Left Heart Hemodynamics Research Articles

Effect Mechanism of Electrocardiogram-Based Intravenous Single-Walled Carbon Nanotubes on Cardiac Function

This research was aimed to adopt electrocardiogram (ECG) and other techniques to explore the effects and mechanisms of single-walled carbon nanotubes (SWCNTs) and their carboxylation modification (C-SWCNTs) on cardiac function in rats. The SWCNTs were oxidized to C-SWCNTs by concentrated sulfuric acid and concentrated nitric acid. The morphology, surface charge, surface group, and water dispersibility of the samples were characterized. Subsequently, 40 SD rats in a 1:1:1:1 ratio were assigned into sham (intravenous injection of 5% glucose), SWCNT (intravenous injection of 2 mg/mL SWCNT glucose dispersion), C-SWCNT (intravenous injection of 2 mg/mL C-SWCNT glucose dispersion), and C-SWCNT+YM groups (treatment in C-SWCNT group was supplemented with an additional 1 mg/mL store-operated calcium entry (SOCE) blocker YM-58483/BTP2). The tail arterial pressure of rats in each group was detected. Left heart function and hemodynamics were detected by cardiac color ultrasonography. Heart parameters were detected by ECG lead II, and the pathological morphology of the heart was detected by hematoxylin-eosin staining. The levels of proteins related to the cardiac calcium signaling were detected by western blot. The results showed that the particle size distributions of SWCNTs and C-SWCNTs were uniform, and C-SWCNTs had better water dispersibility and a negatively charged surface. The results of caudal arterial pressure showed that SBP, DBP, and MBP of the caudal arteries in the SWCNT and C-SWCNT groups were markedly superior to those in sham group (P < 0.05). Cardiac function results showed drastic decreases in LVDd, EF, EDV, SV, and CO and great increases in LVDs, AV-BVmax, and PV-BVmax in the SWCNT and C-SWCNT groups relative to sham group (P < 0.05). The ECG results showed that relative to those in sham group, the amplitudes of the P wave and ST segment in the SWCNT and C-SWCNT groups were increased, the QRS and RR intervals were greatly prolonged, and the amplitude of the R wave was greatly decreased (P < 0.05). Western blot results showed that the SWCNT and C-SWCNT groups had drastically increased protein levels of ORAI-1 and STIM-1 in the heart versus sham group (P < 0.05). The changes in various cardiac parameters in C-SWCNT group were more prominent, and the cardiac pathological score increased markedly versus that in SWCNT group. The protein levels of ORAI-1 and STIM-1 increased notably (P < 0.05). The changes in various cardiac parameters in C-SWCNT+YM group were notably enhanced versus those in the SWCNT and C-SWCNT groups, the cardiac pathological score was obviously reduced, and the protein levels of ORAI-1 and STIM-1 were substantially decreased (P < 0.05). SWCNTs and C-SWCNTs both had cardiotoxic effects in rats, and C-SWCNTs had more obvious toxic effects. Nevertheless, the SOCE inhibitor YM-58483/BTP2 was able to enhance C-SWCNT-induced cardiac dysfunction by inhibiting the expression of calcium signaling-related proteins and affecting the changes in ECG parameters.

STUDY OF CARDIAC FLUID DYNAMICS IN THE RIGHT SIDE OF THE HEART WITH AI PIV

Particle image velocimetry (PIV), when used to investigate cardiac flows, has been restricted to the exploration of left-heart hemodynamics. Easy phantom modeling, simple geometrical assumptions, and the use of modified ultrahigh-frequency 3-D echocardiographic probes dedicated to the left heart are the main reasons for this restriction. However, hemodynamics of the right heart, due to its complex geometry, is still poorly understood. AI PIV, based on deep learning and convolutional neural networks, offers a super-resolution view of the velocity fields. In this paper, we apply this new technique to agitated saline bubble echocardiographic recordings of the right heart. The obtained higher-resolution results show promising patterns and vortices throughout the cardiac cycle, circumventing the abovementioned obstacles. For instance, the annular tricuspid excursion, which has been used for decades as a marker of systolic function of the right ventricle, seems to be crucial for the formation of two diastolic vortices in the right atrium. A lateral counterclockwise vortex and a medial clockwise vortex that direct flow from the low-pressure right atrium to the middle of the tricuspid valve were noted repeatedly throughout different cardiac cycles within the same patients and between different patients.

