Metabolic causes and prevention of ventricular fibrillation during acute coronary syndromes

Outcomes between prediabetes and type 2 diabetes mellitus in older adults with acute myocardial infarction in the era of newer-generation drug-eluting stents: a retrospective observational study

Background

The comparative clinical outcomes between prediabetes and type 2 diabetes mellitus (T2DM) in older adults with AMI in the era of newer-generation drug-eluting stents (DES) are limited. We investigated the 2-year clinical outcomes of these patients.

Methods

A total of 5492 AMI patients aged ≥65 years were classified into three groups according to their glycemic status: normoglycemia (group A: 1193), prediabetes (group B: 1696), and T2DM (group C: 2603). The primary outcome was the occurrence of major adverse cardiac events (MACE), defined as all-cause death, recurrent myocardial infarction (Re-MI), and any repeat revascularization. The secondary outcome was stent thrombosis (ST).

Results

The primary and secondary outcomes cumulative incidences were similar between the prediabetes and T2DM groups. In both the prediabetes and T2DM groups, the cumulative incidences of MACE (adjusted hazard ratio [aHR]: 1.373; p = 0.020 and aHR: 1.479; p = 0.002, respectively) and all-cause death or MI (aHR: 1.436; p = 0.022 and aHR: 1.647; p = 0.001, respectively) were significantly higher than those in the normoglycemia group. Additionally, the cumulative incidence of all-cause death in the T2DM group was significantly higher than that in the normoglycemia group (aHR, 1.666; p = 0.003).

Conclusions

In this retrospective study, despite the 2-year clinical outcomes of the patients with prediabetes and T2DM in the older adults were worse than those in the normoglycemia group; they were similar between the prediabetes and T2DM groups. Hence, comparable treatment strategies should be strengthened between prediabetes and T2DM in older adults with AMI.

Trial registration

Retrospectively registered.

Free fatty acids and heart failure in the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Free fatty acids (FFAs) may be associated with heart failure (HF) risk, but prospective research is lacking.

OBJECTIVE

This study investigated associations between fasting FFAs and HF incidence overall and by ejection fraction (EF) subtypes [HF with preserved EF (HFpEF) and HF with reduced EF (HFrEF)] to evaluate FFAs as a potential biomarker for HF risk prediction.

METHODS

This study was conducted in the Multi-Ethnic Study of Atherosclerosis (MESA) prospective cohort among 6,667 participants with complete baseline (2000-2002) FFAs and HF follow-up (through 2015). Associations between FFAs and HF incidence were evaluated with Cox proportional hazards regression. Cross-sectional associations between FFAs and HF risk markers were also evaluated using linear regression [N-terminal pro-B-type natriuretic peptide (NT-proBNP), left ventricular (LV) mass index] and logistic regression [LV hypertrophy (LVH)]. Stratification and cross-product terms were utilized to evaluate differences by age, sex, race/ethnicity and diabetes.

RESULTS

FFAs were not associated with HF overall or with HFrEF. FFAs were not associated with HFpEF in the overall population or among males, but were borderline positively associated with risk among females (fully-adjusted tertile 3 vs. 1 HR=2.17, 95% CI: 1.06, 4.42) (sex P-interaction=0.05). FFAs were not associated with NT-proBNP, but were inversely associated with LV mass index and LVH with stronger associations among females (P-interaction≥0.10). Associations did not differ by age, race/ethnicity or diabetes status.

CONCLUSIONS

FFAs generally do not appear to be an independent predictor for HF risk. Additional research is needed to confirm findings particularly studies evaluating associations by sex and EF subtypes.

Stress-Induced Hyperglycaemia in Non-Diabetic Patients with Acute Coronary Syndrome: From Molecular Mechanisms to New Therapeutic Perspectives

Stress-induced hyperglycaemia (SIH) at hospital admission for acute coronary syndrome is associated with poor outcome, especially in patients without known diabetes. Nevertheless, insulin treatment in these subjects was not correlated with the reduction of mortality. This is likely due to the fact that SIH in the context of an acute coronary syndrome, compared to that in known diabetes, represents an epiphenomenon of other pathological conditions, such as adrenergic and renin-angiotensin system over-activity, hyperglucagonaemia, increase of circulating free fatty acids and pancreatic beta-cell dysfunction, which are not completely reversed by insulin therapy and so worsen the prognosis. Thus, SIH may be considered not only as a biomarker of organ damage, but also as an indicator of a more complex therapeutic strategy in these subjects. The aim of this review is to analyse the molecular mechanisms by which SIH may favour a worse prognosis in non-diabetic patients with acute coronary syndrome and identify new therapeutic strategies, in addition to insulin therapy, for a more appropriate treatment and improved outcomes.

Developing a Standardized and Reusable Method to Link Distributed Health Plan Databases to the National Death Index: Methods Development Study Protocol

BACKGROUND

Certain medications may increase the risk of death or death from specific causes (eg, sudden cardiac death), but these risks may not be identified in premarket randomized trials. Having the capacity to examine death in postmarket safety surveillance activities is important to the US Food and Drug Administration's (FDA) mission to protect public health. Distributed networks of electronic health plan databases used by the FDA to conduct multicenter research or medical product safety surveillance studies often do not systematically include death or cause-of-death information.

OBJECTIVE

This study aims to develop reusable, generalizable methods for linking multiple health plan databases with the Centers for Disease Control and Prevention's National Death Index Plus (NDI+) data.

METHODS

We will develop efficient administrative workflows to facilitate multicenter institutional review board (IRB) review and approval within a distributed network of 6 health plans. The study will create a distributed NDI+ linkage process that avoids sharing of identifiable patient information between health plans or with a central coordinating center. We will develop standardized criteria for selecting and retaining NDI+ matches and methods for harmonizing linked information across multiple health plans. We will test our processes within a use case comprising users and nonusers of antiarrhythmic medications.

RESULTS

We will use the linked health plan and NDI+ data sets to estimate the incidences and incidence rates of mortality and specific causes of death within the study use case and compare the results with reported estimates. These comparisons provide an opportunity to assess the performance of the developed NDI+ linkage approach and lessons for future studies requiring NDI+ linkage in distributed database settings. This study is approved by the IRB at Harvard Pilgrim Health Care in Boston, MA. Results will be presented to the FDA at academic conferences and published in peer-reviewed journals.

CONCLUSIONS

This study will develop and test a reusable distributed NDI+ linkage approach with the goal of providing tested NDI+ linkage methods for use in future studies within distributed data networks. Having standardized and reusable methods for systematically obtaining death and cause-of-death information from NDI+ would enhance the FDA's ability to assess mortality-related safety questions in the postmarket, real-world setting.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/21811.

Free fatty acids, cardiovascular disease, and mortality in the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Fasting free fatty acid (FFA) levels may be associated with cardiovascular disease (CVD) and mortality, but research among generally healthy adults, females, and racially/ethnically diverse populations is lacking.

OBJECTIVE

The primary aim of this project was to investigate prospective associations between fasting FFAs and coronary heart disease (CHD) and CVD incidence and CVD-specific and all-cause mortality in a generally healthy age, sex, and racially/ethnically heterogeneous population.

