Determinants of left ventricular mass and presence of metabolic risk factors in normotensive individuals

Dysglycemia and increased left ventricle mass in normotensive patients admitted with a first myocardial infarction: prognostic implications of dysglycemia during 14 years of follow-up

Background

Left ventricle mass (LVM) can be influenced by various conditions including hypertension and/or inherent cardiomyopathies. Dysglycemia is also thought to exert an anabolic effect on heart tissue by hyperinsulinemia and thereby promoting increased LVM. The primary aim of this study was to assess the influence of dysglycemia on LVM evaluated by an oral glucose tolerance test (OGTT) in patients admitted with a first myocardial infarction (MI) without hypertension. The secondary aim was to assess the impact of dysglycemia on major adverse cardiovascular events (MACE) and all-cause mortality during long-term follow-up.

Methods

Patients admitted with a first MI without known history of hypertension were included. All patients without previously known type 2 diabetes mellitus (T2DM) had a standardized 2-hour OGTT performed and were categorized as: normal glucose tolerance (NGT), impaired fasting glucose (IFG)/impaired glucose tolerance (IGT) and newly detected T2DM (new T2DM). LVM was measured by echocardiography using Devereaux formula and indexed by body surface area. Multivariate linear regression analysis was used to assess the impact of confounders (dysglycemia by OGTT, known T2DM, age, sex and type of MI) on LVM. Cox proportional hazard model was used to assess the impact of dysglycemia on all-cause mortality and a composite endpoint of MACE (all-cause mortality, MI, revascularisation due to stable angina, coronary artery bypass graft, ischemic stroke or hemorrhagic stroke).

Results

Two-hundred-and-five patients were included and followed up to 14 years. In multivariate regression analysis, LVM was only significantly increased in patients categorized as new T2DM (β = 25.3; 95% CI [7.5–43.0]) and known T2DM (β = 37.3; 95% CI [10.0-64.5]) compared to patients with NGT. Patients with new T2DM showed higher rates of MACE and all-cause mortality compared to patients with IFG/IGT and NGT; however no significantly increased hazard ratio was detected.

Conclusions

Dysglycemia is associated with increasing LVM in normotensive patients with a first acute myocardial infarction and the strongest association was observed in patients with new T2DM and patients with known T2DM. Dysglycemia in normotensive patients with a first MI is not an independent predictor of neither MACE nor all-cause mortality during long-term follow-up compared to normotensive patients without dysglycemia.

Electronic supplementary material

The online version of this article (10.1186/s12872-019-1084-5) contains supplementary material, which is available to authorized users.

Prevalence and Clinical Correlates of Left Ventricular Hypertrophy in Black Africans

INTRODUCTION

African-Americans present higher prevalence of left ventricular hypertrophy (LVH) when compared with white populations. However, there is a lack of information about the prevalence and determinants of LVH in black individuals living in Africa.

METHODS

A cross-sectional study was performed with a non-probabilistic sample comprised of 609 University workers from Angola/Africa, describing the prevalence of LVH and the determinants of left ventricular mass. Echocardiographic measurements were performed and left ventricular mass was indexed to body surface area. Systolic and diastolic blood pressures were measured, along with anthropometric and clinical variables.

RESULTS

Chamber diameter and wall thickness were higher in men compared to women. Additionally, LVM was higher in men (114.2 ± 36 vs 98.4 ± 31.9, P < 0.001), and the overall prevalence of LVH in black Angolans was 41.1%, which tended to be higher in women (44.5 vs 37.4%, P = 0.096). In men, systolic blood pressure and BMI were independently associated with LVM, while age, systolic blood pressure and waist circumference were associated with LVM in women.

CONCLUSIONS

In summary, blood pressure levels were the main determinants of LVH in black Africans, although different anthropometric variables showed mild influence in LVM. Our data suggests that LVH prevalence and determinants in black Africans are similar to that reported for African-Americans.

Association between functional variant of inflammatory system gene (PSMA6) and end-stage kidney disease

Background

The proteasome system is involved in several disorders. The 5′ untranslated region of PSMA6 gene contains a single nucleotide polymorphism (SNP) −8 C/G, associated with diabetes, myocardial infarction and coronary artery disease.

