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1.
J Cardiothorac Vasc Anesth ; 37(10): 1929-1937, 2023 10.
Article in English | MEDLINE | ID: mdl-37422337

ABSTRACT

OBJECTIVE: To define in an experimental model the variance, accuracy, precision, and concordance of single-beat measures of right ventricular (RV) contractility and diastolic capacitance relative to conventional reference standards, and apply the methods to a clinical data set. DESIGN: A retrospective, observational analysis of recorded pressure waveforms and RV volume measurements. SETTING: At a university laboratory. PARTICIPANTS: Archived data from previous studies of anesthetized swine and awake patients undergoing clinically-indicated right-heart catheterization. INTERVENTIONS: Recording of RV pressure with simultaneous measurement of RV volume by conductance (swine) or 3-dimensional (3D) echocardiography (humans) during changes in contractility and/or loading conditions. MEASUREMENTS AND MAIN RESULTS: Using experimental data, single-beat measures of RV contractility quantified as end-systolic elastance, and diastolic capacitance quantified as the predicted volume at an end-diastolic pressure of 15 mmHg (V15), were compared to multi-beat, preload- variant, reference standards using correlation, Bland-Altman analysis, and 4-quadrant concordance testing. This analysis indicated that the methods were not directly interchangeable with reference standards, but were sufficiently robust to suggest potential clinical utility. Clinical application supported this potential by demonstrating enhanced assessment of the response to inhaled nitric oxide in patients undergoing diagnostic right-heart catheterization. CONCLUSIONS: Study results supported the possibility of integrating automated RV pressure analysis with RV volume measured by 3D echocardiography to create a comprehensive assessment of RV systolic and diastolic function at the bedside.


Subject(s)
Heart Ventricles , Ventricular Dysfunction, Right , Animals , Humans , Diastole/physiology , Heart Ventricles/diagnostic imaging , Retrospective Studies , Stroke Volume/physiology , Swine , Systole , Ventricular Function, Right/physiology , Ventricular Pressure/physiology
2.
Am J Physiol Heart Circ Physiol ; 324(4): H391-H410, 2023 04 01.
Article in English | MEDLINE | ID: mdl-36607797

ABSTRACT

This study reports a new methodology for right heart imaging by ultrasound in mice under right ventricular (RV) pressure overload. Pulmonary artery constriction (PAC) or sham surgeries were performed on C57BL/6 male mice at 8 wk of age. Ultrasound imaging was conducted at 2, 4, and 8 wk postsurgery using both classical and advanced ultrasound imaging modalities including electrocardiogram (ECG)-based kilohertz visualization, anatomical M-mode, and strain imaging. Based on pulsed Doppler, the PAC group demonstrated dramatically enhanced pressure gradient in the main pulmonary artery (MPA) as compared with the sham group. By the application of advanced imaging modalities in novel short-axis views of the ventricles, the PAC group demonstrated increased thickness of RV free wall, enlarged RV chamber, and reduced RV fractional shortening compared with the sham group. The PAC group also showed prolonged RV contraction, asynchronous interplay between RV and left ventricle (LV), and passive leftward motion of the interventricular septum (IVS) at early diastole. Consequently, the PAC group exhibited prolongation of LV isovolumic relaxation time, without change in LV wall thickness or systolic function. Significant correlations were found between the maximal pressure gradient in MPA measured by Doppler and the RV systolic pressure by catheterization, as well as the morphological and functional parameters of RV by ultrasound.NEW & NOTEWORTHY The established protocol overcomes the challenges in right heart imaging in mice, thoroughly elucidating the changes of RV, the dynamics of IVS, and the impact on LV and provides new insights into the pathophysiological mechanism of RV remodeling.


Subject(s)
Ventricular Dysfunction, Right , Ventricular Remodeling , Male , Animals , Mice , Mice, Inbred C57BL , Heart , Heart Ventricles/diagnostic imaging , Ultrasonography , Ventricular Dysfunction, Right/diagnostic imaging , Ventricular Dysfunction, Right/etiology , Ventricular Pressure/physiology , Ventricular Function, Right
3.
J Am Soc Echocardiogr ; 36(5): 523-532.e3, 2023 05.
Article in English | MEDLINE | ID: mdl-36632939

