[Computerized interpretation of the electrocardiogram in the diagnosis of left ventricular hypertrophy. The ELECTROPRES project]

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.

Relationship between electrocardiographic left ventricular hypertrophy criteria and vascular structure and function parameters in hypertensive patients

The objective of this study was to determine the electrocardiographic left ventricular hypertrophy (LVH) criterion that best correlated with vascular structure and function parameters in hypertensive patients. A cross-sectional study involving 347 hypertensive patients was performed. The mean age of the subjects was 54.9±11.8 years, and 61% were male. Electrocardiography was used to detect LVH based on the evaluation of 10 criteria, and we defined the voltage-duration product (VDP) complex criterion. The vascular structure was evaluated according to carotid intima-media thickness (C-IMT), and vascular function was evaluated according to pulse wave velocity (PWV), the ambulatory arterial stiffness index (AASI), the home arterial stiffness index, and the peripheral (PAIx) and central (CAIx) augmentation indices. LVH according to at least some electrocardiographic criteria was recorded in 29.10% of the patients (34.10% of females; 25.90% of males). The vascular structure and function parameters showed higher values in the hypertensive patients with LVH. The criterion most closely correlated with C-IMT was Lewis-VDP (r=0.257); with PWV and AASI, the criterion was the Framingham-adjusted Cornell voltage (r=0.228 and r=0.195, respectively); and with CAIx and PAIx, the criterion was Novacode (r=0.226 and r=0.277, respectively). In the multivariate analysis, the association of the vascular structure and function parameters, the VDP complex (multiple linear regression) and the presence of LVH (logistic regression) disappeared after adjusting for age, sex and antihypertensive drugs. The relationship between the electrocardiographic criteria used to detect LVH in hypertensive patients and the vascular structure and function parameters were fundamentally conditioned by age and antihypertensive drug treatment.

Yearly evolution of organ damage markers in diabetes or metabolic syndrome: data from the LOD-DIABETES study

Background

Cardiovascular disease morbidity-mortality is greater in people with type 2 diabetes mellitus or metabolic syndrome. The purpose of this study was to evaluate the yearly evolution of organ damage markers in diabetes or metabolic syndrome, and to analyze the associated factors.

Methods

An observational prospective study was carried out in the primary care setting, involving 112 patients: 68 diabetics and 44 subjects with metabolic syndrome, subjected to 12 months of follow-up. Measurements: traditional cardiovascular risk factors (blood pressure, blood glucose, lipids, smoking, body mass index (BMI) and) and non-traditional risk factors (waist circumference, hsC Reactive Protein and fibrinogen); subclinical vascular (carotid intima-media thickness, pulse wave velocity and ankle/brachial index), cardiac (Cornell voltage-duration product), renal organ damage (creatinine, glomerular filtration and albumin/creatinine index), and antihypertensive and lipid-lowering drugs.

Results

At baseline, the diabetics presented a mean age of 59.9 years, versus 55.2 years in the subjects with metabolic syndrome (p = 0.03). Diastolic blood pressure, total cholesterol and HDL-cholesterol were lower among the patients with diabetes, while blood glucose and HbA1c, as well as antihypertensive and lipid-lowering drug use, were greater. At evaluation after one year, the diabetics showed a decrease in BMI (-0.39), diastolic blood pressure (-3.59), and an increase in fibrinogen (30.23 mg/dL), ankle/brachial index (0.07) and the number of patients with ankle/brachial index pathologic decreased in 6. In turn, the patients with metabolic syndrome showed an increase in HDL-cholesterol (1-91 mg/dL), fibrinogen (25.54 mg/dL), Cornell voltage-duration product (184.22 mm/ms), ankle/brachial index (0.05) and the use of antihypertensive and lipid-lowering drugs, and a reduction in serum glucose (3.74 mg/dL), HOMA, systolic (-6.76 mmHg), diastolic blood pressure (-3.29 mmHg), and pulse wave velocity (-0.72 m/s). The variable that best predicted a decrease in pulse wave velocity in subjects with metabolic syndrome was seen to be an increase in antihypertensive drug use.

Conclusions

The annual assessment of cardiovascular risk factors and the decrease in pulse wave velocity was more favorable in the patients with metabolic syndrome, probably influenced by the increased percentage of subjects treated with antihypertensive and lipid lowering drugs in this group.