Right Ventricular Stroke Volume Research Articles

Three-Dimensional Speckle Tracking Echocardiography Assessment of Right Ventricular Function in Chronic Coronary Syndrome Patients After Percutaneous Coronary Intervention.

This study aimed to assess alterations in right ventricular (RV) function following percutaneous coronary intervention (PCI) in patients with chronic coronary syndromes utilizing three-dimensional speckle tracking echocardiography (3D-STE). A prospective study was conducted involving 136 patients diagnosed with chronic coronary syndromes undergoing PCI, constituting the study group, alongside 110 age- and gender-matched healthy volunteers serving as the control group. Echocardiographic evaluations, including both conventional and three-dimensional assessments, were performed on all study participants at 1-week, 6, and 12 months post-PCI. Parameters such as tricuspid annular plane systolic excursion (TAPSE) were derived from conventional echocardiography, while tricuspid lateral annular systolic velocity (S') was measured via tissue Doppler imaging. 3D-STE was utilized to quantify metrics including right ventricular fractional area change (RVFAC), right ventricular free wall longitudinal strain (RVFWLS), right ventricular global longitudinal strain (RVGLS), right ventricular stroke volume (RVSV), and right ventricular ejection fraction (RVEF). TAPSE, S', RVFAC, RVFWLS, RVGLS, RVSV, and RVEF exhibited significant increases from 1-week to 6 months post-PCI (p < 0.05). However, from 6 to 12 months post-PCI, RVFAC, RVGLS, RVSV, and RVEF demonstrated no notable changes (p > 0.05). Meanwhile, TAPSE, S', and RVFWLS sustained significant elevations: TAPSE (19.63±3.253% to 22.603±2.885%, p < 0.001); S' (10.57±2.643 to 12.61±2.189cm/s, p < 0.001); RVFWLS (18.64±2.745% to 19.926±3.291%, p = 0.002). At 12 months post-PCI, S', RVFAC, RVGLS, RVSV, and RVEF remained lower than those of the healthy control group, but the differences were not statistically significant (p > 0.05). However, RVFWLS was significantly lower compared to the healthy control group (19.926 ± 3.291%vs. 22.10 ± 1.994%, p < 0.001). Following PCI, right ventricular systolic function in patients with chronic coronary syndromes improves significantly over time. However, even at the 12-month post-PCI mark, RVFWLS remains lower than that of the control group. Notably, 3D-STE emerges as a noninvasive method for quantifying right ventricular systolic function post-PCI in chronic coronary syndrome patients.

Cardiovascular magnetic resonance semi-automated threshold-based post-processing of right ventricular volumes in repaired tetralogy of Fallot.

Cardiovascular magnetic resonance (CMR) is the gold-standard to estimate right ventricular (RV) volumes, which are key for clinical management of patients with repaired tetralogy of Fallot (rTOF). Semi-automated threshold-based methods (SAT) have been proposed for CMR post-processing as alternatives to fully manual standard tracing. We investigated the impact of SAT on RV analysis using different thresholds in rTOF patients. RV volumes and mass were estimated using SAT and standard fully manual tracing methods in rTOF patients. Two threshold levels were set for SAT, i.e., default 50 (SAT-50) and 30 (SAT-30). RV stroke volumes (SV) were compared to main pulmonary artery forward flow (MPA-FF). Post-processing time, intra- and interobserver variabilities were compared across methods. Sixty-two CMRs of rTOF patients were analyzed. Compared to the standard fully manual tracing, no significant differences in RV mass, volumes and ejection fraction were observed using SAT-30, whereas SAT-50 significantly underestimated RV end-diastolic-volume index (EDVi) by 10.4% (mean difference of - 11.8 ± 6.2ml/m2, p 0.03) and overestimated RV mass index by 21.8% (mean difference of 14.2 ± 11.9g/m2, p 0.002). Compared to MPA-FF, RVSV by standardfully manual method and SAT-30 showed minor biases, respectively, 0.03ml/m2 and 0.7ml/m2, while SAT-50 underestimated RVSV by 6.86ml/m2 (p < 0.001). In six patients, the degree of RV EDVi underestimation by SAT-50 determined a change of category from dilated to non-dilated RV. Intra- and interobserver variabilities were good to excellent for all methods. Post-processing duration was shorter for SAT compared to standardmanual segmentation (5.5 ± 1.7min vs. 19.5 ± 4.4min, p < 0.001). CMR SAT-30 post-processing is a precise, accurate and time-saving method for biventricular assessment of volumes, ejection fraction and mass in rTOF.

Cardiac MRI traits linked to cardiomyopathy mutations in phenotype naive carriers