ABSTRACT

BACKGROUND: The lack of reliable echocardiographic techniques to assess diastolic function in children is a major clinical limitation. Our aim was to develop and validate the intraventricular pressure difference (IVPD) calculation using blood speckle-tracking (BST) and investigate the method's potential role in the assessment of diastolic function in children. METHODS: Blood speckle-tracking allows two-dimensional angle-independent blood flow velocity estimation. Blood speckle-tracking images of left ventricular (LV) inflow from the apical 4-chamber view in 138 controls, 10 patients with dilated cardiomyopathies (DCMs), and 21 patients with hypertrophic cardiomyopathies (HCMs) <18 years of age were analyzed to study LV IVPD during early diastole. Reproducibility of the IVPD analysis was assessed, IVPD estimates from BST and color M mode were compared, and the validity of the BST-based IVPD calculations was tested in a computer flow model. RESULTS: Mean IVPD was significantly higher in controls (-2.28 ± 0.62 mm Hg) compared with in DCM (-1.21 ± 0.39 mm Hg, P < .001) and HCM (-1.57 ± 0.47 mm Hg, P < .001) patients. Feasibility was 88.3% in controls, 80% in DCM patients, and 90.4% in HCM patients. The peak relative negative pressure occurred earlier at the apex than at the base and preceded the peak E-wave LV filling velocity, indicating that it represents diastolic suction. Intraclass correlation coefficients for intra- and interobserver variability were 0.908 and 0.702, respectively. There was a nonsignificant mean difference of 0.15 mm Hg between IVPD from BST and color M mode. Estimation from two-dimensional velocities revealed a difference in peak IVPD of 0.12 mm Hg (6.6%) when simulated in a three-dimensional fluid mechanics model. CONCLUSIONS: Intraventricular pressure difference calculation from BST is highly feasible and provides information on diastolic suction and early filling in children with heart disease. Intraventricular pressure difference was significantly reduced in children with DCM and HCM compared with controls, indicating reduced early diastolic suction in these patient groups.


Subject(s)
Cardiomyopathy, Dilated , Cardiomyopathy, Hypertrophic , Humans , Child , Ventricular Pressure/physiology , Stroke Volume/physiology , Reproducibility of Results , Echocardiography/methods , Heart Ventricles/diagnostic imaging , Cardiomyopathy, Hypertrophic/diagnostic imaging , Diastole/physiology , Ventricular Function, Left/physiology
4.
Physiol Rep ; 10(22): e15421, 2022 11.
Article in English | MEDLINE | ID: mdl-36394073

ABSTRACT

Acute right ventricular pressure overload (RVPO) occurs following congenital heart surgery and often results in low cardiac output syndrome. We tested the hypothesis that the RV exhibits limited ability to modify substrate utilization in response to increasing energy requirements during acute RVPO after cardiopulmonary bypass (CPB). We assessed the RV fractional contributions (Fc) of substrates to the citric acid cycle in juvenile pigs exposed to acute RVPO by pulmonary artery banding (PAB) and CPB. Sixteen Yorkshire male pigs (median 38 days old, 12.2 kg of body weight) were randomized to SHAM (Ctrl, n = 5), 2-h CPB (CPB, n = 5) or CPB with PAB (PAB-CPB, n = 6). Carbon-13 (13 C)-labeled lactate, medium-chain, and mixed long-chain fatty acids (MCFA and LCFAs) were infused as metabolic tracers for energy substrates. After weaning from CPB, RV systolic pressure (RVSP) doubled baseline in PAB-CPB while piglets in CPB group maintained normal RVSP. Fc-LCFAs decreased significantly in order PAB-CPB > CPB > Ctrl groups by 13 C-NMR. Fc-lactate and Fc-MCFA were similar among the three groups. Intragroup analysis for PAB-CPB showed that the limited Fc-LCFAs appeared prominently in piglets exposed to high RVSP-to-left ventricular systolic pressure ratio and high RV rate-pressure product, an indicator of myocardial oxygen demand. Acute RVPO after CPB strongly inhibits LCFA oxidation without compensation by lactate oxidation, resulting in energy deficiency as determined by lower (phosphocreatine)/(adenosine triphosphate) in PAB-CPB. Adequate energy supply but also metabolic interventions may be required to circumvent these RV energy metabolic abnormalities during RVPO after CPB.


