-II/LC3B-I ratios in the end-stage PAH group were significantly elevated compared to the controls (p = 0.039). Immunofluorescence staining showed a significant increase in the abundance of LC3 puncta in the end-stage PAH group compared to the matched controls. There were no statistically significant differences in the levels of expression of all ubiquitinated proteins when comparing both PAH groups and matched controls. Autophagy may be considered as the mechanism behind the LV mass loss at the end stage of PAH.

The value of right ventricular pulmonary artery coupling in determining the prognosis of patients with sepsis.

The outcomes of patients with sepsis are influenced by the contractile function of the right ventricle (RV), but the impact of cardiopulmonary interaction in ICU-mortality of sepsis patients remains unclear. This study aims to investigate the ICU-mortality impact of right ventricular-pulmonary artery (RV-PA) coupling in patients with sepsis. We employed echocardiography to assess patients with sepsis within the initial 24 h of their admission to the ICU. RV-PA coupling was evaluated using the tricuspid annular plane systolic excursion (TAPSE) to pulmonary artery systolic pressure (PASP) ratio. A total of 92 subjects were enrolled, with 55 survivors and 37 non-survivors. TAPSE/PASP ratio assessed mortality with an area under the curve (AUC) of 0.766 (95% CI 0.670-0.862) and the optimal cutoff value was 0.495 mm/mmHg. We constructed a nomogram depicting the TAPSE/PASP in conjunction with IL-6 and Lac for the joint prediction of sepsis prognosis, and demonstrated the highest predictive capability (AUC = 0.878, 95% CI 0.809-0.948). In conclusion, the TAPSE/PASP ratio demonstrated prognostic value for ICU mortality in sepsis patients. The nomogram, which combines the TAPSE/PASP, IL-6, and LAC, demonstrated enhanced predictive efficacy for the prognosis of sepsis patients.

Multicenter validation study for automated left ventricular ejection fraction assessment using a handheld ultrasound with artificial intelligence.

We sought to validate the ability of a novel handheld ultrasound device with an artificial intelligence program (AI-POCUS) that automatically assesses left ventricular ejection fraction (LVEF). AI-POCUS was used to prospectively scan 200 patients in two Japanese hospitals. Automatic LVEF by AI-POCUS was compared to the standard biplane disk method using high-end ultrasound machines. After excluding 18 patients due to infeasible images for AI-POCUS, 182 patients (63 ± 15 years old, 21% female) were analyzed. The intraclass correlation coefficient (ICC) between the LVEF by AI-POCUS and the standard methods was good (0.81, p < 0.001) without clinically meaningful systematic bias (mean bias -1.5%, p = 0.008, limits of agreement ± 15.0%). Reduced LVEF < 50% was detected with a sensitivity of 85% (95% confidence interval 76%-91%) and specificity of 81% (71%-89%). Although the correlations between LV volumes by standard-echo and those by AI-POCUS were good (ICC > 0.80), AI-POCUS tended to underestimate LV volumes for larger LV (overall bias 42.1 mL for end-diastolic volume). These trends were mitigated with a newer version of the software tuned using increased data involving larger LVs, showing similar correlations (ICC > 0.85). In this real-world multicenter study, AI-POCUS showed accurate LVEF assessment, but careful attention might be necessary for volume assessment. The newer version, trained with larger and more heterogeneous data, demonstrated improved performance, underscoring the importance of big data accumulation in the field.

Efficacy of mitral annular velocity as an alternative marker of left ventricular global longitudinal strain to detect the risk of cancer therapy-related cardiac disorders.

