[The relationship between QRS voltage on ECG (the Minnesota code) and cardiac mortality amongst males. The Reykjavik Study]. / Forspárgildi QRS útslaga á hjartalínuriti, Minnesota-líkanid, un dánartídni karla. Reykjavíkurrannsókn Hjartaverndar.

OBJECTIVE: Left ventricular hypertrophy (LVH) is important clinically because it is associated with heart failure, arrhythmia, myocardial infarction and stroke. The purpose of this study was to assess how well traditional ECG voltage criteria predict coronary heart disease mortality amongst males and to find the QRS voltages that best combine sensitivity and specificity in this sense. MATERIAL AND METHODS: Our study is a random population cohort study initiated in 1967. The study group included males that had been diagnosed with LVH on ECG using the Minnesota code (n=206). The other male participants of the study (n=8595) comprised the control group. The ECG voltage criteria of the Minnesota code were systematically narrowed and the mortality of those who fulfilled the stricter criteria compared with those who did not. RESULTS: There was no significant increase in coronary heart disease mortality difference between those who fulfilled the criteria of the Minnesota code for LVH and those who did not. When the criteria were narrowed there was a trend towards increased mortality with larger QRS voltages, but the trend was not strong. CONCLUSION: The correlation between large QRS voltage on ECG and mortality in males is limited. QRS voltage is an imperfect tool for prediction of cardiac mortality amongst males.

Glucose abnormalities and heart failure predict poor prognosis in the population-based Reykjavík Study.

BACKGROUND: The risk of cardiovascular disease increases progressively with increasing blood glucose from levels well below the diabetic threshold. In the Reykjavík Study the relationship between heart failure and abnormal glucose regulation was already apparent at the level of impaired glucose tolerance. The aim of this study was to determine the prognosis of participants with any glucose abnormality and heart failure and to test whether the combination of these conditions may adversely affect the subsequent prognosis. DESIGN: A prospective population-based study. METHODS: Data from the first visit of 19 381 participants were used. Participants were divided into groups according to their glycaemic and heart failure level, and comparisons were made between the groups and disease-free participants serving as a reference group. The risk of mortality and morbidity was calculated with adjustments for main cardiovascular risk factors and ischaemic heart disease. RESULTS: Participants in the reference group were younger, had lower body mass indices and more seldom a history of myocardial infarction compared with diseased groups. Mortality was lowest in the reference group (P<0.0001) increasing to a maximum in participants with the combination of glucose abnormality and heart failure. Prognostically, the mortality risk associated with abnormal glucose regulation was increased but was lower than the risk of diabetes. The risk of a new myocardial infarction was highest in participants with diabetes [hazard ratio (HR) 1.6; 95% confidence interval (CI) 1.3-2.0] or diabetes in combination with heart failure (HR 1.8; CI 1.1-2.7). CONCLUSIONS: Heart failure or glucose abnormalities are related to increased morbidity and mortality. The combination of glucose abnormality and heart failure did, however, not add further to the unfavourable prognosis in the presence of ischaemic heart disease.

Effects of a 5-lipoxygenase-activating protein inhibitor on biomarkers associated with risk of myocardial infarction: a randomized trial.

CONTEXT: Myocardial infarction (MI) is the leading cause of death in the world. Variants in the 5-lipoxygenase-activating protein (FLAP) gene are associated with risk of MI. OBJECTIVE: To determine the effect of an inhibitor of FLAP on levels of biomarkers associated with MI risk. DESIGN, SETTING, AND PATIENTS: A randomized, prospective, placebo-controlled, crossover trial of an inhibitor of FLAP (DG-031) in MI patients who carry at-risk variants in the FLAP gene or in the leukotriene A4 hydrolase gene. Of 268 patients screened, 191 were carriers of at-risk variants in FLAP (87%) or leukotriene A4 hydrolase (13%). Individuals were enrolled in April 2004 and were followed up by designated cardiologists from a university hospital in Iceland until September 2004. INTERVENTIONS: Patients were first randomized to receive 250 mg/d of DG-031, 500 mg/d of DG-031, 750 mg/d of DG-031, or placebo. After a 2-week washout period, patients received DG-031 if they had received placebo first or placebo if they had received DG-031 first. Treatment periods lasted for 4 weeks. MAIN OUTCOME MEASURES: Changes in levels of biomarkers associated with risk of MI. RESULTS: In response to 750 mg/d of DG-031, production of leukotriene B4 was significantly reduced by 26% (95% confidence interval [CI], 10%-39%; P = .003) and myeloperoxidase was significantly reduced by 12% (95% CI, 2%-21%; P = .02). The higher 2 doses of DG-031 produced a nonsignificant reduction in C-reactive protein (16%; 95% CI, -2% to 31%; P = .07) at 2 weeks. However, there was a more pronounced reduction (25%; 95% CI, 5%-40%; P = .02) in C-reactive protein at the end of the washout period that persisted for another 4 weeks thereafter. The FLAP inhibitor DG-031 was well tolerated and was not associated with any serious adverse events. CONCLUSION: In patients with specific at-risk variants of 2 genes in the leukotriene pathway, DG-031 led to significant and dose-dependent suppression of biomarkers that are associated with increased risk of MI events.

The association between glucose abnormalities and heart failure in the population-based Reykjavik study.

OBJECTIVE: Diabetes is an independent risk factor for heart failure, whereas the relation between heart failure and abnormal glucose regulation (AGR) needs further evaluation. We studied this combination in the Reykjavik Study. RESEARCH DESIGN AND METHODS: The Reykjavik Study, a population-based cohort study during 1967-1997, recruited 19,381 participants aged 33-84 years who were followed until 2002. Oral glucose tolerance tests and chest X-rays were obtained from all participants. Cases were defined in accordance with World Health Organization criteria for type 2 diabetes or AGR (impaired glucose tolerance or impaired fasting glucose) and European Society of Cardiology guidelines for heart failure. RESULTS: The overall prevalence of type 2 diabetes and heart failure was 0.5% in men and 0.4% in women, while AGR and heart failure were found in 0.7% of men and 0.6% of women. Among participants with normal glucose regulation, heart failure was diagnosed in 3.2% compared with 6.0 and 11.8% among those with AGR and type 2 diabetes, respectively. The prevalence of type 2 diabetes in the age-group 45-65 years increased in both sexes during the period (P for trend = 0.007). The odds ratio was 2.8 (95% CI 2.2-3.6) for the association between type 2 diabetes and heart failure and 1.7 (1.4-2.1) between AGR and heart failure. CONCLUSIONS: There is a strong association between any form of glucometabolic perturbation and heart failure. Future studies in this field should focus on all types of glucose abnormalities rather than previously diagnosed diabetes only.

Linkage of essential hypertension to chromosome 18q.

We performed a genomewide scan with 904 microsatellite markers using 120 extended Icelandic families with 490 hypertensive patients. The families were identified by cross-matching a list of hypertensive patients from the Hypertension Clinic of the University Hospital (Landspitalinn) in Iceland with a genealogy database of the entire Icelandic nation. After adding 5 markers, we found linkage to chromosome 18q with an allele-sharing LOD score of 4.60 (P=2.1x 10(-6)). These results provide evidence for a novel susceptibility gene for essential hypertension on chromosome 18q and show that it is possible to study the genetics of essential hypertension without stratifying by subphenotypes.