Methods

We examined 584 patients with end-stage kidney disease (ESKD) and 430 controls. All were genotyped for −8 C/G SNP by polymerase chain reaction and restriction analysis.

Results

We observed lower frequency of CG + GG genotypes in patients than in controls (20 vs. 42 %, p = 0.0038). The odds ratio of 0.34 (95 % CI 0.26–0.45) suggests association of CG + GG with decreased risk of ESKD. We investigated the association between PSMA6 polymorphism and LVH present in 54 % of patients. There was a significant association of CG + GG genotype with LVH, with over 75 % of CG + GG in patients with LVH. This effect was independent from other common causes of LVH—age (OR 1.12, p = 0.643) and hypertension (OR 1.72, p = 0.422).

Conclusion

We demonstrated for the first time that PSMA6 polymorphism might be a protective factor for ESKD. On the other hand, CG + GG genotypes are independently related to LVH in ESKD patients.

Association between left ventricular mass, androgens, adiposity and insulin resistance in girls with precocious pubarche: a case-control study

OBJECTIVE

Precocious pubarche (PP) has been linked to higher prevalence of metabolic disturbances and polycystic ovary syndrome (PCOS). The aim of the study was to assess echocardiographic parameters in PP girls and to analyse their relationship with androgens and insulin resistance (IR).

DESIGN

Case-control study.

PATIENTS

Thirty-five PP girls and 35 healthy age-matched controls.

MEASUREMENTS

Clinical, hormonal and metabolic profiles, echocardiography, body composition and oral glucose tolerance test.

RESULTS

Chronological age (10·04 ± 2·6 years in PP vs 10·13 ± 2·56 years in controls, P = 0·227), and pubertal stage at the time of the study were similar between the groups. PP girls had higher free androgen index (FAI) [1·39 (0·48-3·64) vs 1·06 (0·39-1·7), P = 0·005] and QUICKI (0·58 ± 0·08 vs 0·63 ± 0·12, P = 0·021). However, HOMA-IR was not significantly different between the groups [2·79 (1·84-4·05) vs 2·15 (1·09-3·23), P = 0·085]. After adjusting for total body fat, left ventricular mass (LVM) was higher in the PP group (97·31 ± 33·37 vs 81·25 ± 19·06 g, P = 0·017) as well as A' wave (5·66 ± 1·34 vs 5·09 ± 0·98 cm/s, P = 0·025), a measurement of diastolic function. FAI and total body fat were independent predictors of higher LVM and together with HOMA-IR contributed 72% of LVM variability in the PP group.

CONCLUSION

In this study with PP girls, greater LVM, associated with higher androgen levels, IR and total body fat, occurred early in pubertal development.

Relationship of MTHFR gene polymorphisms with renal and cardiac disease

AIM: To investigate the effects of different methylenetetrahydrofolate reductase (MTHFR) 677C>T gene polymorphism and hyperhomocysteinemia for the development of renal failure and cardiovascular events, which are controversial.

METHODS: We challenged the relationship, if any, of MTHFR 677C>T and MTHFR 1298A>C polymorphisms with renal and heart function. The present article is a reappraisal of these concepts, investigating within a larger population, and including a subgroup of dialysis patients, if the two most common MTHFR polymorphisms, C677T and A1298C, as homozygous, heterozygous or with a compound heterozygous state, show different association with chronic renal failure requiring hemodialysis. MTHFR polymorphism could be a favorable evolutionary factor, i.e., a protective factor for many ominous conditions, like cancer and renal failure. A similar finding was reported in fatty liver disease in which it is suggested that MTHFR polymorphisms could have maintained and maintain their persistence by an heterozygosis advantage mechanism. We studied a total of 630 Italian Caucasian subject aged 54.60 ± 16.35 years, addressing to the increased hazard of hemodialysis, if any, according to the studied MTHFR genetic polymorphisms.

RESULTS: A favorable association with normal renal function of MTHFR polymorphisms, and notably of MTHFR C677T is present independently of the negative effects of left ventricular hypertrophy, increased Intra-Renal arterial Resistance and hyperparathyroidism.

CONCLUSION: MTHFR gene polymorphisms could have a protective role on renal function as suggested by their lower frequency among our dialysis patients in end-stage renal failure; differently, the association with left ventricular hypertrophy and reduced left ventricular relaxation suggest some type of indirect, or concurrent mechanism.

