Why is left ventricular hypertrophy so predictive of morbidity and mortality?

THE ROLE OF LEPTINRESISTANCE IN THE PATHOGENESIS OF OBESITY IN PREGNANT WOMEN

OBJECTIVE

The aim: To investigate the relationship between leptin resistance, lipid and carbohydrate metabolism, blood pressure in obese pregnant women.

PATIENTS AND METHODS

Materials and methods: Under observation were 65 women (main group) with obesity (I degree -27 women, II degree - 24 women, III degree - 14 women) in the II trimester of pregnancy, who were hospitalized in the Department of Pathology of Pregnancy KNP «Maternity Clinical house №1 "in Lviv during 2017-2020 on preeclampsia of varying severity, which were sent for inpatient treatment by women's clinics. The control group consisted of 30 healthy pregnant women without obesity.

RESULTS

Results: Serum leptin in obese women was directly correlated with BMI (r = 0.66, p<0.001), body weight (r = 0.29, p<0.05), total cholesterol (cholesterol) (r = 0, 37, p<0,009), low density lipoproteins (LDL cholesterol) (r = 0.33, p<0.05) and inversely with high density particles (HDL cholesterol) (r = -0.37, p<0.02 ). Studies of carbohydrate metabolism indicate the following correlation coefficients of BMI with glucose level r = 0.351; p<0,001, BMI with the level of C-peptide r = 0,450; p<0,001, BMI with HOMA index r = 0,1504; p = 0.036. Inverse correlations of C-peptide were detected with the level of P (r = -0.169; p = 0.025).

CONCLUSION

Conclusions: The discovery of the relationship between leptin resistance, lipid and carbohydrate metabolism, blood pressure indicates the possibility of using signs of leptin resistance to prevent complications during pregnancy in the second trimester.

Role of global longitudinal strain in discriminating variant forms of left ventricular hypertrophy and predicting mortality

OBJECTIVE

In this study, we aimed to compare the functional adaptations of the left ventricle in variant forms of left ventricular hypertrophy (LVH) and to evaluate the use of two-dimensional speckle tracking echocardiography (2D-STE) in differential diagnosis and prognosis.

METHODS

This was a prospective cohort study of 68 patients with LVH, including 20 patients with non-obstructive hypertrophic cardiomyopathy (HCM), 23 competitive top-level athletes free of cardiovascular disease, and 25 patients with hypertensive heart disease (HHD). All the subjects underwent 2D transthoracic echocardiography (TTE) and 2D-STE. The primary endpoint was all-cause mortality. Global longitudinal strain (GLS) below -12.5% was defined as severely reduced strain, -12.5% to -17.9% as mildly reduced strain, and above -18% as normal strain.

RESULTS

The mean LV-GLS value was higher in athletes than in patients with HCM and HHD with the lowest value being in the HCM group (HCM: -11.4±2.2%; HHD: -13.6±2.6%; and athletes: -15.5±2.1%; p<0.001 among groups). LV-GLS below -12.5% distinguished HCM from others with 65% sensitivity and 77% specificity [area under curve (AUC)=0.808, 95% confidence interval (CI): 0.699-0.917, p<0.001]. The median follow-up duration was 6.4±1.1 years. Overall, 11 patients (16%) died. Seven of these were in the HHD group, and four were in the HCM group. The mean GLS value in patients who died was -11.8±1.5%. LV-GLS was significantly associated with mortality after adjusting age and sex via multiple analysis (RR=0.723, 95% CI: 0.537-0.974, p=0.033). Patients with GLS below -12.5% had a higher risk of all-cause mortality compared with that of patients with GLS above -12.5% according to Kaplan-Meier survival analysis for 7 years (29% vs. 9%; p=0.032). The LV-GLS value predicts mortality with 64% sensitivity and 70% specificity with a cut-off value of -12.5 (AUC=0.740, 95% CI: 0.617-0.863, p=0.012).

CONCLUSION

The 2D-STE provides important information about the longitudinal systolic function of the myocardium. It may enable differentiation variable forms of LVH and predict prognosis.

Influence of early-life body mass index and systolic blood pressure on left ventricle in adulthood - the Cardiovascular Risk in Young Finns Study

BACKGROUND

Increased left ventricular mass (LVM) predicts cardiovascular events and mortality. The objective of this study was to determine whether early-life exposures to body mass index (BMI) and systolic blood pressure (SPB) affects the left ventricular structure in adulthood.

METHODS

We used longitudinal data from a 31-year follow-up to examine the associations between early-life (between ages 6-18) BMI and SPB on LVM in an adult population (N = 1864, aged 34-49). The burden of early-life BMI and SBP was defined as area under the curve.

RESULTS

After accounting for contemporary adult determinants of LVM, early-life BMI burden associated significantly with LVM (3.61 g/SD increase in early-life BMI; [1.94 - 5.28], p < 0.001). Overweight in early-life (age- and sex-specific BMI values corresponding to adult BMI > 25 kg/m²) associated with 4.7% (2.5-6.9%, p < 0.0001) higher LVM regardless of BMI status in adulthood. Overweight in early-life combined with obesity in adulthood (BMI > 30kg/m²) resulted in a 21% (17.3-32.9%, p < 0.0001) increase in LVM. Higher early-life BMI was associated with a risk of developing eccentric hypertrophy. The burden of early-life SPB was not associated with adult LVM or left ventricular remodeling.

CONCLUSIONS

High BMI in early-life confers a sustained effect on LVM and the risk for eccentric hypertrophy independently of adulthood risk factors. KEY MESSAGES Excess in BMI in early-life has an independent effect on LVM and the risk of developing eccentric hypertrophy regardless of overweight status in adulthood. Systolic blood pressure levels in early-life did not have an independent effect on LVM or LV remodeling. The clinical implication of this study is that primary prevention of obesity in early-life may prevent the development of high LVM and eccentric hypertrophy.

Correlation of Coronary Artery Disease and Left Ventricular Hypertrophy

Ischemic heart disease (IHD) is the leading cause of death worldwide, and it is defined as an imbalance between myocardial oxygen supply and demand. Coronary artery disease (CAD) and left ventricular hypertrophy (LVH) are two common causes of IHD that independently result in myocardial ischemia. CAD decreases myocardial blood and oxygen supply whereas LVH increases myocardial oxygen demand. The coexistence of both CAD and LVH results in a significant increase in oxygen demand while simultaneously lowering oxygen supply.

Since hypertension is a shared predisposing condition for both CAD and LVH, the left ventricular (LV) mass on noninvasive echocardiography can reflect on the severity of coronary artery stenosis. In clinical practice, it can help physicians decide whether to perform invasive cardiac catheterization to visualize the extent of the coronary block. Although, both CAD and LVH are directly proportional to mortality risk, the addition of eccentric LVH can further increase morbidity and mortality due to myocardial infarction. Therefore, the latest management of both the acute and chronic phases of CAD places an increased emphasis on controlling the predisposing factors to prevent or reverse LVH. For example, angiotensin-converting enzyme inhibitors and diuretics reduce LV mass by lowering the cardiac preload and afterload. This article aims to investigate the deleterious effects of the collaboration between CAD and LVH, establish a causal relationship, and explore the new prevention and management strategies.

Non-diagnostic autopsy findings in sudden unexplained death victims

BACKGROUND

Several inherited cardiac diseases may lead to sudden cardiac death (SCD) a devastating event in the families. It is crucial to establish a post mortem diagnosis to facilitate relevant work-up and treatment of family members. Sudden unexplained death (SUD) victims constitute roughly one third of all SCD cases in Denmark.

METHODS

This was a single center, retrospective study investigating SUD cases. Victims who died unexplained due to suspected or confirmed cardiac disease were consecutively referred to a third line referral center established in 2005. All autopsy reports were investigated. Victims were divided into two groups: non-diagnostic cardiac findings and normal cardiac findings. None of the included victims had findings consistent with a diagnosis based on existing criteria.

RESULTS

In total, 99 SUD cases were referred. The mean age of the victims was 37 years (range 0-62 years, 75% males). A total of 14 (14%) victims had a cardiovascular diagnosis pre-mortem. Thirty-seven cases had normal cardiac findings and non-diagnostic cardiac findings were found in 62 cases (63%). The five most common findings included ventricular hypertrophy and/or enlarged heart (n = 35, 35%), coronary atheromatosis (n = 31, 31%), myocardial fibrosis (n = 19, 19%), dilated chambers (n = 7, 7%) and myocardial inflammation (n = 5, 5%).

CONCLUSION

One third of SUD victims had normal cardiac findings and non-diagnostic cardiac findings were seen in almost two thirds of the SUD victims. These non-diagnostic findings may be precursors or early markers for underlying structural cardiac disorders or may be innocent bystanders in some cases. Further studies and improved post-mortem examination methods are needed for optimization of diagnostics in SUD.

Genome-wide meta-analysis of SNP and antihypertensive medication interactions on left ventricular traits in African Americans

BACKGROUND

Left ventricular (LV) hypertrophy affects up to 43% of African Americans (AAs). Antihypertensive treatment reduces LV mass (LVM). However, interindividual variation in LV traits in response to antihypertensive treatments exists. We hypothesized that genetic variants may modify the association of antihypertensive treatment class with LV traits measured by echocardiography.