Abstract Hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) are prevalent forms of cardiomyopathies, characterised by changes in cardiac structure and function, associated with an increased risk of atrial fibrillation (AF), heart failure (HF), and sudden cardiac death (SCD). Due to these potential life-threatening consequences close monitoring of genetic mutation carriers of HCM and DCM, is important. However, disease onset in these subjects is highly variable, with a substantial subset of people only developing disease late-in-life, or not at all, making risk stratification challenging. We set out to identify cardiac MRI (CMR) based imaging biomarkers of HCM and DCM carriership in phenotype naïve individuals, which were benchmarked against associations with AF and HF. CMR and whole genome sequencing (n: 42,723) data were sourced from a UK biobank sample free of heart failure at the time of CMR measurements. A previously validated deep learning(DL) network was used to derive 22 CMR traits(1). Adjusted cox regression models were used to determine the CMR associations with the onset of heart failure and atrial fibrillation, providing empirical validation of the DL CMR network. Univariable and multivariable generalised linear models were employed to identify associations with genetic carriership conditional on cardiac risk factors. 14 and 19 CMR measurements were associated with the time until HF (274 cases), AF (704 cases), respectively. These variables included left-ventricle (LV) ejection fraction (EF), LV end systolic volume (ESV), Right-ventricular (RV) EF and right atrial (RA) EF. Using WGS data we identified 154 people with an HCM mutation and 220 with a DCM mutation, where HCM carriership associated with five and DCM with four CMR traits. This included RA-EF (OR 1.26 95%CI 1.10; 1.45), and RV-EF (OR 1.41 95%CI 1.23;1,63) for HCM, and LV-EF (OR 0.72 95%CI 0.62; 0.84), and RV stroke volume (OR 0.75 95CI 0.62; 0.91) for DCM. By combining deep learning of CMR with large sample size WGS we were able to identify cardiac imaging biomarkers of HCM and DCM carriership in apparently healthy subjects. This could prove relevant for early identification and monitoring of phenotype naïve people.

Comparison of different non-invasive estimates of right ventriculo-arterial coupling as outcome predictors in dilated cardiomyopathy

Abstract Right ventriculo-arterial coupling (RVAC) has emerged as an outcome predictor in pulmonary hypertension, but its role in left-sided HF remains to be clarified. Different non-invasive estimates for RVAC have been proposed, but a direct comparison of their prognostic ability is lacking. We sought to evaluate RVAC non-invasively using five different methods in a cohort of patients with dilated cardiomyopathy (DCM) and to assess their prognostic role. We enrolled 121 consecutive patients with non-ischemic DCM in sinus rhythm, who underwent comprehensive echocardiography, including speckle-tracking and 3D analysis. They were prospectively followed for 19±11 months for a composite endpoint of death, nonfatal cardiac arrest and hospitalization. RVAC was measured using five non-invasive estimates: (1) as the tricuspid annular plane systolic excursion (TAPSE)/pulmonary artery systolic pressure (PASP) ratio; (2) as the right ventricular (RV) global longitudinal strain (RV-GLS)/PASP ratio; (3) as the longitudinal strain of the RV free wall (LS-RVFW)/PASP ratio; (4) as the 3D RV ejection fraction (RVEF)/PASP ratio; and (5) as the 3D RV stroke volume (SV)/3D RV end-systolic volume (ESV) ratio. Mean age in the study cohort was 59±14 years and the majority (74%) were men. 55 patients (46%) reached the endpoint: there were 27 deaths, 5 nonfatal cardiac arrests and 23 readmissions for heart failure. Patients with adverse outcome had lower TAPSE/PASP (0.42±0.23 vs. 0.62±0.33, p&amp;lt;0.001), lower RVEF/PASP (0.96±0.49 vs. 1.47±0.67, p&amp;lt;0.001), lower RV SV/ESV (0.57±0.20 vs. 0.93±0.29, p&amp;lt;0.001) and higher RV-GLS/PASP (-0.25±0.20 vs. -0.38±0.23, p=0.002) and LS-RVFW/PASP (-0.28±0.30 vs. -0.51±0.33, p&amp;lt;0.001), reflecting greater ventriculo-vascular decoupling. In univariate Cox regression, all three RVAC indices were outcome predictors: HR=0.09 [95% CI, 0.02-0.37], p=0.001 for TAPSE/PASP, HR=13.67 [95% CI, 2.77-67.48], p=0.001 for RV-GLS/PASP, HR=8.72 [95% CI, 3.24-23.45], p&amp;lt;0.001 for LS-RVFW/PASP, HR=0.27 [95% CI, 0.14-0.50], p&amp;lt;0.001 for RVEF/PASP, HR=0.004 [95% CI, 0.001-0.019], p&amp;lt;0.001 for RV SV/ESV. In ROC analysis, the SV/ESV ratio had the highest AUC (AUC=0.88, p&amp;lt;0.001), a value lower than 0.74 having 86% sensitivity and 77% specificity for event prediction. After adjustment for age, NYHA class, left ventricular ejection fraction, and maximal left atrial volume, all coupling indices remained independent predictors of outcome: HR=1.90 [95% CI, 1.01-3.57], p=0.047 for TAPSE/PASP, HR=2.15 [95% CI, 1.17-3.96], p=0.01 for RV-GLS/PASP, HR=2.48 [95% CI, 1.34-4.60], p=0.004 for LS-RVFW/PASP, HR=3.19 [95% CI, 1.19-8.52], p=0.02 for RVEF/PASP, HR=7.50 [95% CI, 3.47-16.22], p&amp;lt;0.001 for RV SV/ESV. In DCM, RVAC is significantly more impaired in patients with major adverse events. Non-invasive RVAC was an independent predictor of adverse outcome irrespective of the formula used for estimation, but 3D RV SV/ESV ratio had the greatest prognostic power.

