Repeated replication and a prospective meta-analysis of the association between chromosome 9p21.3 and coronary artery disease

BACKGROUND

Recently, genome-wide association studies identified variants on chromosome 9p21.3 as affecting the risk of coronary artery disease (CAD). We investigated the association of this locus with CAD in 7 case-control studies and undertook a meta-analysis.

METHODS AND RESULTS

A single-nucleotide polymorphism (SNP), rs1333049, representing the 9p21.3 locus, was genotyped in 7 case-control studies involving a total of 4645 patients with myocardial infarction or CAD and 5177 controls. The mode of inheritance was determined. In addition, in 5 of the 7 studies, we genotyped 3 additional SNPs to assess a risk-associated haplotype (ACAC). Finally, a meta-analysis of the present data and previously published samples was conducted. A limited fine mapping of the locus was performed. The risk allele (C) of the lead SNP, rs1333049, was uniformly associated with CAD in each study (P<0.05). In a pooled analysis, the odds ratio per copy of the risk allele was 1.29 (95% confidence interval, 1.22 to 1.37; P=0.0001). Haplotype analysis further suggested that this effect was not homogeneous across the haplotypic background (test for interaction, P=0.0079). An autosomal-additive mode of inheritance best explained the underlying association. The meta-analysis of the rs1333049 SNP in 12,004 cases and 28,949 controls increased the overall level of evidence for association with CAD to P=6.04x10(-10) (odds ratio, 1.24; 95% confidence interval, 1.20 to 1.29). Genotyping of 31 additional SNPs in the region identified several with a highly significant association with CAD, but none had predictive information beyond that of the rs1333049 SNP.

CONCLUSIONS

This broad replication provides unprecedented evidence for association between genetic variants at chromosome 9p21.3 and risk of CAD.

Genetic variants within the LPIN1 gene, encoding lipin, are influencing phenotypes of the metabolic syndrome in humans

OBJECTIVE

Lipin, a novel molecular protein expressed by adipocytes, has marked effects on adipose tissue mass, insulin sensitivity, and glucose homeostasis. Thus, we hypothesized that genetic variants within LPIN1 are associated with traits of the metabolic syndrome.

RESEARCH DESIGN AND METHODS

A total of 15 single nucleotide polymorphisms (SNPs) covering the LPIN1 gene region were genotyped in an age- and sex-stratified sample of the general population (Monitoring Trends and Determinants on Cardiovascular Diseases Study Augsburg; DNA and phenotypes of 1,416 Caucasians). Ten SNPs were also genotyped for replication in an independent sample of 1,030 subjects recruited throughout Germany. The metabolic syndrome was defined via the sum of its core components and, additionally, by a factor score derived from factor analysis. Permutation-based methods were used to test the association between genetic LPIN1 variants and metabolic traits for empirical significance.

RESULTS

Linkage disequilibrium (LD) analysis revealed three LD blocks encompassing LPIN1. We identified three associated three-marker haplotypes: one common haplotype (26.8% frequency) increases the risk for the metabolic syndrome (odds ratio 1.6 [95% CI 1.2-2.2]), while the other two, being less common (5.7 and 4.0%), are strongly associated with lower blood pressure levels (systolic blood pressure 127 +/- 18 vs. 135 +/- 20 mmHg; P = 0.0001), a lower BMI (24.6 +/- 3.6 vs. 26.9 +/- 4.1 kg/m(2); P = 3.7 x 10(-7)) and waist circumference (82 +/- 12 vs. 90 +/- 12 cm; P = 3.2 x 10(-8)), lower A1C levels (5.1 +/- 0.7 vs. 5.3 +/- 0.9%; P = 0.0002), as well as a lower metabolic syndrome factor score (-0.67 +/- 1.00 vs. 0.04 +/- 1.24; P = 1.4 x 10(-7)). Furthermore, the frequencies of arterial hypertension (23.7 vs. 46.4%; P = 0.00001), obesity (12.9 vs. 30.8%; P = 0.0003), diabetes (2.2 vs. 8.2%; P = 0.041), and the presence of three or more metabolic syndrome components (3.3 vs. 13.7%; P = 0.002) were significantly lower than in subjects not carrying one of these protective haplotypes. Strong associations were also observed in the replication sample using the same haplotypes but with effects in the opposite direction. CONCLUSIONS These data suggest that allelic variants of the LPIN1 gene have significant effects in human metabolic traits and thus implicate lipin in the pathophysiology of the metabolic syndrome.

Lack of association between the MEF2A gene and myocardial infarction

BACKGROUND

Coronary artery disease (CAD) and myocardial infarction (MI) are caused in part by genetic factors. Recently, the MEF2A gene was linked to MI/CAD in a single pedigree with autosomal-dominant pattern of inheritance. In addition, genetic variants within the gene have been associated with MI in case-control settings, producing inconsistent results.

METHODS AND RESULTS

The MEF2A gene was sequenced in MI patients from 23 MI families (> or =5 affected members per family), but no mutation was identified in any of these extended families. Moreover, the Pro279Leu variant in exon 7 was analyzed in 1181 unrelated MI patients with a positive family history for MI/CAD, in 533 patients with sporadic MI, and in 2 control populations (n=1021 and n=1055), showing no evidence for association with MI/CAD. In addition, a (CAG)n repeat in exon 11 was genotyped in 543 sporadic MI patients and in 1190 controls without evidence for association with MI. Finally, analyzing 11 single-nucleotide polymorphisms from the GeneChip Mapping 500K Array, genotyped in 1644 controls and 753 cases, failed to provide evidence for association (region-wide P=0.23).

CONCLUSIONS

Studying independent samples of >1700 MI patients, 2 large control populations, and multiple families with apparently mendelian inheritance of the disease, we found no evidence for any linkage or association signal in the MEF2A gene.

Familial aggregation of left main coronary artery disease and future risk of coronary events in asymptomatic siblings of affected patients

AIMS

Recently, we observed in a hypothesis-generating exploratory search on the heritability of coronary morphology that left main coronary disease (LMD) was frequently shared by siblings with coronary artery disease (CAD). Thus, our aims were, first, to test specifically the familial aggregation of LMD and second, to investigate whether LMD is a stronger predictor for future incident events than other manifestations of CAD in seemingly healthy siblings of CAD patients.

METHODS AND RESULTS

Coronary angiograms of 1801 patients (n = 882 from the initial exploratory study and 919 additional angiograms) were analysed from families with > or = 2 affected CAD siblings. We estimated the heritability using the variance-component methodology and sibling recurrent risks by logistic regression analysis. Moreover, we studied 1369 healthy siblings of CAD patients with known coronary morphology who had a subsequent coronary event by conducting a prospective, nested case-control study. LMD-frequency was comparable in our initial exploratory study (11%) and the new sample (12%). The heritability of LMD was significant in the exploratory 48%, P = 0.010, in the subsequent 45%, P = 0.045, and in the total study sample 49%, P = 0.002. The sibling recurrent risk ratio to present with LMD was 3.6 [CI 1.7-7.1] when another sibling was affected by LMD. In the prospective study on initially healthy family members of CAD patients, 79 siblings experienced an event during follow-up. LMD was more frequently found in families with an event than in families without (13.9 vs. 6.4%, P = 0.036). The relative risk for initially asymptomatic siblings of patients with LMD to suffer from a coronary event was 2.5 [CI 1.1-5.8] compared with siblings of patients with other manifestations of CAD.

CONCLUSION

These data confirm our initial observation of familial aggregation of LMD. Moreover, in apparently healthy siblings of patients with LMD, this heritable component results in a risk increase for future events that is greater than that of a strong positive family history by itself.

Association between arterial pressure and coronary artery calcification

OBJECTIVES

Coronary artery calcification (CAC) determined by electron beam computed tomography is a predictor of future cardiovascular events. This study investigates conditions affecting CAC severity in patients with coronary artery disease (CAD) undergoing coronary angiography.

METHODS

Presence and degree of CAC were assessed angiographically in 877 CAD patients grouped into no visible CAC (n = 333), mild to moderate CAC (n = 321), and severe CAC (n = 223). Regression analyses investigated relationships between CAC and demographic data, cardiovascular risk factors, and coronary anatomy.

RESULTS

Prevalences of hypertension and systolic blood pressure (SBP) values were higher in individuals with CAC (moderate CAC: 49.5%, 137.5 +/- 18.6 mmHg; severe CAC: 58.3%, 142.1 +/- 20.4 mmHg) compared to individuals with CAD but no CAC (42.0%, 134.0 +/- 18.4 mmHg; both P < 0.001). Likewise, pulse pressure was significantly elevated with increasing degree of CAC (no CAC, 52.3 +/- 13.6 mmHg vs moderate CAC, 55.7 +/- 14.4 mmHg vs severe CAC, 59.1 +/- 15.4 mmHg; P < 0.001). Further determinants of CAC were age, positive family history for CAC and severity of CAD. No differences in CAC severity were found in relation to body mass index, low-density lipoprotein-cholesterol, diabetes, and smoking habits. In multivariate analysis, CAC was independently related to age, SBP or pulse pressure, respectively, positive family history for CAC, and the severity of CAD.

CONCLUSIONS

Of the cardiovascular risk factors, SBP and pulse pressure display the strongest relationship with angiographic detection of CAC. Mechanistic studies need to clarify whether hypertension causes CAC, or whether coronary calcium deposition serves as a marker for a higher degree of vascular calcification and, thus, impaired vascular compliance and higher blood pressure levels.

Genomewide association analysis of coronary artery disease

BACKGROUND

Modern genotyping platforms permit a systematic search for inherited components of complex diseases. We performed a joint analysis of two genomewide association studies of coronary artery disease.