METHODS

We evaluated the main effects of the three most common antihypertensive treatments for AAs as well as the single nucleotide polymorphism (SNP)-by-drug interaction on LVM and relative wall thickness (RWT) in 2,068 participants across five community-based cohorts. Treatments included thiazide diuretics (TDs), angiotensin converting enzyme inhibitors (ACE-Is), and dihydropyridine calcium channel blockers (dCCBs) and were compared in a pairwise manner. We performed fixed effects inverse variance weighted meta-analyses of main effects of drugs and 2.5 million SNP-by-drug interaction estimates.

RESULTS

We observed that dCCBs versus TDs were associated with higher LVM after adjusting for covariates (p = 0.001). We report three SNPs at a single locus on chromosome 20 that modified the association between RWT and treatment when comparing dCCBs to ACE-Is with consistent effects across cohorts (smallest p = 4.7 × 10-8 , minor allele frequency range 0.09-0.12). This locus has been linked to LV hypertrophy in a previous study. A marginally significant locus in BICD1 (rs326641) was validated in an external population.

CONCLUSIONS

Our study identified one locus having genome-wide significant SNP-by-drug interaction effect on RWT among dCCB users in comparison to ACE-I users. Upon additional validation in future studies, our findings can enhance the precision of medical approaches in hypertension treatment.

Marked variation in heritability estimates of left ventricular mass depending on modality of measurement

Left ventricular (LV) hypertrophy is a strong risk factor for heart failure and cardiovascular death. ECG measures of LV mass are estimated as heritable in twin and family-based analyses and heritability estimates of LV mass measured by echocardiography are lower. We hypothesised that CMR-derived measurements, being more precise than echocardiographic measurements, would advance our understanding of heritable LV traits. We phenotyped 116 British families (427 individuals) by CMR and ECG, and undertook heritability analyses using variance-components (QTDT) and GWAS SNP-based (GCTA-GREML) methods. ECG-based traits such as LV mass and Sokolow-Lyon duration showed substantial estimates of heritability (60%), whereas CMR-derived LV mass was only modestly heritable (20%). However, the ECG LV mass was positively correlated with the lateral diameter of the chest (rho = 0.67), and adjustment for this attenuated the heritability estimate (42%). Finally, CMR-derived right ventricular mass showed considerable heritability (44%). Heritability estimates of LV phenotypes show substantial variation depending on the modality of measurement, being greater when measured by ECG than CMR. This may reflect the differences between electrophysiological as opposed to anatomical hypertrophy. However, ECG LV hypertrophy traits are likely to be influenced by genetic association with anthropometric measures, inflating their overall measured heritability.

Inappropriate Left Ventricular Mass and Cardiovascular Disease Events and Mortality in Blacks: The Jackson Heart Study

Background

Left ventricular hypertrophy (LVH) is associated with an increased risk for cardiovascular disease (CVD) events and all‐cause mortality. Many individuals without LVH have a left ventricular mass that exceeds the level predicted by their sex, body size, and cardiac workload, a condition called inappropriate left ventricular mass (iLVM). We investigated the association of iLVM with CVD events and all‐cause mortality among blacks.

Methods and Results

We analyzed data from the Jackson Heart Study, a community‐based cohort of blacks. The current analysis included 4424 participants without CVD and with an echocardiogram at baseline. Among this cohort, the prevalence of iLVM was 13.8%. There were 262 CVD events and 419 deaths over a median follow‐up of 9.7 years (maximum, 12 years). Compared with participants without iLVM, participants with iLVM had a higher rate of CVD events and all‐cause mortality. After multivariable adjustment, including for the presence of LVH, iLVM was associated with an increased risk of CVD events (hazard ratio, 1.87; 95% CI, 1.33–2.62). The multivariable‐adjusted hazard ratio for all‐cause mortality was 1.29 (95% CI, 0.98–1.70). Among participants without and with LVH, the multivariable‐adjusted hazard ratios of iLVM for CVD events were 2.53 (95% CI, 1.68–3.81) and 1.21 (95% CI, 0.74–2.00), respectively (P_interaction=0.029); and for all‐cause mortality, the hazard ratios were 1.24 (95% CI, 0.81–1.89) and 1.26 (95% CI, 0.86–1.85), respectively (P_interaction=0.664).

Conclusions

iLVM is associated with an increased risk for CVD events among blacks without LVH.

A combined linkage, microarray and exome analysis suggests MAP3K11 as a candidate gene for left ventricular hypertrophy

BACKGROUND

Electrocardiographic measures of left ventricular hypertrophy (LVH) are used as predictors of cardiovascular risk. We combined linkage and association analyses to discover novel rare genetic variants involved in three such measures and two principal components derived from them.

METHODS

The study was conducted among participants from the Erasmus Rucphen Family Study (ERF), a Dutch family-based sample from the southwestern Netherlands. Variance components linkage analyses were performed using Merlin. Regions of interest (LOD > 1.9) were fine-mapped using microarray and exome sequence data.

RESULTS

We observed one significant LOD score for the second principal component on chromosome 15 (LOD score = 3.01) and 12 suggestive LOD scores. Several loci contained variants identified in GWAS for these traits; however, these did not explain the linkage peaks, nor did other common variants. Exome sequence data identified two associated variants after multiple testing corrections were applied.

CONCLUSIONS

We did not find common SNPs explaining these linkage signals. Exome sequencing uncovered a relatively rare variant in MAPK3K11 on chromosome 11 (MAF = 0.01) that helped account for the suggestive linkage peak observed for the first principal component. Conditional analysis revealed a drop in LOD from 2.01 to 0.88 for MAP3K11, suggesting that this variant may partially explain the linkage signal at this chromosomal location. MAP3K11 is related to the JNK pathway and is a pro-apoptotic kinase that plays an important role in the induction of cardiomyocyte apoptosis in various pathologies, including LVH.

Loss of cardiac carnitine palmitoyltransferase 2 results in rapamycin-resistant, acetylation-independent hypertrophy

Cardiac hypertrophy is closely linked to impaired fatty acid oxidation, but the molecular basis of this link is unclear. Here, we investigated the loss of an obligate enzyme in mitochondrial long-chain fatty acid oxidation, carnitine palmitoyltransferase 2 (CPT2), on muscle and heart structure, function, and molecular signatures in a muscle- and heart-specific CPT2-deficient mouse (Cpt2^M-/-) model. CPT2 loss in heart and muscle reduced complete oxidation of long-chain fatty acids by 87 and 69%, respectively, without altering body weight, energy expenditure, respiratory quotient, or adiposity. Cpt2M^-/- mice developed cardiac hypertrophy and systolic dysfunction, evidenced by a 5-fold greater heart mass, 60-90% reduction in blood ejection fraction relative to control mice, and eventual lethality in the absence of cardiac fibrosis. The hypertrophy-inducing mammalian target of rapamycin complex 1 (mTORC1) pathway was activated in Cpt2M^-/- hearts; however, daily rapamycin exposure failed to attenuate hypertrophy in Cpt2M^-/- mice. Lysine acetylation was reduced by ∼50% in Cpt2M^-/- hearts, but trichostatin A, a histone deacetylase inhibitor that improves cardiac remodeling, failed to attenuate Cpt2M^-/- hypertrophy. Strikingly, a ketogenic diet increased lysine acetylation in Cpt2M^-/- hearts 2.3-fold compared with littermate control mice fed a ketogenic diet, yet it did not improve cardiac hypertrophy. Together, these results suggest that a shift away from mitochondrial fatty acid oxidation initiates deleterious hypertrophic cardiac remodeling independent of fibrosis. The data also indicate that CPT2-deficient hearts are impervious to hypertrophy attenuators, that mitochondrial metabolism regulates cardiac acetylation, and that signals derived from alterations in mitochondrial metabolism are the key mediators of cardiac hypertrophic growth.

G protein-coupled receptor kinase 2 promotes cardiac hypertrophy

The increase in protein activity and upregulation of G-protein coupled receptor kinase 2 (GRK2) is a hallmark of cardiac stress and heart failure. Inhibition of GRK2 improved cardiac function and survival and diminished cardiac remodeling in various animal heart failure models. The aim of the present study was to investigate the effects of GRK2 on cardiac hypertrophy and dissect potential molecular mechanisms. In mice we observed increased GRK2 mRNA and protein levels following transverse aortic constriction (TAC). Conditional GRK2 knockout mice showed attenuated hypertrophic response with preserved ventricular geometry 6 weeks after TAC operation compared to wild-type animals. In isolated neonatal rat ventricular cardiac myocytes stimulation with angiotensin II and phenylephrine enhanced GRK2 expression leading to enhanced signaling via protein kinase B (PKB or Akt), consecutively inhibiting glycogen synthase kinase 3 beta (GSK3β), such promoting nuclear accumulation and activation of nuclear factor of activated T-cells (NFAT). Cardiac myocyte hypertrophy induced by in vitro GRK2 overexpression increased the cytosolic interaction of GRK2 and phosphoinositide 3-kinase γ (PI3Kγ). Moreover, inhibition of PI3Kγ as well as GRK2 knock down prevented Akt activation resulting in halted NFAT activity and reduced cardiac myocyte hypertrophy. Our data show that enhanced GRK2 expression triggers cardiac hypertrophy by GRK2-PI3Kγ mediated Akt phosphorylation and subsequent inactivation of GSK3β, resulting in enhanced NFAT activity.