PURPOSE: Left ventricular longitudinal function can be rapidly evaluated by measuring S' and mitral annular plane systolic excursion (MAPSE) using tissue Doppler imaging. Even when the image quality is poor and the left ventricular endocardium is not visible, S' and MAPSE can be measured if the mitral annulus is visible. However, the utility of S' and MAPSE in diagnosing cancer therapy-related cardiac dysfunction (CTRCD) remains unclear. This study aimed to examine the diagnostic performance of S' and MAPSE and determine appropriate cutoff values. METHODS: We retrospectively enrolled 279 breast cancer patients who underwent pre- or postoperative chemotherapy with anthracyclines and trastuzumab from April 2020 to November 2022. We compared echocardiographic data before chemotherapy, 6 months after chemotherapy initiation, and 1 year later. CTRCD was defined as a decrease in left ventricular ejection fraction below 50%, with a decrease of ≥10% from baseline or a relative decrease in left ventricular global longitudinal strain (LVGLS) of ≥15%. RESULTS: A total of 256 participants were included in this study, with a mean age of 50.2 ± 11 years. Fifty-six individuals (22%) developed CTRCD within 1 year after starting chemotherapy. The cutoff value for septal S' was 6.85 cm/s (AUC = .81, p < .001; sensitivity 74%; specificity 73%), and for MAPSE was 11.7 mm (AUC = .65, p = .02; sensitivity 79%; specificity 45%). None of the cases with septal S' exceeding 6.85 cm/s had an LVGLS of ≤15%. CONCLUSIONS: Septal S' is a useful indicator for diagnosing CTRCD. HIGHLIGHTS: Septal S' decreased at the same time or earlier than the decrease in LVGLS. The septal S' demonstrated higher diagnostic ability for CTRCD compared to LVGLS.

Ventricular restoration in adults with huge congenital left ventricular aneurysm: report of two cases.

Congenital ventricular aneurysms (CVA) are rare cardiac anomalies that have been predominantly described in the Black population. They are characterized by an akinetic ventricular protrusion that is commonly located at the basal and apical segments. Although the diagnosis is often incidental and the majority of patients are asymptomatic, life-threatening events such as persistent ventricular arrhythmias, CVA rupture, and heart failure are not uncommon. However, no standardized therapy is currently available and good outcomes have been reported with both conservative and surgical management. We report the cases of two young Black African patients with huge symptomatic CVA lesions who underwent successful surgical repair with a ventricular restoration technique. Both cases were consulted for chest pain and dyspnea. Chest X-ray and transthoracic Doppler echocardiography suggested the diagnosis. Thoracic angioscanner and thoracic magnetic resonance imaging confirmed the diagnosis. Both patients underwent successful surgery. This case report aims to revisit the diagnostic and therapeutic approach to this rare pathology, in our professional environment.

Exploratory analysis of predictors of ventricular aneurysm in a cohort of 291 patients with acute myocardial infarction.

OBJECTIVE: In this study, we explored the determinants of ventricular aneurysm development following acute myocardial infarction (AMI), thereby prompting timely interventions to enhance patient prognosis. METHODS: In this retrospective cohort analysis, we evaluated 297 AMI patients admitted to the First People's Hospital of Changzhou. The study was structured as follows. Comprehensive baseline data collection included hematological evaluations, ECG, echocardiography, and coronary angiography upon admission. Within 3 months post-AMI, cardiac ultrasounds were administered to detect ventricular aneurysm development. Univariate and multivariate logistic regression analysis were employed to pinpoint the determinants of ventricular aneurysm formation. Subsequently, a predictive model was formulated for ventricular aneurysm post-AMI. Moreover, the diagnostic efficacy of this model was appraised using the ROC curves. RESULTS: In our analysis of 291 AMI patients, spanning an age range of 32-91 years, 247 were male (84.9%). At the conclusion of a 3-month observational period, the cohort bifurcated into two subsets: 278 patients without ventricular aneurysm and 13 with evident ventricular aneurysm. Distinguishing features of the ventricular aneurysm subgroup were markedly higher values for age, B-type natriuretic peptide(BNP), Left atrium(LA), Left ventricular end-diastolic dimension (LEVDD), left ventricular end systolic diameter (LVEWD), E-wave velocity (E), Left atrial volume (LAV), E/A ratio (E/A), E/e ratio (E/e), ECG with elevated adjacent four leads(4 ST-Elevation), and anterior wall myocardial infarction(AWMI) compared to their counterparts (p < 0.05). Among the singular predictive factors, total cholesterol (TC) emerged as the most significant predictor for ventricular aneurysm development, exhibiting an AUC of 0.704. However, upon crafting a multifactorial model that incorporated gender, TC, an elevated ST-segment in adjacent four leads, and anterior wall infarction, its diagnostic capability: notably surpassed that of the standalone TC, yielding an AUC of 0.883 (z = -9.405, p = 0.000) as opposed to 0.704. Multivariate predictive model included gender, total cholesterol, ST elevation in 4 adjacent leads, anterior myocardial infarction, the multivariate predictive model showed better diagnostic efficacy than single factor index TC (AUC: 0. 883 vs. 0.704,z =-9.405, p = 0.000), it also improved predictive power for correctly reclassifying ventricular aneurysm occurrence in patients with AMI, NRI = 28.42% (95% CI: 6.29-50.55%; p = 0.012). Decision curve analysis showed that the use of combination model had a positive net benefit. CONCLUSION: Lipid combined with ECG model after myocardial infarction could be used to predict the formation of ventricular aneurysm and aimed to optimize and adjust treatment strategies.