Matrix revisited: mechanisms linking energy substrate metabolism to the function of the heart

Metabolic signaling mechanisms are increasingly recognized to mediate the cellular response to alterations in workload demand, as a consequence of physiological and pathophysiological challenges. Thus, an understanding of the metabolic mechanisms coordinating activity in the cytosol with the energy-providing pathways in the mitochondrial matrix becomes critical for deepening our insights into the pathogenic changes that occur in the stressed cardiomyocyte. Processes that exchange both metabolic intermediates and cations between the cytosol and mitochondria enable transduction of dynamic changes in contractile state to the mitochondrial compartment of the cell. Disruption of such metabolic transduction pathways has severe consequences for the energetic support of contractile function in the heart and is implicated in the pathogenesis of heart failure. Deficiencies in metabolic reserve and impaired metabolic transduction in the cardiomyocyte can result from inherent deficiencies in metabolic phenotype or maladaptive changes in metabolic enzyme expression and regulation in the response to pathogenic stress. This review examines both current and emerging concepts of the functional linkage between the cytosol and the mitochondrial matrix with a specific focus on metabolic reserve and energetic efficiency. These principles of exchange and transport mechanisms across the mitochondrial membrane are reviewed for the failing heart from the perspectives of chronic pressure overload and diabetes mellitus.

Framingham score and LV mass predict events in young adults: CARDIA study

BACKGROUND

Framingham risk score (FRS) underestimates risk in young adults. Left ventricular mass (LVM) relates to cardiovascular disease (CVD), with unclear value in youth. In a young biracial cohort, we investigate how FRS predicts CVD over 20 years and the incremental value of LVM. We also explore the predictive ability of different cut-points for hypertrophy.

METHODS

We assessed FRS and echocardiography-derived LVM (indexed by body surface area or height2.7) from 3980 African-American and white Coronary Artery Risk Development in Young Adults (CARDIA) participants (1990-1991); and followed over 20 years for a combined endpoint: cardiovascular death; nonfatal myocardial infarction, heart failure, cerebrovascular disease, and peripheral artery disease. We assessed the predictive ability of FRS for CVD and also calibration, discrimination, and net reclassification improvement for adding LVM to FRS.

RESULTS

Mean age was 30±4 years, 46% males, and 52% white. Event incidence (n=118) across FRS groups was, respectively, 1.3%, 5.4%, and 23.1% (p<0.001); and was 1.4%, 1.3%, 3.7%, and 5.4% (p<0.001) across quartiles of LVM (cut-points 117 g, 144 g, and 176 g). LVM predicted CVD independently of FRS, with the best performance in normal weight participants. Adding LVM to FRS modestly increased discrimination and had a statistically significant reclassification. The 85th percentile (≥116 g/m2 for men; ≥96 g/m2 for women) showed event prediction more robust than currently recommended cut-points for hypertrophy.

CONCLUSION

In a biracial cohort of young adults, FRS and LVM are helpful independent predictors of CVD. LVM can modestly improve discrimination and reclassify participants beyond FRS. Currently recommended cut-points for hypertrophy may be too high for young adults.

Clusters of AMI risk factors and their association with left ventricular hypertrophy: a population-based study within the Skaraborg Project, Sweden

OBJECTIVES

Risk factors for acute myocardial infarction (AMI) are known to cluster and to be differently distributed in men and women. The aim of this study was to sex-specifically explore clusters of acknowledged AMI risk factors by factor analysis, and to study whether such clusters are associated with left ventricular hypertrophy (LVH), used as a subclinical measure of CHD.

METHODS

In 2001-2005, 2328 subjects (30-74 years) were randomly selected from two municipalities in Sweden (participation-rate 76%) and were assessed with regard to cardiovascular risk factors; 852 participants also had an echocardiographic examination performed.

RESULTS

Factor analysis identified three identical factors in men and women. WHR, HOMA-ir, systolic blood pressure, and ApoB/ApoA1 loaded significantly on the principal "metabolic factor", leisure-time physical activity and self-rated health loaded significantly on the "vitality factor", and smoking and alcohol consumption loaded significantly on the "addiction factor". The metabolic factor was associated with LVH in both men (P<0.001) and women (P<0.001), whereas the addiction factor was associated with LVH solely in men (P=0.002).