Pulmonary hypertension is an adverse risk factor for peri-procedural complications in patients undergoing cardioversion for atrial fibrillation

Abstract Background Atrial Fibrillation (AF) poses a significant burden on the American Healthcare system. Heart failure and AF commonly coexist in patients. Elevated left ventricular and atrial pressures result in progressive left atrial dilation and remodeling which in turn predisposes to the generation of AF. Many of these patients develop pulmonary hypertension (PHT) due to the remodeling and elevated left-sided pressures. Cardioversion (CV) for non-valvular atrial fibrillation (AF) is commonplace for patients during their initial presentation. Since many who undergo CV for AF could have PHT, we aimed to assess the periprocedural outcomes in this population. Methods We utilized the National Inpatient Sample from 2016-2019 to identify roughly 330,820 hospitalized adults who had CV for AF. These hospitalizations were further stratified based on the presence of PHT. A multivariate regression model was used to adjust for confounders and analyze the variables. Results Of those who underwent CV for AF, 45,345 (13.7%) had PHT. In-hospital mortality was interestingly lower in those with PHT (9.6% vs 10.37%; p<0.001). Figure 1 shows the Forrest plot for multivariate analysis of in-hospital outcomes when adjusted for patient demographics, comorbidities, and hospital characteristics. When adjusted similarly, patients who underwent CV for AF and PHT had longer length of stay (LOS) by 2.11 days (p<0.001) and had additional hospital costs (HC) of $29,470 (p<0.001). Conclusion In this study, patients who underwent CV for AF with co-existing PHT had significantly worse outcomes in terms of LOS, HC, pulmonary embolism, atrial flutter, VT, SVT, AKI, and intubation. Of note, they interestingly had better outcomes in terms of in-hospital mortality, respiratory failure, and strokes. Returning the patient to sinus rhythm likely improved the left heart hemodynamics reducing post capillary pulmonary hypertension explaining the reduced mortality rate in this population. One major limitation of our study is the lack of outpatient follow up and the inability to differentiate between the different groups of PHT. Since several outcomes are worse in the setting of PHT, potential strategies for aggressive rate and volume control for those in AF should be pursued to avoid negative cardiac remodeling that would predispose to the development of PHT. AF patients with co-existing PHT should be aggressively monitored during hospitalizations as they have the potential to have worse outcomes.

An FSEI approach for the assessment of stenotic aortic valve effects on the left heart hemodynamics

Fluid–structure-electrophysiology interaction (FSEI) deals with (i) the active contraction of the myocardium, (ii) the complex blood motion and (iii) the related deformation of the cardiac tissues. This three-way coupled approach is key for obtaining predictive cardiac information as the tissue kinematics comes as a part of the solution, rather than being imposed as a boundary condition. FSEI is here applied to study the effects induced by aortic valve stenosis on the hemodynamics. This pathology, typically occurring in elderly individuals, is caused by the stiffening of the valve leaflets, thus impairing the valve functioning and reducing the pumping efficiency of the heart. The disease severity is gradually increased within a high-fidelity model for the left heart, while keeping the same geometrical, elastic and electrophysiological properties of the cardiac system, which would be impossible with in-vivo experiments. We observe an increase of the transvalvular pressure drop and of the peak velocity of the systolic jet velocity along with a reduction of the cardiac ejection fraction. Furthermore, a stenotic aortic valve significantly alters the wall shear stresses and their spatial distribution over the aortic arch and valve leaflets, which may induce a remodeling process of the ventricular myocardium. The numerical results from the multi-physics model are fully consistent with the clinical experience, thus further opening the way for computational engineering aided medical diagnostic.

