A general theory of acute and chronic heart failure

Elevated plasma solMER concentrations link ambient PM2.5 and PAHs to myocardial injury and reduced left ventricular systolic function in children

Exposure to fine particulate matter (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) is known to be associated with the polarization of pro-inflammatory macrophages and the development of various cardiovascular diseases. The pro-inflammatory polarization of resident cardiac macrophages (cMacs) enhances the cleavage of membrane-bound myeloid-epithelial-reproductive receptor tyrosine kinase (MerTK) and promotes the formation of soluble MerTK (solMER). This process influences the involvement of cMacs in cardiac repair, thus leading to an imbalance in cardiac homeostasis, myocardial injury, and reduced cardiac function. However, the relative impacts of PM2.5 and PAHs on human cMacs have yet to be elucidated. In this study, we aimed to investigate the effects of PM2.5 and PAH exposure on solMER in terms of myocardial injury and left ventricular (LV) systolic function in healthy children. A total of 258 children (aged three to six years) were recruited from Guiyu (an area exposed to e-waste) and Haojiang (a reference area). Mean daily PM2.5 concentration data were collected to calculate the individual chronic daily intake (CDI) of PM2.5. We determined concentrations of solMER and creatine kinase MB (CKMB) in plasma, and hydroxylated PAHs (OH-PAHs) in urine. LV systolic function was evaluated by stroke volume (SV). Higher CDI values and OH-PAH concentrations were detected in the exposed group. Plasma solMER and CKMB were higher in the exposed group and were associated with a reduced SV. Elevated CDI and 1-hydroxynaphthalene (1-OHNa) were associated with a higher solMER. Furthermore, increased solMER concentrations were associated with a lower SV and higher CKMB. CDI and 1-OHNa were positively associated with CKMB and mediated by solMER. In conclusion, exposure to PM2.5 and PAHs may lead to the pro-inflammatory polarization of cMacs and increase the risk of myocardial injury and systolic function impairment in children. Furthermore, the pro-inflammatory polarization of cMacs may mediate cardiotoxicity caused by PM2.5 and PAHs.

Quantifying myocardial active strain energy density: A comparative analysis of analytic and finite element methods for estimating left ventricular wall stress and strain

AIMS

This study compared commonly used methods for calculating left ventricular wall stress with the finite element analysis and evaluated different approaches to strain estimation. We sought to improve the accuracy of contractance estimation by developing a novel stress equation.

BACKGROUND

Multiple methods for calculating LV contractile stress and strain exist. Contractance is derived from stress and strain information and is a measure of myocardial work per unit volume of muscle. Precise stress and strain information are essential for its accurate evaluation.

METHODS AND RESULTS

We compared widely used methods for stress and strain calculations across diverse clinical scenarios representing distinct types of left ventricular myocardial disease. Our analysis revealed significant discrepancies in both the stress and strain values obtained with different methods. However, a newly developed modified version of the Mirsky equation demonstrated close agreement with the finite element analysis results for circumferential stress, while the Lamé method produced results close to those of finite element analysis for longitudinal stress and improved contractance accuracy.

CONCLUSION

This study highlights significant inconsistencies in stress and strain values calculated using different methods, emphasising the potential impact on contractance calculations and subsequent clinical interpretation. We recommend adopting the Lamé method for longitudinal stress assessment and the modified Mirsky equation for circumferential stress analysis. These methods offer a balance between accuracy and feasibility, making them advantageous for clinical practice. By adopting these recommendations, we can improve the accuracy of LV wall stress and strain estimates, leading to more dependable contractance calculations, better prognostication and improved clinical decisions.

CLINICAL AND TRANSLATIONAL IMPACT STATEMENT

Accurately estimating myocardial stress and strain is of paramount significance in clinical practice because the calculation of the contractance, defined and quantified by myocardial active strain energy density, necessitates correct stress and strain data. Contractance, which assesses myocardial work per unit muscle volume, has emerged as a promising indicator of contractile function and a predictor of future risk. The new recommendations for calculating myocardial stress improve the reliability of calculating contractance and enhance the understanding of myocardial diseases.