Improvement in cardiac function but not structure in adults born preterm following a prescribed moderate to high intensity exercise intervention: a randomized clinical trial

Abstract Background People born preterm (&amp;lt;37 weeks’ gestation) have a potentially adverse cardiac phenotype that progresses with blood pressure elevation and may explain their increased risk of early heart failure and cardiovascular-related mortality. It remains unknown whether lifestyle or pharmacological interventions lead to beneficial left ventricle (LV) and right ventricle (RV) structural and/or functional changes in preterm-born adults. Purpose To determine whether preterm-born adults with elevated and stage 1 hypertension exhibit similar cardiac remodelling following a 16-week aerobic exercise intervention as their term-born peers with comparable blood pressures. Methods We conducted an open, parallel, two-arm superiority randomised controlled (1:1) trial in n=203 adults aged 18-35 years old with elevated or stage 1 hypertension. Participants were randomised to a 16-week aerobic exercise intervention targeting three, 60-minute supervised sessions per week at 60-80% peak heart rate (exercise intervention) or sign-posted to educational materials (controls). In a pre-specified cardiovascular magnetic resonance imaging (CMR) sub-study in n=100 individuals, CMR was performed before and after the 16-week intervention. Group differences in outcome variables after the intervention were examined using ANCOVA adjusting for baseline outcome variables, sex, and age. Interactions between birth category and intervention effect were investigated by including an interaction term in the intervention ANCOVA analyses. Results One hundred participants completed CMR scans at baseline and after the 16-week intervention, with n=47 in the exercise intervention group (n=26 term-born; n=21 preterm-born) and n=53 controls (n=32 term-born; n=21 preterm-born). Cardiac structural measures in preterm-born adults did not change following the intervention. However, term-born adults in the exercise intervention group decreased LV mass to end-diastolic volume ratio (adjusted mean difference: -0.03, 95% CI: -0.06,-0.01, interaction term p=0.027) and increased RV stroke volume (adjusted mean difference: 5.53mL/m2, 95% CI: 2.60,8.47, interaction term p=0.076) versus controls. Preterm-born adults in the exercise intervention group increased LV basal- and mid-ventricular circumferential strain versus controls (adjusted mean difference: -1.33%, 95% CI: -2.07,-0.60, interaction term p=0.057 and adjusted mean difference: -1.54%, 95% CI: -2.46,-0.63, interaction term p=0.046, respectively), which was not observed in term-born adults. Similarly, preterm-born adults improved RV longitudinal strain versus controls (adjusted mean difference: -0.51%, 95% CI: -1.49,0.46, interaction term p=0.053), which was also not observed in term-born adults. Conclusions Aerobic exercise training improves myocardial function but not cardiac structure in preterm-born adults. Modified exercise protocols or combination with pharmacological intervention may lead to additional cardiac remodelling benefits.

Feasibility, reproducibility, and accuracy of echocardiographic right ventricular systolic function assessments in childhood cancer survivors at risk for heart failure.

We sought to assess the feasibility, reproducibility, and accuracy of conventional and newer echocardiographic measures of right ventricular (RV) systolic function in adolescent and young adult childhood cancer survivors treated with anthracyclines. Echocardiography and cardiac magnetic resonance imaging (CMR) were acquired ≤60 days apart in prospectively recruited survivors and RV functional measures were quantitated by blinded observers. Repeat quantitation was performed in a subset to evaluate reproducibility. For each echocardiographic measure, Spearman correlations with CMR measures were calculated, and values in participants with CMR RV ejection fraction (RVEF) ≥48% and RVEF <48% were compared using two sample Wilcoxon rank-sum tests. Among 58 participants, mean age was 18.2 years (range 13.1-25.2) and five participants had CMR RVEF <48%. Intra- and inter-observer coefficients of variation were 8.2%-10.1% and 10.5%-12.0% for adjusted automated strain measures, and 5.2%-8.7% and 2.7% for 3D RVEF, respectively. No echocardiographic measures were significantly correlated with CMR RVEF; only tricuspid annular plane systolic excursion was correlated with CMR RV stroke volume (r=.392, p=.003). Participants with RV dysfunction had worse automated global longitudinal strain (-20.3% vs. -23.9%, p=.007) and free wall longitudinal strain (-23.7% vs. -26.7%, p=.09). Echocardiographic strain and 3D RV function measurements were feasible and reproducible in at-risk childhood cancer survivors. Although not associated with CMR RVEF in this population with predominantly normal RV function, automated strain measurements were more abnormal in participants with RV dysfunction, suggesting potential clinical utility of these measures.

Mechanical and electrical uncoupling: the role of cardiac magnetic resonance imaging in arrhythmogenic cardiomyopathy. Proof of concept.

Arrhythmogenic cardiomyopathy (ACM) is a complex cardiac disorder associated with ventricular arrhythmias. Understanding the relationship between mechanical uncoupling and cardiac structural changes in ACM patients is crucial for improved risk stratification and management. In this study, we enrolled 25 ACM patients (median age 34 years, 72% men) based on the 2019 Modified Task Force and Padua criteria. Patients were categorized by the presence or absence of clinically relevant ventricular tachycardia (crVT), necessitating emergency interventions. Right ventricular-arterial coupling (VAC) was assessed using echocardiography. Low-rank regression splines were employed to model left ventricular ejection fraction (LVEF) and right ventricular ejection fraction (RVEF) in relation to VAC. Positive associations were observed between VAC and LVEF (ρ = 0.472, p = 0.023), RVEF (ρ = 0.522, p = 0.038), and right ventricular (RV) indexed stroke volume (ρ = 0.79, p < 0.001). Patients with crVT exhibited correlations with RV shortening, reduced RVEF (39.6 vs. 32.2%, p = 0.025), increased left ventricular (LV) mass (38.99 vs. 45.55, p = 0.045), and LV end-diastolic volume (LVEDV) (56.99 vs. 68.15 mL/m2, p = 0.045). Positive associations for VAC were noted with LVEDV (p = 0.039) and LV mass (p = 0.039), while negative correlations were observed with RVEF by CMR (p = 0.023) and RV shortening by echocardiography (p = 0.026). Our findings underscore the significance of right VAC in ACM, demonstrating correlations with RV and LVEF, RV stroke volume, and clinically relevant arrhythmias. Insights into RVEF, LV mass, and end-diastolic volume provide valuable contributions to the understanding of ACM pathophysiology and may inform risk assessment strategies.