Subject(s)
Ventricular Dysfunction, Right , Animals , Male , Cardiopulmonary Bypass/adverse effects , Energy Metabolism , Lactates , Swine , Ventricular Pressure/physiology , Weaning
5.
J Vet Cardiol ; 41: 236-248, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35653883

ABSTRACT

INTRODUCTION: Diastolic dysfunction is an early clinical feature of feline hypertrophic cardiomyopathy (HCM). The left ventricular filling in early diastole is facilitated by the diastolic intraventricular pressure gradient (IVPG). The study objectives were to evaluate color Doppler M-mode-derived IVPG calculation in cats as a non-invasive assessment of the left ventricular relaxation property to determine the normal ranges of peak IVPG in cats and investigate the influence of left ventricular function and heart rate (HR). ANIMALS: One hundred and six client-owned apparently healthy cats. METHODS: Prospective cross-sectional study. Quantitative analysis of color Doppler M-mode images was used to estimate total and segmental IVPGs non-invasively. RESULTS: The total IVPG was 0.76 mmHg (95% reference interval (RI): 0.28-1.29 mmHg), the basal IVPG 0.34 mmHg (95% RI: 0.07-0.63 mmHg), and the mid-apical IVPG 0.42 mmHg (95% RI: 0.15-0.71 mmHg). Total and segmental IVPG increased with HR (P < 0.003), while segmental percent IVPG was HR independent. A short isovolumic relaxation time (IVRT) and a high mitral annular velocity in early diastole were associated with an increase in total IVPG (P = 0.008 and P = 0.009, respectively) adjusted for HR. An increase in IVPG was associated with an increase in mitral inflow velocity (P < 0.001). CONCLUSIONS: Feline IVPGs increase with HR and a short IVRT, which was believed to be a normal physiologic adrenergic response associated with an increased sympathetic tone. Future studies of segmental IVPG changes in feline HCM are needed to evaluate the clinical applicability of color Doppler M-mode estimated IVPGs in feline cardiology.


Subject(s)
Cats , Echocardiography, Doppler , Heart Ventricles , Ventricular Function, Left , Animals , Cardiomyopathy, Hypertrophic/diagnostic imaging , Cardiomyopathy, Hypertrophic/veterinary , Cat Diseases/diagnostic imaging , Cross-Sectional Studies , Diastole/physiology , Echocardiography, Doppler/veterinary , Heart Rate , Heart Ventricles/diagnostic imaging , Prospective Studies , Ventricular Function, Left/physiology , Ventricular Pressure/physiology
6.
Physiol Rep ; 10(7): e15238, 2022 04.
Article in English | MEDLINE | ID: mdl-35384363

ABSTRACT

Nearly 1 in every 100 children born have a congenital heart defect. Many of these defects primarily affect the right heart causing pressure overload of the right ventricle (RV). The RV maintains function by adapting to the increased pressure; however, many of these adaptations eventually lead to RV hypertrophy and failure. In this study, we aim to identify the cellular and molecular mechanisms of these adaptions. We utilized a surgical animal model of pulmonary artery banding (PAB) in juvenile rats that has been shown to accurately recapitulate the physiology of right ventricular pressure overload in young hearts. Using this model, we examined changes in cardiac myocyte protein expression as a result of pressure overload with mass spectrometry 4 weeks post-banding. We found pressure overload of the RV induced significant downregulation of cardiac myosin light chain kinase (cMLCK). Single myocyte calcium and contractility recordings showed impaired contraction and relaxation in PAB RV myocytes, consistent with the loss of cMLCK. In the PAB myocytes, calcium transients were of smaller amplitude and decayed at a slower rate compared to controls. We also identified miR-200c, which has been shown to regulate cMLCK expression, as upregulated in the RV in response to pressure overload. These results indicate the loss of cMLCK is a critical maladaptation of the RV to pressure overload and represents a novel target for therapeutic approaches to treat RV hypertrophy and failure associated with congenital heart defects.


Subject(s)
Myosin-Light-Chain Kinase , Ventricular Dysfunction, Right , Animals , Disease Models, Animal , Heart Ventricles/metabolism , Hypertrophy, Right Ventricular/metabolism , Myocytes, Cardiac/metabolism , Rats , Ventricular Dysfunction, Right/etiology , Ventricular Function, Right/physiology , Ventricular Pressure/physiology
7.
J Appl Physiol (1985) ; 132(3): 888-901, 2022 03 01.
Article in English | MEDLINE | ID: mdl-35112927