Tricuspid annular plane systolic excursion/mitral annular plane systolic excursion ratio in critically ill patients: an index of right- and left-ventricular function mismatch and a risk factor for cardiogenic pulmonary edema

BACKGROUND

This study aimed to explore whether the tricuspid annular systolic excursion (TAPSE)/mitral annular systolic excursion (MAPSE) ratio was associated with the occurrence of cardiogenic pulmonary edema (CPE) in critically ill patients.

MATERIALS AND METHODS

This was a prospective observational study conducted in a tertiary hospital. Adult patients admitted to the intensive care unit who were on mechanical ventilation or in need of oxygen therapy were prospectively screened for enrolment. The diagnosis of CPE was determined based on lung ultrasound and echocardiography findings. TAPSE ≥ 17 mm and MAPSE ≥ 11 mm were used as normal references.

RESULTS

Among the 290 patients enrolled in this study, 86 had CPE. In the logistic regression analysis, the TASPE/MAPSE ratio was independently associated with the occurrence of CPE (odds ratio 4.855, 95% CI: 2.215-10.641, p < 0.001). The patients' heart function could be categorized into four types: normal TAPSE in combination with normal MAPSE (TAPSE↑/MAPSE↑) (n = 157), abnormal TAPSE in combination with abnormal MAPSE (TAPSE↓/MAPSE↓) (n = 40), abnormal TAPSE in combination with normal MAPSE (TAPSE↓/MAPSE↑) (n = 50) and normal TAPSE in combination with abnormal MAPSE (TAPSE↑/MAPSE↓) (n = 43). The prevalence of CPE in patients with TAPSE↑/MAPSE↓ (86.0%) was significantly higher than that in patients with TAPSE↑/MAPSE↑ (15.3%), TAPSE↓/MAPSE↓ (37.5%), or TAPSE↓/MAPSE↑ (20.0%) (p < 0.001). The ROC analysis showed that the area under the curve for the TAPSE/MAPSE ratio was 0.761 (95% CI: 0.698-0.824, p < 0.001). A TAPSE/MAPSE ratio of 1.7 allowed the identification of patients at risk of CPE with a sensitivity of 62.8%, a specificity of 77.9%, a positive predictive value of 54.7% and a negative predictive value of 83.3%.

CONCLUSIONS

The TAPSE/MAPSE ratio can be used to identify critically ill patients at higher risk of CPE.

Left ventricular contractance: A new measure of contractile function

AIMS

Myocardial contractility is poorly defined and difficult to compare between studies. Contractance or myocardial active strain energy density (MASED) measures the mechanical work done per unit volume (with units of kJ/m³) by any cardiac tissue during contraction. Contractance is an ideal candidate for measuring contractile function as it combines information from both stress and strain.

METHODS AND RESULTS

Data obtained from three previously published experimental studies using trabecular tissue was used to provide contemporaneous nominal stress and strain data in 18 different scenarios with different loading conditions. Contractance varied in the differing loading conditions with values of 1.16 (low preload), 2.02 (high afterload) and 3.76 kJ/m³ (normal). Contractance varied between 0 with isometric loading and 2.14 kJ/m³ with an isotonic and moderate afterload. Increasing inotropy increased contractance to 4.7 kJ/m³.

CONCLUSION

We showed that calculating MASED was feasible and provided a measure of energy production (work done) per unit volume of myocardium during contraction. The new term for contractile function, contractance, can be defined and quantified by MASED. Contractance measures contractile function in differing preload, afterload and inotropic settings. The method of measuring contractance is transferable to the assessment of global and regional systolic function.

Left ventricular active strain energy density is a promising new measure of systolic function