The prognostic value of right ventricular outflow tract velocity time integral in patients with pulmonary hypertension.

Right ventricular (RV) failure is one of the leading causes of death in patients with pulmonary hypertension (PH). Conventional echocardiographic parameters are not included in risk stratification and follow-up for prognostic assessment due to PH's diverse nature and the RV's complex geometry. RV outflow tract velocity time integral (RVOT VTI) is a simple, non-invasive estimate of pulmonary flow and an echocardiographic surrogate of RV stroke volume. In this study, we aimed to define the prognostic value of RVOT VTI in PH patients. Sixty-three subjects with idiopathic PAH (IPAH) (n=23), connective tissue disease-associated PAH (CTD-associated PAH) (n=19) and chronic thromboembolic pulmonary hypertension (CTEPH) (n=21) were retrospectively included. A comprehensive two-dimensional echocardiographic evaluation, including RVOT-VTI measurement, was performed during the follow-up and the New York Heart Association functional class (NYHA FC), 6min walk distance (6MWD) and brain natriuretic peptide (BNP) levels were recorded. The median age of the whole cohort was 63years (52-68), and 47 (74.6%) of the patients were women. The median follow-up period was 20months (11-33), and 20 (31.7%) patients died in this period. BNP values were higher [317 (210-641) vs 161 (47-466), P=0.02], and 6MWD values were lower [197.5±89.5 vs 339±146.3, P<0.0001] in the non-survivor group, and the non-survivor group had a worse NYHA-FC (P=0.02). Among echocardiographic data, tricuspid annular plane systolic excursion (TAPSE) (15.4±4.8 vs 18.6±4.2, P=0.01) and RVOT VTI (11.9±4.1 vs 17.2±4.3, P<0.0001) values were lower whereas right atrial area (RAA) (26.9±10.1 vs 22.2±7.1, P=0.04) values were higher in the non-survivor group. The area under curve of the RVOT VTI for predicting mortality was 0.82 [95% confidence interval (CI) 0.715-0.940, P<0.0001], and the best cut-off value was 14.7cm with a sensitivity of 80% and specificity of 77%. Survival was significantly lower in subjects with RVOT VTI≤14.7cm (log-rank P<0.0001). Survival rates for patients with RVOT VTI≤14.7cm were 70% at 1year, 50% at 2years, %29 at 3years and 21% at 5years. The univariate determinants of all-cause mortality were BNP [hazard ratio (HR) 1.001 (1.001-1.002), P=0.001], 6MWD [HR 0.994 (0.990-0.999), P=0.012] and NYHA-FC III-IV [HR 3.335 (1.103-10.083), P=0.03], TAPSE [HR 0.838 (0.775-0.929), P=0.001], RAA [HR 1.072 (1.013-1.135), P=0.016] and RVOT VTI [HR 0.819 (0.740-0.906), P<0.0001]. RVOT VTI was found to be the only independent determinant of mortality [HR 0.857 (0.766-0.960), P=0.008]. The decreased RVOT VTI predicts mortality in patients with PH and each 1mm decrease in RVOT VTI increases the risk of mortality by 14.3%. This parameter might serve as an additional parameter in the follow-up of these patients especially when 6MWD and NYHA-FC could not be determined.

Differential Stroke Volume between Left and Right Ventricles as a Predictor of Clinical Outcomes: The MESA Study.

Background Valvular heart disease and intracardiac shunts can disrupt the balance between left ventricular (LV) and right ventricular (RV) stroke volumes. However, the prognostic value of such imbalances has not been established among asymptomatic individuals. Purpose To assess the association between differential ventricular stroke volumes quantified using cardiac MRI and clinical outcomes in individuals without cardiovascular disease. Materials and Methods This secondary analysis of a prospective study included participants without cardiovascular disease at enrollment (July 2000 to July 2002) who underwent cardiac MRI. Differences in stroke volume were calculated as LV stroke volume minus RV stroke volume, and participants were categorized as having balanced (greater than or equal to -30 mL to ≤30 mL), negative (less than -30 mL), or positive (>30 mL) differential stroke volumes. Multivariable Cox proportional hazard regression models were used to test the association between differences in stroke volume and adverse outcomes. Results A cohort of 4058 participants (mean age, 61.4 years ± 10 [SD]; 2120 female) were included and followed up for a median of 18.4 years (IQR, 18.3-18.5 years). During follow-up, 1006 participants died, 235 participants developed heart failure, and 764 participants developed atrial fibrillation. Compared with participants who had a balanced differential stroke volume, those with an increased differential stroke volume showed a higher risk of mortality (hazard ratio [HR], 1.73 [95% CI: 1.12, 2.67]; P = .01), heart failure (HR, 2.40 [95% CI: 1.11, 5.20]; P = .03), and atrial fibrillation (HR, 1.89 [95% CI: 1.16, 3.08]; P = .01) in adjusted models. Participants in the negative group, with a decreased differential stroke volume, showed an increased risk of heart failure compared with those in the balanced group (HR, 2.09 [95% CI: 1.09, 3.99]; P = .03); however, this was no longer observed after adjusting for baseline LV function (P = .34). Conclusion Participants without cardiovascular disease at the time of study enrollment who had an LV stroke volume exceeding the RV stroke volume by greater than 30 mL had an increased risk of mortality, heart failure, and atrial fibrillation compared with those with balanced stroke volumes. ClinicalTrials.gov Identifier: NCT00005487 © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Almeida in this issue.