Carotid Atherosclerosis and Electrocardiographic Left Ventricular Hypertrophy in the General Population: The Namwon Study

This study aimed to investigate the relationship between carotid atherosclerosis and left ventricular hypertrophy on electrocardiogram (ECG-LVH) on adults living in the community. A total of 9,266 adults who participated in the Namwon Study were included in this analysis. Carotid atherosclerosis, including intima-media thickness (IMT) and plaques, were assessed using high-resolution B-mode ultrasound. ECG-LVH was determined using the Sokolow-Lyon voltage (SokV) and Cornell voltage (CorV) criteria. The prevalence of ECG-LVH was 12.7% using the SokV criteria and 9.7% using the CorV criteria. After full adjustment, compared to the lowest quartile of common carotid artery IMT (CCA-IMT), the odds ratios and 95% confidence intervals for ECG-LVH of the carotid IMT quartiles 2, 3, and 4 increased linearly as follows: 1.54 (1.24-1.90), 1.62 (1.31-2.02), and 1.91 (1.54-2.38), respectively, for the SokV criteria (p<0.001); and 1.33 (1.05-1.68), 1.41 (1.11-1.78), and 1.48 (1.16-1.88), respectively, for the CorV criteria (p=0.003). Positive associations between the carotid bulb IMT (CB-IMT) quartiles and the ECG-LVH were also observed, although the magnitudes of association between CB-IMT and ECG-LVH were slightly lower than those of CCA-IMT. However, no significant association between carotid plaques and ECG-LVH as defined by the SokV or CorV criteria was found. The present study demonstrated that increased carotid IMT, but not carotid plaques, is significantly associated with LVH defined by various ECG criteria in a large population.

Assessment of left ventricular function in chronic alcoholics by real-time three-dimensional echocardiography

Chronic alcohol consumption may lead to progressive cardiac dysfunction. The aim of this study was to evaluate the feasibility of using real-time 3-dimensional echocardiography (3DE) on assessing left ventricular (LV) function in chronic alcoholics.We classified 92 male alcoholics into mild, moderate, and severe groups; 30 age-matched controls were also recruited. LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), LV ejection fraction (LVEF), LV mass (LVM), LV mass index (LVMI), and systolic dyssynchrony index (SDI) were measured by 3DE and 2-dimensional echocardiography (2DE).Compared to the control group, LV volume and mass were higher in the moderate and severe alcoholic groups (P < 0.05). The severe alcoholic (symptomatic) group demonstrated decreased LVEF and increased SDI (detected by 3DE) (P < 0.05).Real-time 3DE can detect the increases of LV volumes and mass in asymptomatic alcoholics, and the changes of LVEF and systolic synchrony index in symptomatic alcoholics.

Clinical correlates and prognostic significance of change in standardized left ventricular mass in a community-based cohort of African Americans

Background

Though left ventricular mass (LVM) predicts cardiovascular events (CVD) and mortality in African Americans, limited data exists on factors contributing to change in LVM and its prognostic significance. We hypothesized that baseline blood pressure (BP) and body mass index (BMI) and change in these variables over time are associated with longitudinal increases in LVM and that such increase is associated with greater incidence of CVD.

Methods and Results

We investigated the clinical correlates of change in standardized logarithmically transformed‐LVM indexed to height2.7 (log‐LVMI) and its association with incident CVD in 606 African Americans (mean age 58±6 years, 66% women) who attended serial examinations 8 years apart. Log‐LVMI and clinical covariates were standardized within sex to obtain z scores for both visits. Standardized log‐LVMI was modeled using linear regression (correlates of change in standardized log‐LVMI) and Cox proportional hazards regression (incidence of CVD [defined as coronary heart disease, stroke, heart failure and intermittent claudication]). Baseline clinical correlates (standardized log‐LVM, BMI, systolic BP) and change in systolic BP over time were significantly associated with 8‐year change in standardized log‐LVMI. In prospective analysis, change in standardized LVM was significantly (P=0.0011) associated with incident CVD (hazards ratio per unit standard deviation change log‐LVMI 1.51, 95% CI 1.18 to 1.93).

Conclusions

In our community‐based sample of African Americans, baseline BMI and BP, and change in BP on follow‐up were key determinants of increase in standardized log‐LVMI, which in turn carried an adverse prognosis, underscoring the need for greater control of BP and weight in this group.

Obesity and coronary artery disease: evaluation and treatment

With the increasing prevalence of obesity, clinicians are now facing a growing population of patients with specific features of clinical presentation, diagnostic challenges, and interventional, medical, and surgical management. After briefly discussing the effect of obesity on atherosclerotic burden in this review, we will focus on strategies clinicians might use to ensure better outcomes when performing revascularization in obese and severely obese patients. These patients tend to present comorbidities at a younger age, and their anthropometric features might limit the use of traditional cardiovascular risk stratification approaches for ischemic disease. Alternative techniques have emerged, especially in nuclear medicine. Positron emission tomography-computed tomography might be the diagnostic imaging technique of choice. When revascularization is considered, features associated with obesity must be considered to guide therapeutic strategies. In percutaneous coronary intervention, a radial approach should be favoured, and adequate antiplatelet therapy with new and more potent agents should be initiated. Weight-based anticoagulation should be contemplated if needed, with the use of drug-eluting stents. An "off-pump" approach for coronary artery bypass grafting might be preferable to the use of cardiopulmonary bypass. For patients who undergo bilateral internal thoracic artery grafting, harvesting using skeletonization might prevent deep sternal wound infections. In contrast to percutaneous coronary intervention, lower surgical bleeding has been observed when lean body mass is used for perioperative heparin dose determination.

Cardiac mechanics in patients with human immunodeficiency virus: a study of systolic myocardial deformation in children and young adults

Human immunodeficiency virus (HIV) infection causes dysfunction of different organ systems. Myocardial diastolic dysfunction has been reported previously in an adult HIV population. Our aim was to study myocardial strain in children and young adults infected by HIV who have apparently normal ejection fraction. Forty HIV-infected patients (mean age 20.6 ± 1.5 years) with normal ejection fraction and 55 matched normal controls (mean age 17 ± 1.5 years) were studied by two-dimensional echocardiogram. The images were stored then exported to velocity vector imaging software for analysis. Measures considered were left-ventricular peak global systolic strain (LV S) and strain rate (LV SR) as well as right-ventricular peak global systolic strain (RV S) and strain rate (RV SR). Circumferential measures of the left ventricle included the following: LV circumferential peak global systolic strain (LV circ S), strain rate (LV circ SR), radial velocity (LV rad vel), and rotational velocity (LV rot vel) at the level of the mitral valve. Statistical significance was set at p < 0.05. The means of all longitudinal deformation parameters were significantly lower in HIV patients compared with normal controls: LV S (-14.15 vs. -19.31), LV SR (-0.88 vs. -1.30), RV S (-19.58 vs. -25.09), and RV SR (-1.34 vs. -2.13), respectively (p < 0.05). LV rot vel was lower in patients compared with controls (43.23 vs. 51.71, p = 0.025). LV circ S, LV circ SR, and LV rad vel showed no significant difference between the two groups (p ≥ 0.05). HIV infection affects longitudinal systolic cardiac strain and strain rate in children and young adults. Normal ejection fraction might be attributed to preserved circumferential myocardial deformation. Strain and strain rate may help identify HIV patients at high risk for cardiac dysfunction and allow early detection of silent myocardial depression.

The effects of 17-methoxyl-7-hydroxy-benzene-furanchalcone on the pressure overload-induced progression of cardiac hypertrophy to cardiac failure

We investigated the effects of 17-methoxyl-7-hydroxy-benzene-furanchalcone (MHBFC), which was isolated from the roots of Millettia pulchra (Benth.) Kurz var. Laxior (Dunn) Z.Wei (Papilionaceae) (MKL), on the progression of cardiac hypertrophy to failure in a rat model of abdominal aortic banding (AAB)-induced pressure overloading. Endothelial dysfunction is central to pressure overload-induced cardiac hypertrophy and failure. It would be useful to clarify whether MHBFC could prevent this dysfunction. The effects of pressure overload were assessed in male Sprague-Dawley rats 6 weeks after AAB using the progression of cardiac hypertrophy to heart failure as the endpoint. The AAB-treated rats exhibited a greater progression to heart failure and had significantly elevated blood pressure, systolic and diastolic cardiac dysfunction, and evidence of left ventricular hypertrophy (LVH). LVH was characterized by increases in the ratios of heart and left ventricular weights to body weight, increased myocyte cross-sectional areas, myocardial and perivascular fibrosis, and elevated cardiac hydroxyproline. These symptoms could be prevented by treatment with MHBFC at daily oral doses of 6 and 12 mg/kg for 6 weeks. The progression to cardiac failure, which was demonstrated by increases in relative lung and right ventricular weights, cardiac function disorders and overexpression of atrial natriuretic peptide (ANP) mRNA, could also be prevented. Furthermore, MHBFC partialy rescued the downregulated nitric oxide signaling system, whereas inhibited the upregulated endothelin signaling system, normalizing the balance between these two systems. MHBFC protected the endothelium and prevented the pressure overload-induced progression of cardiac hypertrophy to cardiac failure.