The left ventricular ejection fraction does not accurately predict exercise capacity or symptom severity and has a limited role in predicting prognosis in heart failure. A better method of assessing ventricular performance is needed to aid understanding of the pathophysiological mechanisms and guide management in conditions such as heart failure. In this study, we propose two novel measures to quantify myocardial performance, the global longitudinal active strain energy (GLASE) and its density (GLASED) and compare them to existing measures in normal and diseased left ventricles. GLASED calculates the work done per unit volume of muscle (energy density) by combining information from myocardial strain and wall stress (contractile force per unit cross sectional area). Magnetic resonance images were obtained from 183 individuals forming four cohorts (normal, hypertension, dilated cardiomyopathy, and cardiac amyloidosis). GLASE and GLASED were compared with the standard ejection fraction, the corrected ejection fraction, myocardial strains, stroke work and myocardial forces. Myocardial shortening was decreased in all disease cohorts. Longitudinal stress was normal in hypertension, increased in dilated cardiomyopathy and severely decreased in amyloid heart disease. GLASE was increased in hypertension. GLASED was mildly reduced in hypertension (1.39 ± 0.65 kJ/m3), moderately reduced in dilated cardiomyopathy (0.86 ± 0.45 kJ/m3) and severely reduced in amyloid heart disease (0.42 ± 0.28 kJ/m3) compared to the control cohort (1.94 ± 0.49 kJ/m3). GLASED progressively decreased in the hypertension, dilated cardiomyopathy and cardiac amyloid cohorts indicating that mechanical work done and systolic performance is severely reduced in cardiac amyloid despite the relatively preserved ejection fraction. GLASED provides a new technique for assessing left ventricular myocardial health and contractile function.

The corrected left ventricular ejection fraction: a potential new measure of ventricular function

Left ventricular ejection fraction (LVEF) has a limited role in predicting outlook in heart diseases including heart failure. We quantified the independent geometric factors that determine LVEF using cardiac MRI and sought to provide an improved measure of ventricular function by adjusting for such independent variables. A mathematical model was used to analyse the independent effects of structural variables and myocardial shortening on LVEF. These results informed analysis of cardiac MRI data from 183 patients (53 idiopathic dilated cardiomyopathy (DCM), 36 amyloidosis, 55 hypertensives and 39 healthy controls). Left ventricular volumes, LVEF, wall thickness, internal dimensions and longitudinal and midwall fractional shortening were measured. The modelling demonstrated LVEF increased in a curvilinear manner with increasing mFS and longitudinal shortening and wall thickness but decreased with increasing internal diameter. Controls in the clinical cohort had a mean LVEF 64  ±  7%, hypertensives 66  ±  8%, amyloid 49 ±  16% and DCM 30  ±  11%. The mean end-diastolic wall thickness in controls was 8  ±  1 mm, DCM 8  ±  1 mm, hypertensives 11  ±  3 mm and amyloid 14  ±  3 mm, P < 0.0001). LVEF correlated with absolute wall thickening relative to ventricular size (R² = 0.766). A regression equation was derived from raw MRI data (R² = 0.856) and used to 'correct' LVEF (EF_c) by adjusting the wall thickness and ventricular size to the mean of the control group. Improved quantification of the effects of geometric changes and strain significantly enhances understanding the myocardial mechanics. The EF_c resulted in reclassification of a 'ventricular function' in some individuals and may provide an improved measure of myocardial performance especially in thick-walled, low-volume ventricles.

Endothelial progenitor cells mobilization after maximal exercise according to heart failure severity

BACKGROUND

Vascular endothelial dysfunction is an underlying pathophysiological feature of chronic heart failure (CHF). Patients with CHF are characterized by impaired vasodilation and inflammation of the vascular endothelium. They also have low levels of endothelial progenitor cells (EPCs). EPCs are bone marrow derived cells involved in endothelium regeneration, homeostasis, and neovascularization. Exercise has been shown to improve vasodilation and stimulate the mobilization of EPCs in healthy people and patients with cardiovascular comorbidities. However, the effects of exercise on EPCs in different stages of CHF remain under investigation.

AIM

To evaluate the effect of a symptom-limited maximal cardiopulmonary exercise testing (CPET) on EPCs in CHF patients of different severity.

METHODS

Forty-nine consecutive patients (41 males) with stable CHF [mean age (years): 56 ± 10, ejection fraction (EF, %): 32 ± 8, peak oxygen uptake (VO₂, mL/kg/min): 18.1 ± 4.4] underwent a CPET on a cycle ergometer. Venous blood was sampled before and after CPET. Five circulating endothelial populations were quantified by flow cytometry: Three subgroups of EPCs [CD34⁺/CD45^-/CD133⁺, CD34⁺/CD45^-/CD133⁺/VEGFR₂ and CD34⁺/CD133⁺/vascular endothelial growth factor receptor 2 (VEGFR₂)] and two subgroups of circulating endothelial cells (CD34⁺/CD45^-/CD133^- and CD34⁺/CD45^-/CD133^-/VEGFR₂). Patients were divided in two groups of severity according to the median value of peak VO₂ (18.0 mL/kg/min), predicted peak VO₂ (65.5%), ventilation/carbon dioxide output slope (32.5) and EF (reduced and mid-ranged EF). EPCs values are expressed as median (25th-75th percentiles) in cells/10⁶ enucleated cells.