METHODS

This study was conducted in the Multi-Ethnic Study of Atherosclerosis cohort using baseline (2000-2002) fasting FFAs and outcome data through 2015 (N = 6678). Cox proportional hazards regression was used to calculate hazard ratios for associations between FFAs and CHD, CVD, CVD-specific mortality, and all-cause mortality. Interactions by age, sex, race/ethnicity, and metabolic syndrome were evaluated by stratification and cross-product terms. A secondary analysis was conducted to evaluate associations between FFAs, and inflammatory and endothelial activation biomarkers were evaluated using linear regression (analytic N range: 964-6662).

RESULTS

FFA levels were not associated with CHD or CVD incidence. Higher FFAs were associated with CVD-specific and all-cause mortality, but associations were attenuated in fully adjusted models with a borderline significant association remaining only for all-cause mortality (fully adjusted, per standard deviation increase hazard ratio = 1.07, 95% confidence interval: 1.00-1.14). Associations did not differ by age, sex, race/ethnicity, or metabolic syndrome.

CONCLUSIONS

Fasting FFAs were not associated with CHD, CVD, or CVD-specific mortality and were modestly associated with all-cause mortality, regardless of age, sex, race/ethnicity, or metabolic syndrome status.

Admission Glucose and In-hospital Mortality after Acute Myocardial Infarction in Patients with or without Diabetes: A Cross-sectional Study

Background:

Hyperglycemia on admission has been found to elevate risk for mortality and adverse clinical events after acute myocardial infarction (AMI), but there are evidences that the relationship of blood glucose and mortality may differ between diabetic and nondiabetic patients. Prior studies in China have provided mixed results and are limited by statistical power. Here, we used data from a large, nationally representative sample of patients hospitalized with AMI in China in 2001, 2006, and 2011 to assess if admission glucose is of prognostic value in China and if this relationship differs depending on the presence or absence of diabetes.

Methods:

Using a nationally representative sample of patients with AMI in China in 2001, 2006, and 2011, we categorized patients according to their glucose levels at admission (< 3.9, 3.9–7.7, 7.8–11.0, and ≥11.1 mmol/L) and compared in-hospital mortality across these admission glucose categories, stratified by diabetes status. Among diabetic and nondiabetic patients, separately, we employed logistic regression to assess the differences in outcomes across admission glucose levels while adjusting for the same covariates.

Results:

Compared to patients with euglycemia (5.8%), patients with moderate hyperglycemia (13.1%, odds ratio [OR] = 2.44, 95% confidence interval [CI, 2.08–2.86]), severe hyperglycemia (21.5%, OR = 4.42, 95% CI [3.78–5.18]), and hypoglycemia (13.8%, OR = 2.59, 95% CI [1.68–4.00]), all had higher crude in-hospital mortality after AMI regardless of the presence of recognized diabetes mellitus. After adjustment for patients’ characteristics and clinical status, however, the relationship between admission glucose and in-hospital mortality was different for diabetic and nondiabetic patients (P for interaction = 0.045). Among diabetic patients, hypoglycemia (OR = 3.02, 95% CI [1.20–7.63]), moderate hyperglycemia (OR = 1.75, 95% CI [1.04–2.92]), and severe hyperglycemia (OR = 2.97, 95% CI [1.87–4.71]) remained associated with elevated risk for mortality, but among nondiabetic patients, only patients with moderate hyperglycemia (OR = 2.34, 95% CI [1.93–2.84]) and severe hyperglycemia (OR = 3.92, 95% CI [3.04–5.04]) were at elevated mortality risk and not hypoglycemia (OR = 1.12, 95% CI [0.60–2.08]). This relationship was consistent across different study years (P for interaction = 0.900).

Conclusions:

The relationship between admission glucose and in-hospital mortality differs for diabetic and nondiabetic patients. Hypoglycemia was a bad prognostic marker among diabetic patients alone. The study results could be used to guide risk assessment among AMI patients using admission glucose.

Trial Registration:

www.clinicaltrials.gov, NCT01624883; https://clinicaltrials.gov/ct2/show/NCT01624883

Cardiac damage associated with stress hyperglycaemia and acute coronary syndrome changes according to level of presenting blood glucose

OBJECTIVE

To determine the prevalence of stress hyperglycaemia in people presenting with acute coronary syndrome (ACS), and the relationships between admission glucose and cardiac damage, cardiovascular mortality and morbidity.

METHODS

In a prospective observational study people presenting with ACS at the Gold Coast Hospital had their admission glucose (AG) level tested to determine stress hyperglycaemia. A range of measurements supplemented this data including troponin levels, category of ACS and major adverse coronary events (MACEs) were obtained through hospital records and patient follow-up post-discharge.

RESULTS

One hundred eighty-eight participants were recruited. The prevalence of stress hyperglycaemia in ACS was 44% with 31% having a previous diagnosis of type 2 diabetes and 7.7% had undiagnosed diabetes. The stress hyperglycaemic group had a significantly higher median troponin levels compared to participants with normal blood glucose levels on admission (p<0.05) however the highest presenting glucose group (>15 mmol/L) had troponin levels similar to people presenting with normal blood glucose levels and ACS (p>0.05).

CONCLUSIONS

Cardiac necrosis as measured by troponin levels is significantly increased in people with ACS and stress hyperglycaemia. This study found that one in four participants presenting with ACS and an admission glucose of >7.0 had no previous diagnosis for diabetes.

PRACTICE IMPLICATION

Consistently ordering HbA1C testing on patients with high AG can enable earlier diagnosis and treatment of diabetes.

Prognostic value of admission glycated haemoglobin in unknown diabetic patients with acute myocardial infarction

BACKGROUND

Acute glycometabolic derangement in non-diabetic patients with acute myocardial infarction (AMI) has been reported with discrepant prognostic results. The aim of the present study was to assess the prognostic impact of glycated haemoglobin (HbA1c) levels, reflecting long-term glycometabolic disturbance, in a population of patients without known diabetes mellitus.

METHODS

We examined 601 consecutive prospective patients diagnosed with AMI and unknown diabetes mellitus. We analysed metabolic function as a stratified variable using three groups of patients according to HbA1c: Group 1 (< 5.5%): 222 patients (37%); Group 2 (5.5 to 6.4%): 337 patients (56%); Group 3 (>6.4%): 42 patients (7%). Association between HbA1c groups and classic cardiovascular risk factor and in-hospital outcomes were assessed through univariate and multivariate analysis.

RESULTS

In-hospital mortality was 5% (32/601 patients). Higher HbA1c was associated with poor glycometabolic control, older patients, obesity, hypertension, Killip's class>1, increased heart rate, initial bundle branch block, atrial fibrillation and higher mortality during follow-up. In a multivariate adjusted risk, in-hospital mortality was associated with age (odds ratio (OR)= 1.056; 1-1.1; p=0.006), Killip's class>1 (OR=2.4; 1-6.1; p=0.05) and HbA1c (OR=1.5; 1.15-1.9; p=0.002). Hypertension (OR=0.39; 0.18-0.87; p=0.022) and angiotensin-converting enzyme inhibitors (OR=0.28; 0.12-0.69; p=0.005) were protective factors.

CONCLUSIONS

HbA1c is an important risk marker in the absence of a history of diabetes mellitus in patients with AMI. The optimal management strategy in these patients may contribute to decreased in-hospital mortality.