ABSTRACT

With severe right ventricular (RV) pressure overload, women demonstrate better clinical outcomes compared with men. The mechanoenergetic mechanisms underlying this protective effect, and their dependence on female endogenous sex hormones, remain unknown. To investigate these mechanisms and their impact on RV systolic and diastolic functional adaptation, we created comparable pressure overload via pulmonary artery banding (PAB) in intact male and female Wistar rats and ovariectomized (OVX) female rats. At 8 wk after surgery, right heart catheterization demonstrated increased RV energy input [indexed pressure-volume area (iPVA)] in all PAB groups, with the greatest increase in intact females. PAB also increased RV energy output [indexed stroke or external work (iEW)] in all groups, again with the greatest increase in intact females. In contrast, PAB only increased RV contractility-indexed end-systolic elastance (iEes)] in females. Despite these sex-dependent differences, no statistically significant effects were observed in the ratio of RV energy output to input (mechanical efficiency) or in mechanoenergetic cost to pump blood with pressure overload. These metrics were similarly unaffected by loss of endogenous sex hormones in females. Also, despite sex-dependent differences in collagen content and organization with pressure overload, decreases in RV compliance and relaxation time constant (tau Weiss) were not determined to be sex dependent. Overall, despite sex-dependent differences in RV contractile and fibrotic responses, RV mechanoenergetics for this degree and duration of pressure overload are comparable between sexes and suggest a homeostatic target.NEW & NOTEWORTHY Sex differences in right ventricular mechanical efficiency and energetic adaptation to increased right ventricular afterload were measured. Despite sex-dependent differences in contractile and fibrotic responses, right ventricular mechanoenergetic adaptation was comparable between the sexes, suggesting a homeostatic target.


Subject(s)
Sex Characteristics , Ventricular Dysfunction, Right , Animals , Disease Models, Animal , Female , Heart Ventricles , Humans , Male , Pulmonary Artery , Rats , Rats, Wistar , Ventricular Function, Right/physiology , Ventricular Pressure/physiology
8.
Circ Heart Fail ; 15(1): e009101, 2022 01.
Article in English | MEDLINE | ID: mdl-34963308

ABSTRACT

Right ventricular pressure-volume (PV) analysis characterizes ventricular systolic and diastolic properties independent of loading conditions like volume status and afterload. While long-considered the gold-standard method for quantifying myocardial chamber performance, it was traditionally only performed in highly specialized research settings. With recent advances in catheter technology and more sophisticated approaches to analyze PV data, it is now more commonly used in a variety of clinical and research settings. Herein, we review the basic techniques for PV loop measurement, analysis, and interpretation with the aim of providing readers with a deeper understanding of the strengths and limitations of PV analysis. In the second half of the review, we detail key scenarios in which right ventricular PV analysis has influenced our understanding of clinically relevant topics and where the technique can be applied to resolve additional areas of uncertainty. All told, PV analysis has an important role in advancing our understanding of right ventricular physiology and its contribution to cardiovascular function in health and disease.


Subject(s)
Heart Failure/physiopathology , Stroke Volume/physiology , Ventricular Function, Right/physiology , Ventricular Pressure/physiology , Heart Ventricles/physiopathology , Hemodynamics/physiology , Humans , Ventricular Dysfunction, Right/physiopathology , Ventricular Function, Left/physiology
9.
J Thorac Cardiovasc Surg ; 164(6): e493-e510, 2022 12.
Article in English | MEDLINE | ID: mdl-34922752

ABSTRACT

OBJECTIVES: Right ventricular (RV) failure is a leading cause of death in patients with congenital heart disease. RV failure is kept at bay during childhood. Limited proliferation of cardiomyocytes is present in the postnatal heart. We propose that cardiomyocyte proliferation improves RV adaptation to pressure load (PL). We studied adaptation in response to increased RV PL and the role of increased cardiomyocyte cell cycle activity (CCA) in rat pups growing into adulthood. METHODS: We induced RV PL at day of weaning in rats (3 weeks; 30-40 g) by pulmonary artery banding and followed rats into adulthood (300 g). We performed histological analyses and RNA sequencing analysis. To study the effects of increased cardiomyocyte cell cycle activity, we administered neuregulin-1 (NRG1), a growth factor involved in cardiac development. RESULTS: PL induced an increase in CCA, with subsequent decline of CCA (sham/PL at 4 weeks: 0.14%/0.83%; P = .04 and 8 weeks: 0.00%/0.00%; P = .484) and cardiac function (cardiac index: control/PL 4 weeks: 4.41/3.29; P = .468 and 8 weeks: 3.57/1.44; P = .024). RNA sequencing analysis revealed delayed maturation and increased CCA pathways. NRG1 stimulated CCA (PL vehicle/NRG1 at 2 weeks: 0.62%/2.28%; P = .003), improved cardiac function (cardiac index control vs vehicle/NRG1 at 2 weeks: 4.21 vs 3.07/4.17; P = .009/.705) and postponed fibrosis (control vs vehicle/NRG1 at 4 weeks: 1.66 vs 4.82%/2.97%; P = .009/.078) in RV PL rats during childhood. CONCLUSIONS: RV PL during growth induces a transient CCA increase. Further CCA stimulation improves cardiac function and delays fibrosis. This proof-of-concept study shows that stimulation of CCA can improve RV adaptation to PL in the postnatal developing heart and might provide a new approach to preserve RV function in patients with congenital heart disease.