METHODS

We first identified chromosomal loci that were strongly associated with coronary artery disease in the Wellcome Trust Case Control Consortium (WTCCC) study (which involved 1926 case subjects with coronary artery disease and 2938 controls) and looked for replication in the German MI [Myocardial Infarction] Family Study (which involved 875 case subjects with myocardial infarction and 1644 controls). Data on other single-nucleotide polymorphisms (SNPs) that were significantly associated with coronary artery disease in either study (P<0.001) were then combined to identify additional loci with a high probability of true association. Genotyping in both studies was performed with the use of the GeneChip Human Mapping 500K Array Set (Affymetrix).

RESULTS

Of thousands of chromosomal loci studied, the same locus had the strongest association with coronary artery disease in both the WTCCC and the German studies: chromosome 9p21.3 (SNP, rs1333049) (P=1.80x10(-14) and P=3.40x10(-6), respectively). Overall, the WTCCC study revealed nine loci that were strongly associated with coronary artery disease (P<1.2x10(-5) and less than a 50% chance of being falsely positive). In addition to chromosome 9p21.3, two of these loci were successfully replicated (adjusted P<0.05) in the German study: chromosome 6q25.1 (rs6922269) and chromosome 2q36.3 (rs2943634). The combined analysis of the two studies identified four additional loci significantly associated with coronary artery disease (P<1.3x10(-6)) and a high probability (>80%) of a true association: chromosomes 1p13.3 (rs599839), 1q41 (rs17465637), 10q11.21 (rs501120), and 15q22.33 (rs17228212).

CONCLUSIONS

We identified several genetic loci that, individually and in aggregate, substantially affect the risk of development of coronary artery disease.

Signal transducer of inflammation gp130 modulates atherosclerosis in mice and man

Liver-derived acute phase proteins (APPs) emerged as powerful predictors of cardiovascular disease and cardiovascular events, but their functional role in atherosclerosis remains enigmatic. We report that the gp130 receptor, which is a key component of the inflammatory signaling pathway within hepatocytes, influences the risk of atherosclerosis in a hepatocyte-specific gp130 knockout. Mice on an atherosclerosis-prone genetic background exhibit less aortic atherosclerosis (P < 0.05) with decreased plaque macrophages (P < 0.01). Translating these findings into humans, we show that genetic variation within the human gp130 homologue, interleukin 6 signal transducer (IL6ST), is significantly associated with coronary artery disease (CAD; P < 0.05). We further show a significant association of atherosclerotic disease at the ostium of the coronary arteries (P < 0.005) as a clinically important and heritable subphenotype in a large sample of families with myocardial infarction (MI) and a second independent population–based cohort. Our results reveal a central role of a hepatocyte-specific, gp130-dependent acute phase reaction for plaque development in a murine model of atherosclerosis, and further implicate IL6ST as a genetic susceptibility factor for CAD and MI in humans. Thus, the acute phase reaction should be considered an important target for future drug development in the management of CAD.

The common Y402H variant in complement factor H gene is not associated with susceptibility to myocardial infarction and its related risk factors

Recently, the genetic variant Y402H in the CFH (complement factor H) gene was associated with an increased risk for MI (myocardial infarction) in a prospective Caucasian cohort. In another nested case-control study, however, the CFH-Y402H variant did not carry susceptibility to MI. The aim of the present study was to test for an association between the CFH-Y402H variant and MI in a large case-control sample with a familial background for CAD (coronary artery disease). A total of 2161 individuals from the German MI family study were studied by questionnaire, physical examination and biochemical analyses. MI patients (n=1188; 51.4±8.6 years at first MI) were recruited from families with at least two members affected by MI and/or severe CAD. Spouses, sisters-in-law and brothers-in-law respectively, without MI/CAD were included as unaffected controls (n=973; 56.9±9.8 years). Genotyping was performed using a TaqMan assay. The common Y402H variant in the CFH gene was not associated with classical cardiovascular risk factors (diabetes, hypercholesterolaemia, hypertension, obesity, smoking and C-reactive protein serum levels). No association was found between the CFH-Y402H variant and susceptibility to MI. Separate analyses in both men and women revealed no gender-specific influence of the gene variant on cardiovascular risk factors or MI. This investigation was unable to replicate the association between the common CFH-Y402H variant and susceptibility to MI in our large Caucasian population which is enriched for genetic factors. We conclude that the CFH-Y402H variant has no relevant risk-modifying effect in our population.

A locus on chromosome 10 influences C-reactive protein levels in two independent populations

High sensitivity C-reactive protein (hsCRP) is an independent risk factor for cardiovascular disease, such as stroke or coronary artery disease. Genetic factors influence significantly the inter-individual variability of hsCRP. The aim of this study was to identify genomic regions influencing hsCRP levels. A genome scan was performed in two independent studies of Caucasian populations, namely 513 Western-European families ascertained for myocardial infarction (n = 1,406) and 120 French-Canadian families diagnosed with hypertension (n = 758). In the myocardial infarction families, 31% of the inter-individual variation of hsCRP levels was explained by genetic factors (P = 0.0000015) and loci influencing hsCRP were identified on chromosomes 10 (at 141 cM) and 5 (at 150 cM) with multipoint LOD scores of 3.15 and 2.23, respectively. An additional suggestive signal was detected on chromosome 2 in subset analyses. A similar degree of heritability has been observed in a second independent population of French-Canadian hypertensive families for hsCRP (30%) and linkage results for chromosome 10 were confirmed with maximum LOD score of 2.7. We identified a chromosomal region in two independent populations which influences hsCRP in addition to several unique regions. This provides targets for the identification of genes involved in the regulation of hsCRP and the development and progression of vascular disease, including stroke.

Lymphotoxin-alpha and galectin-2 SNPs are not associated with myocardial infarction in two different German populations

Recent data provided strong evidence for the association of single nucleotide polymorphisms (SNPs) in the lymphotoxin-alpha (LTA) and galectin-2 (LGALS2) genes with myocardial infarction (MI) in a Japanese population. For populations of other genetic background, the relevance of these polymorphisms in the pathogenesis of MI remains controversial. We aimed to define the role of LTA and LGALS2 SNPs in two German MI populations with markedly different ascertainment strategies. Two different MI populations were studied. In the first population, MI patients were ascertained by a strong family history of MI (n = 1214). Controls were unrelated disease-free participants of the study (n = 1080). The second population included patients suffering from sporadic (nonfamilial) MI from the German KORA register (n = 607). The control group consisted of participants of the WHO MONICA survey in Germany (n = 1492). TaqMan assays were used to determine the genotypes of 4 SNPs in the LTA genomic region and 1 SNP in the LGALS2 gene. Single SNPs in both genomic regions as well as haplotypes in the LTA genomic region were tested for association in various models of inheritance. No association with MI could be found for any of the examined SNPs in the LTA genomic region and LGALS2 gene, or for haplotypes spanning the LTA genomic region. In two MI populations of European descent with markedly different ascertainment strategies, we were not able to identify a significant association of SNPs in the LTA genomic region or the LGALS2 gene with MI. These variants are unlikely to play a significant role in populations of European origin.

Epistatic interaction between haplotypes of the ghrelin ligand and receptor genes influence susceptibility to myocardial infarction and coronary artery disease

Data from both experimental models and humans provide evidence that ghrelin and its receptor, the growth hormone secretagogue receptor (ghrelin receptor, GHSR), possess a variety of cardiovascular effects. Thus, we hypothesized that genetic variants within the ghrelin system (ligand ghrelin and its receptor GHSR) are associated with susceptibility to myocardial infarction (MI) and coronary artery disease (CAD). Seven single nucleotide polymorphisms (SNPs) covering the GHSR region as well as eight SNPs across the ghrelin gene (GHRL) region were genotyped in index MI patients (864 Caucasians, 'index MI cases') from the German MI family study and in matched controls without evidence of CAD (864 Caucasians, 'controls', MONICA Augsburg). In addition, siblings of these MI patients with documented severe CAD (826 'affected sibs') were matched likewise with controls (n = 826 Caucasian 'controls') and used for verification. The effect of interactions between genetic variants of both genes of the ghrelin system was explored by conditional classification tree models. We found association of several GHSR SNPs with MI [best SNP odds ratio (OR) 1.7 (1.2-2.5); P = 0.002] using a recessive model. Moreover, we identified a common GHSR haplotype which significantly increases the risk for MI [multivariate adjusted OR for homozygous carriers 1.6 (1.1-2.5) and CAD OR 1.6 (1.1-2.5)]. In contrast, no relationship between genetic variants and the disease could be revealed for GHRL. However, the increase in MI/CAD frequency related to the susceptible GHSR haplotype was abolished when it coincided with a common GHRL haplotype. Multivariate adjustments as well as permutation-based methods conveyed the same results. These data are the first to demonstrate an association of SNPs and haplotypes within important genes of the ghrelin system and the susceptibility to MI, whereas association with MI/CAD could be identified for genetic variants across GHSR, no relationship could be revealed for GHRL itself. However, we found an effect of GHRL dependent upon the presence of a common, MI and CAD susceptible haplotype of GHSR. Thus, our data suggest that specific haplotypes of the ghrelin ligand and its receptor act epistatically to affect susceptibility or tolerance to MI and/or CAD.