Quantitative evaluation of hemodynamic parameters by echocardiography in patients with post-cardiotomy cardiac shock supported by extracorporeal membrane oxygenation

BackgroundWhen drugs fail to reverse post-cardiotomy cardiac shock (PCS), extracorporeal membrane oxygenation (ECMO) is considered the most effective adjuvant strategy. Transthoracic echocardiography is a useful imaging modality for monitoring of cardiac hemodynamics. The aim of this study was to investigate the value of echocardiography for monitoring the left and right heart hemodynamics in PCS patients before, during, and after weaning from ECMO.MethodsFifty-two patients were divided into successful weaning group (group A, n = 23) and non-successful weaning group (group B, n = 29). Hemodynamic parameters measured by echocardiography were collected before, during, and after ECMO. The intra-group changes and inter-group differences were retrospectively analyzed.ResultsIn group A, the central venous pressure (CVP), proximal right ventricular outflow tract (RVOT), tricuspid annular plane systolic excursion (TAPSE), velocity of tricuspid valve (TVDV), and systolic velocity of tricuspid annulus ({text{s}}_{{{text{TV}}}}^{{prime }}) during ECMO were significantly lower than those before ECMO. After ECMO, left ventricular ejection fraction (LVEF), systolic velocity of mitral annulus ({text{s}}_{{{text{MV}}}}^{{prime }}), and velocity–time integral of LV outflow tract (LVOT-VTI) were higher than pre-ECMO levels, and CVP, LVEF, {text{s}}_{{{text{MV}}}}^{{prime }}, LVOT-VTI, RVOT, TAPSE, TVDV and {text{s}}_{{{text{TV}}}}^{{prime }} were higher than those during ECMO (all P < 0.05).In group B, compared to pre-ECMO, subjects exhibited decreased CVP, RVOT, TAPSE, TVDV and {text{s}}_{{{text{TV}}}}^{{prime }} during ECMO. TAPSE, TVDV, and {text{s}}_{{{text{TV}}}}^{{prime }} were continuously lower after ECMO, while CVP and RVOT increased after ECMO (all P < 0.05). After ECMO, LVEF, {text{s}}_{{{text{MV}}}}^{{prime }}, LVOT-VTI, TAPSE, TVDV and {text{s}}_{{{text{TV}}}}^{{prime }} in group A were higher than those in group B (all P < 0.05). Inter-group comparison showed the LVEF and RV Tei indices of group A were significantly different than those of group B before, during, and after ECMO.ConclusionQuantitative assessment of both LV and RV by echocardiography is important for ECMO weaning. Patients with better LVEF and lower RV Tei index may have a better chance of successful weaning from ECMO.

Hemodynamic and anatomic changes after fetal aortic valvuloplasty are associated with procedural success and postnatal biventricular circulation.

There are minimal data characterizing the trajectory of left heart growth and hemodynamics following fetal aortic valvuloplasty (FAV). This retrospective study included patients who underwent FAV between 2000 and 2019, with echocardiograms performed pre-FAV, immediately post-FAV, and in late gestation. Of 118 fetuses undergoing FAV, 106 (90%) underwent technically successful FAV, of which 55 (52%) had biventricular circulation. Technically successful FAV was associated with improved aortic valve growth (p<0.001), sustained antegrade aortic arch (AoA) flow (p=0.02), improved mitral valve (MV) inflow pattern (p=0.002), and favorable patent foramen ovale (PFO) flow pattern (p=0.004) from pre-FAV to late gestation. Compared to patients with univentricular outcome, patients with biventricular outcome had less decrement in size of the left ventricle (LV) (p<0.001) and aortic valve (p=0.005), as well as more physiologic PFO flow (p<0.001) and antegrade AoA flow (p<0.001) from pre-FAV to late gestation. In multivariable analysis, echocardiographic predictors of biventricular outcome were less decline in LV end diastolic dimension (p<0.001), improved PFO flow (p=0.004), and sustained antegrade AoA flow (p=0.002) from pre-FAV to late gestation. Stabilization of left heart growth and improved hemodynamics following successful FAV through late gestation are associated with postnatal biventricular circulation.

Numerical Investigation of the Fetal Left Heart Hemodynamics During Gestational Stages.