Subject(s)
Heart Failure , Ventricular Dysfunction, Right , Rats , Animals , Hypertrophy, Right Ventricular/metabolism , Ventricular Dysfunction, Right/etiology , Ventricular Dysfunction, Right/prevention & control , Ventricular Dysfunction, Right/metabolism , Ventricular Pressure/physiology , Neuregulin-1/genetics , Neuregulin-1/metabolism , Neuregulin-1/pharmacology , Ventricular Function, Right , Myocytes, Cardiac/metabolism , Fibrosis , Heart Failure/metabolism , Cell Cycle , Disease Models, Animal
10.
J Thorac Cardiovasc Surg ; 163(4): e299-e308, 2022 04.
Article in English | MEDLINE | ID: mdl-34446290

ABSTRACT

BACKGROUND: Ventricular interdependence may account for altered ventricular mechanics in congenital heart disease. The present study aimed to identify differences in load-dependent right ventricular (RV)-left ventricular (LV) interactions in porcine models of pulmonary stenosis (PS) and pulmonary insufficiency (PI) by invasive admittance-derived hemodynamics in conjunction with noninvasive cardiovascular magnetic resonance (CMR). METHODS: Seventeen pigs were used in the study (7 with PS, 7 with PI, and 3 controls). Progressive PS was created by tightening a Teflon tape around the pulmonary artery, and PI was created by excising 2 leaflets of the pulmonary valve. Admittance catheterization data were obtained for the RV and LV at 10 to 12 weeks after model creation, with the animal ventilated under temporary diaphragm paralysis. CMR was performed in all animals immediately prior to pressure-volume catheterization. RESULTS: In the PS group, RV contractility was increased, manifested by increased end-systolic elastance (mean difference, 1.29 mm Hg/mL; 95% confidence interval [CI], 0.57-2.00 mm Hg/mL). However, in the PI group, no significant changes were observed in RV systolic function despite significant changes in RV diastolic function. In the PS group, LV end-systolic volume was significantly lower compared with controls (mean difference, 25.1 mL; 95% CI, -40.5 to -90.7 mL), whereas in the PI group, the LV showed diastolic dysfunction, demonstrated by an elevated isovolumic relaxation constant and ventricular stiffness (mean difference, 0.03 mL-1; 95% CI, -0.02 to 0.09 mL-1). CONCLUSIONS: The LV exhibits systolic dysfunction and noncompliance with PI. PS is associated with preserved LV systolic function and evidence of some LV diastolic dysfunction. Interventricular interactions influence LV filling and likely account for differential effects of RV pressure and volume overload on LV function.


Subject(s)
Diastole/physiology , Ventricular Dysfunction/physiopathology , Ventricular Pressure/physiology , Animals , Heart Ventricles/diagnostic imaging , Magnetic Resonance Imaging, Cine , Models, Animal , Pulmonary Valve Insufficiency/physiopathology , Pulmonary Valve Stenosis/physiopathology , Stroke Volume/physiology , Swine , Systole/physiology , Ventricular Dysfunction/diagnostic imaging
11.
Cardiol Young ; 32(8): 1296-1301, 2022 Aug.
Article in English | MEDLINE | ID: mdl-34617506

