LV hypertrophy and diastolic heart failure

Correlation of serum Vascular Endothelial growth factor (VEGF) and cardiovascular risk factors on collateral formation in patients with acute coronary artery syndrome

Coronary collaterals serve as an alternative source of blood flow in obstructive coronary heart disease. Coronary collateral development by releasing various angiogenic growth factors, including vascular endothelial growth factor-A (VEGF-A). Cardiovascular risk factors strongly associated with coronary artery disease include age, sex, elevated serum cholesterol, disturbed carbohydrate metabolism, and elevated blood pressure. A better understanding of the effects of these cardiovascular risk factors and serum VEGF-A level on collateral recruitment is necessary for a better prognosis in coronary artery diseases and new insight for further therapeutic promotion of coronary collaterals.220 consecutive patients undergoing coronary angiography with a mean age of 61 ± 9.83 were selected for the analysis. Two millilitres of blood were taken from the patients for analysis. The blood serum VEGF concentration was quantified via the ELISA method. Angiograms and other clinical reports were collected. Significant coronary artery disease was diagnosed in those with ≥ 70% of stenosis in at least one of the coronary arteries. The angiographic and clinical data were documented. The collateral grading was done according to the Rentrop Scoring system. The serum vascular endothelial growth factor level was correlated with the collateral score and cardiovascular risk factors like age, sex, type ll diabetes, blood pressure, and cholesterol level. An increase in the level of the collateral score was noted with an increase in the level of VEGF in blood serum. A significant association was founded between serum VEGF level and cardiovascular risk factors on collateral formation in patients with diabetes and hypertension. This article is protected by copyright. All rights reserved.

Association between left ventricular diastolic function and right ventricular function and morphology in asymptomatic aortic stenosis

Background

Aortic stenosis (AS) is a progressive disease in which left ventricular (LV) diastolic dysfunction is common. However, the association between diastolic dysfunction and right ventricular (RV) loading conditions and function has not been investigated in asymptomatic AS patients.

Methods and findings

A total of 41 patients underwent right heart catheterization and simultaneous echocardiography at rest and during maximal supine exercise, stratified according to resting diastolic function. Cardiac chamber size and morphology was assessed using cardiac magnetic resonance imaging (cMRI). RV stroke work index, pulmonary artery (PA) compliance, PA elastance, PA pulsatility index, and right atrial pressure (RAP) were calculated at rest and maximal exercise. Ten patients (24%) had normal LV filling pattern, 20 patients (49%) had grade 1, and 11 patients (27%) had grade 2 diastolic dysfunction. Compared to patients with normal diastolic filling pattern, patients with diastolic dysfunction had lower RV end-diastolic volume (66 ± 11 ml/m² vs. 79 ± 15 ml/m², p = 0.02) and end-systolic volume (25 ± 7 ml/m² vs. 32 ± 9 ml/m², p = 0.04). An increase in mean RAP to ≥15 mmHg following exercise was not seen in patients with normal LV filling, compared to 4 patients (20%) with mild and 7 patients (63%) with moderate diastolic dysfunction (p = 0.003). PA pressure and PA elastance was increased in grade 2 diastolic dysfunction and correlated with RV volume and maximal oxygen consumption (r = -0.71, p < 0.001).

Conclusions

Moderate diastolic dysfunction is associated with increased RV afterload (elastance), which is compensated at rest, but is associated with increased RAP and inversely related to maximal oxygen consumption during maximal exercise.

Effect of Percutaneous Coronary Intervention on Left Ventricular Diastolic Function in Patients With Coronary Artery Disease

BACKGROUND

There is considerable disagreement over the effects of percutaneous coronary intervention (PCI) on left ventricular diastolic function that has necessitated the investigation of diastolic indices. The present study was conducted to evaluate left ventricular diastolic function and its indices, three months after performing the PCI procedure in patients with coronary artery disease (CAD).

METHODS

In a quasi-experimental clinical trial study (before and after), 51 patients with CAD scheduled for elective PCI were investigated provided that their Ejection Fraction (EF) was > 30%. Before and three months after PCI, echocardiography was carried out to evaluate left ventricular diastolic indices including the E/Ea as the most important criteria for diagnosis of diastolic heart failure (DHF).

RESULTS

Based on the E/Ea indices and after PCI, the number of patients with DHF decreased significantly: 40 patients (78.4%) before PCI versus 28 patients (54.9%) after PCI (p<0.05). The Mean and Standard error of deceleration time (DT), isovolumic relaxation time (IVRT), early diastolic mitral annulus velocity; Ea (E'), E/Ea and left ventricular ejection function (LVEF) indices underwent significant changes. In addition, MVA dur/PVA dur, PVs/PVd, and E/Ea indices had changed significantly after PCI in both genders. However, no significant difference was reported for the other indices.