Flow-driven hemodynamic forces on the cardiac tissues have critical importance, and have a significant role in the proper development of the heart. These mechanobiological mechanisms govern the cellular responses for the growth and remodeling of the heart, where the altered hemodynamic environment is believed to be a major factor that is leading to congenital heart defects (CHDs). In order to investigate the mechanobiological development of the normal and diseased hearts, identification of the blood flow patterns and wall shear stresses (WSS) on these tissues are required for an accurate hemodynamic assessment. In this study, we focus on the left heart hemodynamics of the human fetuses throughout the gestational stages. Computational fetal left heart models are created for the healthy fetuses using the ultrasound images at various gestational weeks. Realistic inflow boundary conditions are implemented in the models using the Doppler ultrasound measurements for resolving the specific blood flow waveforms in the mitral valve. Obtained results indicate that WSS and vorticity levels in the fetal left heart decrease with the development of the fetus. The maximum WSS around the mitral valve is determined around 36 Pa at the gestational week of 16. This maximum WSS decreases to 11 Pa at the gestational week of 27, indicating nearly three-times reduction in the peak shear stress. These findings reveal the highly dynamic nature of the left heart hemodynamics throughout the development of the human fetus and shed light into the relevance of hemodynamic environment and development of CHDs.

Prognostic role and hemodynamic mechanism of impaired aerobic capacity in adults with Ebstein anomaly

BackgroundPatients with Ebstein anomaly have impaired aerobic capacity, but the relationship between aerobic capacity and clinical outcomes are unknown. The purpose of this study was to determine the prognostic role of aerobic capacity and the hemodynamic mechanism underlying temporal deterioration in aerobic capacity in this population. MethodsRetrospective cohort study of adults with Ebstein anomaly that underwent exercise test (2000–2018). Primary objective was to determine the relationship between aerobic capacity (%-predicted peak oxygen consumption, VO2) and cardiovascular adverse events (death, heart transplant, aborted sudden death, and heart failure hospitalization). Secondary objective was to delineate the relationship between temporal change in hemodynamic indices and subsequent decline in peak VO2. ResultsWe studied 248 patients (peak VO2 22.4 ​± ​7.1 ​ml/kg/min; 64 ​± ​21 %-predicted), and these events occurred during follow-up (death n ​= ​12, transplant n ​= ​1, aborted sudden death n ​= ​7, and heart failure hospitalization n ​= ​11). Peak VO2 was an independent predictor of cardiovascular adverse events (hazard ratio 1.32; 95% confidence interval 1.18–1.59, p ​= ​0.002 per 5%-point decrease). Of 101 patients with ≥2 exercise tests, %-predicted peak VO2 decreased by 2.3%-points/year, and rate of decline correlated with change in right atrial (RA) strain and left heart hemodynamics. Hemodynamic deterioration started with RA dysfunction, followed by left heart hemodynamic impairment, and then decline in peak VO2. ConclusionsPeak VO2 is a predictor of cardiovascular adverse events in Ebstein anomaly. Temporal decline in peak VO2 was preceded by RA dysfunction and left heart hemodynamic impairment suggesting that impaired aerobic capacity represents a late stage in disease pathogenesis.

Sirt1 improves heart failure through modulating the NF-κB p65/microRNA-155/BNDF signaling cascade.

Heart failure (HF) affects over 26 million people worldwide, yet the pathologies of this complex syndrome have not been completely understood. Here, we investigated the involvement of deacetylase Sirtuin 1 (Sirt1) in HF and its downstream signaling pathways. A HF model was induced by the ligation of the left coronary artery in rats, where factors associated with left ventricular echocardiography, heart hemodynamics and ventricular mass indexes were recorded. Collagen volume fraction in heart tissues was determined by Masson’s trichrome staining. Cell models of HF were also established (H2O2, 30 min) in cardiomyocytes harvested from suckling rats. HF rats presented with downregulated expressions of Sirt1, brain-derived neurotrophic factor (BDNF) and exhibited upregulated expressions of NF-κB p65 and miR-155. Repressed Sirt1 expression increased acetylation of NF-κB p65, resulting in the elevation of NF-κB p65 expression. NF-κB p65 silencing improved heart functions, decreased ventricular mass and reduced apoptosis in cardiomyocytes. MiR-155 inhibition upregulated its target gene BDNF, thereby reducing cardiomyocyte apoptosis. Sirt1 overexpression upregulated BDNF, improved heart function, and reduced apoptosis in cardiomyocytes. In conclusion, Sirt1 alleviates HF in rats through the NF-κB p65/miR-155/BDNF signaling cascade.