Hemodynamic and echocardiographic profiles in African American compared with White offspring of hypertensive parents: the HyperGEN study

BACKGROUND

Alterations in cardiovascular structure and function have been shown to precede the finding of elevated blood pressure.

METHODS

This study is part of the Hypertension Genetic Epidemiologic Network (HyperGEN) in which genetic and environmental determinants of hypertension were investigated in 5 geographical field centers. All nonhypertensive offspring (n = 1,035) were included from the entire HyperGEN study population that consists of 2,225 hypertensive patients and 1,380 nonhypertensive patients who had adequate echocardiographic left ventricular (LV) mass measurements. Participants were compared by self-declared race (African American and white).

RESULTS

Nonhypertensive African American offspring were younger (aged 31 years vs. 38 years), more likely to be female, and had a higher body mass index (BMI) and higher systolic blood pressure (SBP) than their white counterparts. After adjusting for age, sex, SBP, pulse pressure (PP), BMI, diabetes status, and family effects, we observed statistically significant and potentially pathophysiological differences (all with P ≤ 0.001) with greater LV mass/height, relative wall thickness, and posterior wall thickness and with lesser midwall shortening, PP/stroke volume, and (PP/stroke volume)/fat-free body mass.

CONCLUSION

This study shows that ethnic differences in hemodynamic and echocardiographic profiles exist in a large, population-based cohort of nonhypertensive offspring of hypertensive parents.

Contemporary predictors of death and sustained ventricular tachycardia in patients with repaired tetralogy of Fallot enrolled in the INDICATOR cohort

OBJECTIVE

Patients with repaired tetralogy of Fallot (TOF) experience increased rates of mortality and morbidity in adulthood. This study was designed to identify risk factors for death and ventricular tachycardia (VT) in a large contemporary cohort of patients with repaired TOF.

METHODS

Subjects with repaired TOF from four large congenital heart centres in the USA, Canada and Europe were enrolled. Clinical, ECG, exercise, cardiac magnetic resonance (CMR) and outcome data were analysed.

RESULTS

Of the 873 patients (median age 24.4 years), 32 (3.7%) reached the primary outcome (28 deaths, 4 sustained VT; median age at outcome 38 years; median time from CMR to outcome 1.9 years). Cox proportional-hazards regression identified RV mass-to-volume ratio ≥ 0.3 g/mL (HR, 5.04; 95% CI 2.3 to 11.0; p<0.001), LV EF z score<-2.0 (HR, 3.34; 95% CI 1.59 to 7.01; p=0.001), and history of atrial tachyarrhythmia (HR, 3.65; 95% CI 1.75 to 7.62; p=0.001) as outcome predictors. RV dysfunction was predictive of the outcome similar to LV dysfunction. In subgroup analysis of 315 subjects with echocardiographic assessment of RV systolic pressure, higher pressure (HR 1.39; 95% CI 1.19 to 1.62; p<0.001) was associated with death and sustained VT independent of RV hypertrophy and LV dysfunction.

CONCLUSIONS

RV hypertrophy, ventricular dysfunction and atrial tachyarrhythmias are predictive of death and sustained VT in adults with repaired TOF. These findings may inform risk stratification and the design of future therapeutic trials.

Meta-analysis of accuracy of left ventricular mass measurement by three-dimensional echocardiography

Left ventricular (LV) hypertrophy is a fundamental prognostic factor in a variety of cardiac diseases. Three-dimensional echocardiography (3DE) has achieved better estimation of LV mass than 2-dimensional echocardiography. However, significant underestimation has often been reported, and no previous study has synthesized these data. The aim of this meta-analysis was to investigate if there has been improvement in the accuracy in LV mass measurement by 3DE over time. Studies comparing LV mass between 3DE and magnetic resonance imaging were eligible. A cumulative meta-analysis was performed to investigate improvement in accuracy, followed by subgroup and meta-regression analysis to reveal factors affecting the bias. A total of 25 studies including 671 comparisons were analyzed. Studies published in or before 2004 showed high heterogeneity (I(2) = 69%) and significant underestimation of LV mass by 3DE (-5.7 g, 95% confidence interval -11.3 to -0.2, p = 0.04). Studies published from 2005 to 2007 were still heterogenous (I(2) = 60%) but showed less systematic bias (-0.5 g, 95% confidence interval -2.5 to 1.5, p = 0.63). In contrast, studies published in or after 2008 were highly homogenous (I(2) = 3%) and showed excellent accuracy (-0.1 g, 95% confidence interval -2.2 to 1.9, p = 0.90). Investigation of factors affecting the bias revealed that evaluation of cardiac patients compared to healthy volunteers led to larger bias (p <0.05). In conclusion, this meta-analysis elucidates the underestimation of LV mass by 3DE, its improvement over the past decade, and factors affecting the bias. These data provide a more detailed basis for improving the accuracy of 3DE, an indispensable step toward further clinical application.

Gq/11-mediated signaling and hypertrophy in mice with cardiac-specific transgenic expression of regulator of G-protein signaling 2

Cardiac hypertrophy is a well-established risk factor for cardiovascular morbidity and mortality. Activation of G(q/11)-mediated signaling is required for pressure overload-induced cardiomyocyte (CM) hypertrophy to develop. We previously showed that among Regulators of G protein Signaling, RGS2 selectively inhibits G(q/11) signaling and its hypertrophic effects in isolated CM. In this study, we generated transgenic mice with CM-specific, conditional RGS2 expression (dTG) to investigate whether RGS2 overexpression can be used to attenuate G(q/11)-mediated signaling and hypertrophy in vivo. Transverse aortic constriction (TAC) induced a comparable rise in ventricular mass and ANF expression and corresponding hemodynamic changes in dTG compared to wild types (WT), regardless of the TAC duration (1-8 wks) and timing of RGS2 expression (from birth or adulthood). Inhibition of endothelin-1-induced G(q/11)-mediated phospholipase C β activity in ventricles and atrial appendages indicated functionality of transgenic RGS2. However, the inhibitory effect of transgenic RGS2 on G(q/11)-mediated PLCβ activation differed between ventricles and atria: (i) in sham-operated dTG mice the magnitude of the inhibitory effect was less pronounced in ventricles than in atria, and (ii) after TAC, negative regulation of G(q/11) signaling was absent in ventricles but fully preserved in atria. Neither difference could be explained by differences in expression levels, including marked RGS2 downregulation after TAC in left ventricle and atrium. Counter-regulatory changes in other G(q/11)-regulating RGS proteins (RGS4, RGS5, RGS6) and random insertion were also excluded as potential causes. Taken together, despite ample evidence for a role of RGS2 in negatively regulating G(q/11) signaling and hypertrophy in CM, CM-specific RGS2 overexpression in transgenic mice in vivo did not lead to attenuate ventricular G(q/11)-mediated signaling and hypertrophy in response to pressure overload. Furthermore, our study suggests chamber-specific differences in the regulation of RGS2 functionality and potential future utility of the new transgenic model in mitigating G(q/11) signaling in the atria in vivo.

Whole-exome sequencing and an iPSC-derived cardiomyocyte model provides a powerful platform for gene discovery in left ventricular hypertrophy

Rationale: Left ventricular hypertrophy (LVH) is a heritable predictor of cardiovascular disease, particularly in blacks. Objective: Determine the feasibility of combining evidence from two distinct but complementary experimental approaches to identify novel genetic predictors of increased LV mass. Methods: Whole-exome sequencing (WES) was conducted in seven African-American sibling trios ascertained on high average familial LV mass indexed to height (LVMHT) using Illumina HiSeq technology. Identified missense or nonsense (MS/NS) mutations were examined for association with LVMHT using linear mixed models adjusted for age, sex, body weight, and familial relationship. To functionally assess WES findings, human induced pluripotent stem cell-derived cardiomyocytes (induced pluripotent stem cell-CM) were stimulated to induce hypertrophy; mRNA sequencing (RNA-seq) was used to determine gene expression differences associated with hypertrophy onset. Statistically significant findings under both experimental approaches identified LVH candidate genes. Candidate genes were further prioritized by seven supportive criteria that included additional association tests (two criteria), regional linkage evidence in the larger HyperGEN cohort (one criterion), and publically available gene and variant based annotations (four criteria). Results: WES reads covered 91% of the target capture region (of size 37.2 MB) with an average coverage of 65×. WES identified 31,426 MS/NS mutations among the 21 individuals. A total of 295 MS/NS variants in 265 genes were associated with LVMHT with q-value <0.25. Of the 265 WES genes, 44 were differentially expressed (P < 0.05) in hypertrophied cells. Among the 44 candidate genes identified, 5, including HLA-B, HTT, MTSS1, SLC5A12, and THBS1, met 3 of 7 supporting criteria. THBS1 encodes an adhesive glycoprotein that promotes matrix preservation in pressure-overload LVH. THBS1 gene expression was 34% higher in hypertrophied cells (P = 0.0003) and a predicted conserved and damaging NS variant in exon 13 (A2099G) was significantly associated with LVHMT (P = 4 × 10⁻⁶). Conclusion: Combining evidence from cutting-edge genetic and cellular experiments can enable identification of novel LVH risk loci.