ABSTRACT

INTRODUCTION: Systemic ventricular end-diastolic pressure is an important haemodynamic variable in adult patients with Fontan circulation. Risk factors associated with elevated end-diastolic pressure have not been clearly identified in this population. METHODS: All patients > 18 years with Fontan circulation who underwent cardiac catheterisation at our centre between 1/08 and 3/19 were included. Relevant patient variables were extracted. Univariate and multivariate general linear models were analysed to identify variables associated with end-diastolic pressure. RESULTS: Forty-two patients were included. Median age was 24.0 years (20.9-29.0) with a body mass index of 23.7 kg/m2 (21.5-29.7). 10 (23.8%) patients had a systemic right ventricle. The median (Interquartile range) and mean pulmonary artery pressure were 11.0 mmHg (9.0-12.0) and 16.0 mmHg (13.0-18.0), respectively. On univariate analysis, end-diastolic pressure was positively associated with body mass index (p < 0.01), age > 25 years (p = 0.04), symptoms of heart failure (p < 0.01), systemic ventricular systolic pressure (p = 0.03), pulmonary artery mean pressure (p < 0.01), and taking diuretics (p < 0.01) or sildenafil (p < 0.01). End-diastolic pressure was negatively associated with aortic saturation (p < 0.01). On multivariate analysis, end-diastolic pressure was positively associated with age ≥ 25 years (p < 0.01), and body mass index (p = 0.04). CONCLUSIONS: In a cohort of adult patients with Fontan circulation undergoing catheterisation, end-diastolic pressure was positively associated with age ≥ 25 years and body mass index on multivariate analysis. Maintaining a healthy body mass index may offer haemodynamic benefit in adults with Fontan physiology.


Subject(s)
Fontan Procedure , Heart Defects, Congenital , Adult , Blood Pressure/physiology , Body Mass Index , Diastole , Fontan Procedure/adverse effects , Heart Defects, Congenital/diagnosis , Humans , Retrospective Studies , Ventricular Pressure/physiology , Young Adult
12.
Nutrients ; 13(9)2021 Sep 18.
Article in English | MEDLINE | ID: mdl-34579143

ABSTRACT

Recent studies demonstrated that metabolic syndrome and cardiovascular diseases could be elicited by developmental programming, which is regulated by prenatal nutritional and environmental stress. In this study, we utilized a rat model to examine the effect of excessive maternal fructose intake during pregnancy and lactation on cardiac development and progression of pressure overload-induced cardiac hypertrophy in offspring. Transverse aortic constriction (TAC) was performed on 3-month-old male offspring to induce ventricular pressure overload. Four weeks post-TAC, echocardiographic assessment as well as histopathological and biochemical examinations were performed on the myocardium of the offspring. Echocardiographic and gross examinations showed that heart weight, interventricular septal thickness in diastole (IVD; d), and left ventricular posterior wall thickness in diastole (LVPW; d) were elevated in offspring with TAC and further increased by maternal fructose exposure (MFE). However, the left ventricular ejection function was not significantly affected. Myocardial histopathological examination revealed that the indices of fibrosis and oxidative stress were higher in offspring with MFE and TAC than those in animals receiving either treatment. Molecular examinations on the myocardium demonstrated an MFE-induced upregulation of p38-MAPK signaling. Next generation sequence (NGS) analysis indicated a modulation of the expression levels of several cardiac hypertrophy-associated genes, including GPR22, Myh7, Nppa, P2RX4, and Npy by MFE. Subsequent RT-PCR indicated that MFE regulated the expression levels of genes responsive to cardiac hypertrophy (i.e., Myh-7, ANP) and oxidative stress (i.e., GR, GPx, and NQO-1). In conclusion, MFE during pregnancy and lactation modulated myocardial gene expression, increased oxidative stress, and exacerbated ventricular pressure overload-induced cardiac remodeling in rat offspring.


Subject(s)
Cardiomegaly/etiology , Fructose/adverse effects , Heart/growth & development , Myocardium/pathology , Prenatal Exposure Delayed Effects , Ventricular Pressure/physiology , Animals , Aorta , Cardiomegaly/genetics , Constriction , Female , Fructose/administration & dosage , Gene Expression , Heart/drug effects , Heart/embryology , Lactation , Male , Myocardium/metabolism , Oxidative Stress , Pregnancy , Rats
13.
Circ Heart Fail ; 14(11): e008779, 2021 11.
Article in English | MEDLINE | ID: mdl-34503353