Association of a functional polymorphism in the CYP4A11 gene with systolic blood pressure in survivors of myocardial infarction

OBJECTIVE

Survivors of myocardial infarction (MI) are known to have a high prevalence of arterial hypertension which, at the same time, imposes a major risk to such patients. Genetic variants of the arachidonic acid monooxygenase CYP4A11 may result in decreased synthesis of 20-hydroxyeicostatetraenoic acid (20-HETE), experimental hypertension and elevated blood pressure levels in humans. The present study aimed to investigate the impact of the functionally relevant T8590C polymorphism of this gene on blood pressure and the prevalence of hypertension in MI patients.

METHODS

Survivors of MI from the MONICA Augsburg MI registry (n = 560) were studied after a mean of 5.6 years after the acute event. Participants were examined by standardized anthropometric and echocardiographic measurements, as well as genotyping for CYP4A11 T8590C allele status.

RESULTS

Genotype frequencies in MI patients (TT = 71.8%, CT = 26.2%, CC = 2.0%) did not differ from those in population-based controls (n = 1363; TT = 75.4%, CT = 22.5% and CC = 2.1%, P = 0.22). MI survivors with the CC genotype displayed higher systolic blood pressure levels (CC: 143.4 +/- 4.9 mmHg versus CT: 134.5 +/- 1.3 mmHg and TT: 131.1 +/- 0.8 mmHg; P = 0.02) and a non-significant trend towards higher diastolic blood pressure levels (CC: 88.4 +/- 3.0 mmHg versus CT: 84.9 +/- 0.8 mmHg and TT: 83.9 +/- 0.5 mmHg; P = 0.17) in multivariate models. Accordingly, the C allele was related to elevated odds ratios for hypertension in a recessive [4.14; 95% confidence interval (CI) = 1.07-15.96, P = 0.04] and in a dominant model (1.50; 95% CI = 1.03-2.20, P = 0.04), respectively. No blood pressure-independent association of the T8590C polymorphism with echocardiographic parameters of left ventricular function and/or geometry was found.

CONCLUSION

The data obtained in the present study strengthen the evidence of an association of the CYP4A11 T8590C polymorphism with blood pressure levels and hypertension prevalence. Particularly, the risk of arterial hypertension is substantially higher in MI patients homozygous for the CC allele. By contrast, no evidence was obtained for an association between this genotype and MI.

Impact of Diabetes on QT Dynamicity in Patients With and Without Myocardial Infarction: The KORA Family Heart Study

INTRODUCTION

Patients with diabetes mellitus (DM) have an unfavorable prognosis after myocardial infarction (MI), partially due to a higher risk of sudden cardiac death (SCD). QT dynamicity is an independent predictor of SCD in post-MI patients. However, the effects of diabetes on QT dynamicity in patients with MI have not been described.

METHODS

We studied 468 survivors of MI (67 with DM) from the population-based MONICA registry (KORA Family Heart Study), Augsburg, Germany, by standardized questionnaire, anthropometry, electrocardiogram (ECG), 30-minute-Holter-ECG-recordings and echocardiography. In addition, 422 siblings without prior MI (22 with DM) were studied by the same protocol.

RESULTS

Among post-MI patients, the QT/RR slope was significantly steeper in diabetics than in nondiabetics (0.096 +/- 0.057 vs 0.077 +/- 0.045; P = 0.002). Likewise, among siblings without MI, the QT/RR slope was steeper in diabetics than in nondiabetics (0.104 +/- 0.053 vs 0.080 +/- 0.042; P = 0.008). The association of DM with steeper QT/RR slope remained significant in multivariate models in post-MI patients (beta: -0.14; P = 0.004) as well as in individuals without MI (beta: -0.10; P = 0.047).

CONCLUSIONS

In a large population of survivors of MI and unaffected siblings, patients and siblings presenting with DM exhibited an abnormal QT rate-dependence, compared with individuals without DM in both groups. Thus, diabetes itself may be a major determinant of ventricular arrhythmias, independently of a previous MI. These observations might in part explain the higher incidence of sudden cardiac death and ventricular arrhythmias in patients with DM.

IL6 gene promoter polymorphisms and type 2 diabetes: joint analysis of individual participants' data from 21 studies

Several lines of evidence indicate a causal role of the cytokine interleukin (IL)-6 in the development of type 2 diabetes in humans. Two common polymorphisms in the promoter of the IL-6 encoding gene IL6, -174G>C (rs1800795) and -573G>C (rs1800796), have been investigated for association with type 2 diabetes in numerous studies but with results that have been largely equivocal. To clarify the relationship between the two IL6 variants and type 2 diabetes, we analyzed individual data on >20,000 participants from 21 published and unpublished studies. Collected data represent eight different countries, making this the largest association analysis for type 2 diabetes reported to date. The GC and CC genotypes of IL6 -174G>C were associated with a decreased risk of type 2 diabetes (odds ratio 0.91, P = 0.037), corresponding to a risk modification of nearly 9%. No evidence for association was found between IL6 -573G>C and type 2 diabetes. The observed association of the IL6 -174 C-allele with a reduced risk of type 2 diabetes provides further evidence for the hypothesis that immune mediators are causally related to type 2 diabetes; however, because the association is borderline significant, additional data are still needed to confirm this finding.

Association of the Ghrelin Receptor Gene Region With Left Ventricular Hypertrophy in the General Population

Growth hormone (GH) can influence left ventricular myocardial growth, structure, and function. The GH secretagogue receptor (GHSR, ghrelin receptor) is known to be involved in GH release and is expressed in the myocardium. We hypothesized that genetic variants within the GHSR are associated with parameters of left ventricular mass (LVM) and geometry. Ten single-nucleotide polymorphisms (SNPs) covering the gene region were genotyped in 1230 members of the general population (Monitoring Trends and Determinants on Cardiovascular Diseases Augsburg Echocardiographic Substudy). Linkage disequilibrium analysis revealed a linkage disequilibrium block consisting of 5 SNPs forming 2 common haplotypes. One haplotype was found significantly more often in subjects without left ventricular hypertrophy ([LVH] 69% versus 59%; permutated P =0.0015), whereas the second haplotype was significantly more frequent in individuals with LVH (32% versus 26%; P =0.019). Homozygous subjects presented with an increase of risk with respect to all heart size parameters. A significantly increasing frequency of the risk haplotype could be observed from the lowest (20.9%) to the highest quintile (31.0%) of gender-specific LVM distributions ( P =0.0096). We found association of the minor alleles of individual single nucleotide polymorphisms contributing to the haplotypes with higher LVM indices, septal wall thickness, and different LVH criteria consistent in men and women in matched cases and controls (LVM, women: 144.8±30.9 [noncarrier] versus 171.3±36.0 [homozygous], P =0.001; men: 186.7±42.4 versus 236.3±64.5, P =0.002). These data suggest that common variants in the GHSR region are associated with parameters of LVM and geometry independent of blood pressure and body mass in the general population and, thus, may be involved in the pathogenesis of LVH.

Association of the metabolic syndrome with early coronary disease in families with frequent myocardial infarction

This study examined the extent to which the metabolic syndrome (MS) augments the risk for major cardiovascular events in healthy patients with a strong genetic background for coronary artery disease (CAD). In a prospective cohort study, we examined 1,316 patients without previously diagnosed CAD or diabetes mellitus. Patients were participants of the Regensburg Myocardial Infarction Family Study, in which > or = 2 family members had severe CAD and 1 had myocardial infarction (MI) at < 60 years of age. During a 2-year follow-up, the incidence of first cardiovascular events (MI, revascularization, and cardiac death) was compared between those with and without the MS at baseline. In all previously unaffected family members, the presence of MS increased the hazard ratio for first manifestation of CAD by a factor of 1.9 (p = 0.030), which resulted in an event rate of 7.1% during follow-up. Specifically in young patients (< or = 50 years old, n = 422), we identified the MS as a major event predictor that conferred a 5.8-fold increased relative risk for first cardiovascular events compared with patients without the MS (95% confidence interval 1.4 to 23.8, p = 0.015, event rate 6.2%). Remarkably, of the individual MS components, obesity was strongly associated with incident MI (relative risk 4.4, 95% confidence interval 1.5 to 13.0, p = 0.007). Thus, the MS strongly predicts cardiac morbidity and mortality in healthy patients with a family background of CAD.

Association of angiotensin-converting enzyme 2 (ACE2) gene polymorphisms with parameters of left ventricular hypertrophy in men. Results of the MONICA Augsburg echocardiographic substudy

Angiotensin-converting enzyme (ACE) activity is considered to be of major importance for the conversion of angiotensin (Ang) I to Ang II. Recently, a second ACE, named ACE2, has been identified. Experimental data provide evidence that ACE2 might be involved in modulating cardiac structure and function. In the present explorative study, we assessed whether polymorphisms in the ACE2 gene are related to echocardiographically determined parameters of left ventricular mass, structure or function in the general population. Five intronic single nucleotide polymorphisms (SNPs) were genotyped using the 5'-exonuclease activity (TaqMan) assay in the echocardiographic substudy of the third MONICA Augsburg survey. As ACE2 is located on the X chromosome, women and men were analysed separately. Four SNPs showed high pairwise linkage disequilibrium (rs4646156, rs879922, rs4240157 and rs233575). The minor alleles of these four SNPs were associated with higher left ventricular mass index (LVMI) and higher septal wall thickness (SWT) in men. Likewise, male carriers of a common haplotype (frequency 29.9%) consisting of the minor alleles of these four SNPs displayed higher values for LVMI and SWT than non-carriers (LVMI: TGGC 98.8+/-1.52 vs non-TGGC 94.8+/-0.99 g/m(2), p=0.027; SWT: TGGC 11.5+/-0.14 vs non-TGGC 11.1+/-0.09 mm, p=0.019). Furthermore, this haplotype was associated with an increased odds ratio (OR) for left ventricular hypertrophy (OR 3.10, p=0.006). In women, similar but less pronounced and consistent trends were observed. No association was observed between any of these SNPs and parameters of left ventricular systolic or diastolic function nor with blood pressure levels. This study provides evidence that genetic variants in the ACE2 gene may be associated with left ventricular mass, SWT and left ventricular hypertrophy in hemizygous men.