Transmural APD heterogeneity determines ventricular arrhythmogenesis in LQT8 syndrome: Insights from Bidomain computational modeling.

Long QT Syndrome type 8 (LQT8) is a cardiac arrhythmic disorder associated with Timothy Syndrome, stemming from mutations in the CACNA1C gene, particularly the G406R mutation. While prior studies hint at CACNA1C mutations' role in ventricular arrhythmia genesis, the mechanisms, especially in G406R presence, are not fully understood. This computational study explores how the G406R mutation, causing increased transmural dispersion of repolarization, induces and sustains reentrant ventricular arrhythmias. Using three-dimensional numerical simulations on an idealized left-ventricular model, integrating the Bidomain equations with the ten Tusscher-Panfilov ionic model, we observe that G406R mutation with 11% and 50% heterozygosis significantly increases transmural dispersion of repolarization. During S1-S4 stimulation protocols, these gradients facilitate conduction blocks, triggering reentrant ventricular tachycardia. Sustained reentry pathways occur only with G406R mutation at 50% heterozygosis, while neglecting transmural heterogeneities of action potential duration prevents stable reentry, regardless of G406R mutation presence.

Cardiac Perforation Caused By Pectus Excavatum Metal Bar Stabilizer: A Case Report.

This paper reports the case of a female patient who underwent minimally invasive repair of pectus excavatum (MIRPE) in another service that evolved with bar rotation and cardiac perforation caused by the left stabilizer. The unique and frightening aspect of the case is that despite having the stabilizer inside the ventricle, the patient was oligosymptomatic: occasional chest pain and respiratory discomfort. Preoperative imaging showed rotation of the bar with stabilizers within the thoracic cavity. During surgery, intense ossification was observed around the prosthesis and it was noted that the left stabilizer had perforated the patient's left ventricle. Cardiac repair required a Clamshell incision and cardiopulmonary bypass. This case reinforces the validity of late radiological follow-up after MIRPE in an attempt to avoid this type of event, and the need to reevaluate the use of stabilizers perpendicular to the bar since they are not safe to prevent rotation of these implants.

Variant patterns of electrical activation and recovery in normal human hearts revealed by noninvasive electrocardiographic imaging.

AIMS: Although electrical activity of the normal human heart is well characterized by the electrocardiogram, detailed insights into within-subject and between-subject variations of ventricular activation and recovery by noninvasive electroanatomic mapping are lacking. We characterized human epicardial activation and recovery within and between normal subjects using non-invasive electrocardiographic imaging (ECGI) as a basis to better understand pathology. METHODS AND RESULTS: Epicardial activation and recovery were assessed by ECGI in 22 normal subjects, 4 subjects with bundle branch block (BBB) and 4 with long-QT syndrome (LQTS). We compared characteristics between the ventricles [left ventricle (LV) and right ventricle (RV)], sexes, and age groups (<50/≥50years). Pearson's correlation coefficient (CC) was used for within-subject and between-subject comparisons. Age of normal subjects averaged 49 ± 14 years, 6/22 were male, and no structural/electrical heart disease was present. The average activation time was longer in LV than in RV, but not different by sex or age. Electrical recovery was similar for the ventricles, but started earlier and was on average shorter in males. Median CCs of between-subject comparisons of the ECG signals, activation, and recovery patterns were 0.61, 0.32, and 0.19, respectively. Within-subject beat-to-beat comparisons yielded higher CCs (0.98, 0.89, and 0.82, respectively). Activation and/or recovery patterns of patients with BBB or LQTS contrasted significantly with those found in the normal population. CONCLUSION: Activation and recovery patterns vary profoundly between normal subjects, but are stable individually beat to beat, with a male preponderance to shorter recovery. Individual characterization by ECGI at baseline serves as reference to better understand the emergence, progression, and treatment of electrical heart disease.