Correlation between Electrocardiogram Changes and Right Ventricular Systolic Function in Patients with Chronic Atrial Fibrillation

Background: Chronic atrial fibrillation (CAF) induces various electric disturbances, and a single mutation can cause multifarious phenotypes or combinations. Identifying the correlation of electrocardiogram changes corresponding to the disorders of electrical activity with right ventricular systolic function (RVSF) is important for the treatment and prognosis of CAF. Therefore, this study explored the correlation of electrocardiogram changes and RVSF in patients with CAF. Methods: From March 2022, to March 2023, 97 patients with CAF admitted to the Department of Cardiology of our hospital (study group) and 100 normal people who received health examination (control group) were subjected to echocardiogram and electrocardiogram to record relevant parameters for correlation analysis. Results: Significant differences were found in the electrocardiogram indices and right heart function parameters between the two groups. The study group had significantly higher heart rate, QTc interval, QT interval and T wave time than the control group (p &lt; 0.05). The study group showed significantly higher right ventricular end-diastolic volume (RVEDV) and right ventricular end-systolic volume (RVESV), and lower right ventricular stroke volume (RVSV) and right ventricular ejection fraction (RVEF) than the control group (p &lt; 0.05). Pearson correlation analysis showed that QTc interval, QT interval, and T wave time were positively correlated with RVESV (p &lt; 0.05); QTc interval, QT interval, and T wave time were negatively correlated with RVSV (p &lt; 0.05); and QTc interval was negatively correlated with RVEF (p &lt; 0.05). Conclusion: A correlation exists between electrocardiogram changes and RVSF in patients with CAF.

Mechanical and electrical uncoupling: the role of cardiac magnetic resonance imaging in arrhythmogenic cardiomyopathy proof of concept

Abstract Funding Acknowledgements None. Introduction Arrhythmogenic Cardiomyopathy (ACM) has a high risk of sudden cardiac death, especially under 60 years old (1:5,000 prevalence). ACM involves the replacement of normal heart tissue with fibro-adipose tissue in specific areas of the right ventricle (RV). Cardiac Magnetic Resonance Imaging (CMR) is vital for ACM stratification and prognosis, focusing on RV volume and ejection fraction. Simulations suggest that ACM's abnormal deformation patterns are primarily due to mechanical changes like reduced contractility and increased stiffness, rather than electrical issues. Ventriculo-arterial coupling (VAC) is a valuable metric for assessing RV efficiency, with the TAPSE/sPAP index reflecting the RV's length-force relationship. CMR assists in ACM stratification and prognosis, with VAC potentially serving as a key predictor of outcomes based on mechanical and structural abnormalities identified through CMR. Purpose Examine and establish a relationship between mechanical uncoupling, ventricular arrhythmias, and findings from CMR in patients with ACM. Methods We examined 25 ACM patients (median age 34, 72% men) using the 2019 Modified Task Force and Padua criteria. We investigated two key factors in ACM: Right ventricular-arterial coupling (TAPSE/SPAP ratio) and clinically relevant ventricular tachycardia (requiring cardioversion). We compared clinical, ECG, and imaging data (transthoracic echocardiogram and CMR as the gold standard). We used Spearman rank tests for correlations, Fisher exact tests for nominal characteristics, and Mann-Whitney-U tests for group comparisons. In predefined regression models involving left ventricular ejection fraction (LVEF) and right ventricular ejection fraction (RVEF) function with VAC, we used flexible nonparametric regressions. A p-value &amp;lt;0.05 was considered statistically significant. The analysis was conducted using SPSSv22 and SAS-University-Edition. Results A positive association of VAC with LVEF (ρ=0.472, p=0.023), RVEF (ρ=0.522, p=0.038) and RV indexed stroke volume (ρ=0.79, p&amp;lt;0.001) was found. Low-rank regression splines showed a mainly positive association of LVEF (df=3 F=20.75 p&amp;lt;0.001), RVEF (df=4 F=24.34 p&amp;lt;0.001) and the RV indexed stroke volume, a positive linear association (df=1 F=31.67 p&amp;lt;0.001). In comparison with patients without crVT, those with crVT had a positive correlation with RV shortening, reduced RVEF (39.6 vs. 32.2%. p=0.025), higher LV mass (38.99 vs. 45.55, p=0.045), and LV end-diastolic volume (LVEDV) (56.99 vs. 68.15 ml/m2, p=0.045) by echocardiogram and CMR respectively; notwithstanding positive associations for VAC were seen with LVEDV (p=0.039), LV mass (p=0.039); and negative with RVEF by CMR (p=0.023), and RV shortening by echo (p=0.026). Conclusions We found that right VAC by echo correlates with RV and LV EF by CMR and RV stroke volume in patients with ACM. RVEF, LV mass, and end-diastolic volume correlate with clinically relevant arrhythmias.