RESULTS

Patients with lower peak VO₂ increased the mobilization of CD34⁺/CD45^-/CD133⁺ [pre CPET: 60 (25-76) vs post CPET: 90 (70-103) cells/10⁶ enucleated cells, P < 0.001], CD34⁺/CD45^-/CD133⁺/VEGFR₂ [pre CPET: 1 (1-4) vs post CPET: 5 (3-8) cells/10⁶ enucleated cells, P < 0.001], CD34⁺/CD45^-/CD133^- [pre CPET: 186 (141-361) vs post CPET: 488 (247-658) cells/10⁶ enucleated cells, P < 0.001] and CD34⁺/CD45^-/CD133^-/VEGFR₂ [pre CPET: 2 (1-2) vs post CPET: 3 (2-5) cells/10⁶ enucleated cells, P < 0.001], while patients with higher VO₂ increased the mobilization of CD34⁺/CD45^-/CD133⁺ [pre CPET: 42 (19-73) vs post CPET: 90 (39-118) cells/10⁶ enucleated cells, P < 0.001], CD34⁺/CD45^-/CD133⁺/VEGFR₂ [pre CPET: 2 (1-3) vs post CPET: 6 (3-9) cells/10⁶ enucleated cells, P < 0.001], CD34⁺/CD133⁺/VEGFR₂ [pre CPET: 10 (7-18) vs post CPET: 14 (10-19) cells/10⁶ enucleated cells, P < 0.01], CD34⁺/CD45^-/CD133^- [pre CPET: 218 (158-247) vs post CPET: 311 (254-569) cells/10⁶ enucleated cells, P < 0.001] and CD34⁺/CD45^-/CD133^-/VEGFR₂ [pre CPET: 1 (1-2) vs post CPET: 4 (2-6) cells/10⁶ enucleated cells, P < 0.001]. A similar increase in the mobilization of at least four out of five cellular populations was observed after maximal exercise within each severity group regarding predicted peak, ventilation/carbon dioxide output slope and EF as well (P < 0.05). However, there were no statistically significant differences in the mobilization of endothelial cellular populations between severity groups in each comparison (P > 0.05).

CONCLUSION

Our study has shown an increased EPCs and circulating endothelial cells mobilization after maximal exercise in CHF patients, but this increase was not associated with syndrome severity. Further investigation, however, is needed.

Outcome differences in acute vs. acute on chronic heart failure and cardiogenic shock

Aims

Despite advances in coronary reperfusion and percutaneous mechanical circulatory support, mortality among patients presenting with cardiogenic shock (CS) remains unacceptably high. Clinical trials and risk stratification tools have largely focused on acute CS, particularly secondary to acute coronary syndrome. Considerably less is understood about CS in the setting of acute decompensation in patients with chronic heart failure (HF). We sought to compare outcomes between patients with acute CS and patients with acute on chronic decompensated HF presenting with laboratory and haemodynamic features consistent with CS.

Methods and results

Sequential patients admitted with CS at a single quaternary centre between January 2014 and August 2017 were identified. Acute on chronic CS was defined by having a prior diagnosis of HF. Initial haemodynamic and laboratory data were collected for analysis. The primary outcome was in‐hospital mortality. Secondary outcomes were use of temporary mechanical circulatory support, durable ventricular assist device implantation, total artificial heart implantation, or heart transplantation. Comparison of continuous variables was performed using Student's t‐test. For categorical variables, the χ² statistic was used. A total of 235 patients were identified: 51 patients (32.8%) had acute CS, and 184 patients (64.3%) had acute decompensation of chronic HF with no differences in age (52 ± 22 vs. 55 ± 14 years, P = 0.28) or gender (26% vs. 23%, P = 0.75) between the two groups. Patients with acute CS were more likely to suffer in‐hospital death (31.4% vs. 9.8%, P < 0.01) despite higher usage of temporary mechanical circulatory support (52% vs. 25%, P < 0.01) compared with patients presenting with acute on chronic HF. The only clinically significant haemodynamic differences at admission were a higher heart rate (101 ± 29 vs. 82 ± 17 b.p.m., P < 0.01) and wider pulse pressure (34 ± 19 vs. 29 ± 10 mmHg, P < 0.01) in the acute CS group. There were no significant differences in degree of shock based on commonly used CS parameters including mean arterial pressure (72 ± 12 vs. 74 ± 10 mmHg, P = 0.23), cardiac output (3.9 ± 1.2 vs. 3.8 ± 1.2 L/min, P = 0.70), or cardiac power index (0.32 ± 0.09 vs. 0.30 ± 0.09 W/m², P = 0.24) between the two groups.