Pulmonary and systemic hemodynamics are associated with myocardial injury in the acute respiratory distress syndrome.

BackgroundWhether right and left heart hemodynamics are associated with myocardial injury in the acute respiratory distress syndrome (ARDS) is not known.MethodsWe performed a retrospective cohort study of subjects who had right heart catheterization within the ALVEOLI trial and Fluid and Catheter Treatment Trial. Myocardial injury was assessed using a highly sensitive troponin assay (hsTn; Abbot ARCHITECT). Hemodynamic variables included right atrial pressure, pulmonary artery wedge pressure, cardiac index and stroke volume, pulmonary vascular resistance, pulmonary arterial compliance, and pulmonary effective arterial elastance. We performed linear, logistic, and Cox regression to determine the association of hemodynamic variables with myocardial injury and to determine if hemodynamics mediated the association between myocardial injury and death.ResultsAmong 252 ARDS patients, median day 0 troponin was 65.4 (13.8–397.8) ng/L. Lower cardiac index (β −0.23 SE 0.10; P < 0.001) and stroke volume (β −0.26 SE 0.005; P < 0.001), higher pulmonary vascular resistance (β 0.22 SE 0.11; P < 0.001), lower pulmonary arterial compliance (β −0.24 SE 0.06; P < 0.001), and higher arterial elastance (β 0.27 SE 0.43; P < 0.001) were associated with greater myocardial injury in univariable and adjusted models. Changes in stroke volume, cardiac index, pulmonary arterial compliance, pulmonary vascular resistance, and arterial elastance were all associated with progressive myocardial injury over three days. hsTn levels were associated with mortality; however, the association was attenuated after adjustment for each of stroke volume, pulmonary vascular resistance, pulmonary arterial compliance, and arterial elastance.ConclusionPulmonary vascular hemodynamics are associated with myocardial injury in ARDS, while filling pressures are not. Pulmonary vascular disease may represent a treatable contributor to myocardial injury in ARDS.

Heightened Dependence of Left-Heart Filling Pressures on Right-Heart Failure in Congenital Heart Disease

BackgroundPulmonary artery wedge pressure (PAWP) is often elevated in patients with right-sided congenital heart disease (CHD), raising the possibility of coexisting left-heart disease, but pressure-volume relationships in the left and right sides of the heart influence one another through interdependence, which may be amplified in patients with CHD. MethodsWe hypothesized that increases in PAWP in patients with CHD would be more strongly related to ventricular interdependence compared with patients who have isolated left-heart disease such as heart failure with preserved ejection fraction (HFpEF). Ventricular interdependence was assessed by the relationship between PAWP and right-atrial pressure (RAP), RAP/PAWP ratio, and the left-ventricular (LV) eccentricity index. ResultsPAWP was elevated (≥15 mm Hg) in 49% of patients with CHD (n = 449). There was a very strong correlation between RAP and PAWP in CHD (r = 0.81, P < 0.001) that greatly exceeded the respective correlation in HFpEF (n = 160; r = 0.58, P < 0.001; P < 0.001 between groups). RAP/PAWP ratio and LV eccentricity index were higher in CHD than HFpEF (1.26 ± 0.18 vs 1.05 ± 0.14, P = 0.007) and (0.80 ± 0.21 vs 0.59 ± 0.19, P < 0.001), respectively. RAP (but not PAWP) was an independent predictor of death/transplant (hazard ratio 1.86 per 5 mm Hg, 95% confidence interval, 1.39-2.45, P = 0.002). ConclusionsLeft-heart filling pressures are commonly elevated in right-sided CHD, but this is related predominantly to right-heart failure and enhanced ventricular interdependence rather than left-heart disease. These data provide new insight into the basis of abnormal left-heart hemodynamics in patients with CHD and reinforce the importance of therapeutic interventions targeted to the right heart.