Cardiovascular phenotypes and functional parameters in the general population--results of the MONICA/KORA studies

The MONICA/KORA surveys are characterized by a careful and broad investigation of multiple cardiovascular phenotypes. Particularly, repeated blinded measurements of blood pressure, comprehensive echocardiographic and electrocardiographic evaluations as well as differentiation between fat and fat-free body mass have led to manifold innovative observations. Specifically, genetic and serological markers of the renin angiotensin system could be associated with high blood pressure and left ventricular hypertrophy. The same applies to the importance of parameters of body composition as obesity and muscular mass. Moreover, the prevalence of heart failure in the general population could be determined for the first time in Germany. Additionally, the prevalence of left ventricular systolic and diastolic dysfunction could be obtained in the region of the survey, exemplarily for the Federal Republic of Germany. Finally, the surveys of the population random sample were used to define normal serum levels of natriuretic peptides. In summary, the evaluation of cardiovascular phenotypes in the MONICA/KORA surveys resulted in a -- in the European region unique -- documentation of cardiovascular functional parameters in the general population. Moreover, multiple epidemiological observations as to pathophysiologically relevant topics of heart and vascular diseases could be studied in extraordinary details.

Association of the T8590C polymorphism of CYP4A11 with hypertension in the MONICA Augsburg echocardiographic substudy

Genetic variants of the arachidonic acid monooxygenase CYP4A11 result in decreased synthesis of 20-hydroxyeicostatetraenoic acid and experimental hypertension. Moreover, in humans, the T8590C polymorphism of CYP4A11 displayed association with arterial hypertension. The aim of the present study was to further investigate this association in a large population-based sample. Therefore, the participants of the echocardiographic substudy of the third MONICA (MONitoring trends and determinants In CArdiovascular disease) survey (n=1397) were studied by standardized anthropometric, echocardiographic, and biochemical measurements as well as genotyping for CYP4A11 T8590C allele status. Individuals with the CC genotype have higher systolic (CC 141.4+/-3.17 mm Hg versus CT 134.2+/-0.97 mm Hg and TT 134.3+/-0.53 mm Hg; P=0.03) and diastolic blood pressure levels (CC 85.4+/-2.06 mm Hg versus CT 80.3+/-0.63 mm Hg and TT 80.7+/-0.34 mm Hg; P=0.02). Accordingly, the odds ratio (adjusted for age, body mass index, and gender) of the CC genotype versus the CT and TT genotypes for hypertension was 3.31 (95% confidence interval [CI]), 1.38 to 7.96; P=0.016) in the entire study population, with similar trends in men (4.30 [95% CI, 1.08 to 17.15]) and women (2.93 [95% CI, 0.88 to 9.84]). Consistent with the renal effects of the gene, no blood pressure-independent association between the T8590C polymorphism and echocardiographic parameters of left ventricular function and geometry was found. In conclusion, our data strengthen the association between the T8590C polymorphism of CYP4A11 and hypertension and suggest a recessive mode of inheritance. In contrast, we found no blood pressure-independent modulatory effect of CYP4A11 T8590C on cardiac size, structure, and function.

Functional improvement in heart failure patients treated with beta-blockers is associated with a decline of cytokine levels

BACKGROUND

In patients with severe heart failure (CHF), chronically elevated cytokine levels document a systemic inflammation. Experimental data suggest that activation of the beta-adrenergic system may participate in this inflammatory response. Herein, we studied as to whether beta-adrenergic blockade on top of standard CHF therapy affects plasma cytokine levels (interleukin-6 [IL-6] and tumor necrosis factor alpha [TNFalpha]). Moreover, we studied if beta-blocker related changes of these cytokines correspond to changes in left ventricular (LV) function and exercise capacity.

METHODS

In a prospective study, 21 patients with stable CHF (NYHA functional class II-III, ejection fraction <40%, mean age 57.6+/-12.4 years) were treated with captopril (100-150 mg/day), furosemide (40-120 mg/day), and/or digoxin (0.1-0.2 mg/day) for at least 1 month before they entered a 4 week run-in period in which dosages were kept unchanged. Metoprololsuccinate was administered in increasing dosages (up to 190 mg/day) for the following 3 months. Clinical, echocardiographic, spiroergometric, and biochemical changes were assessed at the start and the end of the run-in period as well as after 3 month of beta-blockade.

RESULTS

As compared to 210 healthy volunteers, CHF patients, prior to beta-blockade, presented with markedly elevated IL-6 (8.9+/-9.9 vs. 2.1+/-0.5 pg/ml; p<0.05) and TNFalpha levels (1.51+/-0.49 vs. 0.64+/-0.15 pg/ml; p<0.05) levels. In CHF patients, 3 month of beta-blockade lowered heart rate (84+/-14 vs. 68+/-12 bpm; p<0.01), systolic (131+/-7 vs. 118+/-6 mm Hg; p<0.01), and diastolic blood pressure (78+/-5 vs. 71+/-6 mm Hg; p<0.01). Spiroergometric determined VO2 max (17.8+/-4.5 vs. 19.8+/-4.3 ml/min kg; p=0.013) increased significantly during 3 month of beta-blockade. Moreover, LV functional parameters tended to improve but the interindividual response varied and changes were non-significant. Interestingly, IL-6 levels decreased markedly during beta-blockade (8.9+/-9.9 vs. 4.5+/-3.1 pg/ml; p=0.036), whereas TNFalpha levels remained unchanged. Moreover, significant positive correlations were found between decrease of IL-6 levels and left ventricular end diastolic diameters (r2=0.59; p=0.012), whereas an inverse correlation was found between the decrease of IL-6 and the increase of VO2 max (r2=0.54; p=0.037), respectively.

CONCLUSION

In heart failure patients, beta-blockade may lower IL-6 but not TNFalpha levels. Changes of IL-6 during beta-blockade may be related to changes of LV function and geometry.

Effect of Compensated Renal Dysfunction on Approved Heart Failure Markers

Brain natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP) are markers of heart failure. Although renal dysfunction may increase plasma concentrations, the magnitude of this effect has not been assessed in a head-to-head comparison between the clinically approved tests. We assessed the effect of compensated renal dysfunction on BNP (Triage BNP; Biosite) and NT-proBNP (elecsys proBNP; Roche) in 469 randomly selected stable outpatients after myocardial infarction (MI; Monitoring Trends and Determinants in Cardiovascular Diseases [MONICA] register Augsburg) who were characterized with respect to renal function (glomerular filtration rate [GFR]; Cockroft method) and left ventricular (LV) ejection fraction (EF) and mass (2D echocardiography). BNP and NT-proBNP were elevated in MI patients with LV dysfunction (LVD; EF <35%) compared with MI patients with preserved EF (>45%; BNP 139±27 pg/mL versus 75±6; NT-proBNP 816±237 pg/mL versus 243±20; both P <0.03). Among all MI patients, the prevalence of renal dysfunction (GFR <85 mL/min) was 24%. BNP and NT-proBNP were significantly elevated in MI patients with renal dysfunction (BNP 132±17 pg/mL versus 68±4 without renal dysfunction; NT-proBNP 535±80 pg/mL versus 232±19; both P <0.05), and both markers were correlated with GFR in univariate and multivariate analyses (all P <0.01). When binary cut-off values were stratified according to the absence or presence of renal dysfunction (BNP 75 pg/mL and 125 pg/mL, respectively; NT-proBNP 100 pg/mL and 350pg/mL, respectively), the predictive power of both markers for the detection of LVD increased substantially. BNP and NT-proBNP are almost similarly influenced by mild-to-moderate renal dysfunction. Renal dysfunction is a potential cause of elevated marker concentrations in the absence of LVD, and cut-off concentrations should be stratified according to renal function.

NT-ProBNP in Outpatients After Myocardial Infarction: Interaction Between Symptoms and Left Ventricular Function and Optimized Cut-Points

BACKGROUND

N-terminal pro-brain natriuretic peptide (NT-proBNP) allows us to rule out left ventricular dysfunction (LVD) in the general population at a recommended cut-off concentration of 125 pg/mL. It was our objective to reassess this cut-point in outpatients after myocardial infarction.

METHODS AND RESULTS

NT-proBNP was assessed in 418 randomly selected outpatients who had experienced myocardial infarction and 352 siblings who had not experienced myocardial infarction (control). Left ventricular ejection fraction (LVEF) and mass-index (LVMI) were assessed by echocardiography. NT-proBNP was elevated in outpatients after myocardial infarction (mean [+/-SEM], 305 +/- 25 pg/mL vs control, 84 +/- 8 pg/mL; P < .01) and was correlated inversely with LVEF ( P < .001). When patients were stratified according to the presence or absence of heart failure, NT-proBNP was elevated significantly throughout all LVEF strata (each P < .05). On regression analysis, NT-proBNP was correlated independently with LVEF, LVMI, heart failure, and glomerular filtration rate (all P < .01). In patients with heart failure, the optimal cut-point for the detection of an LVEF <35% was 348 pg/mL (sensitivity 80%; specificity 69%) and for the detection of an LVEF <45% was 260 pg/mL (sensitivity 60%; specificity 60%). The relative risk for LVD in the presence of elevated NT-proBNP increased from 2.7 to 7.7 (EF < 35%) and from 1.4 to 2.4 (EF < 45%) when these cut-points were applied instead of the 125 pg/mL cut-point. An LVEF of <35% could be ruled out in symptomatic outpatients after myocardial infarction with a negative predictive value of 97% (cut-point 348 pg/mL) and in asymptomatic outpatients after myocardial infarction with a negative predictive value of 98% (cut-point 157 pg/mL).