Conclusions

Current definitions and risk stratification models for CS based on clinical trials performed in the setting of acute coronary syndrome may not accurately reflect CS in patients with acute on chronic HF. Further investigation into CS in patients with acute on chronic HF is warranted.

The end of the unique myocardial band: Part II. Clinical and functional considerations

Two of the leading concepts of mural ventricular architecture are the unique myocardial band and the myocardial mesh model. We have described, in an accompanying article published in this journal, how the anatomical, histological and high-resolution computed tomographic studies strongly favour the latter concept. We now extend the argument to describe the linkage between mural architecture and ventricular function in both health and disease. We show that clinical imaging by echocardiography and magnetic resonance imaging, and electrophysiological studies, all support the myocardial mesh model. We also provide evidence that the unique myocardial band model is not compatible with much of scientific research.

Restoration of cardiac function after anaemia-induced heart failure in zebrafish

AIMS

New therapeutic approaches are needed to fight against the growing epidemic of heart failure. Unlike mammals, zebrafish possess the incredible ability to regenerate cardiac tissue after acute trauma such as apical resection. Yet, the ability of zebrafish to recover after a chronic stress leading to heart failure has not been reported. The aim of this study was to test whether zebrafish can recover a normal cardiac function after anaemia-induced heart failure.

METHODS AND RESULTS

Eight- to ten-month-old zebrafish were treated with phenylhydrazine hydrochloride, an anaemia inducer, to generate heart failure. Treatment was stopped after 5 weeks and fish were followed-up for 3 weeks. Assessment of ventricular function by ultrasound at the end of the treatment revealed an increase in ventricle diameter (+47%) and a decrease in heart rate (-36%) and fractional shortening (-30%). A decrease in swim capacity was also observed (-31%). Tissue staining showed a thickening of the ventricular wall (5-fold), cell apoptosis and proliferation but no fibrosis. Expression of foetal genes, angiogenic factor and inflammation markers was increased, and β-adrenergic receptor-1 was decreased. Three weeks after phenylhydrazine hydrochloride withdrawal, all parameters returned to baseline and the fish recovered a normal cardiac function, tissue morphology and gene expression.

CONCLUSIONS

Zebrafish are able to completely recover from anaemia-induced heart failure. This model represents a unique opportunity to investigate the mechanisms of cardiac repair and may lead to the discovery of novel therapeutic targets of heart failure.

A multidimensional sight on cardiac failure: uncovered from structural to molecular level

Heart failure is one of the leading causes of death, with high mortality rate within 5 years after diagnosis. Treatment and prognosis options for heart failure primarily targeted on hemodynamic and neurohumoral components that drive progressive deterioration of the heart. However, given the multifactorial background that eventually leads to the "phenotype" named heart failure, better insight into the various components may lead to personalized treatment opportunities. Indeed, currently used criteria to diagnose and/or classify heart failure are possibly too focused on phenotypic improvement rather than the molecular driver of the disease and could therefore be further refined by integrating the leap of molecular and cellular knowledge. The ambiguity of the ejection fraction-based classification criteria became evident with development of advanced molecular techniques and the dawn of omics disciplines which introduced the idea that disease is caused by a myriad of cellular and molecular processes rather than a single event or pathway. The fact that different signaling pathways may underlie similar clinical manifestations calls for a more holistic study of heart failure. In this context, the systems biology approach can offer a better understanding of how different components of a system are altered during disease and how they interact with each other, potentially leading to improved diagnosis and classification of this condition. This review is aimed at addressing heart failure through a multilayer approach that covers individually some of the anatomical, morphological, functional, and tissue aspects, with focus on cellular and subcellular features as an alternative insight into new therapeutic opportunities.

