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Left Atrial Remodeling and Atrioventricular Coupling in a Canine Model of Early Heart Failure With Preserved Ejection Fraction.

ABSTRACT: BACKGROUND:Left atrial (LA) compliance and contractility influence left ventricular stroke volume. We hypothesized that diminished LA compliance and contractile function occur early during the development of heart failure with preserved ejection fraction (HFpEF) and impair overall cardiac performance. METHODS AND RESULTS:Cardiac magnetic resonance imaging, echocardiography, left ventricular and LA pressure-volume studies, and tissue analyses were performed in a model of early HFpEF (elderly dogs, renal wrap-induced hypertension, exogenous aldosterone; n=9) and young control dogs (sham surgery; n=13). Early HFpEF was associated with LA enlargement, cardiomyocyte hypertrophy, and enhanced LA contractile function (median active emptying fraction 16% [95% confidence interval, 13-24]% versus 12 [10-14]%, P=0.008; end-systolic pressure-volume relationship slope 2.4 [1.9-3.2]mm?Hg/mL HFpEF versus 1.5 [1.2-2.2]mm?Hg/mL controls, P=0.01). However, atrioventricular coupling was impaired and the curvilinear LA end-reservoir pressure-volume relationship was shifted upward/leftward in HFpEF (LA stiffness constant [?LA] 0.16 [0.11-0.18]mm?Hg/mL versus 0.06 [0.04-0.10]mm?Hg/mL controls; P=0.002), indicating reduced LA compliance. Impaired atrioventricular coupling and lower LA compliance correlated with lower left ventricular stroke volume. Total fibrosis and titin isoform composition were similar between groups; however, titin was hyperphosphorylated in HFpEF and correlated with ?LA. LA microvascular reactivity was diminished in HFpEF versus controls. LA microvascular density tended to be lower in HFpEF and inversely correlated with ?LA. CONCLUSIONS:In early-stage hypertensive HFpEF, LA cardiomyocyte hypertrophy, titin hyperphosphorylation, and microvascular dysfunction occur in association with increased systolic and diastolic LA chamber stiffness, impaired atrioventricular coupling, and decreased left ventricular stroke volume. These data indicate that maladaptive LA remodeling occurs early during HFpEF development, supporting a concept of global myocardial remodeling.

SUBMITTER: Zakeri R

PROVIDER: S-EPMC5082983 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature

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Left Atrial Remodeling and Atrioventricular Coupling in a Canine Model of Early Heart Failure With Preserved Ejection Fraction.

Zakeri Rosita R Moulay Gilles G Chai Qiang Q Ogut Ozgur O Hussain Saad S Takahama Hiroyuki H Lu Tong T Wang Xiao-Li XL Linke Wolfgang A WA Lee Hon-Chi HC Redfield Margaret M MM

Circulation. Heart failure 20161010 10

<h4>Background</h4>Left atrial (LA) compliance and contractility influence left ventricular stroke volume. We hypothesized that diminished LA compliance and contractile function occur early during the development of heart failure with preserved ejection fraction (HFpEF) and impair overall cardiac performance.<h4>Methods and results</h4>Cardiac magnetic resonance imaging, echocardiography, left ventricular and LA pressure-volume studies, and tissue analyses were performed in a model of early HFpE ...[more]

PMID: 27758811

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Project description:BackgroundLeft atrial (LA) size is an established marker of risk for adverse outcomes in heart failure with preserved ejection fraction (HFpEF). However, the independent prognostic importance of LA function in HFpEF is not known.Methods and resultsWe assessed LA function measured by speckle-tracking echocardiography in 357 patients with HFpEF enrolled in the Treatment Of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist (TOPCAT) trial who were in sinus rhythm at the time of echocardiography. Lower peak LA strain, indicating LA dysfunction, was associated with older age, higher prevalence of atrial fibrillation and left ventricular (LV) hypertrophy, worse LV and right ventricular systolic function, and worse LV diastolic function. At a mean follow-up of 31 months (interquartile range, 18-43months), 91 patients (25.5%) experienced the primary composite end point of cardiovascular death, HF hospitalization, and aborted sudden death. Lower peak LA strain was associated with a higher risk of the composite end point (hazard ratio, 0.96 per unit of reduction in strain; 95% confidence interval, 0.94-0.99; P=0.009) and of HF hospitalization alone (hazard ratio, 0.95 per unit of reduction in strain; 95% confidence interval, 0.92-0.98; P=0.003). The association of LA strain with incident HF hospitalization remained significant after adjustment for clinical confounders, but not after further adjustment for LV global longitudinal strain and the E/E' ratio, parameters of LV systolic and diastolic function, respectively.ConclusionsLA dysfunction in HFpEF is associated with a higher risk of HF hospitalization independent of potential clinical confounders, but not independent of LV strain and filling pressure. Impairment in LV systolic and diastolic function largely explains the association between impaired LA function and higher risk of HF hospitalization in HFpEF.Clinical trial registrationURL: http://www.clinicaltrials.gov. Unique identifier: NCT00094302.

