Diabetes mellitus and atrial fibrillation: perspectives on epidemiological and pathophysiological links

The risk of type 2-diabetes among persons with intellectual disability: a Danish population-based matched cohort study

BACKGROUND

Previous research shows that obesity, unhealthy eating, physical inactivity and a high use of psychotropic medications are prevalent among persons with intellectual disability (ID), which might increase the risk of type 2-diabetes (T2DM). This study aims to investigate: (1) whether persons with ID have an increased risk of T2DM compared with an age- and sex-matched reference group and (2) differences in T2DM risk by sex, birth year, ID inclusion diagnosis and ID severity.

METHODS

This study is a nationwide cohort study, including 65 293 persons with ID and 659 723 persons in an age- and sex-matched reference group without ID. Incidence rates for T2DM were calculated and Cox proportional regression models were used to estimate adjusted hazard ratios (aHRs) for the association between ID and T2DM. Follow-up began from the 1 January 1977 (when T2DM data were available), participants' 22nd birthday or from the date the participants immigrated to Denmark, whichever came last and continued until the onset of T2DM, emigration, death or end of follow-up (31 December 2021), whichever came first.

RESULTS

Persons with ID had more than double risk of T2DM compared with the reference group [aHR = 2.15, 95% confidence interval (CI): 2.09-2.20]. The strongest associations were found among women, persons born between 1980 and 1999 and among persons with mild ID.

CONCLUSIONS

Persons with ID have an increased risk of T2DM. This knowledge is important in relation to the development and prioritising of preventive initiatives among persons with ID in the healthcare sector. Future research should focus on the underlying mechanisms that can explain the possible association between ID and T2DM as it allows a more targeted prevention strategy.

Assessing the association between triglyceride-glucose index and atrial fibrillation: a systematic review and meta-analysis

BACKGROUND

An essential relationship between insulin resistance (IR) and atrial fibrillation (AF) has been demonstrated. Among the methods used to assess IR, the triglyceride-glucose (TyG) index is the more straightforward, dimensionless, and low-cost tool. However, the possible usage of this index in clinical practice to predict and diagnose AF has yet to be determined and consolidated.

OBJECTIVE AND RATIONALE

Herein, we performed a systematic review and meta-analysis to assess the association between the TyG index and AF.

METHODS

Databases (PubMed, Embase, Scopus, and Web of Science) were systematically searched for studies evaluating the TyG index in AF. The inclusion criteria were observational studies investigating AF and TyG index correlation in individuals older than 18 years, while preclinical studies and those without the relevant data were excluded. Random effect meta-analyses comparing TyG levels between AF and non-AF cases, AF recurrence after radiofrequency ablation, and post-procedural AF were performed using standardized mean differences (SMD) with their matching 95% confidence intervals (CIs).

RESULTS

Our screening identified nine studies to be analyzed, including 6,171 participants including 886 with AF. The meta-analysis demonstrated that the TyG index resulted higher in patients with AF than non-AF counterparts (SMD 1.23, 95% CI 0.71 to 1.75, I2 98%, P < 0.001). Subgroup analysis showed the same results for post-procedure AF (SMD 0.99, 95% CI 0.78 to 1.20, I2 10%, P < 0.001) and post-ablation AF (SMD 1.25, 95% CI 1.07 to 1.43, I2 46%, P < 0.001), while no difference was found in population-based cohorts (SMD 1.45, 95% CI - 0.41 to 3.31, I2 100%, P = 0.13). Publication year (P = 0.036) and sample size (P = 0.003) showed significant associations with the effect size, using multivariable meta-regression.

CONCLUSION

The TyG index is an easy-to-measure surrogate marker of IR in patients with AF. Further clinical studies are warranted to demonstrate its ability for routine clinical use and as a screening tool.

Heterogeneity of outcomes within diabetic patients with atrial fibrillation on edoxaban: a sub-analysis from the ETNA-AF Europe registry

BACKGROUND

Recent data have suggested that insulin-requiring diabetes mostly contributes to the overall increase of thromboembolic risk in patients with atrial fibrillation (AF) on warfarin. We evaluated the prognostic role of a different diabetes status on clinical outcome in a large cohort of AF patients treated with edoxaban.

METHODS

We accessed individual patients' data from the prospective, multicenter, ETNA-AF Europe Registry. We compared the rates of ischemic stroke/transient ischemic attack (TIA)/systemic embolism, myocardial infarction (MI), major bleeding and all-cause death at 2 years according to diabetes status.