Computational fluid dynamics of blood flow in an idealized left human heart.

We construct an idealized computational model of the left human heart for the study of the blood flow dynamics in the left atrium and ventricle. We solve the Navier-Stokes equations in the ALE formulation and we prescribe the left heart wall displacement based on physiological data; moreover, we consider the presence of both the mitral and aortic valves through the resistive method. We simulate the left heart hemodynamics by means of the finite element method and we consider the variational multiscale large eddy simulation (LES) formulation to account for the transitional and nearly turbulent regimes of the blood flow in physiological conditions. The main contribution of this paper is the characterization of the blood flow in an idealized configuration of the left heart aiming at reproducing function in normal conditions. Our assessment is based on the analysis of instantaneous and phase averaged velocity fields, blood pressure, and other clinically meaningful fluid dynamics indicators. Finally, we show that our idealized computational model can be suitably used to study and critically discuss pathological scenarios like that of a regurgitant mitral valve.

Fetal hemodynamic response to aortic valvuloplasty and postnatal outcome: a European multicenter study

Fetal aortic stenosis may progress to hypoplastic left heart syndrome. Fetal valvuloplasty (FV) has been proposed to improve left heart hemodynamics and maintain biventricular (BV) circulation. The aim of this study was to assess FV efficacy by comparing survival and postnatal circulation between fetuses that underwent FV and those that did not. This was a retrospective multicenter study of fetuses with aortic stenosis that underwent FV between 2005 and 2012, compared with contemporaneously enrolled natural history (NH) cases sharing similar characteristics at presentation but not undergoing FV. Main outcome measures were overall survival, BV-circulation survival and survival after birth. Secondary outcomes were hemodynamic change and left heart growth. A propensity score model was created including 54/67 FV and 60/147 NH fetuses. Analyses were performed using logistic, Cox or linear regression models with inverse probability of treatment weighting (IPTW) restricted to fetuses with a propensity score of 0.14-0.9, to create a final cohort for analysis of 42 FV and 29 NH cases. FV was technically successful in 59/67 fetuses at a median age of 26 (21-34) weeks. There were 7/72 (10%) procedure-related losses, and 22/53 (42%) FV babies were delivered at < 37 weeks. IPTW demonstrated improved survival of liveborn infants following FV (hazard ratio, 0.38; 95% CI, 0.23-0.64; P= 0.0001), after adjusting for circulation and postnatal surgical center. Similar proportions had BV circulation (36% for the FV cohort and 38% for the NH cohort) and survival was similar between final circulations. Successful FV cases showed improved hemodynamic response and less deterioration of left heart growth compared with NH cases (P≤ 0.01). We report improvements in fetal hemodynamics and preservation of left heart growth following successful FV compared with NH. While the proportion of those achieving a BV circulation outcome was similar in both cohorts, FV survivors showed improved survival independent of final circulation to 10 years' follow-up. However, FV is associated with a 10% procedure-related loss and increased prematurity compared with the NH cohort, and therefore the risk-to-benefit ratio remains uncertain. We recommend a carefully designed trial incorporating appropriate and integrated fetal and postnatal management strategies to account for center-specific practices, so that the benefits achieved by fetal therapy vs surgical strategy can be demonstrated clearly. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Cardiac extracellular matrix is associated with adverse outcome in patients with chronic heart failure.

Accumulation of extracellular matrix (ECM) is known to play a crucial role in the pathophysiology of heart failure (HF). However, its prognostic relevance is poorly investigated. A total of 73 HF patients who underwent LV endomyocardial biopsy were enrolled in our study. ECM area was quantified by TissueFAXS and ImageJ software. Patients were followed-up at 6-month intervals. The study endpoint was defined as hospitalization for a cardiac reason and/or cardiac death. Furthermore, the influence of the ECM on invasively measured haemodynamic parameters was tested. During a median follow-up period of 9.0 months, 34 patients (46.6%) reached the combined endpoint. Median ECM area was 30.5%. Patients with ECM area ≥30.5% experienced significantly more events (67.6% vs. 25.0%, P < 0.001) in comparison with patients with an ECM area <30.5%. ECM area was independently associated with outcome in the total HF cohort [hazard ratio (HR) 1.041, 95% confidence interval (CI) 1.017-1.066, P = 0.001] as well as in HF patients with preserved (HR 1.079, 95% CI 1.001-1.163, P =0 .046) or reduced ejection fraction (HR 1.149, 95% CI 1.036-1.275, P = 0.009). Positive correlations were found between ECM area and LV end-diastolic pressure (P = 0.021, R = 0.303), pulmonary artery wedge pressure (P = 0.042, R = 0.249), mean pulmonary arterial pressure (P = 0.035, R = 0.258), as well as right atrial pressure (P = 0.003, R = 0.353). ECM area within the LV myocardium correlates with left and right heart haemodynamics and is associated with clinical course in various non-ischaemic HF types.