Impact of admission blood glucose levels on prognosis of elderly patients with ST elevation myocardial infarction treated by primary percutaneous coronary intervention

Objective

Admission hyperglycemia in acute myocardial infarction (MI) is related with increased in-hospital and long term mortality and major cardiac adverse events. We aimed to investigate how admission hyperglycemia affects the short and long term outcomes in elderly patients (> 65 years) after primary percutaneous coronary intervention for ST elevation myocardial infarction.

Methods

We retrospectively analyzed 677 consecutive elderly patients (mean age 72.2 ± 5.4). Patients were divided into two groups according to admission blood glucose levels. Group 1: low glucose group (LLG), glucose < 168 mg/dL; and Group 2: high glucose group (HGG), glucose > 168 mg/dL.

Results

In-hospital, long term mortality and in-hospital major adverse cardiac events were higher in the high admission blood glucose group (P < 0.001). Multivariate regression analysis showed: Killip > 1, post-thrombolysis in MI < 3 and admission blood glucose levels were independent predictors of in-hospital adverse cardiac events (P < 0.001).

Conclusions

Admission hyperglycemia in elderly patients presented with ST elevation myocardial infarction is an independent predictor of in-hospital major adverse cardiac events and is associated with in-hospital and long term mortality.

Plasma osmolality predicts clinical outcome in patients with acute coronary syndrome undergoing percutaneous coronary intervention

AIMS

The impact of plasma osmolality on clinical outcome in acute coronary syndrome (ACS) patients has not been investigated so far.

METHODS

In a retrospective analysis, we included 985 patients with ACS undergoing percutaneous coronary intervention (PCI). Plasma osmolality was calculated using concentrations of sodium, plasma glucose, and blood urea nitrogen at admission. Patients were stratified by quartiles (Q) of admission osmolality, clinical outcome was compared between those groups. The primary endpoints were in-hospital, 30-day, and 1-year mortality.

RESULTS

Univariate analysis in the Cox proportional-hazards model revealed significantly higher rates of in-hospital death for patients with osmolality in Q4, as compared to patients with osmolality in Q1-3 (HR 5.4, 95% CI 3.3-9.0, p<0.01). After adjustment for confounding baseline variables, osmolality in Q4 was associated with 2.8-fold hazard of in-hospital death (HR 2.75, 95% CI 1.35-5.61, p=0.005). Upon multivariate analysis, admission osmolality in Q4 vs. Q1-3 was associated with higher mortality rates after 30 days (HR 2.53, 95% CI 1.23-5.21, p=0.012) and 1 year (HR 1.73, 95% CI 1.02-2.91, p=0.04). Moreover, we performed landmark analysis in order to exclude critically ill patients, which revealed similar adjusted rates of death beyond 30 days to 1 year (HR 1.21, 95% CI 0.55-2.66, p=0.642).

CONCLUSIONS

Using the 4th quartile of plasma osmolality at admission as a natural cut-off point, osmolality in Q4, as compared to Q1-3, was significantly predictive of short term but not long-term outcome in ACS patients undergoing coronary stenting. Our data suggest osmolality to be an independent, feasible, and cost-effective tool for rapid risk stratification in ACS patients.

Plasma free Fatty Acid concentrations as a marker for acute myocardial infarction

BACKGROUND

Acute myocardial infarction carries a high mortality among cardiac patients.The discovery of the fact that certain enzymes like CPK, LDH liberated into circulation following necrosis of the myocardial cells came as boon for physicians and patients. There has been a constant search of different parameters for the diagnosis and management of CoronaryArtery Diseases (CAD).

AIM

The present study was undertaken to investigate a possible relation between the changes in plasma free fatty acid (FFA) concentration and acute myocardial infarction.

MATERIAL AND METHODS

Fifty cases (25 males and 25 females) of acute myocardial infarction were selected for the present study. All the patients were in the age group of 40-70 years. For the control group fifty (25 male and 25 female) subjects of same age group were selected from patient's relatives and friends. Plasma free fatty acid concentration was estimated by Titrametric method of Trout et al., (1960), a modified version of Dole (1956).

STATISTICAL ANALYSIS

The statistical analysis of the data of the present study was done by using SPSS, version 14.0.1 was used.

RESULTS

Our study showed a significant increase in plasma FFA in the first 24 hours of acute myocardial infarction with subsequent normalisation on the 7th day.The difference between the first and the seventh day was statistically significant.

CONCLUSION

The FFA were found raised in cases of acute myocardial infarction.On the basis of present study, it is worth to say that estimation of serum free fatty acid should be done routinely at the earliest opportunity in all cases of acute myocardial infarction.

Association of dysglycemia and all-cause mortality across the spectrum of coronary artery disease

OBJECTIVE

To assess the association between fasting plasma glucose (FPG) and all-cause mortality across the spectrum of coronary artery disease (CAD).

PATIENTS AND METHODS

The study included 18,999 patients during a study period of April 1, 2004, through October 31, 2010. The primary end points were in-hospital and follow-up all-cause mortality. According to the quartiles of FPG levels, patients were categorized into 4 groups: quartile 1, less than 5.1 mmol/L; quartile 2, 5.1 to less than 5.9 mmol/L; quartile 3, 5.9 to less than 7.5 mmol/L; and quartile 4, 7.5 mmol/L or greater. The conversion factor for units of plasma glucose is 1.00 mmol/L equals 18 mg/dL. Presented as mg/dL, the 4 quartile ranges of plasma glucose concentrations used in our data analysis are ≤90.0 mg/dL, 90.1-106.0 mg/dL, 106.1 mg/dL-135.0 mg/dL and ≥135.1 mg/dL. Quartile 1 was recognized as the lower glycemic group, quartiles 2 and 3 as the normoglycemic groups, and quartile 4 as the higher glycemic group.

RESULTS

In patients with acute myocardial infarction, all-cause mortality for the dysglycemic groups was higher than for the normoglycemic groups: in-hospital mortality for quartiles 1, 2, 3, and 4 was 1.0%, 0.9%, 0.2%, and 1.5%, respectively (P=.001); follow-up mortality for quartiles 1, 2, 3, and 4 was 1.7%, 0.9%, 0.3%, and 1.8%, respectively (P<.001). In patients with stable CAD, no significant differences in mortality were found among groups. However, in patients with unstable angina pectoris, the normoglycemic groups had lower follow-up mortality and roughly equal in-hospital mortality compared with the dysglycemic groups. After adjusting for confounding factors, this observation persisted.

CONCLUSION

The association between lower FPG level and mortality differed across the spectrum of CAD. In patients with acute myocardial infarction, there was a U-shaped relationship. In patients with stable CAD or unstable angina pectoris, mildly to moderately decreasing FPG level was associated with neither higher nor lower all-cause mortality.

Plasma free fatty acids and risk of heart failure: the Cardiovascular Health Study

BACKGROUND

Although plasma free fatty acid (FFA) concentrations have been associated with lipotoxicity, apoptosis, and risk of diabetes mellitus and coronary heart disease, it is unclear whether FFA levels are associated with heart failure (HF).