Accuracy of Shunt Volume Measured by Three-Dimensional Echocardiography and Cardiac Magnetic Resonance in Patients With an Atrial Septal Defect and a Dilated Right Ventricle

The accuracy of right ventricular (RV) quantification by three-dimensional echocardiography (3DE) has been reported mainly in patients with a normal right ventricle (RV). However, there are no data regarding the accuracy of 3DE in patients with a dilated RV, as in shunt diseases. In this study, we evaluated the accuracy of 3DE and that of volumetric (Vol) cardiac magnetic resonance (CMR) for assessment of RV and left ventricular (LV) stroke volume (SV) and the pulmonary (Qp)/systemic (Qs) blood flow ratio in patients with an atrial septal defect (ASD) using the two-dimensional phase contrast (2DPC) method as the gold standard. We retrospectively investigated 83 patients with ASD who underwent transcatheter closure and clinically indicated CMR and 3DE examinations. The ratio Qp/Qs was calculated using RV and LV SV measured by full-volume volumetric 3DE (Vol-3DE) and CMR (Vol-CMR) and by two-dimensional pulsed Doppler quantification (2D-Dop); the parameters were compared using 2DPC-CMR as the gold standard. There was no significant difference in the Qp/Qs value between 2DPC-CMR and Vol-3DE (2.29±0.70 vs 2.21±0.63, P=.79) and 2D-Dop (vs 2.21±0.65, P=1.00); however, a significant difference was found between 2DPC-CMR and Vol-CMR (P<.001). The Qp/Qs value obtained using Vol-3DE showed the best correlation with 2DPC-CMR (r=0.93, P<.001). The RV and LV SV values obtained by Vol-3DE showed the best correlation with 2DPC-CMR (RV SV, r=0.82, P<.001; LV SV, r=0.73, P<.001), although the absolute values were underestimated. Qp/Qs was more accurately evaluated by Vol-3DE than by Vol-CMR or 2D-Dop. Three-dimensional echocardiography assessment was feasible and reproducible even in a dilated RV.

Impact of modulating pulmonary artery pressure on resting right ventricular function in endurance-trained and untrained individuals

Prolonged endurance training is associated with critical adaptations to right ventricular (RV) structure and function that facilitate the achievement of higher exercise capacity, peak cardiac output, and RV stroke volume in the face of large increases in pulmonary artery pressures (afterload) and RV wall stress. Compared to the left ventricle, the RV is more sensitive to increases in afterload during exercise. However, the independent effect of increased afterload on RV function in endurance trained (Trained) vs untrained individuals remain unknown. Trained were considered those with a maximal oxygen consumption ( V̇O2max) &gt;60ml/kg/min (male) or &gt;55ml/kg/min (female) while untrained were defined as V̇O2max &lt;45ml/kg/min. Using echocardiography, this retrospective study sought to evaluate RV systolic function (RV global longitudinal strain [GLS]) and ventriculo-arterial coupling (ratio of RV GLS to pulmonary artery systolic pressure [PASP]) in Trained and untrained individuals while manipulating PASP. Ten participants (5 Trained and 5 Untrained) underwent resting echocardiography while breathing moderate (pressure of inspired oxygen; PiO2=89 mmHg) and severe hypoxia (PiO2=79 mmHg; order randomized) to increase PASP. Separately, eight participants (4 Trained and 4 untrained) inhaled nitric oxide (iNO; 40ppm) during echocardiography to lower PASP. Moderate and severe hypoxia increased PASP by 2.3 ± 1.3mmHg and 3.5 ± 1.8mmHg, respectively, while iNO decreased PASP by 2.6 ± 2.4mmHg, with no between group differences observed. Cardiac output was not different between any condition. A fitness-by-hypoxia interaction was observed in RV GLS in moderate hypoxia suggesting Trained had lower RV function during moderate hypoxia as compared to untrained (Untrained: -23.1 ± 4.4% vs. Trained: -20.2 ± 2.7%; p&lt;0.01). No differences in RV GLS were observed with iNO (p=0.98). The ratio of RV GLS to PASP was significantly different between groups at moderate hypoxia (Untrained: -1.06 ± 0.09%/mmHg vs. Trained: -0.85 ± 0.12%/mmHg; p=0.04) but not severe hypoxia (p=0.78). These findings suggest reducing PASP did not alter RV function or ventriculo-arterial coupling, however, Trained individuals experienced differential RV function responses when PASP is experimentally increased with hypoxia. Natural Sciences and Engineering Research Council of Canada. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Microtubules distinctly contribute to the performance of the healthy and pressure-overloaded RV

Introduction: Microtubules (MT) are a key contributor to cardiomyocyte contractility and mechanics. Recently, our group reported that acute depolymerization of MT reduces viscosity and elasticity and alters anisotropy of healthy and pressure-overloaded right ventricular (RV) tissues. While RV free wall viscosity and elasticity are distinctly upregulated with chronic pressure overload, how organ function is affected by viscoelastic contribution of the MT remains unknown. Our aim was to investigate the role of MT polymerization in RV function from its effect on RV tissue viscoelasticity. We hypothesized that the MT differentially contributes to healthy and pressure-overloaded RV function. Methods: All procedures and methods were approved by Colorado State University IACUC. Pulmonary hypertension (PH) was induced in 6-week-old male rats via 3-week monocrotaline treatment. Healthy age- and sex-matched rats served as control. Pressure-volume (PV) relationships were obtained by RV catheterization before and after intramyocardial injections of 0.3mM colchicine (COL) to acutely depolymerize the MT network and reduce tissue viscoelasticity. Functional impacts were evaluated by monitoring changes in RV end-systolic pressure (ESP), cardiac output (CO), stroke volume (SV), ejection fraction (EF), dP/dt max and min, cardiac effciency (CE), and the end-systolic pressure-volume relation (ESPVR). Results: As expected, monocrotaline treatment induced marked PH and RV contractile dysfunction, indicated by a significant elevation of RV ESP with reduced CO and ESPVR. In the healthy RV, COL treatment led to marked reductions in all functional parameters, indicating that the MT network is critical to maintain RV performance and contractile function in the healthy heart. In the pressure-overloaded RV, COL treatment similarly reduced SV, CO, EF, and dP/dt max and min, but increased CE and ESPVR, indicating that MT depolymerization improved mechanical effciency and contractility. To rule out effects caused by bolus injections alone, we administered a similar quantity of saline and observed no effects on the PV parameters in healthy RV. Discussion: Our study is the first to investigate the acute effect of MT depolymerization on RV function in healthy and diseased states. We found distinct contributions of MT to the contractile function and mechanical effciency of healthy and pressure-overloaded RVs. These findings reveal a critical influence of tissue viscoelasticity on RV physiology and dysfunction, emphasizing the importance of considering myocardial viscoelastic behavior in future studies investigating cardiac remodeling and heart failure pathophysiology. This work is partially supported by the National Science Foundation (NSF) grant 2244994. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Comparative Study of Cardiovascular Effects of Selected Pulmonary Vasodilators in Canine Models of Mitral Valve Disease.