Agreement between heart failure patients and providers in assessing New York Heart Association functional class

BACKGROUND

Uncertainty persists regarding whether patient assessment of New York Heart Association (NYHA) functional classification should be preferred over provider assessment among patients with heart failure (HF).

OBJECTIVES

To compare patient against provider NYHA assessments, and both to distance walked on a 6-minute walk test (6MWT) among patients with HF.

METHODS

In this prospective study, we enrolled 101 HF patients who self-assessed NYHA classification. Health care providers who were blinded to patient ratings of NYHA also rated NYHA. Patients completed a 6MWT according to a standardized protocol. We used Spearman coefficients (rs) to evaluate the correlations between variables.

RESULTS

Patient- and provider-determined NYHA class were poorly correlated, but the relationship was statistically significant (rs = 0.40, p < 0.001). Patients consistently reported better NYHA class (class I: 72% vs 15%) than providers. Provider-determined NYHA had a stronger correlation with 6MWT distance (rs = -0.36, p < 0.001 vs. rs = -0.22, p = 0.03). Providers assigned a worse class to older patients who had comorbidity; patients with dyspnea and longer HF duration assigned themselves a worse class.

CONCLUSION

Patients and providers exhibited poor agreement in NYHA assignment.

Cardiovascular Mechanisms of Extravascular Lung Water Accumulation in Divers

This study assessed the relation between altered cardiac function and the development of interstitial pulmonary edema in scuba divers. Fifteen healthy men performed a 30-minute scuba dive in open sea. They were instructed to fin for 30 minutes and were wearing wet suits. Before and immediately after immersion, cardiac indexes and extravascular lung water were measured using echocardiography and lung ultrasound, respectively. The mean ultrasound lung comet score increased from 0 to 4.6 ± 3.4. The diameter of the inferior caval vein increased by 47 ± 5.2%, systolic pulmonary artery pressure by 105 ± 8.6%, left atrial volume by 18.0 ± 3.3%, and left ventricle end-diastolic volume by 10 ± 2.4% suggesting that both right and left ventricular (LV) filling pressures were elevated. Doppler studies showed an increased mitral E peak (+2.5 ± 0.3%) and E/A ratio (+22.5 ± 3.4%) with a decreased mitral A peak (-16.4 ± 2.7%), E peak deceleration time (-14.5 ± 2.4%) consistent with rapid early LV filling but without a change in LV stroke volume. There was an increase in right/left ventricle diameter ratio (+33.6 ± 4.8%) suggesting a relative increase in right-sided heart output compared with the left. Furthermore, the lung comet score correlated significantly with inferior caval vein diameter, systolic pulmonary artery pressure, right/left ventricle diameter ratio, and E-wave deceleration time. In conclusion, the altered right/left heart stroke volume balance could play an essential role in the development of immersion pulmonary edema. Our findings have important implications for the pathogenesis of cardiogenic pulmonary edema.

Treatment of Heart Failure With Reduced Ejection Fraction-Recent Developments

Heart failure with reduced ejection fraction (HFrEF) represents at least half of the cases of heart failure, which is a syndrome defined as the inability of the heart to supply the body's tissues with an adequate amount of blood under conditions of normal cardiac filling pressure. HFrEF is responsible for high costs and rates of mortality, morbidity, and hospital admissions, mainly in developed countries. Thus, the need for better diagnostic methods and therapeutic approaches and consequently better outcomes is clear. In this article, we review the principal aspects of pathophysiology and diagnosis of HFrEF, with focus on emerging biomarkers and on recent echocardiographic methods for the assessment of left ventricular function. Furthermore, we discuss several major developments in pharmacological and nonpharmacological treatment of HFrEF in the last years, including cardiac resynchronization therapy, implantable cardioverter defibrillators, and the recent and promising drug LCZ696, focusing on current indications, unanswered questions, and other relevant aspects.