METHODS AND RESULTS

To test the hypothesis that plasma concentration of FFAs is positively associated with incident HF, we prospectively analyzed data on 4248 men and women free of HF at baseline and >65 years old from the Cardiovascular Health Study. FFA concentration was measured in duplicate by the Wako enzymatic method. Incident HF was validated by a centralized Events Committee. We used Cox proportional hazards to estimate the hazard ratio of HF per SD of FFAs. During a median follow-up of 10.5 years, a total of 1286 new cases of HF occurred. In a multivariable model adjusting for clinic site, comorbidity, demographic, anthropometric, and lifestyle factors, each SD (0.2 mEq/L) higher plasma FFA was associated with 12% (95% confidence interval, 6%-19%) higher risk of HF. Controlling for time-varying diabetes mellitus and coronary heart disease did not change the results (hazard ratio per SD, 1.16 [95% confidence interval, 1.09-1.23]).

CONCLUSIONS

A single measure of plasma FFA obtained later in life is associated with a higher risk of HF in older adults. Additional studies are needed to explore biological mechanisms by which FFAs may influence the risk of HF and determine whether FFAs could serve as a novel pharmacological target for HF prevention.

Hyperglycemia at admission and during hospital stay are independent risk factors for mortality in high risk cardiac patients admitted to an intensive cardiac care unit

AIMS

Hyperglycemia is associated with increased mortality in cardiac patients. However, the predictive value of admission- and average glucose levels in patients admitted to an intensive cardiac care unit (ICCU) has not been described.

METHODS

Observational study of patients admitted to the ICCU of a tertiary medical center in whom glucose levels were measured at and during admission. Over a 19-month period, 1713 patients were included. Mean age was 63±14 years, 1228 (72%) were male, 228 (17%) had known diabetes. Median (interquartile) glucose levels at admission were 7.9 (6.5-10.1) mmol/l; median glucose levels during ICCU admission (873 patients with three or more measurements) were 7.3 (6.7-8.3) mmol/l. Cox regression analysis was performed including the variables age, gender, admission diagnosis, length of stay, prior (cardio)vascular disease and diabetes.

RESULTS

A 1 mmol/l increase in admission glucose level (above 9 mmol/l) was associated with a 10% (95% confidence interval (CI): 7 -13%) increased risk for all-cause mortality. A 1 mmol/l higher average glucose level (above 8 mmol/l) was an additional independent predictor of mortality (HR 1.11, 95% CI: 1.03 - 1.20). At 30 days, 16.8% (97/579) of the patients with an admission glucose level in the highest tertile (>9.8 mmol/L) had died vs 5.2% (59/1134) of those with a lower admission glucose level.

CONCLUSION

In a high risk ICCU population, both high admission glucose levels as well as high average glucose levels during hospitalization were independently associated with increased mortality, even when accounting for other risk factors and parameters of disease severity.

Nonesterified fatty acids and risk of sudden cardiac death in older adults

BACKGROUND

Although nonesterified fatty acids (NEFA) have been positively associated with coronary heart disease risk factors, limited and inconsistent data are available on the relation between NEFA and sudden cardiac death.

METHODS AND RESULTS

Using a prospective design, we studied 4657 older men and women (mean age, 75 years) from the Cardiovascular Health Study (1992-2006) to evaluate the association between plasma NEFA and the risk of sudden cardiac death in older adults. Plasma concentrations of NEFA were measured using established enzymatic methods, and sudden death was adjudicated using medical records, death certificates, proxy interview, and autopsy reports. We used Cox proportional hazard models to estimate multivariable-adjusted relative risks. During a median follow-up of 10.0 years, 221 new cases of sudden cardiac death occurred. In a multivariable model adjusting for age, sex, race, clinic site, alcohol intake, smoking, prevalent coronary heart disease and heart failure, and self-reported health status, relative risks (95% confidence interval) for sudden cardiac death were 1.0 (ref), 1.15 (0.81-1.64), 1.06 (0.72-1.55), and 0.91 (0.60-1.38) across consecutive quartiles of NEFA concentration. In secondary analyses restricted to the first 5 years of follow-up, we also did not observe a statistically significant association between plasma NEFA and sudden cardiac death.

CONCLUSIONS

Our data do not provide evidence for an association between plasma NEFA measured late in life and the risk of sudden cardiac death in older adults.

Influence of Abnormal Fasting Plasma Glucose on Left Ventricular Function in Older Patients With Acute Myocardial Infarction

We assessed whether the admission fasting plasma glucose (FPG) levels were associated with all-cause mortality and left ventricular (LV) function in older patients with acute myocardial infarction (AMI). A total of 1854 consecutive patients were categorized into 4 groups: hypoglycemia, euglycemia, mild hyperglycemia, and severe hyperglycemia. The primary outcomes were in-hospital/3-year mortality and LV function. There was a near-linear relationship between FPG and Killip class. However, no significant correlation was found between FPG levels and LV ejection fraction. Both FPG levels and Killip classes were all independent significant predictors of mortality. Compared with the euglycemia group, both the hypo- and hyperglycemia groups were associated with higher in-hospital and 3-year mortality. In older patients with AMI, the FPG values had differential influences on LV function and mortality. There was a U-shaped relationship between FPG and in-hospital/3-year mortality, and a near-linear relationship between increased admission glucose levels and higher Killip classification.

Prognostic implications of stress hyperglycemia in acute ST elevation myocardial infarction. Prospective observational study

INTRODUCTION AND OBJECTIVES

In patients with acute myocardial infarction, elevation of plasma glucose levels is associated with worse outcomes. The aim of this study was to evaluate the association between stress hyperglycemia and in-hospital mortality in patients with acute myocardial infarction with ST-segment elevation (STEMI).

METHODS

We analyzed 834 consecutive patients admitted for STEMI to the Coronary Care Unit of our center. Association between admission glucose and mortality was assessed with Cox regression analysis. Discriminative accuracy of the multivariate model was assessed by Harrell's C statistic.

RESULTS

Eighty-nine (10.7%) patients died during hospitalization. Optimal threshold glycemia level of 140mg/dl on admission to predict mortality was obtained by ROC curves. Those who presented glucose ≥140mg/dl showed higher rates of malignant ventricular tachyarrhythmias (28% vs. 18%, P=.001), complicative bundle branch block (5% vs. 2%, P=.005), new atrioventricular block (9% vs. 5%, P=.05) and in-hospital mortality (15% vs. 5%, P<.001). Multivariate analysis showed that those with glycemia ≥140mg/dl exhibited a 2-fold increase of in-hospital mortality risk (95% CI: 1.2-3.5, P=.008) irrespective of diabetes mellitus status (P-value for interaction=0.487 and 0.653, respectively).

CONCLUSIONS

Stress hyperglycemia on admission is a predictor of mortality and arrhythmias in patients with STEMI and could be used in the stratification of risk in these patients.

Effect of abnormal fasting plasma glucose level on all-cause mortality in older patients with acute myocardial infarction: results from the Beijing Elderly Acute Myocardial Infarction Study (BEAMIS)

OBJECTIVE

To assess whether the relationship between abnormal fasting plasma glucose (FPG) levels and patient outcomes holds for both older men and older women with acute myocardial infarction (AMI).