Previous reports have shown that various oral pulmonary vasodilators are effective against canine pulmonary hypertension (PH). However, no studies have compared their hemodynamic effects. We aimed to compare the hemodynamic effects of 15 µg/kg beraprost sodium, 1.0 mg/kg sildenafil, and their combination, in dogs with experimentally induced mitral regurgitation. This experimental crossover study evaluated the hemodynamic and functional effects of oral pulmonary vasodilators by application of right-sided heart catheterization and echocardiography. Beraprost significantly decreased pulmonary and systemic vascular resistance. Additionally, beraprost increased right-ventricular stroke volume and left-ventricular cardiac output without worsening left-heart size and left-atrial pressure. The pulmonary vasodilatory effects of sildenafil were stronger, and its systemic vasodilatory effects were weaker than those of beraprost. However, sildenafil significantly increased the left-ventricular volume, left-atrial pressure indicator, and right-ventricular cardiac output. Combination therapy resulted in the strongest pulmonary and systemic vasodilating effects without worsening the left-heart size and left-atrial pressure indicators. Both beraprost and sildenafil were effective against canine PH; however, sildenafil was associated with the risk of worsening left-heart loading. Combination therapy with beraprost and sildenafil synergistically dilated pulmonary and systemic vessels, indicating a more potent treatment option for severe PH cases.

Improvement in right heart function following kidney transplantation in esrd patients: insights from speckle tracking echocardiography analysis.

Chronic kidney disease (CKD) is commonly associated with unfavorable cardiovascular outcomes and remains the leading cause of mortality in individuals with end-stage renal disease (ESRD). Despite substantial knowledge about the impact of CKD on the left heart, the right heart, which holds significant clinical relevance, has often been overlooked and inadequately assessed in ESRD patients who have undergone kidney transplant (KTx). This study aimed to evaluate the effects of KTx on the right heart chambers in ESRD patients. 57 adult KTx candidates were enrolled in this prospective longitudinal study, while 49 of them were included in the final assessment. Patients underwent a comprehensive cardiac assessment, including conventional echocardiography, speckle tracking echocardiography, and three-dimensional heart modeling both before and after surgery. Echocardiographic assessments showed significant increases in right ventricular (RV) ejection fraction, RV fractional area change (RVFAC), tricuspid annular plain systolic excursion, RV fractional shortening, right atrial (RA) reservoir, conduit, and booster strains, and RV global longitudinal strain (RVGLS). Moreover, significant reductions in RV end-diastolic volume (RVEDV), RV end-systolic volume (RVESV), RV stroke volume, RV end-diastolic diameter (RVEDD) in mid-cavity view, systolic pulmonary artery pressure was observed (all P values < 0.05). However, no significant difference was found in S velocity, as well as RVEDD in basal and apex-to-annulus view. Moreover, pre-KTx measurements of RVGLS, RVEDD (apex-to-annulus diameter), RV fractional shortening, and S velocity were predictors of RVGLS after KTx. RA conduit strain was also identified as a predictor of RA conduit strain after KTx. Additionally, age, RVEDV, RVESV, RVFAC, and RA reservoir strain before KTx were identified as independent predictors of RA reservoir strain after KTx. The findings of this study demonstrate a significant improvement in right heart function following KTx. Furthermore, strain analysis can provide valuable insights for predicting right heart function after KTx.

Impact of respiratory cycle during mechanical ventilation on beat-to-beat right ventricle stroke volume estimation by pulmonary artery pulse wave analysis.

The same principle behind pulse wave analysis can be applied on the pulmonary artery (PA) pressure waveform to estimate right ventricle stroke volume (RVSV). However, the PA pressure waveform might be influenced by the direct transmission of the intrathoracic pressure changes throughout the respiratory cycle caused by mechanical ventilation (MV), potentially impacting the reliability of PA pulse wave analysis (PAPWA). We assessed a new method that minimizes the direct effect of the MV on continuous PA pressure measurements and enhances the reliability of PAPWA in tracking beat-to-beat RVSV. Continuous PA pressure and flow were simultaneously measured for 2-3min in 5 pigs using a high-fidelity micro-tip catheter and a transonic flow sensor around the PA trunk, both pre and post an experimental ARDS model. RVSV was estimated by PAPWA indexes such as pulse pressure (SVPP), systolic area (SVSystAUC) and standard deviation (SVSD) beat-to-beat from both corrected and non-corrected PA signals. The reference RVSV was derived from the PA flow signal (SVref). The reliability of PAPWA in tracking RVSV on a beat-to-beat basis was enhanced after accounting for the direct impact of intrathoracic pressure changes induced by MV throughout the respiratory cycle. This was evidenced by an increase in the correlation between SVref and RVSV estimated by PAPWA under healthy conditions: rho between SVref and non-corrected SVSD -0.111 (0.342), corrected SVSD 0.876 (0.130), non-corrected SVSystAUC 0.543 (0.141) and corrected SVSystAUC 0.923 (0.050). Following ARDS, correlations were SVref and non-corrected SVSD -0.033 (0.262), corrected SVSD 0.839 (0.077), non-corrected SVSystAUC 0.483 (0.114) and corrected SVSystAUC 0.928 (0.026). Correction also led to reduced limits of agreement between SVref and SVSD and SVSystAUC in the two evaluated conditions. In our experimental model, we confirmed that correcting for mechanical ventilation induced changes during the respiratory cycle improves the performance of PAPWA for beat-to-beat estimation of RVSV compared to uncorrected measurements. This was demonstrated by a better correlation and agreement between the actual SV and the obtained from PAPWA.