CONCLUSION

NT-proBNP is higher in outpatients after myocardial infarction than in the general population. In symptomatic patients, a cut-point of 348 pg/mL yields satisfactory sensitivity and specificity for the detection of significant LVD (EF < 35%). Furthermore, significant LVD can be virtually ruled out in symptomatic and asymptomatic outpatients after myocardial infarction at below-threshold concentrations.

Failure to achieve recommended LDL cholesterol levels by suboptimal statin therapy relates to elevated cardiac event rates

OBJECTIVES

The majority of patients with myocardial infarction (MI) and hypercholesterolaemia does not achieve guideline recommended low-density lipoprotein cholesterol (LDL) levels. Suboptimal dosages of statins explain this dilemma in most patients.

DESIGN AND SETTING

We evaluated the relationship between statin treatment quality (optimal: LDL<115 mg/dl, suboptimal: LDL>/=115 mg/dl, no statin therapy despite hypercholesterolaemia) and the subsequent incidence of coronary events (coronary death, nonfatal MI, bypass surgery) over a 30 months follow-up in a large cohort of post MI patients with hypercholesterolaemia (n=2045). Analysis was performed in a nested case-control manner comparing 173 cases with a coronary event and 346 matched controls.

RESULTS

Patients who developed a coronary event were treated optimally in 11.0%, suboptimally in 43.4% (p<0.05 vs. optimal treatment) and were untreated in 45.7% (p<0.001 vs. optimal treatment). Respective numbers in event-free patients were 21.4%, 47.7%, and 30.9%. After adjustment for most potential confounders, including all cardiovascular risk factors and medication, the relative risk of future non-fatal MI and coronary death associated with a suboptimal statin treatment was 2.02 (95% CI 1.04 to 4.18) compared to optimal statin treatment. Moreover, the statin equivalent dose in optimally treated individuals was significantly higher than in suboptimally treated individuals (0.85+/-0.03 vs. 0.78+/-0.02, p<0.05).

CONCLUSION

In this community-based study, a lipid lowering therapy with statins into the recommended target range of LDL levels may be associated with decreased cardiovascular risk compared to a statin therapy without titrating the LDL level below 115 mg/dl. Thus, the quality of statin treatment was identified as an independent predictor of coronary events in post MI patients.

Distinct Heritable Patterns of Angiographic Coronary Artery Disease in Families With Myocardial Infarction

BACKGROUND

Coronary artery disease (CAD) and myocardial infarction (MI) are significantly determined by genetic background. Whether distinct angiographic features of CAD are affected by inherited factors has never been investigated. Thus, we analyzed comprehensively the extent to which various aspects of CAD, including disease severity, distribution of lesions, presence of coronary calcification, morphology of stenoses, and anatomic characteristics, are under genetic control.

METHODS AND RESULTS

We retrospectively studied the coronary angiograms of 882 siblings with CAD from 401 families. These families were ascertained through index patients defined by MI before the age of 60 years and at least 1 sibling with MI or coronary revascularization procedures. Heritability calculations were performed with variance-component analysis. Additionally, recurrence risks to siblings were analyzed. Traditional cardiovascular risk factors and age at the first coronary event displayed significant heritable components. After adjustment for age and sex, significant heritabilities were identified for proximal stenoses, in particular, left main CAD (h2=0.49+/-0.12; P=0.01), coronary calcification (h2=0.51+/-0.17; P=0.001), and ectatic coronary lesions (h2=0.52+/-0.07; P=0.001). In contrast, no heritability was found for distal disease (h2=0.05+/-0.19; NS), the pattern of coronary arterial blood supply, or the number of diseased vessels. Calculation of recurrence risks in siblings largely confirmed the heritability estimates.

CONCLUSIONS

Distinct morphological characteristics associated with CAD show different degrees of heritability. Notably, the most hazardous localizations, like left main or proximal disease, display a high heritability. In contrast, some features of coronary morphology, such as distal disease, do not appear to be markedly influenced by heritable factors.

Sudden cardiac death in myotonic dystrophy type 2

Medical records and follow-up data were reviewed in 297 genetically proven myotonic dystrophy type 2 (DM2) patients. Patients were selected by the criteria of cardiac sudden death before age 45. Sudden death occurred in four patients, three of whom were cardiological asymptomatic, and one with a history of heart failure. Cardiac histopathology showed dilated cardiomyopathy in all, and conduction system fibrosis in two patients. Pathogenetic CCUG ribonuclear inclusions were demonstrable in cardiomyocytes.

No association of interleukin-6 gene polymorphism (−174 G/C) with myocardial infarction or traditional cardiovascular risk factors

BACKGROUND

Recently, a polymorphism at position -174 (G>C) of the interleukin-6 (IL-6) promoter was found to be associated with an increased prevalence of myocardial infarction (MI). The aim of the present study was to further investigate the association of the IL-6 -174 G/C allele status with specific end organ damage, i.e. myocardial infarction in large population-based samples.

METHODS

Individuals from two Bavarian samples of MI patients (total n=1322) and the population-based Augsburg MONICA survey (1023 unselected controls) were studied by questionnaire, physical examination, echocardiographical assessment and biochemical analyses. The -174 G/C polymorphism was genotyped using a newly established PCR-RFLP. IL-6 levels were measured in a subset of 574 MI patients.

RESULTS

In the population-based sample, the IL-6 genotype was neither associated with traditional cardiovascular risk factors (systolic and diastolic blood pressure, total cholesterol, HDL and LDL cholesterol, body mass index, diabetes mellitus) nor with cardiac structural or functional parameters (left ventricular mass index, ejection fraction, diastolic inflow pattern). Moreover, the genotype distribution of the -174 G/C polymorphism was not different in MI patients (GG: 34.1%; GC: 47.4%; CC: 18.5%) and population-based controls (GG: 32.4%; GC: 48.8%; CC: 18.9%) (p=0.67). IL-6 levels were neither related to the -174 G/C polymorphism (p=0.29) nor to ACE-inhibitor treatment (2.16 with vs. 2.09 pg/ml without ACE-inhibitor, p=0.27). However, patients receiving statins displayed significantly lower IL-6 levels (1.83 vs. 2.32 pg/ml in the group without statins, p<0.0001).

CONCLUSIONS

This extensive investigation failed to obtain evidence that the IL-6 -174 G/C promoter polymorphism affects traditional cardiovascular risk factors or the prevalence of myocardial infarction in a Caucasian sample.

Lack of association of a 9 bp insertion/deletion polymorphism within the bradykinin 2 receptor gene with myocardial infarction

The BK (bradykinin) B2 receptor is the major cellular mediator of the effects of BK. A 9 bp deletion in the promoter of the receptor gene represents an allelic variant that is associated with enhanced mRNA expression levels. We tested whether this polymorphism is associated with the prevalence of MI (myocardial infarction) or with echocardiographically determined left ventricular function in post-MI patients. Patients with documented MI (n=484), matched controls and controls without evidence of coronary heart disease (n=1363) constituted cases and controls. MI patients and controls were carefully matched for age, gender and cardiovascular risk factors. Genotype distributions of the 9 bp insertion/deletion polymorphism were similar across the groups: −9/−9, −9/+9 and +9/+9 were 22.1, 49.5 and 28.5% in MI patients, and 23.0, 44.6 and 32.5% in matched control subjects respectively. The lack of association was also observed in selected subgroups, stratified by age, gender and cardiovascular risk factors. Furthermore, there was no relation between this polymorphism and left ventricular systolic function in post-MI patients. These findings indicate that the 9 bp insertion/deletion polymorphism of the BK B2 receptor gene is neither related to the prevalence of MI nor to left ventricular function after MI.

Association of the heart rate turbulence with classic risk stratification parameters in postmyocardial infarction patients

The heart rate turbulence (HRT) parameters were introduced for risk stratification of ventricular arrhythmias in postmyocardial infarction patients. However, the relationship of these parameters with other risk stratificators such as heart rate variability (HRV), repolarization parameters or left ventricular function is unknown. Furthermore, the influence of age and medication on HRT remains to be evaluated. Holter ECG's of 509 post-MI patients (1-10 years after MI) were screened for single ventricular extrasystole. In 196 patients the parameters' turbulence onset (TO) and turbulence slope (TS) could be computed. A pathological TO (>0%) and TS (<2.5 ms) was found in 58 and 54 patients, respectively. HRT was not related to gender, but was correlated with age (TS: r = 0.209, P < 0.01). No relationship was observed between QT interval, QTc interval or QT dispersion and HRT parameters. Individuals with a pathological HRT showed decreased HRV values (e.g., PNN50: 2.8 vs. 11.5; P < 0.001). Of all MI patients with systolic left ventricular dysfunction (EF < 45%, n = 46), 18 showed a pathological TO (39%) compared to 34 out of 142 patients (24%) with an EF > 45%. In contrast, the percentage of pathological HRT was not different between patients with left ventricular hypertrophy (16 out of 59, 27%) compared to patients without LVH (38 out of 133, 28%). The HRT was pathological in 14 out of 24 patients with diabetes mellitus (58%) compared to 40 out of 172 (23%) normoglycemic patients (TO: -0.6 +/- 3.1 vs. -2.5 +/- 5.5, P < 0.02). HRT was similar in patients with ss-blockers (n = 96) as in patients without ss-blockers (n = 100). In stable post-MI patients, HRT is influenced by age and left ventricular function and correlates with heart rate variability. Therapy with ss-blockers has no influence on HRT, while diabetic patients may have an increased likelihood of pathological HRT.