PATIENTS AND METHODS

From April 1, 2004, to October 31, 2006, a total of 2016 consecutive older patients (age ≥65 years) presenting with AMI were screened. Of these patients, 1854 were consecutively enrolled in the study. Patients were categorized into 4 groups: the hypoglycemic group (FPG, ≤90.0 mg/dL [to convert to mmol/L, multiply by 0.0555]; n=443, 23.9%), the euglycemic group (FPG, 90.1-126.0 mg/dL; n=812, 43.8%), the mildly hyperglycemic group (FPG, 126.1-162.0 mg/dL; n=308, 16.6%), and the severely hyperglycemic group (FPG, ≥162.1 mg/dL; n=291, 15.7%). The primary outcomes were rates of in-hospital and 3-year mortality.

RESULTS

Female patients were older and had a higher incidence of diabetes mellitus but lower rates of smoking and use of invasive therapy. Men tended to have a higher frequency of hypoglycemia, whereas women tended to have a higher frequency of hyperglycemia. No significant difference was found in in-hospital (10.9% vs 9.1%; P=.36) or 3-year (24.5% vs 24.5%; P=.99) mortality between male and female patients, and FPG-associated mortality did not vary significantly by sex.

CONCLUSION

An increased FPG level was associated with a relatively higher risk of in-hospital mortality in men but not in women. Nonetheless, increased and decreased FPG levels at admission could predict higher mortality rates regardless of sex. There was a striking U-shaped relationship between FPG levels and in-hospital and 3-year mortality. The effect of abnormal FPG level on outcomes among older patients with AMI did not vary significantly by sex.

The role of insulin therapy and glucose normalisation in patients with acute coronary syndrome

Patients with acute myocardial infarction (AMI) and diabetes mellitus, as well as patients admitted with elevated blood glucose without known diabetes, have impaired outcome. Therefore intensive glucose-lowering therapy with insulin (IGL) has been proposed in diabetic or hyperglycaemic patients and has been shown to improve survival and reduce incidence of adverse events. The current manuscript provides an overview of randomised controlled trials investigating the effect of IGL. Furthermore, systematic glucose-insulin-potassium infusion (GIK) has been studied to improve outcome after AMI. In spite of positive findings in some early studies, GIK did not show any beneficial effects in recent clinical trials and thus this concept has been abandoned. While IGL targeted to achieve normoglycaemia improves outcome in patients with AMI, achievement of glucose regulation is difficult and carries the risk of hypoglycaemia. More research is needed to determine the optimal glucose target levels in AMI and to investigate whether computerised glucose protocols and continuous glucose sensors can improve safety and efficacy of IGL.

An overview of glycemic control in the coronary care unit with recommendations for clinical management

The observation that elevated glucose occurs frequently in the setting of acute myocardial infarction was made decades ago. Since then numerous studies have documented that hyperglycemia is a powerful risk factor for increased mortality and in-hospital complications in patients with acute coronary syndromes. While some questions in this field have been answered in prior investigations, many critical gaps in knowledge continue to exist and remain subjects of intense debate. This review summarizes what is known about the relationship between hyperglycemia, glucose control, and outcomes in critically ill patients with acute coronary syndromes, addresses the gaps in knowledge and controversies, and offers general recommendations regarding glucose management in the coronary care unit.

Artificial selection for whole animal low intrinsic aerobic capacity co-segregates with hypoxia-induced cardiac pump failure

Oxygen metabolism is a strong predictor of the general health and fitness of an organism. In this study, we hypothesized that a divergence in intrinsic aerobic fitness would co-segregate with susceptibility for cardiovascular dysfunction. To test this hypothesis, cardiac function was assessed in rats specifically selected over nineteen generations for their low (LCR) and high (HCR) intrinsic aerobic running capacity. As an integrative marker of native aerobic capacity, run time to exhaustion between LCR and HCR rats had markedly diverged by 436% at generation nineteen of artificial selection. In vivo assessment of baseline cardiac function by echocardiography and catheter-based conductance micromanometry showed no marked difference in cardiac performance. However, when challenged by exposure to acute hypoxia, cardiac pump failure occurred significantly earlier in LCR rats compared to HCR animals. Acute cardiac decompensation in LCR rats was exclusively due to the development of intractable irregular ventricular contractions. Analysis of isolated cardiac myocytes showed significantly slower sarcomeric relaxation and delayed kinetics of calcium cycling in LCR myocytes compared to HCR myocytes. This study also revealed that artificial selection for low native aerobic capacity is a novel pathologic stimulus that results in myosin heavy chain isoform switching in the heart as shown by increased levels of beta-MHC in LCR rats. Together, these results provide evidence that alterations in sub-cellular calcium handling and MHC isoform composition are associated with susceptibility to compensatory cardiac remodeling and hypoxia induced pump failure in animals with low intrinsic aerobic capacity.

Elevated admission glucose and mortality in elderly patients hospitalized with heart failure

BACKGROUND

Although some professional societies recommend target-driven glucose control for all hospitalized patients, the association between elevated glucose and adverse outcomes has not been well established in patients hospitalized with heart failure.

METHODS AND RESULTS

We evaluated a nationally representative cohort of 50,532 elderly patients hospitalized with heart failure in the United States between April 1998 and June 2001. The association between admission glucose and all-cause mortality at 30 days and 1 year was analyzed with multivariable Cox regression models, both in the entire cohort and in patients with and without diabetes mellitus. After multivariable adjustment, no significant relationship was found between glucose and 30-day mortality (for glucose groups of >110 to 140, >140 to 170, >170 to 200, and >200 mg/dL; hazard ratios for 30-day mortality were 1.09 (95% confidence interval, 0.98 to 1.22), 1.27 (95% confidence interval, 1.11 to 1.45), 1.16 (95% confidence interval, 0.98 to 1.37), and 1.00 (95% confidence interval, 0.87 to 1.15), respectively, versus glucose < or =110 mg/dL; P for linear trend=0.53). Results were similar for 1-year mortality and did not differ between patients with and without known diabetes mellitus (for diabetesxglucose interaction, P=0.11 and 0.55 for 30-day and 1-year mortality, respectively).

CONCLUSIONS

We found no significant association between admission glucose levels and mortality in a large cohort of patients hospitalized with heart failure. Our findings suggest that the relationship between hyperglycemia and adverse outcomes seen in acute myocardial infarction cannot be automatically extended to patients hospitalized with other cardiovascular conditions.

Effect of insulin infusion on electrocardiographic findings following acute myocardial infarction: importance of glycaemic control

AIMS

To determine the effects of insulin infusion and blood glucose levels during acute myocardial infarction (AMI) on electrocardiographic (ECG) features of myocardial electrical activity.

METHODS

ECGs at admission and 24 h were examined in a randomized study of insulin infusion vs. routine care for AMI patients with diabetes or hyperglycaemia. Results were analysed according to treatment allocation and also according to average blood glucose level.

RESULTS

ECG characteristics were similar at admission in both groups. Patients allocated to conventional treatment had prolongation of the QT interval (QTc) after 24 h but those receiving infused insulin did not. In patients with a mean blood glucose in the first 24 h > 8.0 mmol/l, new ECG conduction abnormalities were significantly more common than in patients with mean blood glucose <or= 8.0 mmol/l (15.0% vs. 6.0%, P < 0.05).

CONCLUSIONS

Prevention of QTc prolongation by administration of insulin may reflect a protective effect on metabolic and electrical activity in threatened myocardial tissue. Abnormalities of cardiac electrical conduction may also be influenced by blood glucose.