Functional scaffold-free 3-D cardiac microtissues: a novel model for the investigation of heart cells

To bridge the gap between two-dimensional cell culture and tissue, various three-dimensional (3-D) cell culture approaches have been developed for the investigation of cardiac myocytes (CMs) and cardiac fibroblasts (CFs). However, several limitations still exist. This study was designed to develop a cardiac 3-D culture model with a scaffold-free technology that can easily and inexpensively generate large numbers of microtissues with cellular distribution and functional behavior similar to cardiac tissue. Using micromolded nonadhesive agarose hydrogels containing 822 concave recesses (800 μm deep × 400 μm wide), we demonstrated that neonatal rat ventricular CMs and CFs alone or in combination self-assembled into viable (Live/Dead stain) spherical-shaped microtissues. Importantly, when seeded simultaneously or sequentially, CMs and CFs self-sorted to be interspersed, reminiscent of their myocardial distribution, as shown by cell type-specific CellTracker or antibody labeling. Microelectrode recordings and optical mapping revealed characteristic triangular action potentials (APs) with a resting membrane potential of -66 ± 7 mV (n = 4) in spontaneously contracting CM microtissues. Under pacing, optically mapped AP duration at 90% repolarization and conduction velocity were 100 ± 30 ms and 18.0 ± 1.9 cm/s, respectively (n = 5 each). The presence of CFs led to a twofold AP prolongation in heterogenous microtissues (CM-to-CF ratio of 1:1). Importantly, Ba(2+)-sensitive inward rectifier K(+) currents and Ca(2+)-handling proteins, including sarco(endo)plasmic reticulum Ca(2+)-ATPase 2a, were detected in CM-containing microtissues. Furthermore, cell type-specific adenoviral gene transfer was achieved, with no impact on microtissue formation or cell viability. In conclusion, we developed a novel scaffold-free cardiac 3-D culture model with several advancements for the investigation of CM and CF function and cross-regulation.

Competing cardiovascular outcomes associated with electrocardiographic left ventricular hypertrophy: the Atherosclerosis Risk in Communities Study

BACKGROUND

Individuals with electrocardiographically determined left ventricular hypertrophy (ECG LVH) are at risk of multiple cardiovascular disease (CVD) outcomes simultaneously. The study sought to characterise the competing incidences for subtypes of first CVD events or non-CVD death in those with and without ECG LVH.

METHODS

Participants in the Atherosclerosis Risk in Communities (ARIC) Study were included. ECG LVH was defined according to Sokolow-Lyon criteria. Competing Cox models were used to compare hazards for diverse outcomes within groups (e.g., among those with ECG LVH) and for a given event between groups (ECG LVH vs. no ECG LVH).

RESULTS

After 15 years, men with ECG LVH at baseline (N=383) had a cumulative incidence of first CVD events and non-CVD deaths of 29.2% and 6.1%, respectively (HR 4.86; 95% CI 3.04 to 7.77). In men without ECG LVH (N=6576) the incidence of any first CVD event and non-CVD death was 18.9% and 6.9%, respectively (HR 2.67; 2.39 to 2.98). Similar associations were observed in women (N=381 with and N=8187 without ECG LVH). Coronary heart disease (CHD) was the most common first event in men with ECG LVH (15.0%) and heart failure was the most common first event in women with ECG LVH (10.5%). After adjustment for risk factors including systolic blood pressure, any CVD event remained the most likely first event.

CONCLUSIONS

Among middle-aged individuals with ECG LVH, the most likely first events are CHD in men and heart failure in women; these results may have implications for preventive approaches.

Subclinical coronary atherosclerosis predicts cardiovascular risk in different stages of hypertension: result of the Heinz Nixdorf Recall Study

Prehypertension is a frequent condition and has been demonstrated to increase cardiovascular risk. However, the association with coronary atherosclerosis as part of target organ damage is not well understood. We investigated the cross-sectional relationship and longitudinal outcome between blood pressure categories and coronary artery calcification (CAC), quantified by electron beam computed tomography, in 4181 participants from the population-based Heinz Nixdorf Recall Study cohort. At baseline, we observed a continuous increase in calcium scores with increasing blood pressure categories. During a median follow-up period of 7.18 years, 115 primary end points (2.8%; fatal and nonfatal myocardial infarction) and 152 secondary end points (3.6%; stroke and coronary revascularization) occurred. We observed a continuous increase in age- and risk factor-adjusted secondary endpoints (hazard ratios [95% CI]) with increasing blood pressure categories (referent: normotension) in men: prehypertension, 1.80 (0.53-6.13); stage 1 hypertension, 2.27 (0.66-7.81); and stage 2 hypertension, 4.10 (1.27-13.24) and in women: prehypertension, 1.13 (0.34-3.74); stage 1 hypertension, 2.14 (0.67-6.85); and stage 2 hypertension, 3.33 (1.24-8.90), respectively, but not in primary endpoints. Cumulative event rates were determined by blood pressure categories and the CAC. In prehypertension, the adjusted hazard ratios for all of the events were, for CAC 1 to 99, 2.05 (0.80-5.23; P=0.13); 100 to 399, 3.12 (1.10-8.85; P=0.03); and ≥400, 7.72 (2.67-22.27; P=0.0002). Risk of myocardial infarction and stroke in hypertension but also in prehypertension depends on the degree of CAC. This marker of target-organ damage might be included, when lifestyle modification and pharmacotherapeutic effects in prehypertensive individuals are tested to avoid exposure to risk and increase benefit.

Connecting cerebral white matter lesions and hypertensive target organ damage

Chronic hypertension leads to concomitant remodeling of the cardiac and vascular systems and various organs, especially the brain, kidney, and retina. The brain is an early target of organ damage due to high blood pressure, which is the major modifiable risk factor for stroke and small vessel disease. Stroke is the second leading cause of death and the number one cause of disability worldwide and over 80% of strokes occur in the elderly. Preclinical hypertensive lesions in most target organs are clearly identified: left ventricular hypertrophy for the heart, microalbuminuria for the kidney, fundus abnormalities for the eye, and intima-media thickness and pulse wave velocity for the vessels. However, early hypertensive brain damage is not fully studied due to difficulties in access and the expense of techniques. After age, hypertension is the most-important risk factor for cerebral white matter lesions, which are an important prognostic factor for stroke, cognitive impairment, dementia, and death. Studies have shown an association between white matter lesions and a number of extracranial systems affected by high BP and also suggest that correct antihypertensive treatment could slow white matter lesions progression. There is strong evidence that cerebral white matter lesions in hypertensive patients should be considered a silent early marker of brain damage.

Operative Myocardial Protection in Patients with Left Ventricular Hypertrophy: The Role of Systemic Hypothermia

OBJECTIVES

Myocardial hypertrophy represents a great challenge in cardiac surgery. Several strategies have been described to protect the hypertrophied myocardium during cardiopulmonary bypass, and aortic clamping, yet the ideal strategy has not been identified. This study investigates the use of moderate systemic hypothermia (MSH) as an adjuvant method to protect the hypertrophied myocardium in patients undergoing aortic valve replacement (AVR).

METHODS

Twenty eight patients undergoing AVR were divided into two groups, (Group I) received continuous cold 5-8 °C retrograde blood cardioplegia (CRBC) and their body temperature was cooled down to 23-26 °C. (Group II) also received CRBC but their body temperature was kept at 32-34 °C.

RESULTS

No operative morality (30 days) was noted in both groups. Postoperative reduction in ejection fraction (EF) was seen in nine patients of group I and in twelve patients of group II (P < 0.05). The need for multiple inotropes was more in group II (eight patients) than in group I (two patients) (P < 0.001). IABP was needed in three patients of group II and non in group I (P < 0.01).

CONCLUSION

Moderate systemic hypothermia might have a role in protecting hypertrophied myocardium in patients undergoing AVR.

SNP-SNP interactions dominate the genetic architecture of candidate genes associated with left ventricular mass in African-Americans of the GENOA study

BACKGROUND

Left ventricular mass (LVM) is a strong, independent predictor of heart disease incidence and mortality. LVM is a complex, quantitative trait with genetic and environmental risk factors. This research characterizes the genetic architecture of LVM in an African-American population by examining the main and interactive effects of individual candidate gene single nucleotide polymorphisms (SNPs) and conventional risk factors for increased LVM.

METHODS

We used least-squares linear regression to investigate 1,878 SNPs from 234 candidate genes for SNP main effects, SNP-risk factor interactions, or SNP-SNP interactions associated with LVM in 1,328 African-Americans from the Genetic Epidemiology Network of Arteriopathy (GENOA) study. We reduced the probability of false positive results by implementing three analytic criteria: 1) the false discovery rate, 2) cross-validation, and 3) testing for internal replication of results.