Assessing hemodynamics noninvasively in patients with heart failure.

Describe the contemporary assessment of cardiac hemodynamics using a comprehensive echo-Doppler examination in the heart failure (HF) patient. Cardiac flow and filling pressures, on both the left and right sides of the heart, are fundamental to the accurate assessment of the HF patient. Accurate assessment of left ventricular (LV) and right ventricular (RV) systolic and diastolic function is necessary to establish, or exclude, HF as a cause or component of dyspnea in a given patient and to help determine causes of hemodynamic instability in HF patients. Variables such as spectral Doppler (mitral and tricuspid inflow, pulmonary and hepatic venous flow, and pulmonary valve regurgitation signal), tissue Doppler imaging, and speckle tracking, applied to the left and right heart, can help to accurately estimate cardiac hemodynamics. A comprehensive echocardiogram with Doppler can provide an accurate assessment of left and right heart hemodynamics that is fundamental to the assessment and management of the HF patient.

In vitro assessment of mitral valve function in cyclically pressurized porcine hearts

Recent approaches to the in vitro experimental study of cardiac fluid mechanics involve the use of whole biological structures to investigate in the lab novel therapeutic approaches for the treatment of heart pathologies. To enhance reliability and repeatability, the influence of the actuation strategy of the experimental apparatuses on the biomechanics of biological structures needs to be assessed.Using echography and intracardiac high-speed imaging, we compared the mitral valve (MV) anatomo-functional features (coaptation areas/lengths, papillary muscles-valvular plane distances) in two passive-beating-heart mock loops with internal (IPML) or external (EPML) pressurization of the ventricular chamber.Both apparatuses showed fluid dynamic conditions that closely resembled the physiology. The MVs analyzed in the EPML presented coaptation areas and lengths that were systematically higher, and exhibited greater variability from early-to peak-systole, as compared to those in the IPML. Moreover, in the EPML, the MV leaflets exhibited a convexity with high curvature toward the atrium. With the IPML, MV coaptation lengths ranged similar to available clinical data and the papillary muscles-valve plane distances were more stable throughout systole.In conclusion, both the apparatuses allow for reproducing in vitro the left heart hemodynamics, in terms of flow rates and pressures, with proper mitral valve continence. Results suggest that the IPML is more suitable for replicating the physiological MV functioning, while the EPML may have more potential as a model for the study of MV pathologies.

Transseptal and transmitral Parachute® implantation in conjunction with "MitraClipping".

Parachute® implantation (PI) is an attractive treatment option for patients with left ventricular apical aneurysms (LVAA). So far, only the retrograde approach has been approved for PI. Unfortunately, severe functional mitral regurgitation (MR) restricts PI. Thus, we were intrigued to combine PI and MitraClip therapy (MCT) as a new transvenous hybrid concept. PI was performed via a transseptally placed MitraClip guide in six consecutive patients (age 73.8±5.2; 66% male). Immediately after PI, MR was treated by MCT. Invasive right and left heart haemodynamics were taken before and after PI and MCT, respectively. Procedural success was 100%. PI induced a numerical increase in cardiac output (CO: +36.4; p=0.15) and stroke volume (SV: +30.1%; p=0.09), despite some evidence of MR aggravation. Subsequent MCT successfully reduced MR at least to mild in five patients and to moderate in one patient. SV and CO demonstrated a further increase (SV: +44.3%, p=0.03; CO: +44.5%; p=0.03). The study documents for the first time the feasibility of transseptal and transmitral PI. Nevertheless, pre-procedural MR seems to counteract the beneficial effects of PI. Hence, the combined transseptal approach of PI and MCT seems to be the appropriate strategy in patients with significant MR and LVAA.