Glucose-insulin therapy, plasma substrate levels and cardiac recovery after cardiac ischemic events

Introduction

The potential usefulness of glucose-insulin therapy relies to a large extent on the premise that it prevents hyperglycemia and hyperlipidemia following cardiac ischemic events.

Methods

In this review we evaluate the literature concerning plasma glucose and free fatty acids levels during and following cardiac ischemic events.

Results

The data indicate that hyperlipidemia and hyperglycemia most likely occur during acute coronary ischemic syndromes in the conscious state (e.g. acute myocardial infarction) and less so during reperfusion following CABG reperfusion. This is in accordance with observations that glucose-insulin therapy during early reperfusion post CABG may actually cause hypolipidemia, because substantial hyperlipidemia does not appear to occur during that stage of cardiac surgery.

Discussion

Considering recent data indicating that hypolipidemia may be detrimental for cardiac function, we propose that free fatty acid levels during reperfusion post CABG with the adjunct glucose-insulin therapy need to be closely monitored.

Conclusion

From a clinical point of view, a strategy directed at monitoring and thereafter maintaining plasma substrate levels in the normal range for both glucose (4–6 mM) and FFA (0.2–0.6 mM) as well as stimulation of glucose oxidation, promises to be the most optimal metabolic reperfusion treatment following cardiac ischemic episodes. Future (preclinical and subsequently clinical) investigations are required to investigate whether the combination of glucose-insulin therapy with concomitant lipid administration may be beneficial in the setting of reperfusion post CABG.

The prognostic significance of serum glucose levels after the onset of ventricular arrhythmia on in-hospital mortality of patients with acute coronary syndrome

BACKGROUND

Several studies have illustrated the role played by serum glucose levels in cardiovascular morbidity and mortality in general and, more particularly, after an acute coronary event.

AIM

The aim of this study was to evaluate the impact of serum potassium and glucose levels on in-hospital mortality in patients with ischemic heart disease, who exhibited severe ventricular arrhythmia.

METHODS

We enrolled 162 consecutive patients who were referred to our institution for an acute coronary event and presented with sustained ventricular tachycardia or ventricular fibrillation during the first 24 hours of hospitalization. Serum potassium and glucose levels were measured in all patients at the onset of tachycardia and after 2, 4, 6, 12, 36, 48 hours.

RESULTS

During hospitalization, 23 out of 162 patients died (61% males). Serum glucose levels at the onset of the arrhythmia, as well as after 2, 12, 36 and 48 hours, were higher in the deceased (onset: 228.8 +/- 108 vs. 158 +/- 68 mg/dl, p = 0.0001, 2 h: 182 +/- 109 vs. 149 +/- 59 mg/dl, p = 0.03, 12 h: 155.5 +/- 72 vs. 128 +/- 48 mg/dl, p = 0.025, 36 h: 163.8 +/- 63 vs.116 +/- 42 mg/dl, p = 0.002, and 48 h: 138 +/- 64 vs. 122 +/- 42 mg/dl, p = 0.05, respectively), even after adjustment for age, sex, diabetes, left ventricular ejection fraction, type of acute coronary syndrome and site of infarction and medication intake. There was no difference in serum potassium levels between the deceased and survivors.

CONCLUSION

Serum glucose levels at the onset of arrhythmia and 2, 36 and 48 hours later seem to have prognostic significance for in-hospital mortality in patients hospitalized for an acute coronary event, who exhibit severe ventricular arrhythmia.

Hyperglycemia and acute coronary syndrome: a scientific statement from the American Heart Association Diabetes Committee of the Council on Nutrition, Physical Activity, and Metabolism

Hyperglycemia is common and associated with markedly increased mortality rates in patients hospitalized with acute coronary syndromes (ACS). Despite the fact that several studies have documented this association, hyperglycemia remains underappreciated as a risk factor, and it is frequently untreated in ACS patients. This is in large part due to limitations of prior studies, and the remaining critical gaps in our understanding of the relationship between hyperglycemia and poor outcomes. The main objective of the present statement is to summarize the current state of knowledge regarding the association between elevated glucose and patient outcomes in ACS and to outline the most important knowledge gaps in this field. These gaps include the need to specifically define hyperglycemia, develop optimal ways of measuring and tracking glucose values during ACS hospitalization, and better understand the physiological mechanisms responsible for poor outcomes associated with hyperglycemia. The most important issue, however, is whether elevated glucose is a direct mediator of adverse outcomes in ACS patients or just a marker of greater disease severity. Given the marked increase in short- and long-term mortality associated with hyperglycemia, there is an urgent need for definitive large randomized trials to determine whether treatment strategies aimed at glucose control will improve patient outcomes and to define specific glucose treatment targets. Although firm guidelines will need to await completion of these clinical trials, the present statement also provides consensus recommendations for hyperglycemia management in patients with ACS on the basis of the available data.

Glucometrics in patients hospitalized with acute myocardial infarction: defining the optimal outcomes-based measure of risk

BACKGROUND

Hyperglycemia on admission is associated with an increased mortality rate in patients with acute myocardial infarction. Whether metrics that incorporate multiple glucose assessments during acute myocardial infarction hospitalization are better predictors of mortality than admission glucose alone is not well defined.

METHODS AND RESULTS

We evaluated 16,871 acute myocardial infarction patients hospitalized from January 2000 to December 2005. Using logistic regression models and C indexes, 3 metrics of glucose control (mean glucose, time-averaged glucose, hyperglycemic index), each evaluated over 3 time windows (first 24 hours, 48 hours, entire hospitalization), were compared with admission glucose for their ability to discriminate hospitalization survivors from nonsurvivors. Models were then used to evaluate the relationship between mean glucose and in-hospital mortality. All average glucose metrics performed better than admission glucose. The ability of models to predict mortality improved as the time window increased (C indexes for admission, mean 24 hours, 48 hours, and hospitalization glucose were 0.62, 0.64, 0.66, 0.70; P<0.0001). Statistically significant but small differences in C indexes of mean glucose, time-averaged glucose, and hyperglycemic index were seen. Mortality rates increased with each 10-mg/dL rise in mean glucose > or = 120 mg/dL (odds ratio, 1.8; P=0.003 for glucose 120 to < 130 mg/dL) and with incremental decline < 70 mg/dL (odds ratio, 6.4; P=0.01 versus glucose 100 to < 110 mg/dL). The slope of these relationships was steeper in patients without diabetes.

CONCLUSIONS

Measures of persistent hyperglycemia during acute myocardial infarction are better predictors of mortality than admission glucose. Mean hospitalization glucose appears to be the most practical metric of hyperglycemia-associated risk. A J-shaped relationship exists between average glucose and mortality, with both persistent hyperglycemia and hypoglycemia associated with adverse prognosis.