Evaluation of the prognostic value of papillary muscle-free strain in patients with hypertrophic cardiomyopathy.

BACKGROUND: The prognosis of hypertrophic cardiomyopathy (HCM) varies from mild disease with a normal life expectancy to heart failure and sudden cardiac death (SCD). The identification of patients who are at high risk for SCD remains challenging. AIMS: In this study, we evaluated the prognostic value of papillary muscle-free strain in HCM patients. METHODS AND RESULTS: Seventy-nine patients with a diagnosis of HCM were included in this study. Patients were divided into low/intermediate-risk (n = 57) and high-risk (n = 22) groups. Two-dimensional (2-D) echocardiography and strain imaging were performed for each patient. The mean age of the study population was 53.85 ± 15.88 years; 47 (59.5%) of them were male. During a mean follow-up duration of 74.45 ± 17.03 months, 12 patients died. A comparison of the low-intermediate and high-SCD risk groups revealed that patients in the high-SCD risk group had greater maximal wall thickness, interventricular septum thickness, posterior wall thickness, and left ventricular mass index (LVMI) and lower (less negative) global longitudinal, anterolateral papillary muscle (ALPM) and posteromedial papillary muscle (PMPM) free strain. Additionally, a history of syncope and ICD implantation were found to be more common in patients with high SCD risk scores. The SCD risk score was positively correlated with the global longitudinal strain, ALPM-free strain, and PMPM-free strain (r = .528, r = .658, and r = .600, respectively; p < .001 for all). Our results showed that the LVMI, presence of syncope, global longitudinal strain, and ALPM-free strain were predictors of death. CONCLUSIONS: Decreased papillary muscle-free strain values might have prognostic value in patients with HCM.

A Novel Workflow for Electrophysiology Studies in Patients with Brugada Syndrome.

Brugada Syndrome (BrS) is a primary electrical epicardial disease characterized by ST-segment elevation followed by a negative T-wave in the right precordial leads on the surface electrocardiogram (ECG), also known as the 'type 1' ECG pattern. The risk stratification of asymptomatic individuals with spontaneous type 1 ECG pattern remains challenging. Clinical and electrocardiographic prognostic markers are known. As none of these predictors alone is highly reliable in terms of arrhythmic prognosis, several multi-factor risk scores have been proposed for this purpose. This article presents a new workflow for processing endocardial signals acquired with high-density RV electro-anatomical mapping (HDEAM) from BrS patients. The workflow, which relies solely on Matlab software, calculates various electrical parameters and creates multi-parametric maps of the right ventricle. The workflow, but it has already been employed in several research studies involving patients carried out by our group, showing its potential positive impact in clinical studies. Here, we will provide a technical description of its functionalities, along with the results obtained on a BrS patient who underwent an endocardial HDEAM.

Retrospective Cohort Study of Additional Procedures and Transplant-Free Survival for Patients With Functionally Single Ventricle Disease Undergoing Staged Palliation in England and Wales.