First in human implantation of the mechanical expanding Lotus® valve in degenerated surgical valves in mitral position.

Implantation of transcatheter heart valves (THV) into degenerated surgical valves is an emerging therapy for selected high-risk patients. Although, CE mark of most THV is limited for native aortic valvular stenosis, transcatheter valve implantation into degenerated bioprostheses, even in mitral position is very intriguing. After placement of a cerebral protection device (Claret Sentinel®), three consecutive patients (age, 79.0 ± 6.1; log EuroSCORE I: 33.3 ± 9.2%) with a degenerated mitral bioprosthesis were treated by transapical implantation of the Lotus® valve (Boston Scientific Inc.). In addition, a SwanGanz catheter was introduced in the pulmonary artery for hemodynamic assessments all patients. Procedural success was 100%. Valve implantation was performed without rapid ventricular pacing. Resheating was performed in two patients due to suboptimal initial positioning. Invasive online hemodynamics revealed stable blood pressure in all patients. After Lotus® valve implantation, valvular mitral regurgitation was completely eliminated in all patients. One patient had a mild paravalvular leak of the surgical bioprosthesis, which was present before implantation. Invasive right and left heart hemodynamics showed an immediate improvement after Lotus® valve implantation. Mean mitral surface area (2.1 ± 0.2 cm(2) ) and mean gradient (3.7 ± 2.1 mm Hg) demonstrated satisfactory results. All patients were immediately extubated and discharged from the hospital without any adverse event. This study demonstrates for the first time the feasibility of transapical Lotus® Valve implantation in degenerated mitral bioprostheses. The controlled mechanical Lotus® valve expansion with remarkably stable hemodynamics throughout the procedure offers a new and valuable treatment option.

Spectral Doppler interrogation of the pulmonary veins in atrial septal defect.

The various components of the pulmonary venous (PV) flow are linked to physiological and pathological changes that predominantly occur in the left heart. Thus, spectral Doppler interrogation of the PVs provides hemodynamic insight mainly into left-sided cardiac function. An exception to the dependence of PV flow on left heart events occurs in the setting of an atrial septal defect (ASD). The latter causes a portion of the PV blood flow, intended to cross the mitral valve, to be channeled into the more compliant right heart. This phenomenon makes the PV flow more dependent on the left-to-right interatrial shunt. The identification on the PV Doppler of a pattern that suggests uncoupling with left heart hemodynamics should raise the suspicion of an underlying ASD.

Bench Models for Assessing the Mechanics of Mitral Valve Repair and Percutaneous Surgery.

Rapid preclinical evaluations of mitral valve (MV) mechanics are currently best facilitated by bench models of the left ventricle (LV). This review aims to provide a comprehensive assessment of these models to aid interpretation of their resulting data, inform future experimental evaluations, and further the translation of results to procedure and device development. For this review, two types of experimental bench models were evaluated. Rigid LV models were characterized as fluid-mechanical systems capable of testing explanted MVs under static and or pulsatile left heart hemodynamics. Passive LV models were characterized as explanted hearts whose left side is placed in series with a static or pulsatile flow-loop. In both systems, MV function and mechanics can be quantitatively evaluated. Rigid and passive LV models were characterized and evaluated. The materials and methods involved in their construction, function, quantitative capabilities, and disease modeling were described. The advantages and disadvantages of each model are compared to aid the interpretation of their resulting data and inform future experimental evaluations. Repair and percutaneous studies completed in these models were additionally summarized with perspective on future advances discussed. Bench models of the LV provide excellent platforms for quantifying MV repair mechanics and function. While exceptional work has been reported, more research and development is necessary to improve techniques and devices for repair and percutaneous surgery. Continuing efforts in this field will significantly contribute to the further development of procedures and devices, predictions of long-term performance, and patient safety.