Secondary prevention of CHD in UK men: the Diet and Reinfarction Trial and its sequel

The Diet and Reinfarction Trial (DART) involved 2033 men (mean age 56.5 years) recovering from myocardial infarction. They were randomly allocated to receive advice or to receive no advice on each of three dietary factors: an increase in fatty fish intake; a reduction in fat intake with an increase in polyunsaturated fat:saturated fat; an increased intake of cereal fibre. Compliance was satisfactory with the fish and fibre advice, but less so with the fat advice. The men given fish advice had 29% lower 2-year all-cause mortality; the other forms of advice did not have any significant effects. The Diet and Angina Randomized Trial (DART-2) involved 3114 men (mean age 61.1 years) with stable angina, who were followed up for 3-9 years. Advice to eat oily fish or take fish oil did not affect all-cause mortality, but it was associated with a significant increase in sudden cardiac death (P=0.018), and this effect was largely confined to the subgroup given fish oil capsules. Advice to eat more fruit and vegetables had no effect, probably because of poor compliance. The outcome of DART-2 appears to conflict with that of DART and some other studies; various possible explanations are considered. Nutritional interventions are not equally acceptable and should be tailored to the individuals for whom they are intended. Various distinct groups have a raised risk of CHD, and it cannot be assumed that the same nutritional interventions are appropriate to them all. Nutritional supplements do not necessarily have the same effects as the foods from which they are derived.

Effects of low molecular weight heparin on the frequencies of intradialytic arrhythmias in hemodialysis patients

Arrhythmia is known to cause sudden death in hemodialysis patients. Heparin administration releases lipoprotein lipase from the capillary endothelial cell surface, resulting in an increase in the plasma levels of free fatty acids; higher levels of free fatty acids may affect the occurrence of arrhythmias. This study assessed whether the occurrence of arrhythmias during hemodialysis could be suppressed by replacing unfractionated heparin with low molecular weight heparin. Ten dialysis patients who had supraventricular premature contraction and/or ventricular premature contraction were monitored by the Holter electrocardiograph system during hemodialysis. To investigate the effect of each form of heparin on plasma lipid metabolism, the lipoprotein lipase and lipid levels before and during hemodialysis were measured. The occurrence of arrhythmias was significantly suppressed in hemodialysis using low molecular weight heparin, as compared with hemodialysis using unfractionated heparin. Lower lipoprotein lipase and free fatty acids levels were also observed in hemodialysis using low molecular weight heparin. The authors concluded that hemodialysis using low molecular weight heparin instead of unfractionated heparin could be effective in protecting hemodialysis patients with arrhythmias against arrhythmia-related cardiac events.

Abnormalities of whole body protein turnover, muscle metabolism and levels of metabolic hormones in patients with chronic heart failure

OBJECTIVE

It is well known that chronic heart failure (CHF) is associated with insulin resistance and cachexia, but little is known about the underlying substrate metabolism. The present study was undertaken to identify disturbances of basal glucose, lipid and protein metabolism.

DESIGN

We studied eight nondiabetic patients with CHF (ejection fraction 30 +/- 4%) and eight healthy controls. Protein metabolism (whole body and regional muscle fluxes) and total glucose turnover were isotopically assayed. Substrate oxidation were obtained by indirect calorimetry. The metabolic response to exercise was studied by bicycle ergometry exercise.

RESULTS

Our data confirm that CHF patients have a decreased lean body mass. CHF patients are characterised by (i) decreased glucose oxidation [glucose oxidation (mg kg(-1) min(-1)): 1.25 +/- 0.09 (patients) vs. 1.55 +/- 0.09 (controls), P < 0.01] and muscle glucose uptake [a - v diff(glucose) (micromol L(-1)): -10 +/- 25 (patients) vs. 70 +/- 22 (controls), P < 0.01], (ii) elevated levels of free fatty acids (FFA) [FFA (mmol L(-1)): 0.72 +/- 0.05 (patients) vs. 0.48 +/- 0.03 (controls), P < 0.01] and 3-hydroxybutyrate and signs of elevated fat oxidation and muscle fat utilization [a - v diff(FFA) (mmol L(-1)): 0.12 +/- 0.02 (patients) vs. 0.05 +/- 0.01 (controls), P < 0.05] and (iii) elevated protein turnover and protein breakdown [phenylalanine flux (micromol kg(-1) h(-1)): 36.4 +/- 1.5 (patients) vs. 29.6 +/- 1.3 (controls), P < 0.01]. Patients had high circulating levels of noradrenaline, glucagon, and adiponectin, and low levels of ghrelin. We failed to observe any differences in metabolic responses between controls and patients during short-term exercise.

CONCLUSIONS

In the basal fasting state patients with CHF are characterized by several metabolic abnormalities which may contribute to CHF pathophysiology and may provide a basis for targeted intervention.

Free fatty acids are independently associated with all-cause and cardiovascular mortality in subjects with coronary artery disease

CONTEXT

Free fatty acids (FFAs) are associated with several cardiovascular risk factors and exert harmful effects on the myocardium.

OBJECTIVE

The aim of our study was to elucidate the relationship between FFAs and mortality in subjects who underwent coronary angiography.

DESIGN, SETTING, AND PARTICIPANTS

Ludwigshafen Risk and Cardiovascular Health is a prospective cohort study of Caucasians who had undergone coronary angiography at baseline (1997-2000). During a median time of follow-up of 5.38 yr, 513 deaths had occurred among 3315 study participants with measured FFAs.

MAIN OUTCOME MEASURE

Hazard ratios for mortality according to FFA levels were measured.

RESULTS

At the fourth quartile of FFAs, fully adjusted hazard ratios for death from any cause and cardiovascular causes were 1.58 (P = 0.002) and 1.83 (P = 0.001), respectively. In persons with angiographic coronary artery disease (CAD), stable CAD, and unstable CAD, the predictive value of FFAs was similar to that in the entire cohort, but the association did not attain statistical significance in persons without CAD analyzed separately. FFA levels were not related to the presence of angiographic CAD but were elevated in subjects with unstable CAD, compared with probands with stable CAD. Furthermore, FFAs increased with the severity of heart failure and were positively correlated with N-terminal pro-B-type natriuretic peptide (P < 0.001).

CONCLUSIONS

FFA levels independently predict all-cause and cardiovascular mortality in subjects with angiographic CAD. A possible diagnostic use of FFAs warrants further studies, but our results may underline the importance of therapeutic approaches to influence FFA metabolism.

Size of myocardial infarction induced by ischaemia/reperfusion is unaltered in rats with metabolic syndrome

Obesity is associated with metabolic syndrome and increased incidence of and mortality from myocardial infarction. The aim of the present study was to develop an animal model with metabolic syndrome and examine how that influences size of myocardial infarcts induced by occlusion and reperfusion of the left anterior descending coronary artery. Sprague–Dawley rats (n=105) were fed either LF (low-fat) or MHF (moderately high-fat) diets for 13 weeks before coronary occlusion for 45 min, followed by reperfusion for 60 min. Compared with LF-fed and lean MHF-fed rats, obese MHF-fed rats developed metabolic disturbances similar to those seen in the metabolic syndrome, including being overweight by 24% (compared with lean MHF-fed rats), having 74% more visceral fat (compared with LF-fed rats), 15% higher blood pressure (compared with LF-fed rats), 116% higher plasma insulin (compared with lean MHF-fed rats), 10% higher fasting plasma glucose (compared with LF-fed rats), 35% higher non-fasting plasma glucose (compared with lean MHF-fed rats), 36% higher plasma leptin (compared with lean MHF-fed rats) and a tendency to lower plasma adiponectin and higher plasma non-esterified fatty acids. Infarct size was similar in the three groups of rats (36±14, 42±18 and 41±14% in obese MHF-fed, lean MHF-fed and LF-fed rats respectively). In conclusion, rats fed a MHF diet developed metabolic syndrome, but this did not influence myocardial infarct size.