CONCLUSIONS

The consistent pattern in the clustering of acknowledged AMI risk factors suggests common underlying mechanisms in both men and women. However, whereas the metabolic factor was paramount in both men and women in the association with LVH, the addiction factor had an impact solely in men. As LVH often precedes AMI, a deeper understanding of risk factors for LVH, including consideration of the supposed sex differences, can be useful in order to explore prevention strategies for AMI.

Association of heart rate and left ventricular structure in a rural population in Korea

Abstract We investigated the association of heart rate (HR) and estimated glomerular filtration rate (eGFR) with left ventricular (LV) structure in a multi-rural cohort project in Korea. A total of 3215 subjects were analyzed for factors related to Echo-LV mass index (LVMI). eGFR was positively associated with both types of LVMI whereas HR was negatively associated with both. Odd ratios (ORs) (highest versus lowest quartiles) for LVMI by height(2.7) were significant for HR (OR: 0.441, p = 0.0035 in males; OR: 0.638, p = 0.0226 in females), and for eGFR (OR:1.643, p = 0.0145) in females. In conclusion, in addition to age, systolic blood pressure and body mass index, eGFR is positively associated with echocardiographic LVMI and HR is negatively associated with echocardiographic LVMI.

Renal insufficiency in non-diabetic subjects: relationship of MTHFR C677t gene polymorphism and left ventricular hypertrophy

BACKGROUND

Association of methylenetetrahydrofolate reductase (MTHFR) 677C>T gene polymorphism with hyperhomocysteinemia, renal failure, and cardiovascular events is controversial. We investigated the relationship of MTHFR 677C>T polymorphisms with left ventricular hypertrophy (LVH) and renal insufficiency.

METHODS

Glomerular filtration rate (GFR) and left myocardial ventricular mass/m2 were assessed in 138 non-diabetic subjects (age, 50.93 ± 14.85 years; body mass index, 27.95 ± 5.98 kg/m(2)), 38 no-mutation wild MTHFR C677CC, 52 heterozygous MTHFR C677CT, and 48 homozygous MTHFR C677TT, all with adequate adherence to current international healthy dietary guidelines. Serum homocysteine, insulin resistance, high-sensitivity C-reactive-protein (hsCRP), parathyroid hormone, and renal artery resistive index (RRI) were challenged by odds ratio analysis and multiple linear regression models.

RESULTS

MTHFR 677C>T polymorphism showed higher GFR (73.8 ± 27.99 vs. 58.64 ± 29.95; p= 0.001) and lower renal failure odds (OR, 0.443; 95% confidence interval, 0.141-1.387) in comparison with wild MTHFR genotype. A favorable effect on GFR of MTHFR polymorphism is presented independently by the negative effects of LVH, increased intra-renal arterial resistance, and hyperparathyroidism; GFR is the significant predictive factor to LVH.

CONCLUSIONS

Renal insufficiency in non-diabetic subjects is explained by interactions of MTHFR C677T polymorphism mutation with LVH, hsCRP, intact parathyroid hormone (iPTH), and RRI. Sign of these predictive effects is opposite: subjects with MTHFR 677C>T polymorphism have lower likelihood of renal insufficiency; differently, wild-type MTHFR genotype subjects have lower GFR and greater hsCRP, iPTH, RRI, and LVH.

Leg blood pressure measured in orthostatic posture is associated with left ventricular mass in normotensive subjects

BACKGROUND

Changing from a supine to an orthostatic posture is associated with substantial increments in leg blood pressure (BP) levels, which could ultimately influence the hemodynamic burden imposed on the heart. This study investigated the relationship between brachial and leg BP measurements and the left cardiac chamber's structure and assessed the role of body posture changes in this regard.

METHODS

One hundred and thirty normotensive, nondiabetic, nonsmoking, normolipemic subjects were evaluated by a clinical history, anthropometry, the analysis of metabolic parameters, echocardiography, and the measurement of BP in the arm and the calf in both supine and orthostatic positions.