KCNJ11 polymorphisms and sudden cardiac death in patients with acute myocardial infarction

PURPOSE

Patients with an acute myocardial infarction (AMI) are of high risk to develop ischemia-induced ventricular arrhythmias, leading to sudden cardiac death (SCD) in about one third of all AMI patients. The individual susceptibility to ischemia-induced arrhythmias may be modified by polymorphisms in genes encoding ion channels. The cardiac ATP-dependent potassium channel (K(ATP)) current is generated by ion channels encoded by the KCNJ11 gene and the SUR2a gene. Opening of the K(ATP) channel during ischemia results in action potential shortening in various studies and may therefore influence the outcome of AMI patients.

METHODS

Using a three-primer strategy, we sequenced the complete coding and adjacent 5' and 3' sequences of the intronless KCNJ11 gene (1.3 kb) prospectively in two groups. Patients of group 1 (n = 84) survived three or more transmyocardial infarctions without developing any ventricular arrhythmias. Patients of group 2 died suddenly from their first myocardial infarction (n = 86), most of them witnessed SCDs.

RESULTS

We identified a total of six known polymorphisms (K23E, A190A, L267V, L270V, I337V, and K281K) and two new polymorphisms (L267L, 3'UTR +62 G/A). The allele, genotype, and haplotype frequencies did not differ between the two groups. All polymorphisms were found to be in Hardy-Weinberg equilibrium. In addition, we identified two novel missense mutations in a highly conserved region of the gene in two patients of group 2 (P266T and R371H) with yet unknown functional consequences.

CONCLUSION

In this study of AMI patients, SCD was not related to polymorphisms in the KCNJ11 gene.

Cardiovascular risk factors and estimated risk for CAD in a randomized trial comparing calcineurin inhibitors in renal transplantation

Cardiovascular morbidity and mortality is high in patients following renal transplantation. The present analysis assessed major cardiovascular risk factors and estimated the risk of coronary artery disease in the largest present-day comparative trial of tacrolimus vs. microemulsified cyclosporine A. In this 6-month study, 557 patients were randomly allocated to therapy with tacrolimus (n = 286) or cyclosporine A (n = 271) concomitantly with azathioprine and corticosteroids. The primary endpoint was the incidence of and time to acute rejection. Blood pressure, serum cholesterol, HDL cholesterol, triglycerides, and blood glucose were measured at baseline, and at months 1, 3, and 6. Ten-year risk of coronary heart disease was estimated according to the Framingham risk algorithm. Tacrolimus resulted in significantly lower summary measures (time-weighted average) of serum cholesterol (p = 0.0004) and mean arterial blood pressure (p = 0.0156), but in a higher summary measure of blood glucose (p = 0.0028) than cyclosporine. The summary measure of serum triglycerides was not different between treatment groups (p = 0.368). The mean 10-year coronary artery disease risk estimate was significantly lowered in men (p = 0.0032) treated with tacrolimus, but was unchanged in women. Tacrolimus and cyclosporine A microemulsion exert a compound-specific impact on cardiovascular risk factors and appear to affect the predicted rate of cardiovascular morbidity in different manners.

Angiotensin converting enzyme gene polymorphism and myocardial infarction a large association and linkage study

The DD genotype of the angiotensin converting enzyme (ACE) polymorphism has been associated with myocardial infarction (MI). However, sample sizes of many case-control studies showing positive association were small and data were inconsistent. Furthermore, no family-based study is available. In a case-control study frequencies of the ACE genotypes were compared in 1319 unrelated patients with previous MI before 60 years of age (616 from the MONICA Augsburg region and 703 from rehabilitation centers in south Germany) and in 2381 population controls from the MONICA Augsburg study region). Furthermore, linkage and association of the ACE I/D polymorphism with MI were tested in 246 informative families using the sib-transmission/disequilibrium test (S-TDT).Overall, no excess of the D allele was found in MI patients (frequency 0.53 versus 0.57 in the general population; P=0.2). The ACE DD genotype was even slightly less frequent in groups with MI compared to the general population controls (0.26 versus 0.33 in women and 0.28 versus 0.33 in men). Similar results were also obtained in 247 men with low cardiovascular risk. In the family-based study, the frequency of the D allele was not different in siblings with or without previous MI (0.53 versus 0.50, respectively; S-TDT P=0.15) indicating no linkage or association of the D allele with MI. In a case-control study of MI patients and controls from the general population as well as a family study neither association nor linkage of the ACE D allele with MI was detected despite sample sizes that were among the largest samples studied so far.

Association of polymorphisms of the apolipoprotein(a) gene with lipoprotein(a) levels and myocardial infarction

BACKGROUND

Serum lipoprotein(a) [Lp(a)] concentration is largely determined by variability at the apolipoprotein(a) gene locus. Most prominent effects relate to polymorphisms in the promoter (a pentanucleotide [PN] repeat) and coding regions (a kringle IV [K4] repeat), the latter of which also affects Lp(a) particle size. The impact of these polymorphisms on cardiovascular risk is poorly understood.

METHODS AND RESULTS

We studied both polymorphisms and Lp(a) levels in 834 registry-based myocardial infarction (MI) patients (38% women) and 1548 population-based controls. Lp(a) concentrations were inversely related with the numbers of K4 and PN repeats. However, the effect of the PN polymorphism was restricted to subjects producing small Lp(a) particles (<or=8 PN 66.1 mg/dL versus >8 PN 8.7 mg/dL; P<0.0001). The odds to present with MI were elevated in individuals producing small Lp(a) particles (<or=22 K4 repeats; OR 1.47 for men and 1.69 for women; P<0.002) and in women with <or=8 PN repeats (OR 1.46, P=0.009). Interestingly, in women, the frequent haplotype with <or=8 PN and <or=22 K4 repeats, which is related to high levels of small Lp(a) particles, resulted in an elevated OR for MI (1.79; P=0.01) independently of Lp(a) serum concentration.

CONCLUSIONS

The K4 and PN repeat polymorphisms largely explain the high variability of serum Lp(a) levels. A haplotype with <or=8 PN and <or=22 K4 repeats is characterized by high concentrations of small Lp(a) particles. Our observation that this haplotype was associated with MI independently of Lp(a) serum levels may suggest that Lp(a) particle size in addition to its concentration may modulate MI risk in women.

Prevalence of left ventricular diastolic dysfunction in the community. Results from a Doppler echocardiographic-based survey of a population sample

AIMS

The prevalence of left ventricular diastolic abnormalities in the general population is largely unclear. Thus, the aim of this study was, firstly, to identify abnormal diastolic function by echocardiography in an age-stratified population-based European sample (MONICA Augsburg, n=1274, 25 to 75 years, mean 51+/-14) and, secondly, to analyse clinical and anthropometric parameters associated with diastolic abnormalities.

METHODS AND RESULTS

The overall prevalence of diastolic abnormalities, as defined by the European Study Group on Diastolic Heart Failure (i.e. age dependent isovolumic relaxation time (92-105 ms) and early (E-wave) and late (A-wave) left ventricular filling (E/A-ratio, 1-0.5)) was 11.1%. When only subjects treated with diuretics or with left atrial enlargement were considered (suggesting diastolic dysfunction) the prevalence was 3.1%. The prevalence of diastolic abnormalities varied according to age: from 2.8% in individuals aged 25-35 years to 15.8% among those older than 65 years (P<0.01). Significantly higher rates of diastolic abnormalities were observed in men as compared to women (13.8% vs 8.6%, P<0.01). Independent predictors of diastolic abnormalities were arterial hypertension, evidence of left ventricular (LV) hypertrophy, and coronary artery disease. Interestingly, in the absence of these predisposing conditions, diastolic abnormalities (4.3%) or diastolic dysfunction (1.1%) were rare, even in subjects older than 50 years of age (4.6%) and (1.2%), respectively. In addition to these factors, diastolic dysfunction was related to high body mass index, high body fat mass, and diabetes mellitus.

CONCLUSION

The prevalences of diastolic abnormalities and diastolic dysfunction are higher than that of systolic dysfunction and are increased (despite age-dependent diagnostic criteria) in the elderly. However, in the absence of risk factors for diastolic abnormalities or diastolic dysfunction, namely LV hypertrophy, arterial hypertension, coronary artery disease, obesity and diabetes the condition is rare even in elderly subjects. These data allow speculation on whether diastolic heart failure may be prevented by improved implementation of measures directed against predisposing conditions.

[Genetic factors in myocardial infarction--Results from a candidate gene and a genome-wide approach between beta blockers]

BACKGROUND

Coronary artery disease and myocardial infarction are the most frequent causes of death in the Western societies. Even nowadays, every second myocardial infarction is lethal and hits the patients unexpectedly without previous signs or symptoms. In order to install preventive measures most efficiently, it is necessary to have a detailed knowledge on the pathophysiology of the disease. The identification of patients who are at high risk for suffering from myocardial infarction can be done with epidemiological methods, such as the determination of "traditional" risk factors, like arterial hypertension, hypercholesterolemia, diabetes mellitus or smoking), or eventually in the future using molecular genetic testing. This is of great importance especially for asymptomatic siblings and children from myocardial infarction patients.