BACKGROUND: Reinterventions may influence the outcomes of children with functionally single-ventricle (f-SV) congenital heart disease. METHODS AND RESULTS: We undertook a retrospective cohort study of children starting treatment for f-SV between 2000 and 2018 in England, using the national procedure registry. Patients were categorized based on whether they survived free of transplant beyond 1 year of age. Among patients who had transplant-free survival beyond 1 year of age, we explored the relationship between reinterventions in infancy and the outcomes of survival and Fontan completion, adjusting for complexity. Of 3307 patients with f-SV, 909 (27.5%), had no follow-up beyond 1 year of age, among whom 323 (35.3%) had ≥1 reinterventions in infancy. A total of 2398 (72.5%) patients with f-SV had transplant-free survival beyond 1 year of age, among whom 756 (31.5%) had ≥1 reinterventions in infancy. The 5-year transplant-free survival and cumulative incidence of Fontan, among those who survived infancy, were 93.4% (95% CI, 92.4%-94.4%) and 79.3% (95% CI, 77.4%-81.2%), respectively. Both survival and Fontan completion were similar for those with a single reintervention and those who had no reinterventions. Patients who had >1 additional surgery (adjusted hazard ratio, 3.93 [95% CI, 1.87-8.27] P<0.001) had higher adjusted risk of mortality. Patients who had >1 additional interventional catheter (adjusted subdistribution hazard ratio, 0.71 [95% CI, 0.52-0.96] P=0.03) had a lower likelihood of achieving Fontan. CONCLUSIONS: Among children with f-SV, the occurrence of >1 reintervention in the first year of life, especially surgical reinterventions, was associated with poorer prognosis later in childhood.

Assessment of cancer therapy-related cardiac dysfunction in breast cancer women using a new speckle tracking echocardiography index: The GAVS.

BACKGROUND: Recently, peak atrial longitudinal strain (PALS) has emerged as a possible predictor of Cancer therapy-related cardiac dysfunction (CTRCD) in cancer patients (CP), in addition to left ventricular global longitudinal strain (GLS). Thus, considering the link between left atrium and left ventricle, the aim of this study was to assess the global atrio-ventricular strain (GAVS) in CP, to detect early cardiotoxicity. METHODS: A prospective study was carried out enrolling 131 breast cancer women (mean age 51.4 ± 10.4 years) receiving anti-cancer treatment. Clinical and echocardiographic evaluation was performed at baseline (T0), 3 (T1), 6 (T2) and 12 months (T3) after starting treatment. CTRCD was defined according to the 2022 ESC Cardio-Oncology guidelines. RESULTS: Forty-four patients developed CTRCD (3 moderate and 41 mild CTRCD group A) and 87 patients did not (group B). In group A, significant changes in GLS, PALS, GAVS, LASi (left atrial stiffness index) and LVEF/GLS occurred earlier than LVEF, that reduced significantly only at T3 (p-value < .05). Significant changes in LASi, PALS and GAVS occurred even in group B but reduction in GAVS (-21% vs. -5%) and PALS (-24% vs. -12%) was significantly greater in group A compared to group B (p-value = .04). CONCLUSIONS: Our study confirms high sensitivity of speckle tracking echocardiography in detecting subclinical myocardial damage in CP and the usefulness of a multiparametric echocardiographic evaluation including PALS and GLS (GAVS) for having a global evaluation of the phenomenon cardiotoxicity.

Application of apical myocardial perfusion quantitative analysis by contrast-enhanced ultrasound utilizing high-frequency linear probe.

BACKGROUND: Due to insufficient near-field resolution and artifacts, it is challenging to evaluate the left ventricular apical perfusion with phased-array probes. By combining high-frequency linear probe and contrast-enhanced ultrasound (CEUS), imaging of apical myocardial perfusion could be improved. The study aims to evaluate the preliminary application of CEUS by high-frequency linear probes to assess the apical perfusion. METHODS: The study enrolled retrospectively 91 patients to test the feasibility of the novel method. In protocol 1, patients were stratified into a group with left anterior descending artery (LAD) stenosis (N = 40) and a group without LAD stenosis or coronary artery disease (N = 41) based on the degree of coronary artery narrowing, quantified by >50% stenosis in coronary angiography. Receiver operating characteristics (ROC) analysis was performed to test the diagnostic value of perfusion parameters. In protocol 2, the reproducibility of high-frequency linear probe in apical perfusion analysis was compared with the conventional phased-array probe in 30 patients. RESULTS: (1) The novel method is feasible in 81(89.01%) patients. (2) In protocol 1, to detect LAD stenosis, the best cut-off of ß, T, A, and MBF were 10.32, 3.28, 9.39, and 4.99, respectively. Area under the curve of ß, T, A, and MBF were .880, .881, .761, and .880, respectively. (3) In protocol 2, compared with phased-array probe, the quantitative analysis of high-frequency linear probe is of high reproducibility and could get good curve fitting (R2 = .29 vs. R2 = .71, P < .01). CONCLUSION: Observation of apical perfusion using this method is feasible and quantitative analysis allows an accurate and convenient identification of LAD stenosis. This method provides an alternative for patients who have difficulties in visualizing the apical region with a phased-array probe.