RESULTS

Out of an overall population of 13,133 patients, 2885 had diabetes (22.0%), 605 of whom (21.0%) were on insulin. The yearly incidence of ischemic stroke/TIA/systemic embolism was 0.86% in patients without diabetes, 0.87% in diabetic patients not receiving insulin (p = 0.92 vs no diabetes) and 1.81% in those on insulin (p = 0.002 vs no diabetes; p = 0.014 vs diabetes not on insulin). The annual rates of MI and major bleeding were 0.40%, 0.43%, 1.04% and 0.90%, 1.10% and 1.71%, respectively. All-cause yearly mortality was 3.36%, 5.02% and 8.91%. At multivariate analysis, diabetes on insulin was associated with a higher rate of ischemic stroke/TIA/systemic embolism [adjusted HR 2.20, 95% CI 1.37-3.54, p = 0.0011 vs no diabetes + diabetes not on insulin] and all-cause death [aHR 2.13 (95% CI 1.68-2.68, p < 0.0001 vs no diabetes]. Diabetic patients not on insulin had a higher mortality [aHR 1.32 (1.11-1.57), p = 0.0015], but similar incidence of stroke/TIA/systemic embolism, MI and major bleeding, vs those without diabetes.

CONCLUSIONS

In a real-world cohort of AF patients on edoxaban, diabetes requiring insulin therapy, rather than the presence of diabetes per se, appears to be an independent factor affecting the occurrence of thromboembolic events during follow-up. Regardless of the diabetes type, diabetic patients had a lower survival compared with those without diabetes.

Atrial Fibrillation and Diabetes Mellitus: Dangerous Liaisons or Innocent Bystanders?

Atrial fibrillation (AF) is the most common arrhythmia in adults and diabetes mellitus (DM) is a major risk factor for cardiovascular diseases. However, the relationship between both pathologies has not been fully documented and new evidence supports the existence of direct and independent links. In the myocardium, a combination of structural, electrical, and autonomic remodeling may lead to AF. Importantly, patients with AF and DM showed more dramatic alterations than those with AF or DM alone, particularly in mitochondrial respiration and atrial remodeling, which alters conductivity, thrombogenesis, and contractile function. In AF and DM, elevations of cytosolic Ca²⁺ and accumulation of extra cellular matrix (ECM) proteins at the interstitium can promote delayed afterdepolarizations. The DM-associated low-grade inflammation and deposition/infiltration of epicardial adipose tissue (EAT) enforce abnormalities in Ca²⁺ handling and in excitation-contraction coupling, leading to atrial myopathy. This atrial enlargement and the reduction in passive emptying volume and fraction can be key for AF maintenance and re-entry. Moreover, the stored EAT can prolong action of potential durations and progression from paroxysmal to persistent AF. In this way, DM may increase the risk of thrombogenesis as a consequence of increased glycation and oxidation of fibrinogen and plasminogen, impairing plasmin conversion and resistance to fibrinolysis. Additionally, the DM-associated autonomic remodeling may also initiate AF and its re-entry. Finally, further evidence of DM influence on AF development and maintenance are based on the anti-arrhythmogenic effects of certain anti-diabetic drugs like SGLT2 inhibitors. Therefore, AF and DM may share molecular alterations related to Ca²⁺ mobility, mitochondrial function and ECM composition that induce atrial remodeling and defects in autonomic stimulation and conductivity. Likely, some specific therapies could work against the associated cardiac damage to AF and/or DM.

Atrial fibrillation - Can HbA1c levels really predict the risk?

BACKGROUND

Diabetes is associated with higher mortality and worse post-operative outcomes in patients undergoing coronary artery bypass grafting and HbA1c levels have consistently been reported to be associated with adverse post-operative outcomes. However, the role of HbA1c still remains unclear with regards to the occurrence of atrial fibrillation.

METHOD

Data for the patients undergoing off-pump coronary artery bypass grafting was analysed in a retrospective fashion. Patients were divided into-those with HbA1c < 6.5% and those with HbA1c ≥ 6.5% and the incidence of atrial fibrillation observed in these two groups. We also compared patient who developed atrial fibrillation in the post-operative period and compared them with those who did not.