POLYMORPHISMS

Although traditional risk factors occur frequently in families, they explain only in part the familial accumulation of coronary artery disease. Furthermore, stron genetic effects on the development of coronary artery disease and myocardial infarction have been demonstrated in several studies. These genetic effects can be examined by 1. a candidate gene approach, or 2. a systematic screening of the whole genome. In the first step, several polymorphisms (sequence variations) wee examined in several candidate genes in which a significant influence on a cardiovascular risk factor or intermediate phenotype (such as atherogeneic lipid profile or arterial hypertension) has been shown in the literature. We thus examined in a large population of patients with myocardial infarction and a sample of the general population the effects of the HindIII polymorphism in the lipoproteinlipase gene, of the -344T/C promoter polymorphism in the aldosterone synthase gene and of the 825C/T polymorphism in the gene of the beta3 subunit of the G protein gene (GNB3). In the general population, we could show an association with unfavorable lipid levels in men and in postmenopausal (but not premenopausal) women for the H2H2 genotype of the HindIII lipoproteinlipase polymorphism. However, the theoretical increase in risk for this genotype is not large enough to demonstrate a significant association with myocardial infarction in the population examined. With the promoter polymorphism in the aldosterone synthase gene, anthropometrical and echocardiographical data did not suggest that the polymorphism is a risk factor for myocardial infarction nor for left ventricular remodeling after myocardial infarction, which was observed in earlier studies. Furthermore, we could show an association with arterial hypertension in our general population sample with the polymorphism in the GNB3 gene. However, no association could be demonstrated for this polymorphism with myocardial infarction. AFFECTED SIB-PAIR APPROACH: In a systematic screening of the genome for genes that are relevant in the pathogenesis of coronary artery disease or myocardial infarction, an affected sib-pair approach was followed. 1,261 families were identified in which at least two brothers or sisters were affected with myocardial infarction or severe coronary artery disease, such as percutaneous coronary intervention or coronary after bypass grafting. In a subpopulation of 513 families and 1,407 individuals, we performed a total genome screening. The analyses using the variance component method and the SOLAR program revealed a susceptibility locus for myocardial infarction of chromosome 14q32 with a lod score of 3.89 (genome-wide p < 0.05). This locus comprises a region of about seven centi-Morgan and contains approximately 150 genes. Furthermore, a comprehensive analysis including the cardiovascular risk factors showed that 1. this myocardial infarction locus is unique and does not overlap with chromosomal loci for well-established risk factors, 2. cardiovascular risk factors, such as Lp(a), diabetes mellitus, serum lipids, or arterial hypertension have strong genetic components.

CONCLUSION

These findings do not exclude a role of cardiovascular s do not exclude a role of cardiovascular risk factors or candidate genes in the pathogenesis of myocardial infarction, but rather demonstrate that risk factors may act as surrogates of specific underlying disease mechanisms. It is thus necessary to perform a comprehensive analysis of complex polygenic diseases, such as myocardial infarction, including both, established cardiovascular risk factors and genomic data.

Relation of the G protein beta3-subunit polymorphism with left ventricle structure and function

The G protein beta3-subunit C825T polymorphism results in a truncated splice variant protein that is associated with enhanced transmembrane signaling, increased proliferative activity, and arterial hypertension. The aim of the present study was to further investigate the association of this polymorphism with left ventricular (LV) structure and function. A total of 2052 individuals from a large-scale population-based sample were investigated for the G protein beta3-subunit C825T polymorphism and echocardiographic parameters of LV structure and function. Complete genotyping and echocardiographic data were available in 1720 individuals (829 men and 891 women). The mean LV mass indices in men with CC (n=384) and TT (n=84) genotypes were 98.3+/-1.2 g/m2 and 100.0+/-2.8 g/m2, respectively (P=0.64). In women, the corresponding values were 83.1+/-1.0 g/m2 for the CC genotype (n=397) and 83.8+/-2.1 g/m2 for the TT genotype (n=91, P=0.32). Likewise, LV dimensions or parameters of the diastolic function and serologic markers of LV mass were not associated with the C825T variant. Finally, multivariate analyses accounting for potentially confounding factors failed to show any influence of this polymorphism on echocardiographic parameters. In conclusion, we were not able to confirm the previously published associations of the G protein beta3-subunit C825T polymorphism with LV structure and diastolic function.

Peroxisome proliferator--activated receptor alpha gene regulates left ventricular growth in response to exercise and hypertension

BACKGROUND

Left ventricular hypertrophy (LVH) occurs as an adaptive response to a physiological (such as exercise) or pathological (valvular disease, hypertension, or obesity) increase in cardiac work. The molecular mechanisms regulating the LVH response are poorly understood. However, inherited defects in fatty acid oxidation are known to cause severe early-onset cardiac hypertrophy. Peroxisome proliferator--activated receptor alpha (PPARalpha) regulates genes responsible for myocardial fatty acid oxidation and is downregulated during cardiac hypertrophy, concomitant with the switch from fatty acid to glucose utilization.

METHODS AND RESULTS

The role of PPARalpha in left ventricular growth was investigated in 144 young male British Army recruits undergoing a 10-week physical training program and in 1148 men and women participating in the echocardiographic substudy of the Third Monitoring Trends and Determinants in Cardiovascular Disease (MONICA) Augsburg study. A G/C polymorphism in intron 7 of the PPARalpha gene significantly influenced left ventricular (LV) growth in response to exercise (P=0.009). LV mass increased by 6.7 +/- 1.5 g in G allele homozygotes but was significantly greater in heterozygotes for the C allele (11.8 +/- 1.9 g) and in CC homozygotes (19.4 +/- 4.2 g). Likewise, C allele homozygotes had significantly higher LV mass, which was greater still in hypertensive subjects, and a higher prevalence of LVH in the Third MONICA Augsburg study.

CONCLUSIONS

We demonstrate that variation in the PPARalpha gene influences human left ventricular growth in response to exercise and hypertension, indicating that maladaptive cardiac substrate utilization can play a causative role in the pathogenesis of LVH.

A comprehensive linkage analysis for myocardial infarction and its related risk factors

Coronary artery disease and myocardial infarction (MI) are leading causes of death in the western world. Numerous studies have shown that risk factors such as diabetes mellitus, arterial hypertension and hypercholesterolemia contribute to the development of the disease. Although each risk factor by itself is partly under genetic control, a positive family history is an independent predictor, which suggests that there are additional susceptibility genes. We have scanned the whole genome in 513 families to identify chromosomal regions linked to myocardial infarction and related risk factors that are known to be under genetic control. Here we show, by using variance component analysis and incorporating risk factors, that risk of myocardial infarction maps to a single region on chromosome 14 with a significant lod score of 3.9 (pointwise P=0.00015, genome-wide P<0.05), providing evidence of a principal MI locus. To characterize this locus we analyzed each risk factor by itself. Serum concentrations of lipoprotein (a) show linkage to both the apolipoprotein (a) locus (lod score 26.99) and a new locus on chromosome 1 (lod score 3.8). There is suggestive linkage for diabetes mellitus on chromosome 6 (lod score 2.96), for hypertension on chromosomes 1 and 6, for high-density and low-density lipoprotein cholesterol on chromosomes 1 and 17, and for triglyceride concentrations on chromosome 9. Although some of these risk factors overlap with previously identified loci, none overlaps with the newly identified susceptibility locus for myocardial infarction and coronary artery disease.

Do siblings of myocardial infarction patients have a specific management of hypertension?

The aim of this study was to determine whether the management of hypertension differs between siblings of myocardial infarction patients and the general population. Siblings aged 35 to 74 years, unaffected by myocardial infarction, were drawn from the Augsburg Family Heart Study, conducted in 1996-1997 in southern Germany (n = 524). The reference group consisted of participants of the third MONICA population-based survey conducted in 1994-1995 in the same area, who were aged 35 to 74 years and also unaffected by myocardial infarction (n = 3802). Prevalence, awareness, treatment and control of hypertension (defined by blood pressure > or = 140/90 mm Hg or use of antihypertensive medication) were compared between the two groups. The result was that the prevalence of hypertension was higher in the siblings (men: age-adjusted OR = 1.31, 95% CI: 0.99-1.75; women: age-adjusted OR = 1.83, 95% CI: 1.39-2.41). Male hypertensive siblings were more often aware and treated for hypertension than male hypertensives of the reference group whereas the level of awareness and treatment was comparable between female hypertensives of the two groups. In both genders, no difference in the degree of control was shown between hypertensives of the two groups. In conclusion the siblings and their physicians should pay more attention to the family history of myocardial infarction in order to improve the management of hypertension in this high risk group.

N-terminal pro-brain natriuretic peptide after myocardial infarction: a marker of cardio-renal function

N-terminal pro-brain natriuretic peptide (NT-proBNP) is increased early after acute myocardial infarction. We assessed the relationship of NT-proBNP with left ventricular function and mass as well as with renal function, hemodynamic, and anthropometric variables in 625 outpatients in the chronic phase after myocardial infarction and 465 siblings without infarction (control). NT-proBNP was measured by nonextracted, enzyme-linked, sandwich immunoassay. NT-proBNP was correlated with left ventricular ejection fraction, mass index, and renal function, in addition to infarction history, gender, and age, in univariate and multivariate analysis (all P<0.01). Increases in NT-proBNP observed in subjects with infarction (96.6+/-13.7 versus 31.2+/-1.8 pmol/L in control subjects, P<0.001) were particularly pronounced in the presence of significant left ventricular dysfunction (182.8+/-41.9 pmol/L), left ventricular hypertrophy (214.5+/-61.7 pmol/L), and renal dysfunction (210.3+/-51.4 pmol/L, all P<0.01). Patients with an ejection fraction <35% were detected by NT-proBNP with a sensitivity, specificity, and negative predictive value of 75%, 62%, and 99%, respectively, at an optimal cutoff of 44 pmol/L. Patients with an ejection fraction <35% and concomitant left ventricular hypertrophy were detected with a sensitivity, specificity, and negative predictive value of 90%, 80%, and 99.9%, respectively, at a cutoff of 76 pmol/L. Similar results were obtained for patients with an ejection fraction <35% and concomitant renal dysfunction at a cutoff of 162 pmol/L. NT-proBNP is a biochemical marker of integrated cardio-renal function in the chronic phase after myocardial infarction and a potential diagnostic tool for the detection and exclusion of significant left ventricular dysfunction. Cutoff concentrations have to be chosen according to renal function to optimize the predictive value of NT-proBNP.