The Relationship Between Left Ventricular Wall Thickness, Myocardial Shortening, and Ejection Fraction in Hypertensive Heart Disease: Insights From Cardiac Magnetic Resonance Imaging

Hypertensive heart disease is often associated with a preserved left ventricular ejection fraction despite impaired myocardial shortening. The authors investigated this paradox in 55 hypertensive patients (52±13 years, 58% male) and 32 age- and sex-matched normotensive control patients (49±11 years, 56% male) who underwent cardiac magnetic resonance imaging at 1.5T. Long-axis shortening (R=0.62), midwall fractional shortening (R=0.68), and radial strain (R=0.48) all decreased (P<.001) as end-diastolic wall thickness increased. However, absolute wall thickening (defined as end-systolic minus end-diastolic wall thickness) was maintained, despite the reduced myocardial shortening. Absolute wall thickening correlated with ejection fraction (R=0.70, P<.0001). In multiple linear regression analysis, increasing wall thickness by 1 mm independently increased ejection fraction by 3.43 percentage points (adjusted β-coefficient: 3.43 [2.60-4.26], P<.0001). Increasing end-diastolic wall thickness augments ejection fraction through preservation of absolute wall thickening. Left ventricular ejection fraction should not be used in patients with hypertensive heart disease without correction for degree of hypertrophy.

Physiological mechanisms of pulmonary hypertension

Pulmonary hypertension is usually related to obstruction of pulmonary blood flow at the level of the pulmonary arteries (eg, pulmonary embolus), pulmonary arterioles (idiopathic pulmonary hypertension), pulmonary veins (pulmonary venoocclusive disease) or mitral valve (mitral stenosis and regurgitation). Pulmonary hypertension is also observed in heart failure due to left ventricle myocardial diseases regardless of the ejection fraction. Pulmonary hypertension is often regarded as a passive response to the obstruction to pulmonary flow. We review established fluid dynamics and physiology and discuss the mechanisms underlying pulmonary hypertension. The important role that the right ventricle plays in the development and maintenance of pulmonary hypertension is discussed. We use principles of thermodynamics and discuss a potential common mechanism for a number of disease states, including pulmonary edema, through adding pressure energy to the pulmonary circulation.

Determinants of temporal changes in galectin-3 level in the general population: Data of PREVEND

BACKGROUND

High baseline galectin-3 levels are associated with increased risk for adverse cardiovascular outcomes in the general population, but determinants of changes in galectin-3 levels over time have not been established. Therefore, we aimed to identify determinants of (temporal) change in galectin-3 levels.

METHODS

Galectin-3 plasma levels were measured in a large community based cohort (PREVEND study) at 3 different time points: at baseline, after ~4 and ~9years. The association of baseline clinical and biochemical factors and (temporal) changes in galectin-3 level was assessed using multivariable mixed-effects regression modeling.

RESULTS

In 4355 subjects, galectin-3 plasma levels were available at all time points (mean age: 48±12years; 50% female). Median galectin-3 level at baseline was 10.7 [8.9-12.7] ng/mL which gradually increased to 11.5 [9.4-14.3] ng/mL after ~9years. Using mixed-effects regression modeling, we first validated as independent determinants of baseline circulating galectin-3: eGFR (chi square (χ(2)):210.27, p<0.0001), gender (χ(2):43.85; p<0.0001), BMI (χ(2):19.68, p=0.0001), NT-proBNP (χ(2):18.76, p=0.0001) and serum (total) cholesterol (χ(2):8.63, p=0.01). Furthermore, we identified urinary albumin excretion (χ(2):34.03, p-value: <0.0001) and systolic blood pressure (χ(2):16.81, p=0.002) as independent determinants of temporal changes of galectin-3.

CONCLUSIONS

In the general population, urinary albumin excretion >30mg/24h and systolic blood pressure >170mmHg were identified as significant determinants of dynamic increases in galectin-3 levels over time. These results implicate that treatment of high blood pressure might be effective to prevent increasing galectin-3 levels and its associated conditions.

Left ventricular ejection fraction is determined by both global myocardial strain and wall thickness

Objectives

The purpose of this study was to determine the mathematical relationship between left ventricular ejection fraction and global myocardial strain. A reduction in myocardial strain would be expected to cause a fall in ejection fraction. However, there is abundant evidence that abnormalities of myocardial strain can occur with a normal ejection fraction. Explanations such as a compensatory increase in radial or circumferential strain are not supported by clinical studies. We set out to determine the biomechanical relationship between ejection fraction, wall thickness and global myocardial strain.