CONCLUSION

The E/Ea ratio as an important criterion for diagnosis of DHF was improved after PCI. Improvement of several other diastolic indices was observed after the PCI procedure. It can be concluded that PCI can be an effective treatment modality in patients with left ventricular diastolic indices.

A novel mechanism involving four-and-a-half LIM domain protein-1 and extracellular signal-regulated kinase-2 regulates titin phosphorylation and mechanics

Understanding mechanisms underlying titin regulation in cardiac muscle function is of critical importance given recent compelling evidence that highlight titin mutations as major determinants of human cardiomyopathy. We previously identified a cardiac biomechanical stress-regulated complex at the cardiac-specific N2B region of titin that includes four-and-a-half LIM domain protein-1 (Fhl1) and components of the mitogen-activated protein signaling cascade, which impacted muscle compliance in Fhl1 knock-out cardiac muscle. However, direct regulation of these molecular components in mediating titin N2B function remained unresolved. Here we identify Fhl1 as a novel negative regulator of titin N2B levels and phosphorylation-mediated mechanics. We specifically identify titin N2B as a novel substrate of extracellular signal regulated-kinase-2 (Erk2) and demonstrate that Fhl1 directly interferes with Erk2-mediated titin-N2B phosphorylation. We highlight the critical region in titin-N2B that interacts with Fhl1 and residues that are dependent on Erk2-mediated phosphorylation in situ. We also propose a potential mechanism for a known titin-N2B cardiomyopathy-causing mutation that involves this regulatory complex. These studies shed light on a novel mechanism regulating titin-N2B mechano-signaling as well as suggest that dysfunction of these pathways could be important in cardiac disease states affecting muscle compliance.

Elucidation of spatially distinct compensatory mechanisms in diastole: radial compensation for impaired longitudinal filling in left ventricular hypertrophy

Cardiac output maintenance is so fundamental that, when regional systolic function is impaired, as during ischemia, nonischemic segments compensate by becoming hypercontractile. By analogy, diastolic compensatory mechanisms that maintain filling volume must exist but remain to be fully elucidated. Viewing filling in spatially distinct (longitudinal, radial) mechanistic terms facilitates elucidation of diastolic compensatory mechanisms. Because impairment of longitudinal (long axis) diastolic function (DF) in left ventricular hypertrophy (LVH) is established, we hypothesized that to maintain filling volume, radial (short-axis) filling function would compensate. In 20 normal left ventricular ejection fraction (LVEF) subjects (10 with LVH, 10 without LVH), we analyzed longitudinal function via Doppler tissue imaging of mitral annular motion and radial function as change in short-axis endocardial dimension via M-mode. The spatial (long axis, short axis) endocardial LV dimensions and their changes allowed assignment of E-wave filling volume into (cylindrical geometry-based) longitudinal and radial components. Despite indistinguishable (P = 0.70) E-wave velocity-time integrals (E-wave filling volume surrogate), systolic stroke volumes, and end-diastolic volumes in the LVH and control groups, longitudinal volume in absolute terms and the percent of E-wave volume accommodated longitudinally were reduced in the LVH group (P < 0.05 and P < 0.01, respectively), whereas the percent of E-wave volume accommodated radially was enhanced (P < 0.01). We conclude that, in normal LVEF (decreased longitudinal volume accommodation) LVH subjects vs. controls, spatially distinct compensatory mechanisms in diastole manifest as increased radial volume accommodation per unit of E-wave filling volume. Assessment of spatially distinct diastolic compensatory mechanisms in other pathophysiological subsets is warranted.

Isolated diastolic dysfunction--diagnostic value of tissue Doppler imaging, colour M-mode and N-terminal pro B-type natriuretic peptide

INTRODUCTION

For diagnosis of diastolic dysfunction of the left ventricle (DDF), measurement of relaxation velocity (V(R)) by tissue Doppler imaging (V(R)), flow propagation velocity of transmitral inflow (v(p)) as well as the measurement of serum levels of N-terminal pro b-type natriuretic peptide (NT-proBNP) compete with the standard echocardiographic DDF-measures because of several disadvantages of the latter.

METHODS

We examined the diagnostic value of method 1, 2 and NT-proBNP in 120 patients with echocardiographic-proven DDF and in 20 patients without. Patients were classified according to the DDF-stage by standard echocardiographic parameters (transmitral E/A-ratio, deceleration time, isovolumetric relaxation time) into stage I, II and III and furthermore subdivided by the presence of dyspnoea.

RESULTS

V(R) and v(p) were significantly lower in patients with DDF than in patients without DDF, with no difference between the various DDF stages. Symptomatic patients showed a trend to a lower V(R). NT-proBNP was elevated in patients with DDF: Symptomatic patients with a DDF at stage I and patients with a DDF at stage II and III independent of the presence of symptoms had elevated NT-proBNP levels.

CONCLUSION

All three methods tested identified patients with DDF. NT-proBNP and v(p) were able to discriminate between symptomatic and asymptomatic patients.