[Inpatient rehabilitation improves implementation of therapeutic guidelines for secondary prevention in patients with coronary heart disease]

In Germany, measures for secondary prevention in patients with coronary artery disease are poorly utilized. We therefore investigated whether a cardiac in-hospital rehabilitation and education program may enhance the implementation of respective guidelines in patients with severe coronary artery disease (CAD). Specifically, we developed a case-control design in siblings with severe CAD in order to achieve optimal matching for patients with or without participation in the rehabilitation program. By the screening of more than 200,000 patient charts in 15 cardiac rehabilitation clinics, we identified 1500 families in which at least two siblings suffered from severe coronary artery disease. In 268 such sibling pairs, siblings were discordant with respect to participation in a 3-4 week cardiac in-hospital rehabilitation program. The coronary risk profile was studied, first, retrospectively at the time of hospitalization for acute MI or revascularization procedures and, secondly, prospectively at the time of follow-up (on average 5.2 years later). At the time of the acute cardiac event, both groups showed an equal risk factor distribution suggesting appropriate matching. However, at follow-up the number of individuals taking antihypertensive medication and displaying effective antihypertensive treatment (< or = 140/90 mmHg) was significantly higher in the rehabilitation group (92.2 vs. 82.1%, p < 0.01; 59.7 vs. 37.2%). Accordingly, rehabilitation siblings presented with significantly lower systolic (137 +/- 1 vs. 145 +/- 1 mmHg; p < 0.01) and diastolic blood pressure (82 +/- 1 vs. 85 +/- 1 mmHg; p < 0.01). The utilization of CSE inhibitors was also significantly higher in siblings participating in the rehabilitation program (57.5 vs. 43.1%; p < 0.01), leading to significantly lower blood lipid levels in these siblings (total cholesterol 225 +/- 3 vs. 236 +/- 3 mg/dL, p < 0.01; LDL cholesterol 148 +/- 3 vs. 158 +/- 3 mg/dL, p < 0.01). Moreover, participation in the cardiac rehabilitation stimulated markedly more smokers to quit (80.8 vs. 57.6%, p < 0.01). Additionally, there was a strong temporal trend from 1997 until 2000 towards improved control of arterial hypertension in rehabilitation siblings. In parallel, the utilization of CSE inhibitors increased over time and LDL cholesterol decreased. These favorable temporal trends were also observed in siblings not participating in the rehabilitation program, however, to a lesser extent. Taken together, in the last four years, the implementation of secondary preventive strategies in patients with cardiac disease improved. Siblings who participated in a rehabilitation program displayed a better control of cardiovascular risk factors as compared to those not participating in such a program. Thus, an in-hospital cardiac rehabilitation program may successfully encourage the implementation of measures for secondary prevention and enhance the treatment of coronary risk factors.

Long-term effects of in-hospital cardiac rehabilitation on the cardiac risk profile. A case-control study in pairs of siblings with myocardial infarction

AIMS

In the general population, measures for secondary prevention of myocardial infarction are poorly utilized. Our aim was therefore to analyse whether post-myocardial infarction in-hospital rehabilitation and education programmes improve the subsequent utilization of preventive strategies.

METHODS AND RESULTS

We screened 93 500 patient charts in cardiac rehabilitation clinics to identify a myocardial infarction patient with a sibling, who likewise had a myocardial infarction prior to the age of 60 years but was discordant with respect to the participation in cardiac in-hospital rehabilitation. In 92 such sibling pairs the coronary risk profile was studied by standardized questionnaire, biochemical measurements and physical examination. At the time of the acute myocardial infarction, both groups showed an equal risk factor distribution. However, at follow-up (on average 5.5 years after myocardial infarction), rehabilitation-siblings presented with significantly lower systolic (137+/-2 vs 150+/-3 mmHg, P<0.01) and diastolic blood pressure (82+/-1 vs 89+/-1 mmHg, P<0.01). Antihypertensive drug therapy resulted more often in effective (<or=140/90 mmHg) control of blood pressure (58% vs 29%, P<0.01). Blood lipid levels and smoking prevalence tended to be lower in rehabilitation-siblings. Significantly fewer rehabilitation-siblings presented with two or more modifiable risk factors (OR 0.36 (CI 0.17-0.76); P<0.01). There was a strong tendency towards fewer recurrent cardiac events (re-myocardial infarction, coronary angioplasty, coronary artery bypass grafting) during follow-up in rehabilitation-siblings (OR 0.57 (CI 0.31-1.04); P=0.07).

CONCLUSION

An in-hospital programme for cardiac rehabilitation may successfully encourage therapy to modify risk factors and thus enhance the long-term implementation of secondary prevention.

Siblings of myocardial infarction patients are overlooked in primary prevention of cardiovascular disease

AIMS

Patients with arterial hypertension or hypercholesterolaemia may benefit from medical therapy for primary prevention of myocardial infarction. Preventive therapy may be particularly effective in individuals with a positive family history for myocardial infarction since such subjects are at high risk for coronary events. The objective of this population-based study was to analyse the risk profile as well as the current utilization of preventive strategies in asymptomatic siblings of patients with myocardial infarction.

METHODS AND RESULTS

We studied siblings of 325 patients with premature myocardial infarction from the Augsburg MONICA myocardial infarction registry by standardized questionnaire, blood pressure recordings, and biochemical measurements. Out of 580 siblings, 510 were free of coronary heart disease symptoms. With multiple risk factors being present in most asymptomatic siblings, 29.4% of asymptomatic individuals had an estimated individual 10-year risk for a major cardiovascular event of > or = 20%, or when projected to the age of 60. According to the guidelines of the European Societies of Cardiology, Atherosclerosis, and Hypertension (ESC/EAS/ESH) from 1994 (1998 guidelines in parenthesis) dietary and lifestyle interventions were indicated for arterial hypertension in 48.1% (43.0%) and/or for hypercholesterolaemia in 17.3% (78.8%). Drug treatment was indicated for arterial hypertension in 27.9% (30.6%) and for hypercholesterolaemia in 13.6% (19.1%) of asymptomatic siblings. Of those individuals with the respective indication, actual drug treatment was given for arterial hypertension in 91.5% (83.3%) and for hypercholesterolaemia in 46.4% (33.0%). However, treatment targets were reached in only 31.0% (28.2%) with arterial hypertension and in 7.2% (5.2%) with hypercholesterolaemia, respectively.

CONCLUSIONS

Most asymptomatic individuals with positive fraternal family history have more than one modifiable risk factor. Interestingly, a large number of these individuals appears to be under medical surveillance as many receive some sort of drug treatment. However, this therapy did not meet the treatment goals in the majority of those with arterial hypertension and/or hypercholesterolaemia. Thus, although individuals with a positive fraternal history for myocardial infarction can be easily identified, implementation of sufficient preventive strategies continues to be poor in a Western European country.

The D-allele of the ACE polymorphism is related to increased QT dispersion in 609 patients after myocardial infarction

AIMS

Prolongation of QT dispersion can be observed in some patients with myocardial infarction and serves as a possible independent risk factor for sudden cardiac death. Angiotensin-converting enzyme (ACE) inhibition has been shown to reduce QT dispersion in myocardial infarction patients. We hypothesized that ACE gene I/D polymorphism, which is known to modulate ACE activity, may also affect QT dispersion after myocardial infarction.

METHODS AND RESULTS

We studied 609 myocardial infarction patients (532 men, aged 56.1+/-0.3; mean 5.5 years after myocardial infarction) from a population-based myocardial infarction register by standardized questionnaire, anthropometry, ECG, echocardiography, and genotyping of ACE I/D polymorphism. In addition, 540 unaffected siblings (251 men, age 54.6+/-0.4 years) of these patients were studied by the same protocol. As compared with their healthy siblings, mean QT dispersion was prolonged in myocardial infarction patients (65.9+/-1.4 ms vs 91.2+/-2.3 ms, respectively, P<0.001). QT dispersion was negatively correlated to left ventricular ejection fraction (P<0.005). The ACE DD-genotype was associated with longer QT dispersion in myocardial infarction patients (103.0+/-4.6 ms vs 81.9+/-4.5 ms in the II group, P<0.001). This association was noted to be strong in multivariate analyses that included age, gender, ejection fraction, left ventricular end-diastolic diameter, medication, and heart rate. In contrast, no association between the ACE DD-genotype and QT dispersion was detected in healthy siblings of myocardial infarction patients.

CONCLUSION

Thus, the ACE D-allele may be associated with increased QT dispersion in patients after myocardial infarction but not in healthy subjects. An interaction of myocardial damage and genetic predisposition that both enhance the activity of the renin angiotensin system may decrease the repolarization homogeneity of the heart.