Biventricular finite element modeling of the fetal heart in health and during critical aortic stenosis.

Finite Element simulations are a robust way of investigating cardiac biomechanics. To date, it has only been performed with the left ventricle (LV) alone for fetal hearts, even though results are likely different with biventricular (BiV) simulations. In this research, we conduct BiV simulations of the fetal heart based on 4D echocardiography images to show that it can capture the biomechanics of the normal healthy fetal heart, as well as those of fetal aortic stenosis better than the LV alone simulations. We found that performing LV alone simulations resulted in overestimation of LV stresses and pressures, compared to BiV simulations. Interestingly, inserting a compliance between the LV and right ventricle (RV) in the lumped parameter model of the LV only simulation effectively resolved these overestimations, demonstrating that the septum could be considered to play a LV-RV pressure communication role. However, stresses and strains spatial patterns remained altered from BiV simulations after the addition of the compliance. The BiV simulations corroborated previous studies in showing disease effects on the LV, where fetal aortic stenosis (AS) drastically elevated LV pressures and reduced strains and stroke volumes, which were moderated down with the addition of mitral regurgitation (MR). However, BiV simulations enabled an evaluation of the RV as well, where we observed that effects of the AS and MR on pressures and stroke volumes were generally much smaller and less consistent. The BiV simulations also enabled investigations of septal dynamics, which showed a rightward shift with AS, and partial restoration with MR. Interestingly, AS tended to enhance RV stroke volume, but MR moderated that down.

Tricuspid regurgitation in pulmonary arterial hypertension: a right ventricular volumetric and functional analysis.

The consequences of tricuspid regurgitation (TR) for right ventricular (RV) function and prognosis in pulmonary arterial hypertension (PAH) are poorly described and effects of tricuspid valve repair on the RV are difficult to predict. In 92 PAH patients with available cardiac magnetic resonance (CMR) studies, TR volume was calculated as the difference between RV stroke volume and forward stroke volume, i.e. pulmonary artery (PA) stroke volume. Survival was estimated from the time of the CMR scan to cardiopulmonary death or lung transplantation. In a subgroup, pressure-volume loop analysis including two-parallel elastances was applied to evaluate effective elastances, including net afterload (effective arterial elastance (E a)), forward afterload (effective pulmonary arterial elastance (E pa)) and backward afterload (effective tricuspid regurgitant elastance (E TR)). The effects of tricuspid valve repair were simulated using the online software package Harvi. 26% of PAH patients had a TR volume ≥30 mL. Greater TR volume was associated with increased N-terminal pro-brain natriuretic peptide (p=0.018), mean right atrial pressure (p<0.001) and RV end-systolic and -diastolic volume (both p<0.001). TR volume ≥30 mL was associated with a poor event-free survival (p=0.008). In comparison to E a, E pa correlated better with indices of RV dysfunction. Lower end-systolic elastance (E es) (p=0.002) and E TR (p=0.030), higher E pa (p=0.001) and reduced E es/E pa (p<0.001) were found in patients with a greater TR volume. Simulations predicted that tricuspid valve repair increases RV myocardial oxygen consumption in PAH patients with severe TR and low E es unless aggressive volume reduction is accomplished. In PAH, TR has prognostic significance and is associated with low RV contractility and RV-PA uncoupling. However, haemodynamic simulations showed detrimental consequences of tricuspid valve repair in PAH patients with low RV contractility.

How Right is the Right Ventricle in Predicting Cardiac Mortality in Cardiac Failure: A 6-year Prospective Cohort Study.

Two-dimensional speckle tracking echocardiography (2D-STE) and three-dimensional echocardiography (3DE) may overcome many limitations of the conventional 2D echocardiography (2DE) in assessing right ventricular (RV) function. We sought to determine whether characteristics of the right atrium and right ventricle as measured by 2D-STE and 3DE are associated with cardiac mortality in patients with ischemic heart failure, over a 6-year follow-up. The inclusion criteria were ischemic cardiomyopathy with left ventricular ejection fraction of <40% diagnosed using standard 2DE, 2D-STE, and 3DE examination. Patients were followed for 6 years, and cardiac mortality was recorded. The study sample comprised a total of 54 participants. During the period of follow-up, 24% (13/54) died. The 2DE models showed that being older, having a higher body mass index (BMI), having higher systolic pulmonary artery pressure (SPAP), and a lower RV global longitudinal strain were associated with cardiac mortality in our cohort after 6-year follow-up. Finally, the 3DE models showed that in addition to being older, having higher BMI, having a higher SPAP baseline, lower baseline 3DE RV stroke volume, and larger 3DE RV end-diastolic volume and 3DE RV end-systolic volume were associated with cardiac mortality over 6-year follow-up. This study provides evidence that RV dysfunction as seen on 2D-STE and 3DE could be associated with increased risk of cardiac-related mortality in patients with heart failure over 6 years.