RESULTS

We identified 409 SNP-SNP interactions passing all three criteria, while no SNP main effects or SNP-risk factor interactions passed all three. A multivariable model including four SNP-SNP interactions explained 11.3% of the variation in LVM in the full GENOA sample and 5.6% of LVM variation in independent test sets.

CONCLUSIONS

The results of this research underscore that context dependent effects, specifically SNP-SNP interactions, may dominate genetic contributions to variation in complex traits such as LVM.

Heritability and genetic linkage of left ventricular mass, systolic and diastolic function in hypertensive African Americans (From the GENOA Study)

BACKGROUND

Much of the interindividual variation in left ventricular (LV) structure and function is unexplained by established risk factors and may be due to novel or genetic factors. We used pedigree information from 454 tandem markers across the genome to estimate the heritability and linkage of various echocardiographic measures of LV structure and function in a cohort of African-American hypertensive siblings.

METHODS

LV mass was calculated according to the American Society of Echocardiography (ASE) simplified cubed equation and indexed to height(2.7). Fractional shortening (FS) was calculated as the percent change in the internal diameter between diastole and systole. Ejection fraction (EF) was calculated from ventricular diameters. Peak mitral early and late diastolic filling velocities were measured from the transmitral pulsed Doppler profile. The maximum-likelihood heritability estimate for each phenotype was obtained using a variance components method. Linkage analyses were performed using the multipoint variance components-based approach.

RESULTS

There was moderate heritability for LV mass index (34%), interventricular septal thickness (29%), diastolic diameter (42%), EF (40%), FS (39%), and mitral early and late diastolic filling velocities (37 and 45%, respectively). The greatest evidence of genetic linkage was observed for LV mass index on chromosome 3 (logarithm of odds (LOD) score = 2.38), LV EF on chromosome 12 (LOD score = 2.39), and mitral E-wave velocity (MVE) on chromosome 19 (LOD score = 2.69).

CONCLUSIONS

In this African-American cohort of hypertensive siblings, the greatest evidence for linkage of LV structure and function was on chromosomes 3, 12, and 19.

Risk reduction after regression of echocardiographic left ventricular hypertrophy in hypertension: a meta-analysis

BACKGROUND

The prognostic relevance of echocardiographic left ventricular hypertrophy (LVH) regression in hypertension is uncertain. The aim of this study was to perform an updated meta-analysis about the impact of LVH regression on the occurrence of cardiovascular events in hypertensive patients.

METHODS

We searched for studies on echocardiographic LVH regression and prognosis in hypertension that compared patients with or without LVH regression or groups including subjects with or without LVH regression and reported adjusted hazard ratio (HR) for calculating the overall effect size.

RESULTS

Five studies were identified (3,149 patients, mean age range 48-66 years, 58% men). Follow-up echocardiography was performed after a mean period ranging from 1 to 5 years. Entire follow-up duration ranged from 3 to 9 years. Globally, 333 cardiovascular events occurred. Three whole studies and subgroups of two others were included in the meta-analysis, comprising 2,449 patients, 1,900 (78%) with baseline LVH and 969 (51%) with LVH regression, who experienced 304 events. The overall adjusted HR of total cardiovascular events was 0.54, 95% confidence interval (CI) 0.35-0.84, P = 0.007, for LVH regression/persistent normal left ventricular (LV) mass vs. LVH persistence/LVH development. Heterogeneity was found between studies. Higher baseline prevalence of comorbid conditions and Japanese ethnicity seemed to be associated with lower benefit from LVH regression.

CONCLUSIONS

This meta-analysis indicates that regression of echocardiographic LVH in hypertension, even after adjustment for various confounders, is associated with reduction of cardiovascular events. However, future studies are needed to evaluate whether LVH regression is of benefit for all hypertensive patients and ethnic groups.

Experimental therapies in hypertrophic cardiomyopathy

The quintessential clinical diagnostic phenotype of human hypertrophic cardiomyopathy (HCM) is primary cardiac hypertrophy. Cardiac hypertrophy is also a major determinant of mortality and morbidity including the risk of sudden cardiac death (SCD) in patients with HCM. Reversal and attenuation of cardiac hypertrophy and its accompanying fibrosis is expected to improve morbidity as well as decrease the risk of SCD in patients with HCM.The conventionally used pharmacological agents in treatment of patients with HCM have not been shown to reverse or attenuate established cardiac hypertrophy and fibrosis. An effective treatment of HCM has to target the molecular mechanisms that are involved in the pathogenesis of the phenotype. Mechanistic studies suggest that cardiac hypertrophy in HCM is secondary to activation of various hypertrophic signaling molecules and, hence, is potentially reversible. The hypothesis is supported by the results of genetic and pharmacological interventions in animal models. The results have shown potential beneficial effects of angiotensin II receptor blocker losartan, mineralocorticoid receptor blocker spironolactone, 3-hydroxy-3-methyglutaryl-coenzyme A reductase inhibitors simvastatin and atorvastatin, and most recently, N-acetylcysteine (NAC) on reversal or prevention of hypertrophy and fibrosis in HCM. The most promising results have been obtained with NAC, which through multiple thiol-responsive mechanisms completely reversed established cardiac hypertrophy and fibrosis in three independent studies. Pilot studies with losartan and statins in humans have established the feasibility of such studies. The results in animal models have firmly established the reversibility of established cardiac hypertrophy and fibrosis in HCM and have set the stage for advancing the findings in the animal models to human patients with HCM through conducting large-scale efficacy studies.

AKAP-Lbc mobilizes a cardiac hypertrophy signaling pathway

Elevated catecholamines in the heart evoke transcriptional activation of the Myocyte Enhancer Factor (MEF) pathway to induce a cellular response known as pathological myocardial hypertrophy. We have discovered that the A-Kinase Anchoring Protein (AKAP)-Lbc is upregulated in hypertrophic cardiomyocytes. It coordinates activation and movement of signaling proteins that initiate MEF2-mediated transcriptional reprogramming events. Live-cell imaging, fluorescent kinase activity reporters, and RNA interference techniques show that AKAP-Lbc couples activation of protein kinase D (PKD) with the phosphorylation-dependent nuclear export of the class II histone deacetylase HDAC5. These studies uncover a role for AKAP-Lbc in which increased expression of the anchoring protein selectively amplifies a signaling pathway that drives cardiac myocytes toward a pathophysiological outcome.

Carvedilol in hypertension treatment

Although β-blockers have been previously shown to effectively reduce blood pressure (BP) and have been used for hypertension treatment for over 40 years, their effect on cardiovascular morbidity and mortality in hypertensive patients remains controversial and its use in uncomplicated hypertension is currently under debate. However, data on the above field derive mainly from studies which were conducted with older agents, such as atenolol and metoprolol, while considerable pharamacokinetic and pharmacodynamic heterogeneity is present within the class of β-blockers. Carvedilol, a vasodilating non-cardioselective β-blocker, is a compound that seems to give the opportunity to the clinician to use a cardioprotective agent without the concerning hemodynamic and metabolic actions of traditional β-blocker therapy. In contrast with conventional β-blockers, carvedilol maintains cardiac output, has a less extended effect on heart rate and reduces BP by decreasing vascular resistance. Further, several studies has shown that carvedilol has a beneficial or at least neutral effect on metabolic parameters, such as glycemic control, insulin sensitivity, and lipid metabolism, suggesting that they could be used in subjects with the metabolic syndrome or diabetes without negative consequences. This article summarizes the distinct pharmacologic, hemodynamic, and metabolic properties of carvedilol in relation to conventional β-blockers, attempting to examine the potential use of this agent for hypertension treatment.

Racial disparities in health care access and cardiovascular disease indicators in Black and White older adults in the Health ABC Study

OBJECTIVE

Black adults consistently exhibit higher rates of and poorer health outcomes due to cardiovascular disease (CVD) than other racial groups, independent of differences in socioeconomic status (SES). Whether factors related to health care access can further explain racial disparities in CVD has not been thoroughly examined.

METHOD

Using logistic regression, the authors examined racial and health care (i.e., health insurance and access to care) associations with CVD indicators (i.e., hypertension, low ankle-arm index, and left ventricular hypertrophy) in the Health, Aging, and Body Composition Study, a longitudinal study of well-functioning older adults.

RESULTS

Older Black versus White adults had significantly worse health care. Overall, health care reduced the significant association between being Black and CVD only slightly, while race remained strongly associated with CVD after adjusting for demographics, SES, body mass index, and comorbidity.

DISCUSSION

Research on health care quality may contribute to our understanding of these disparities.