RESULTS

Significant correlation coefficients between the leg BP measurements and the cardiac structure were detected, especially between the orthostatic pulse pressure (PP) and the left ventricular (LV) wall thickness (r = 0.38; P < 0.001), the orthostatic PP and the LV mass (r = 0.37; P < 0.001), and the orthostatic systolic BP (SBP) and the left atrial size (r = 0.35; P < 0.001). Stepwise and standard regression analysis adjusted for brachial BP and anthropometric and metabolic variables confirmed that the leg orthostatic PP was independently related to the LV wall thickness and mass. Moreover, the leg orthostatic SBP was associated with the left atrial dimension even after adding the LV mass to the statistical models. Finally, triglyceride levels and body surface area showed significant relationship with leg orthostatic PP and SBP, whereas brachial orthostatic PP and SBP were only associated with age and anthropometric variables.

CONCLUSIONS

Orthostatic leg BP is independently associated with the cardiac structure in normotensive subjects.

A follow-up study for left ventricular mass on chromosome 12p11 identifies potential candidate genes

Background

Left ventricular mass (LVM) is an important risk factor for cardiovascular disease. Previously we found evidence for linkage to chromosome 12p11 in Dominican families, with a significant increase in a subset of families with high average waist circumference (WC). In the present study, we use association analysis to further study the genetic effect on LVM.

Methods

Association analysis with LVM was done in the one LOD critical region of the linkage peak in an independent sample of 897 Caribbean Hispanics. Genotype data were available on 7085 SNPs from 23 to 53 MB on chromosome 12p11. Adjustment was made for vascular risk factors and population substructure using an additive genetic model. Subset analysis by WC was performed to test for a difference in genetic effects between the high and low WC subsets.

Results

In the overall analysis, the most significant association was found to rs10743465, downstream of the SOX5 gene (p = 1.27E-05). Also, 19 additional SNPs had nominal p < 0.001. In the subset analysis, the most significant difference in genetic effect between those with high and low WC occurred with rs1157480 (p = 1.37E-04 for the difference in β coefficients), located upstream of TMTC1. Twelve additional SNPs in or near 6 genes had p < 0.001.

Conclusions

The current study supports previously identified evidence by linkage for a genetic effect on LVM on chromosome 12p11 using association analysis in population-based Caribbean Hispanic cohort. SOX5 may play an important role in the regulation of LVM. An interaction of TMTC1 with abdominal obesity may contribute to phenotypic variation of LVM.

Novel quantitative trait locus is mapped to chromosome 12p11 for left ventricular mass in Dominican families: the Family Study of Stroke Risk and Carotid Atherosclerosis

Background

Left ventricular mass (LVM) is an important risk factor for stroke and vascular disease. The genetic basis of LVM is unclear although a high heritability has been suggested. We sought to map quantitative trait loci (QTL) for LVM using large Dominican families.

Methods

Probands were selected from Dominican subjects of the population-based Northern Manhattan Study (NOMAS). LVM was measured by transthoracic echocardiography. A set of 405 microsatellite markers was used to screen the whole genome among 1360 subjects from 100 Dominican families who had complete phenotype data and DNA available. A polygenic covariate screening was run to identify the significant covariates. Variance components analysis was used to estimate heritability and to detect evidence for linkage, after adjusting for significant risk factors. Ordered-subset Analysis (OSA) was conducted to identify a more homogeneous subset for stratification analysis.

Results

LVM had a heritability of 0.58 in the studied population (p < 0.0001). The most significant evidence for linkage was found at chromosome 12p11 (MLOD = 3.11, empirical p = 0.0003) with peak marker at D12S1042. This linkage was significantly increased in a subset of families with the high average waist circumference (MLOD = 4.45, p = 0.0045 for increase in evidence for linkage).

Conclusion

We mapped a novel QTL near D12S1042 for LVM in Dominicans. Enhanced linkage evidence in families with larger waist circumference suggests that gene(s) residing within the QTL interact(s) with abdominal obesity to contribute to phenotypic variation of LVM. Suggestive evidence for linkage (LOD = 1.99) has been reported at the same peak marker for left ventricular geometry in a White population from the HyperGEN study, underscoring the importance of this QTL for left ventricular phenotype. Further fine mapping and validation studies are warranted to identify the underpinning genes.