ABSTRACT

BACKGROUND: In ≈25% of patients with heart failure and reduced left-ventricular ejection fraction, right-ventricular (RV), and left-ventricular (LV) filling pressures are discordant (ie, one is elevated while the other is not). Whether clinical assessment allows detection of this discordance is unknown. We sought to determine the agreement of clinically versus invasively determined patterns of ventricular congestion. METHODS: In 156 heart failure and reduced LV ejection fraction subjects undergoing invasive hemodynamic assessment, we categorized patterns of ventricular congestion (no congestion, RV only, LV only, or both) based on clinical findings of RV (jugular venous distention) or LV (hepatojugular reflux, orthopnea, or bendopnea) congestion. Agreement between clinically and invasively determined (RV congestion if right atrial pressure [RAP] ≥10 mm Hg and LV congestion if pulmonary capillary wedge pressure [PCWP] ≥22 mm Hg) categorizations was the primary end point. RESULTS: The frequency of clinical patterns of congestion was: 51% no congestion, 24% both RV and LV, 21% LV only, and 4% RV only. Jugular venous distention had excellent discrimination for elevated RAP (C=0.88). However, agreement between clinical and invasive congestion patterns was poor, к=0.44 (95% CI, 0.34-0.55). While those with no clinical congestion usually had low RAP and PCWP (67/79, 85%), over one-half (24/38, 64%) with isolated LV clinical congestion had PCWP <22 mm Hg, most (5/7, 71%) with isolated RV clinical congestion had PCWP ≥22 mm Hg, and ≈one-third (10/32, 31%) with both RV and LV clinical congestion had elevated RAP but PCWP <22 mm Hg. CONCLUSIONS: While clinical examination allows accurate detection of elevated RAP, it does not allow accurate detection of discordant RV and LV filling pressures.


Subject(s)
Heart Failure/physiopathology , Pulmonary Wedge Pressure/physiology , Stroke Volume/physiology , Ventricular Dysfunction, Left/physiopathology , Hemodynamics/physiology , Humans , Male , Middle Aged , Physical Examination/methods , Ventricular Function, Left/physiology , Ventricular Pressure/physiology
14.
Am J Physiol Heart Circ Physiol ; 321(2): H369-H381, 2021 08 01.
Article in English | MEDLINE | ID: mdl-34213390

ABSTRACT

Cardiopulmonary sympathetic control is exerted via stellate ganglia (SG); however, little is known about how neuronal firing patterns in the stellate ganglion relate to dynamic physiological function in the heart and lungs. We performed continuous extracellular recordings from SG neurons using multielectrode arrays in chloralose-anesthetized pigs (n = 6) for 8-9 h. Respiratory and left ventricular pressures (RP and LVP, respectively) and the electrocardiogram (ECG) were recorded concomitantly. Linkages between sampled spikes and LVP or RP were determined using a novel metric to evaluate specificity in neural activity for phases of the cardiac and pulmonary cycles during resting conditions and under various cardiopulmonary stressors. Firing frequency (mean 4.6 ± 1.2 Hz) varied spatially across the stellate ganglion, suggesting regional processing. The firing pattern of most neurons was synchronized with both cardiac (LVP) and pulmonary (RP) activity indicative of cardiopulmonary integration. Using the novel metric to determine cardiac phase specificity of neuronal activity, we found that spike density was highest during diastole and near-peak systole. This specificity was independent of the actual LVP or population firing frequency as revealed by perturbations to the LVP. The observed specificity was weaker for RP. Stellate ganglion neuronal populations exhibit cardiopulmonary integration and profound specificity toward the near-peak systolic phase of the cardiac cycle. This novel approach provides practically deployable tools to probe stellate ganglion function and its relationship to cardiopulmonary pathophysiology.NEW & NOTEWORTHY Activity of stellate ganglion neurons is often linking indirectly to cardiac function. Using novel approaches coupled with extended period of recordings in large animals, we link neuronal population dynamics to mechanical events occurring at near-peak systole. This metric can be deployed to probe stellate ganglion neuronal control of cardiopulmonary function in normal and disease states.


Subject(s)
Heart/physiology , Neurons/physiology , Pressure , Respiratory Physiological Phenomena , Stellate Ganglion/physiology , Stress, Physiological/physiology , Ventricular Pressure/physiology , Animals , Aorta , Cardiac Pacing, Artificial , Electrocardiography , Microelectrodes , Respiratory Function Tests , Respiratory Mechanics , Spatio-Temporal Analysis , Stellate Ganglion/cytology , Sus scrofa , Swine , Sympathetic Nervous System/physiology , Vena Cava, Inferior
16.
Physiol Rep ; 9(10): e14768, 2021 05.
Article in English | MEDLINE | ID: mdl-34042307