Methods

The study used an established abstract model of left ventricular contraction to examine the effect of global myocardial strain and wall thickness on ejection fraction. Equations for the relationship between ejection fraction, wall thickness and myocardial strain were obtained using curve fitting methods.

Results

The mathematical relationship between ejection fraction, ventricular wall thickness and myocardial strain was derived as follows: φ = e^{(0.14Ln(ε) + 0.06)ω + (0.9Ln(ε) + 1.2)}, where φ is ejection fraction (%), ω is wall thickness (cm) and ε is myocardial strain (−%).

Conclusion

The findings of this study explain the coexistence of reduced global myocardial strain and normal ejection fraction seen in clinical observational studies. Our understanding of the pathophysiological processes in heart failure and associated conditions is substantially enhanced. These results provide a much better insight into the biophysical inter-relationship between myocardial strain and ejection fraction. This improved understanding provides an essential foundation for the design and interpretation of future clinical mechanistic and prognostic studies.

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Ejection fraction has a limited value in predicting mortality and functional capacity.

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Myocardial mechanics including the relationship between myocardial strain and ejection fraction are currently poorly understood.

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We showed that there is biophysical relationship between end-diastolic wall thickness, myocardial strain and ejection fraction.

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Such a relationship explains the poor correlation of ejection fraction with prognosis and functional capacity.

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The study provides the foundation for determining the relationship between ventricular hypertrophy, ejection fraction and prognosis.

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The vital role of the right ventricle in the pathogenesis of acute pulmonary edema

The development of acute pulmonary edema involves a complex interplay between the capillary hydrostatic, interstitial hydrostatic, and oncotic pressures and the capillary permeability. We review the pathophysiological processes involved and illustrate the concepts in a number of common clinical situations including heart failure with normal and reduced ejection fractions, mitral regurgitation, and arrhythmias. We also describe other rarer causes including exercise, swimming, and diving-induced acute pulmonary edema. We suggest a unifying framework in which the critical abnormality is a mismatch or imbalance between the right and left ventricular stroke volumes. In conclusion, we hypothesize that increased right ventricular contraction is an important contributor to the sudden increase in capillary hydrostatic pressure, and therefore, a central mechanism involved in the development of alveolar edema.

Potential role of dipeptidyl peptidase IV in the pathophysiology of heart failure

Dipeptidyl peptidase IV (DPPIV) is a widely expressed multifunctional serine peptidase that exists as a membrane-anchored cell surface protein or in a soluble form in the plasma and other body fluids. Numerous substrates are cleaved at the penultimate amino acid by DPPIV, including glucagon-like peptide-1 (GLP-1), brain natriuretic peptide (BNP) and stromal cell-derived factor-1 (SDF-α), all of which play important roles in the cardiovascular system. In this regard, recent reports have documented that circulating DPPIV activity correlates with poorer cardiovascular outcomes in human and experimental heart failure (HF). Moreover, emerging evidence indicates that DPPIV inhibitors exert cardioprotective and renoprotective actions in a variety of experimental models of cardiac dysfunction. On the other hand, conflicting results have been found when translating these promising findings from preclinical animal models to clinical therapy. In this review, we discuss how DPPIV might be involved in the cardio-renal axis in HF. In addition, the potential role for DPPIV inhibitors in ameliorating heart disease is revised, focusing on the effects of the main DPPIV substrates on cardiac remodeling and renal handling of salt and water.

Developmental and organ-specific toxicity of cucurbit[7]uril: in vivo study on zebrafish models

The macrocyclic Cucurbit[7]uril was evaluated for its in vivo toxicity profile, including developmental toxicity and organ-specific toxicities using zebrafish models.

Swimming-induced pulmonary oedema in two triathletes: a novel pathophysiological explanation

Swimming-induced pulmonary oedema/edema (SIPO/SIPE) is likely to become commoner with increasing popularity of endurance sports meaning an increased awareness by participants, organisers and medical personnel is important, especially as individuals are at increased risk of future life threatening episodes and drowning if an accurate diagnosis and appropriate advice are not given. The most important risk factors we identified are a highly trained individual, competitive exercise, hypertension and cold environment.