Project description:Background Maximal left atrial (LA) volume is reported by most echocardiography laboratories and is associated with clinical outcomes in patients with heart failure (HF). Recent studies suggest that minimal LA volume may better reflect left ventricular filling pressure and may be more prognostic than maximal LA volume. This study assessed the prognostic value of indexed minimal LA volume (LAVImin) in patients with HF with preserved ejection fraction. Methods and Results We assessed the relationship of LAVImin with a primary composite end point of cardiovascular death, aborted cardiac death, or HF hospitalization in 347 patients with HF with preserved ejection fraction enrolled from the Americas region in TOPCAT (Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist Trial). We compared LAVImin with indexed maximal LA volume with respect to their prognostic values. In addition, we assessed if LA functional parameters provide additional prognostic information over LAVImin. During a median follow-up of 2.5 years, 107 patients (31%) experienced a primary composite end point. LAVImin was associated with increased risk of a primary composite outcome (hazard ratio [HR], 1.35; 95% CI, 1.12-1.61) and HF hospitalization alone (HR, 1.42; 95% CI, 1.17-1.71) after adjusting for clinical confounders and ejection fraction. In contrast, indexed maximal LA volume was not related to the primary composite outcome, but related to HF alone (HR, 1.25; 95% CI, 1.02-1.54). In comparison with indexed maximal LA volume, LAVImin was significantly more prognostic for primary composite outcome (P for comparison=0.032). Both LA emptying fraction and LA strain were prognostic of primary outcome independent of LAVImin (all P<0.05). Conclusions In patients with HF with preserved ejection fraction, LAVImin was more predictive of cardiovascular outcome than indexed maximal LA volume, suggesting this measure may be more physiologically relevant and might better identify patients at high risk for cardiovascular events. LA functional parameters provide prognostic information independent of LAVImin. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT00094302.

Project description:AimsTwo key echocardiographic parameters that are currently used to diagnose heart failure (HF) with preserved ejection fraction (HFpEF) are left atrial volume index (LAVi) and left ventricular mass index (LVMi). We investigated whether patients' characteristics, biomarkers, and co-morbidities are associated with these parameters and whether the relationships differ between patients with HFpEF or HF with reduced ejection fraction (HFrEF).MethodsWe consecutively enrolled 831 outpatients with typical signs and symptoms of HF and elevated N-terminal prohormone of brain natriuretic peptide (NT-proBNP) levels and categorized patients based upon left ventricular ejection fraction (LVEF): LVEF < 40% (HFrEF), LVEF between 40% and 50% (HF with mid-range ejection fraction), and LVEF ≥ 50% (HFpEF). The study includes consecutively enrolled HF patients from an HF outpatient clinic at a tertiary medical centre in the Netherlands. All patients underwent baseline characterization, laboratory measurements, and echocardiography.ResultsFour hundred sixty-nine patients had HFrEF, 189 HF with mid-range ejection fraction, and 173 HFpEF. The patients with HFrEF were rather male [HFrEF: 323 (69%); HFpEF: 80 (46%); P < 0.001], and the age was comparable (HFrEF 67 ± 13; HFpEF 70 ± 14; P = 0.069). In HFpEF, more patients had hypertension [190 (40.5%); 114 (65.9%); P < 0.001], higher body mass indices (27 ± 8; 30 ± 7; P < 0.001), and atrial fibrillation [194 (41.4); 86 (49.7); P = 0.029]. The correlation analyses showed that in HFrEF patients, LAVi was significantly associated with age (β 0.293; P < 0.001), male gender (β 0.104; P = 0.042), body mass index (β -0160; P = 0.002), diastolic blood pressure (β -0.136; P < 0.001), New York Heart Association (β 0.174; P = 0.001), atrial fibrillation (β 0.381; P < 0.001), galectin 3 (β 0.230; P < 0.001), NT-proBNP (β 0.183; P < 0.001), estimated glomerular filtration rate (β -0.205; P < 0.001), LVEF (β -0.173; P = 0.001), and LVMi (β 0.337; P < 0.001). In HFpEF patients, only age (β 0.326; P < 0.001), atrial fibrillation (β 0.386; P < 0.001), NT-proBNP (β 0.176; P = 0.036), and LVMi (β 0.213; P = 0.013) were associated with LAVi.ConclusionsAlthough LVMi and LAVi are hallmark parameters to diagnose HFpEF, they only correlate with a few characteristics of HF and mainly with atrial fibrillation. In contrast, in HFrEF patients, LAVi relates strongly to several other HF parameters. These findings underscore the complexity in visualizing the pathophysiology of HFpEF and question the relation between cardiac structural remodeling and the impact of co-morbidities.