Resveratrol inhibits cardiac hypertrophy via AMP-activated protein kinase and Akt

Whereas studies involving animal models of cardiovascular disease demonstrated that resveratrol is able to inhibit hypertrophic growth, the mechanisms involved have not been elucidated. Because studies in cells other than cardiomyocytes revealed that AMP-activated protein kinase (AMPK) and Akt are affected by resveratrol, we hypothesized that resveratrol prevents cardiac myocyte hypertrophy via these two kinase systems. Herein, we demonstrate that resveratrol reduces phenylephrine-induced protein synthesis and cell growth in rat cardiac myocytes via alterations of intracellular pathways involved in controlling protein synthesis (p70S6 kinase and eukaryotic elongation factor-2). Additionally, we demonstrate that resveratrol negatively regulates the calcineurin-nuclear factor of activated T cells pathway thus modifying a critical component of the transcriptional mechanism involved in pathological cardiac hypertrophy. Our data also indicate that these effects of resveratrol are mediated via AMPK activation and Akt inhibition, and in the case of AMPK, is dependent on the presence of the AMPK kinase, LKB1. Taken together, our data suggest that resveratrol exerts anti-hypertrophic effects by activating AMPK via LKB1 and inhibiting Akt, thus suppressing protein synthesis and gene transcription.

Regression of echocardiographic left ventricular hypertrophy after 2 years of therapy reduces cardiovascular risk in patients with essential hypertension

BACKGROUND

There is still ambiguity about the prognostic relevance of regression of left ventricular hypertrophy (LVH) (as revealed by echocardiography) in a large population of subjects with hypertension, with and without evidence of LVH in their electrocardiograms (ECGs). This holds true even after adjusting for various confounders including in treatment ambulatory blood pressure (BP). The most suitable time point for a follow-up echocardiography also remains a matter for debate. In this study, we investigated the prognostic relevance of regression of LVH after 2 years of therapy, in a large population of subjects with hypertension, and possessing the aforesaid characteristics.

METHODS

The occurrence of adverse cardiovascular events was evaluated in 387 patients with LVH shown by echocardiography at baseline, and these patients were studied again after 2 years of therapy. At the second examination, 245 subjects showed regression of LVH, whereas 142 did not.

RESULTS

During the time period before the subsequent follow up (6.2 +/- 3 years, range 1.9-12.9 years), 59 first adverse events (26 cardiac and 33 cerebrovascular) had occurred among these subjects. The event rates per 100 patient-years in patients with and without LVH regression were 1.06 and 4.4, respectively. After adjusting for several covariates at the 2-year visit, including in treatment ambulatory BP, Cox regression analysis showed that cardiovascular risk was significantly lower in patients with LVH regression than in those without (RR 0.36, 95% CI 0.19-0.68, P = 0.002). When left ventricular (LV) mass index reduction was analyzed instead of LVH status, it was found to be significantly associated with reduced risk (RR 0.62 per 1-s.d. decrease, 95% CI 0.44-0.88, P = 0.01).

CONCLUSIONS

Regression of LVH, as revealed by echocardiography after 2 years of therapy, is associated with reduced cardiovascular risk in patients with hypertension, whether or not LVH was revealed in their ECGs. This holds true even after adjusting for various confounders including in treatment ambulatory BP.

Predictors of on-duty coronary events in male firefighters in the United States

Coronary heart disease (CHD) accounts for 39% of "on-duty" deaths in firefighters in the United States. No studies have examined the factors that distinguish fatal from nonfatal work-associated CHD events. Male firefighters experiencing on-duty CHD events were retrospectively investigated to identify cardiovascular risk factors predictive of case fatality; 87 fatalities (death within 24 hours of the event) were compared with 113 survivors who retired with disability pensions for heart disease after on-duty nonfatal events. Cardiovascular risk factors were then examined for associations with case fatality. Predictors of CHD death in multivariate analyses were a previous diagnosis of CHD (or peripheral/cerebrovascular disease) (odds ratio [OR] 4.09, 95% confidence intervals [CI] 1.58 to 10.58), current smoking (OR 3.68, 95% CI 1.61 to 8.45), and hypertension (OR 4.15, 95% CI 1.83 to 9.44). Age < or =45 years, diabetes mellitus, and serum cholesterol level were not significant predictors of case fatality. In conclusion, previous CHD, current smoking, and hypertension are strong predictors of fatality in male firefighters experiencing on-duty CHD events. Accordingly, prevention efforts should include early detection and control of hypertension, smoking cessation/prohibition, and the restriction of most firefighters with significant CHD from strenuous duties.

Echocardiographic left ventricular mass index predicts incident stroke in African Americans: Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND AND PURPOSE

Despite theories that link stroke to left ventricular mass, few large, population-based studies have examined the predictive value of echocardiographically derived left ventricular mass index (LVMI) to incident stroke in African Americans.

METHODS

Participants in the Jackson cohort of the Atherosclerotic Risk in Communities study have had extensive baseline evaluations, have undergone echocardiography during the third examination (1993-1995), and have been followed up for incident cardiovascular disease including ischemic stroke.

RESULTS

The study population consisted of 1792 participants, of whom 639 (35.7%) were men and the mean+/-SD age was 58.8+/-5.7 years. Compared with those without ischemic stroke, those with ischemic stroke had a higher frequency of hypertension (85.6% vs 58.7%) and diabetes (46.9% vs 21.0%). Left ventricular hypertrophy was more prevalent in those with stroke (62.2% vs 38.6%). During a median follow-up of 8.8 years, 98 incident strokes occurred (6.5 per 1000 person-years). LVMI was independently associated with stroke after adjusting for age, sex, hypertension, systolic blood pressure, smoking, diabetes, total to HDL cholesterol ratio, body mass index, and low left ventricular ejection fraction (adjusted hazard ratio per 10 g/m(2.7) increment of LVMI=1.15; 95% CI, 1.02 to 1.28). The relation remained statistically significant after adding left atrial size and mitral annular calcification to the multivariable model.

CONCLUSIONS

In this large, population-based African American cohort, we found that echocardiographic LVMI was an independent predictor of incident ischemic stroke even after taking into account traditional clinical risk factors.

ECM remodeling in hypertensive heart disease

Hypertensive heart disease (HHD) occurs in patients that clinically have both diastolic and systolic heart failure and will soon become the most common cause of heart failure. Two key aspects of heart failure secondary to HHD are the relatively highly prevalent LV hypertrophy and cardiac fibrosis, caused by changes in the local and systemic neurohormonal environment. The fibrotic state is marked by changes in the balance between MMPs and their inhibitors, which alter the composition of the ECM. Importantly, the fibrotic ECM impairs cardiomyocyte function. Recent research suggests that therapies targeting the expression, synthesis, or activation of the enzymes responsible for ECM homeostasis might represent novel opportunities to modify the natural progression of HHD.

Genetic Variations Associated With Echocardiographic Left Ventricular Traits in Hypertensive Blacks

Echocardiographic measures of cardiac target organ damage, including left ventricular mass and relative wall thickness, are powerful predictors of heart disease morbidity and mortality. The aim of this study is to investigate whether single nucleotide polymorphisms in candidate genes for hypertension and heart disease have effects on quantitative measures of hypertensive cardiac target organ damage, independent of their actions on blood pressure levels, in a cohort of hypertensive black sibships. To detect replication of genetic effects across samples, this study took advantage of the affected sibling pair design and created 2 samples, each with 448 unrelated individuals. As part of the Genetic Epidemiology Network of Arteriopathy Study, subjects were screened using 2D echocardiography, and 395 single nucleotide polymorphisms in 80 candidate genes were genotyped. Linear regression was used to test for single nucleotide polymorphisms significantly associated with left ventricular mass index (g/m 2.7 ) or relative wall thickness after adjusting for associated covariates. Significant single nucleotide polymorphisms were subsequently tested for consistent directionality in genotype–phenotype relationships across samples. Three single nucleotide polymorphisms, 1 each in the APOE , SCN7A , and SLC20A1 genes, were significantly associated in both samples with left ventricular mass index and had replicate genotype–phenotype relationships. One in the ADRB1 gene was significantly associated with relative wall thickness with replicate effects in both samples. We identified genetic variation that significantly influences left ventricular traits with replicable effects in a cohort of hypertensive, black siblings.

Relation of left ventricular hypertrophy to regional cerebral blood flow: single photon emission computed tomography abnormalities in essential hypertension

Several reports have shown that left ventricular hypertrophy (LVH) is an independent predictor of acute cerebrovascular events. The aim of the present study was to investigate the relationship between LVH and cerebral blood flow in middle-aged patients with essential hypertension. Forty never-treated hypertensive patients (24 men, 16 women, aged 50-60 years) without clinical evidence of target organ damage were studied. Regional cerebral blood flow was measured by means of single photon emission computed tomography of the brain. Twenty-nine patients showed echocardiographic criteria of LVH; 11 patients did not show this feature. No differences were found in regional cerebral blood flow ratio of all brain areas studied between hypertensives with or without LVH except for the striatum area. The regional cerebral blood flow ratio was significantly reduced in the striatum region of hypertensive patients with LVH, compared with patients without LVH (91.5+/-7.4 vs 98.1+/-8.3; P=.023). This relationship remained significant after adjusting for blood pressure. The authors conclude that the presence of LVH in middle-aged patients with essential hypertension is associated with a reduction of regional cerebral blood flow in the striatum area.