Dyslipidemia is Associated with Ventricular Tachyarrhythmia in Patients with Acute ST-Segment Elevation Myocardial Infarction

BACKGROUND

Ventricular tachyarrhythmia developing in the acute stage of myocardial infarction (MI) is an important cause of sudden cardiac death. The aim of this study was to determine whether dyslipidemia is associated with the occurrence of ventricular tachycardia/fibrillation (VT/VF) during the acute stage of ST-segment elevation MI (STEMI).

METHODS

A total of 58 patients experiencing VT/VF within 24 hours after the onset of MI were selected as the study group. A group of 58 patients with MI but without VT/VF was selected as the control group matched for sex (overall, 104 males), age (overall, 58 +/- 10 years), and the use of thrombolytic therapy (n = 82). The lipid profiles including total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglyceride were measured during the first week and at the third month after the index MI. Other coronary risk factors, and clinical, hemodynamic and angiographic characteristics were also included in the assessment.

RESULTS

During the acute stage, patients with VT/VF had higher levels of LDL-C and lower blood pressure on initial arrival at our hospital. At the 3-month follow-up, those patients with VT/VF showed higher levels of TC, LDL-C and triglyceride. Multivariate analysis revealed that LDL-C (p < 0.001) at the 3-month follow-up, mean blood pressure on arrival (p < 0.01), and the difference in triglyceride levels between the first week and the third month (p < 0.05) were independent predictors for the occurrence of VT/VF in the acute stage of MI.

CONCLUSION

This study suggests that dyslipidemia imposes a higher risk of developing tachyarrhythmia in the acute phase of STEMI.

Admission glucose and mortality in elderly patients hospitalized with acute myocardial infarction: implications for patients with and without recognized diabetes

BACKGROUND

The relationship between admission glucose levels and outcomes in older diabetic and nondiabetic patients with acute myocardial infarction is not well defined.

METHODS AND RESULTS

We evaluated a national sample of elderly patients (n=141,680) hospitalized with acute myocardial infarction from 1994 to 1996. Admission glucose was analyzed as a categorical (< or =110, >110 to 140, >140 to 170, >170 to 240, >240 mg/dL) and continuous variable for its association with mortality in patients with and without recognized diabetes. A substantial proportion of hyperglycemic patients (eg, 26% of those with glucose >240 mg/dL) did not have recognized diabetes. Fewer hyperglycemic patients without known diabetes received insulin during hospitalization than diabetics with similar glucose levels (eg, glucose >240 mg/dL, 22% versus 73%; P<0.001). Higher glucose levels were associated with greater risk of 30-day mortality in patients without known diabetes (for glucose range from < or =110 to >240 mg/dL, 10% to 39%) compared with diabetics (range, 16% to 24%; P for interaction <0.001). After multivariable adjustment, higher glucose levels continued to be associated with a graded increase in 30-day mortality in patients without known diabetes (referent, glucose < or =110 mg/dL; range from glucose >110 to 140 mg/dL: hazard ratio [HR], 1.17; 95% CI, 1.11 to 1.24; to glucose >240 mg/dL: HR, 1.87; 95% CI, 1.75 to 2.00). In contrast, among diabetic patients, greater mortality risk was observed only in those with glucose >240 mg/dL (HR, 1.32; 95% CI, 1.17 to 1.50 versus glucose < or =110 mg/dL; P for interaction <0.001). One-year mortality results were similar.

CONCLUSIONS

Elevated glucose is common, rarely treated, and associated with increased mortality risk in elderly acute myocardial infarction patients, particularly those without recognized diabetes.

Ventricular fibrillation: basic concepts

This brief overview serves as an introduction to the vast array of basic and clinical concepts that are pertinent to the basic understanding of ventricular fibrillation, its genesis, and its clinical management.

Fatty Acid Translocase/CD36 Deficiency Does Not Energetically or Functionally Compromise Hearts Before or After Ischemia

Background— Evidence from humans suggests that fatty acid translocase (FAT)/CD36 deficiency can lead to functionally and/or energetically compromised hearts, but the data are equivocal, and the subject remains controversial. In this report we assessed the contribution of FAT/CD36 to overall fatty acid oxidation rates in the intact heart and determined the effect of FAT/CD36 on energy metabolism during reperfusion of ischemic hearts.

Methods and Results— Isolated working hearts from wild-type and FAT/CD36-knockout (KO) mice were perfused with Krebs-Henseleit solution containing 0.4 or 1.2 mmol/L [U- 3 H]palmitate, 5 mmol/L [U- 14 C]glucose, 2.5 mmol/L calcium, and 100 μU/mL insulin at a preload pressure of 11.5 mm Hg and afterload pressure of 50 mm Hg. Hearts were aerobically perfused for 30 minutes or aerobically perfused for 30 minutes, followed by 18 minutes of global no-flow ischemia and 40 minutes of aerobic reperfusion. Rates of fatty acid oxidation in FAT/CD36-KO hearts were significantly lower than in wild-type hearts at both concentrations of palmitate (0.4 or 1.2 mmol/L). In addition, hearts from FAT/CD36-KO mice displayed a compensatory increase in glucose oxidation rates. On aerobic reperfusion after ischemia, cardiac work of FAT/CD36-KO hearts recovered to the same extent as wild-type hearts.

Conclusions— FAT/CD36-deficient hearts are not energetically or functionally compromised and are not more sensitive to ischemic injury because glucose oxidation can compensate for the loss of fatty acid–derived ATP.

Failing atrial myocardium: energetic deficits accompany structural remodeling and electrical instability

The failing ventricular myocardium is characterized by reduction of high-energy phosphates and reduced activity of the phosphotransfer enzymes creatine kinase (CK) and adenylate kinase (AK), which are responsible for transfer of high-energy phosphoryls from sites of production to sites of utilization, thereby compromising excitation-contraction coupling. In humans with chronic atrial fibrillation (AF) unassociated with congestive heart failure (CHF), impairment of atrial myofibrillar energetics linked to oxidative modification of myofibrillar CK has been observed. However, the bioenergetic status of the failing atrial myocardium and its potential contribution to atrial electrical instability in CHF have not been determined. Dogs with (n = 6) and without (n = 6) rapid pacing-induced CHF underwent echocardiography (conscious) and electrophysiological (under anesthesia) studies. CHF dogs had more pronounced mitral regurgitation, higher atrial pressure, larger atrial area, and increased atrial fibrosis. An enhanced propensity to sustain AF was observed in CHF, despite significant increases in atrial effective refractory period and wavelength. Profound deficits in atrial bioenergetics were present with reduced activities of the phosphotransfer enzymes CK and AK, depletion of high-energy phosphates (ATP and creatine phosphate), and reduction of cellular energetic potential (ATP-to-ADP and creatine phosphate-to-Cr ratios). AF duration correlated with left atrial area (r = 0.73, P = 0.01) and inversely with atrial ATP concentration (r = -0.75, P = 0.005), CK activity (r = -0.57, P = 0.054), and AK activity (r = -0.64, P = 0.02). Atrial levels of malondialdehyde, a marker of oxidative stress, were significantly increased in CHF. Myocardial bioenergetic deficits are a conserved feature of dysfunctional atrial and ventricular myocardium in CHF and may constitute a component of the substrate for AF in CHF.