Project description:AimsExercise intolerance is the leading manifestation of heart failure with preserved or mid-range ejection fraction (HFpEF or HFmrEF), and left atrial (LA) function might contribute to modulating left ventricular filling and pulmonary venous pressures. We aim to assess the association between LA function and maximal exercise capacity in patients with HFpEF or HFmrEF.Methods and resultsSixty-five patients, prospectively enrolled in the German HFpEF Registry, were analysed. Inclusion criteria were New York Heart Association functional class ? II, left ventricular ejection fraction > 40%, structural heart disease or diastolic dysfunction, and elevated levels of N terminal pro brain natriuretic peptide (NT-proBNP). LA function was evaluated through speckle-tracking echocardiography by central reading in the Charité Academic Echocardiography core lab. All patients underwent maximal cardiopulmonary exercise test and were classified according to a peak VO2 cut-off of prognostic value (14 mL/kg/min). NT-pro-BNP was measured. Twenty-nine patients (45%) reached a peak VO2 < 14 mL/kg/min (mean value 12.4 ± 1.5) and 36 patients (55%) peak VO2 ? 14 mL/kg/min (mean value 19.4 ± 3.9). There was no significant difference in left ventricular ejection fraction (60 ± 9 vs. 59 ± 8%), left ventricular mass (109 ± 23 vs. 112 ± 32 g/m2 ), LA volume index (45 ± 17 vs. 47 ± 22 mL/m2 ), or E/e´ (13.1 ± 4.7 vs. 13.0 ± 6.0) between these groups. In contrast, all LA strain measures were impaired in patients with lower peak VO2 (reservoir strain 14 ± 5 vs. 21 ± 9%, P = 0.002; conduit strain 9 ± 2 vs. 13 ± 4%, P = 0.001; contractile strain 7 ± 4 vs. 11 ± 6%, P = 0.02; reported lower limits of normality for LA reservoir, conduit and contractile strains: 26.1%, 12.0%, and 7.7%). In linear regression analysis, lower values of LA reservoir strain were associated with impaired peak VO2 after adjustment for age, sex, body mass index, heart rhythm (sinus/AFib), and log-NTproBNP [? 0.29, 95% confidence interval (CI) 0.02-0.30, P = 0.02], with an odds ratio 1.22 (95% CI 1.05-1.42, P = 0.01) for peak VO2 < 14 mL/kg/min for LA reservoir strain decrease after adjustment for these five covariates. Adding left ventricular ejection fraction, it did not influence the results. On the other hand, the addition of LA strain to the adjustment parameters alone described above provided a significant increase of the predictive value for lower peak VO2 values (R2 0.50 vs. 0.45, P = 0.02). With receiver operating characteristic curve analysis, we identified LA reservoir strain < 22% to have 93% sensitivity and 49% specificity in predicting peak VO2 < 14 mL/kg/min. Using this cut-off, LA reservoir strain < 22% was associated with peak VO2 < 14 mL/kg/min in logistic regression analysis after comprehensive adjustment for age, sex, body mass index, heart rhythm, and log-NTproBNP [odds ratio 95% CI 10.4 (1.4-74), P = 0.02].ConclusionsIn this HFpEF and HFmrEF cohort, a reduction in LA reservoir strain was a sensible marker of decreased peak exercise capacity. Therefore, LA reservoir strain might be of clinical value in predicting exercise capacity in patients with HFpEF or HFmrEF.

Dataset Information

Left Atrial Remodeling and Atrioventricular Coupling in a Canine Model of Early Heart Failure With Preserved Ejection Fraction.

Publications

Left Atrial Remodeling and Atrioventricular Coupling in a Canine Model of Early Heart Failure With Preserved Ejection Fraction.

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