Evaluation of Intraoperative Right Ventricular Myocardial Work Indices in Left Ventricular Assist Device Implantation: A Case Report.

Right ventricular myocardial work is an echocardiographic technique yielding significant insights into cardiac mechanics, energetics, and efficiency. Combining right ventricular myocardial strain with loading conditions correlates with invasively measured myocardial work and myocardial oxygen consumption. This method has not yet been described intraoperatively by transesophageal echocardiography. We describe this technique during a left ventricular assist device implantation. This case demonstrates that right ventricular myocardial work indices can be monitored intraoperatively and might assist decisions during left ventricular assist device implantation.

[A Giant Pseudoaneurysm Associated with a True Left Ventricular Aneurysm].

A 66-year-old man developed exertional dyspnea. The patient had undergone total arch replacement for a dissecting aortic arch aneurysm at the age of 53 and conservative treatment for myocardial infarction at the age of 60. Several imaging studies revealed a giant pseudoaneurysm that likely originated from a true ventricular aneurysm. The pseudoaneurysm severely compressed the right ventricle. Surgery was promptly performed. The patient had a history of cardiac surgery and had exclusively dense pericardium adhesion. Therefore, we incised the pseudoaneurysm and sutured the rupture orifice directly from inside the pseudoaneurysm under rapid pacing. This approach may represent an effective surgical alternative in patients with small rupture orifice and dense adhesions.

[Malignant Solitary Fibrous Tumor Compressing the Right Ventricle].

An 84-year-old woman was referred to our department with an abnormal mass detected on a chest computed tomography (CT) scan. The CT scan revealed a tumor between the sternum and the right ventricle, fed by the left internal thoracic artery. Multiple hepatic nodules were also observed. An ultrasound-guided biopsy was performed on the liver nodule, which was diagnosed as a solitary fibrous tumor. The tumor was compressing the heart, and the patient was at risk of sudden death, therefore, a decision was made to resect tumor. Preoperative embolization of the left internal thoracic artery was performed to prevent massive intraoperative bleeding. The tumor was resected via a median sternotomy approach. Intraoperatively, feeding vessels entering the tumor from the diaphragm were also identified. Total blood loss was 70 ml. The postoperative course was uneventful.

Right ventricular diastolic adaptation to pressure overload in different rat strains.

Different rat strains are used in various animal models of pulmonary hypertension and right ventricular (RV) failure. No systematic assessment has been made to test differences in RV response to pressure overload between rat strains. We compared RV adaptation to pulmonary trunk banding (PTB) in Wistar (W), Sprague Dawley (SD), and Fischer344 (F) rats by hemodynamic profiling focusing on diastolic function. Age-matched male rat weanlings were randomized to sham surgery (W-sham, n = 5; SD-sham, n = 4; F-sham, n = 4) or PTB (W-PTB, n = 8; SD-PTB, n = 8; F-PTB, n = 8). RV function was evaluated after 5 weeks by echocardiography, cardiac MRI, and invasive pressure-volume measurements. PTB caused RV failure and increased RV systolic pressures four-fold in all three PTB groups compared with sham. W- and SD-PTB had a 2.4-fold increase in RV end-systolic volume index compared with sham, while F-PTB rats were less affected. Diastolic and right atrial impairment were evident by increased RV end-diastolic elastance, filling pressure, and E/e' in PTB rats compared with sham, again F-PTB the least affected. In conclusions, PTB caused RV failure with signs of diastolic dysfunction. Despite a similar increase in RV systolic pressure, F-PTB rats showed less RV dilatation and a more preserved diastolic function compared with W- and SD-PTB.