Left ventricular hypertrophy, subclinical atherosclerosis, and inflammation

To elucidate mechanisms by which left ventricular (LV) hypertrophy (LVH) increases the risk of atherosclerotic heart disease, we sought to determine whether LVH is independently associated with coronary artery calcium (CAC) and serum C-reactive protein (CRP) levels in the general population. The Dallas Heart Study is a population-based sample in which 2633 individuals underwent cardiac MRI to measure LV structure, electron beam CT to measure CAC, and measurement of plasma CRP. We used univariate and multivariable analyses to determine whether LV mass and markers of concentric LV hypertrophy or dilation were associated with CAC and CRP. Increasing quartiles of LV mass indexed to fat-free mass, LV wall thickness, and concentricity, but not LV volume, were associated with CAC in both men and women (P<0.001). After adjustment for traditional cardiovascular risk factors and statin use, LV wall thickness and concentricity remained associated with CAC in linear regression (P<0.001 for each). These associations were particularly robust in blacks. LV wall thickness and concentricity were also associated with elevated CRP levels (P=0.001 for both) in gender-stratified univariate analyses, although these associations did not persist in multivariable analysis. In conclusion, concentric LVH is an independent risk factor for subclinical atherosclerosis. LVH is also associated with an inflammatory state as reflected in elevated CRP levels, although this relationship appears to be mediated by comorbid conditions. These data likely explain in part why individuals with LVH are at increased risk for myocardial infarction.

Relationship of visceral adiposity to cardiovascular disease risk factors in black and white teens

OBJECTIVE

We tested the hypothesis that visceral adiposity, compared with general adiposity, would explain more of the variance in cardiovascular disease (CVD) risk factors.

RESEARCH METHOD AND PROCEDURES

Subjects were 464 adolescents (238 black and 205 girls). Adiposity measures included visceral adipose tissue (VAT; magnetic resonance imaging), percent body fat (%BF; DXA), BMI, and waist girth (anthropometry). CVD risk factors were fasting insulin, fibrinogen, total to high-density lipoprotein-cholesterol ratio, triglycerides (TGs), systolic blood pressure, and left ventricular mass indexed to height2.7.

RESULTS

After adjustment for age, race, and sex, all adiposity indices explained significant proportions of the variance in all of the CVD risk factors; %BF tended to explain more variance than VAT. Regression models that included both %BF and VAT found that both indices explained independent proportions of the variance only for total to high-density lipoprotein-cholesterol ratio. For TGs, the model that included both %BF and VAT found that only VAT was significant. For systolic blood pressure and left ventricular mass indexed to height2.7, anthropometric measures explained more of the variance than VAT and %BF.

DISCUSSION

The hypothesis that visceral adiposity would explain more variance in CVD risk than general adiposity was not supported in this relatively large sample of black and white adolescents. Only for TGs did it seem that VAT was more influential than %BF. Perhaps the deleterious effect of visceral adiposity becomes greater later in life as it increases in proportion to general adiposity.

Evaluation of Left Ventricular Functions after Aortic Valve Replacement in a Specific Young Male Patient Population with Pure Aortic Insufficiency or Aortic Stenosis: 5-Years Follow-up

BACKGROUND

The aim of this study was to evaluate the left ventricular functions and the regression of left ventricular hypertrophy after aortic valve replacement (AVR) in young male patients with pure aortic stenosis or aortic insufficiency with no additional disease.

METHODS

Young male patients who underwent AVR because of pure aortic stenosis (AS = 68) and insufficiency (AI = 70) were enrolled in the study. The mean age was 23.2 +/- 1.3 and 22.6 +/- 1.6 years, respectively. The follow-up time was 5 years. The parameters checked by transthoracic echocardiography were interventricular septum diastolic thickness, left ventricular posterior wall diastolic thickness, left ventricular end-diastolic diameter, left ventricle mass, left ventricle mass index, ejection fraction, and peak aortic gradient. Relative ventricle wall thickness was also calculated. Both groups values from the preoperative, postoperative sixth month, second year, and fifth year time intervals were compared.

RESULTS

In the AS group, the preoperative left ventricular ejection fraction (%) value of 53.68 +/- 5.04 increased to 63.24 +/- 4.11 at the end of the fifth year. In the AI group, the preoperative left ventricular ejection fraction (%) value of 48.40 +/- 3.56 increased to 59.77 +/- 2.75 at the end of the fifth year. The other left ventricular geometric parameters were also compared within each group. At the end of the fifth year, there were significant and positive changes in each group.

CONCLUSION

The regression of the left ventricular parameters is a process that occurs over many years following the correction of the primary hemodynamic abnormality. Although the results were similar in the AI and AS group, in the AS group the remodeling process had earlier results than in the AI group.

Left Ventricular Geometry and Renal Function in Hypertensive Patients With Diastolic Heart Failure

BACKGROUND

The objective is to define the relationship between cardiac geometry and renal function in hypertensive subjects with and without diastolic heart failure (DHF).

METHODS

This is a prospective observational study in a tertiary-care teaching institute in a 15-month period of consecutive hospitalized hypertensive patients. Patients on dialysis therapy or with atrial fibrillation, systolic heart failure, gross proteinuria, and glomerular diseases were excluded. Two-dimensional echocardiography was performed and stable glomerular filtration rate (GFR) was calculated by using the Modification of Diet in Renal Disease formula. Patients were classified into stage 1 to 5 chronic kidney disease (CKD).

RESULTS

Five hundred forty hypertensive patients were separated into 2 groups: 286 patients with DHF and 254 patients without DHF. Mean age was 69.1 +/- 13.7 (SD) years in general. In patients with DHF, from stages 1 to 5 CKD, there was a significant graded increase in left ventricular mass index (from 117.3 to 162.4 g/m(2)) and relative wall thickness (from 0.42 to 0.52) and a significant graded decrease in aortic cusp separation (from 1.85 to 1.55 cm). Among echocardiographic variables, left ventricular mass index and relative wall thickness were associated inversely and aortic cusp separation was associated directly with GFR. In the absence of DHF, only left ventricular mass index was associated inversely with GFR, suggesting a prominent role of aortic cusp separation and relative wall thickness in the variability in GFR in patients with DHF through a hemodynamic disturbance.

CONCLUSION

Hemodynamic alterations have a prominent role in the variability of GFR in patients with CKD with DHF. Adverse cardiac geometry is linked to the severity of CKD in hypertensive patients, raising the possibility of preserving both cardiac and renal function by means of hypertension control.

Left ventricular geometric patterns in the Jackson cohort of the Atherosclerotic Risk in Communities (ARIC) Study: clinical correlates and influences on systolic and diastolic dysfunction

BACKGROUND

The distribution and determinants of left ventricular (LV) geometric patterns and their relation to LV function in African Americans is not well described despite higher rates of LV hypertrophy and cardiovascular mortality reported in this group.

PURPOSE

This study investigates the distribution and clinical correlates of LV geometric patterns and how these patterns relate to function in a population-based African American cohort.

METHODS

The study population included participants in the Jackson cohort of ARIC, who underwent echocardiograms between 1993 and 1995. We defined 4 geometric patterns (normal geometry, concentric remodeling [CR], eccentric hypertrophy [EH], and concentric hypertrophy [CH]) according to LV mass index and relative wall thickness. Multiple logistic regression was used to assess the association of geometric patterns to systolic dysfunction and diastolic dysfunction, adjusting for traditional coronary risk factors.

RESULTS

There were 1849 participants in the study population (mean age 59 years, 65% women). Concentric remodeling and CH were highly prevalent. Concentric hypertrophy and EH groups had the highest rates of hypertension, obesity, and diabetes mellitus. Compared to the normal geometric pattern, EH was related to systolic dysfunction (OR 24.27, CI 6.71-87.80), and CH was related to diastolic dysfunction 1.58 (1.04-2.39). Concentric remodeling was not related to systolic or diastolic dysfunction.

CONCLUSION

In this large middle-aged African American cohort, CR and CH are prevalent. Hypertension, diabetes mellitus, and obesity are associated with both CH and EH. Concentric hypertrophy is strongly associated with diastolic dysfunction; EH is strongly associated with systolic dysfunction. Concentric remodeling, however, is not related to either systolic or diastolic dysfunction.

Potential impact of carbohydrate and fat intake on pathological left ventricular hypertrophy

Currently, a high carbohydrate/low fat diet is recommended for patients with hypertension; however, the potentially important role that the composition of dietary fat and carbohydrate plays in hypertension and the development of pathological left ventricular hypertrophy (LVH) has not been well characterized. Recent studies demonstrate that LVH can also be triggered by activation of insulin signaling pathways, altered adipokine levels, or the activity of peroxisome proliferator-activated receptors (PPARs), suggesting that metabolic alterations play a role in the pathophysiology of LVH. Hypertensive patients with high plasma insulin or metabolic syndrome have a greater occurrence of LVH, which could be due to insulin activation of the serine-threonine kinase Akt and its downstream targets in the heart, resulting in cellular hypertrophy. PPARs also activate cardiac gene expression and growth and are stimulated by fatty acids and consumption of a high fat diet. Dietary intake of fats and carbohydrate and the resultant effects of plasma insulin, adipokine, and lipid concentrations may affect cardiomyocyte size and function, particularly in the setting of chronic hypertension. This review discusses potential mechanisms by which dietary carbohydrates and fats ca affect cardiac growth, metabolism, and function, mainly in the context of pressure overload-induced LVH.