ABSTRACT

Coronary artery disease (CAD) can adversely affect left ventricular (LV) performance during exercise by impairment of contractile function in the presence of increasing afterload. By performing invasive measures of LV pressure-volume and coronary pressure and flow during exercise, we sought to accurately measure this with comparison to the control group. Sixteen patients, with CCS class >II angina and CAD underwent invasive simultaneous measurement of left ventricular pressure-volume and coronary pressure and flow velocity during cardiac catheterization. Measurements performed at rest were compared with peak exercise using bicycle ergometry. The LV contractile function was measured invasively using the end-systolic pressure-volume relationship, a load independent marker of contractile function (Ees). Vascular afterload forces were derived from the ratio of LV end-systolic pressure to stroke volume to generate arterial elastance (Ea). These were combined to assess cardiovascular performance (ventricular-arterial [VA] coupling ratio [Ea/Ees]). Eleven patients demonstrated flow-limiting (FL) CAD (hyperemic Pd/Pa <0.80; ST-segment depression on exercise); five patients without flow-limiting (NFL) CAD served as the control group. Exercise in the presence of FL CAD was associated impairment of Ees, increased Ea, and deterioration of VA coupling. In the control cohort, exercise was associated with increased Ees and improved VA coupling. The backward compression wave energy directly correlated with the magnitude contraction as measured by dP/dTmax (r = 0.88, p = 0.004). This study demonstrates that in the presence of flow-limiting CAD, exercise to maximal effort can lead to impairment of LV contractile function and a deterioration in VA coupling compared to a control cohort.


Subject(s)
Cardiac Catheterization/methods , Coronary Artery Disease/physiopathology , Exercise/physiology , Myocardial Contraction/physiology , Stroke Volume/physiology , Ventricular Pressure/physiology , Aged , Cohort Studies , Coronary Artery Disease/therapy , Coronary Circulation/physiology , Electrocardiography/methods , Female , Humans , Male , Middle Aged , Prospective Studies , Radial Artery/physiology , Ventricular Function, Left/physiology
20.
Am J Cardiol ; 146: 62-68, 2021 05 01.
Article in English | MEDLINE | ID: mdl-33539862

ABSTRACT

Current risk models have only limited accuracy in predicting transcatheter aortic valve Implantation (TAVI) outcomes and there is a paucity of clinical variables to guide patient management after the procedure. The prognostic impact of elevated left ventricular end-diastolic pressure (LVEDP) in TAVI patients is unknown. The aim of the present study was to evaluate the prognostic value of after-procedural LVEDP in patients who undewent TAVI. Consecutive patients with severe symptomatic aortic stenosis who undewent TAVI were divided into 2 groups according to after-procedural LVEDP above and below or equal 12 mm Hg. Collected data included baseline clinical, laboratory and echocardiographic variables. We evaluated the impact of elevated vs. normal LVEDP on in-hospital outcomes, short- and long-term mortality. Eight hundred forty-five patients were included in the study with complete in-hospital and late mortality data available for all survivors (median follow-up 29.5 months [IQR 16.5 to 48.0]). The mean age (±SD) was 82.3±6.2 years and mean Society of Thoracic Surgery score was 4.0%±3.0%. Patients with LVEDP>12 mm Hg (n = 591, 70%) and LVEDP≤12 mm Hg (n = 254, 30%) had a 6-months mortality rate of 6.8% and 2%, respectively (P=0.004) and a 1-year mortality rate of 10.1% vs 4.9%, respectively (p = 0.017). By multivariable analysis, after-procedural LVEDP>12 mm Hg was independently associated with all-cause mortality (HR 2.45, 95% CI 1.58 to 3.76, p <0.001) during long-term follow-up. In conclusion, elevated after-procedural LVEDP in patients who undewent TAVI is an independent predictor of mortality following TAVI. Further research regarding the use of LVEDP as a tool for after-procedural medical management is warranted.


Subject(s)
Aortic Valve Stenosis/surgery , Aortic Valve/surgery , Stroke Volume/physiology , Transcatheter Aortic Valve Replacement/methods , Ventricular Function, Left/physiology , Ventricular Pressure/physiology , Aged, 80 and over , Aortic Valve/diagnostic imaging , Aortic Valve Stenosis/diagnosis , Aortic Valve Stenosis/physiopathology , Diastole , Echocardiography , Female , Follow-Up Studies , Humans , Male , Postoperative Period , Prospective Studies , Retrospective Studies , Risk Factors , Severity of Illness Index , Time Factors , Treatment Outcome
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