RESULTS

Of the 5259 patients included in the study HbA1c was <6.5 in 2808 (53.4%) patients and was ≥6.5 in 2451 (46.6%) patients; 623 (11.8%) patients in our study developed atrial fibrillation. Onset of atrial fibrillation in the post-operative period was seen most commonly 235 (38.3%) on between 24 and 48 h after the operation with more than half of them 338 (54.2%) occurring within the first 48 h. On multivariate analysis, HbA1c was not a risk factor for atrial fibrillation (odd's ratio 1.144, 95% confidence interval 0.967-1.354). Only increased age (odd's ratio 1.08; 95% confidence interval 1.069-1.091); EuroSCORE (odd's ratio 1.073; 95% confidence interval 1.048-1.099); history of recent MI (odd's ratio 0.768; 95% confidence interval 0.606-0.971) and peripheral vascular disease (odd's ratio 1.667; 95% confidence interval 1.091-2.517) were found to be independently associated with increased risk of atrial fibrillation in the post-operative period.

CONCLUSIONS

After adjusting for confounders HbA1c levels do not independently predict risk of atrial fibrillation after off-pump coronary artery bypass grafting.

Catheter ablation in atrial fibrillation: is there a mortality benefit in patients with diabetes and heart failure?

Atrial fibrillation (AF) is the most commonly sustained arrhythmia, and patients with diabetes mellitus (DM) exhibit an increased incidence of AF. Besides DM, heart failure (HF) shares pathophysiological links with AF, mainly related to the pathological remodeling of hearts affected by structural disease. As in a vicious circle, AF may contribute to HF worsening and increased mortality in patients with structural heart diseases, and the outcome may be further impaired when concomitant DM is present. Although no data directly referring to DM patients with HF are available, indirect information can be drawn from large studies on patients with HF and AF. The present review discusses the outcome of AF ablation in patients with DM and HF, focusing on safety, efficacy, and most particularly on hard endpoints such as mortality and thromboembolic event incidence.

A review of factors associated with maintenance of sinus rhythm after elective electrical cardioversion for atrial fibrillation

Atrial fibrillation is the most common heart-rhythm disorder, affecting about 1.5% to 2% of the population with an increased risk of mortality and morbidity due to stroke, thromboembolism, and heart failure. If the conversion back to sinus rhythm does not happen spontaneously, pharmacological or electrical cardioversion (ECV) is the next available treatment options for some patients. However, the long-term success following ECV is variable. This review describes the factors that are associated with maintenance of sinus rhythm following ECV and proposes a clinical strategy based on the available evidence.

Xanthine Oxidase Inhibitor Allopurinol Prevents Oxidative Stress-Mediated Atrial Remodeling in Alloxan-Induced Diabetes Mellitus Rabbits

Background

There are several mechanisms, including inflammation, oxidative stress and abnormal calcium homeostasis, involved in the pathogenesis of atrial fibrillation. In diabetes mellitus (DM), increased oxidative stress may be attributable to higher xanthine oxidase activity. In this study, we examined the relationship between oxidative stress and atrial electrical and structural remodeling, and calcium handling abnormalities, and the potential beneficial effects of the xanthine oxidase inhibitor allopurinol upon these pathological changes.

Methods and Results

Ninety rabbits were randomly and equally divided into 3 groups: control, DM, and allopurinol‐treated DM group. Echocardiographic and hemodynamic assessments were performed in vivo. Serum and tissue markers of oxidative stress and atrial fibrosis, including the protein expression were examined. Atrial interstitial fibrosis was evaluated by Masson trichrome staining. I_CaL was measured from isolated left atrial cardiomyocytes using voltage‐clamp techniques. Confocal microscopy was used to detect intracellular calcium transients. The Ca²⁺ handling protein expression was analyzed by Western blotting. Mitochondrial‐related proteins were analyzed as markers of mitochondrial function. Compared with the control group, rabbits with DM showed left ventricular hypertrophy, increased atrial interstitial fibrosis, oxidative stress and fibrosis markers, I_CaL and intracellular calcium transient, and atrial fibrillation inducibility. These abnormalities were alleviated by allopurinol treatment.

Conclusions

Allopurinol, via its antioxidant effects, reduces atrial mechanical, structural, ion channel remodeling and mitochondrial synthesis abnormalities induced by DM‐related increases in oxidative stress.

Interdisciplinary approach to compensation of hypoglycemia in diabetic patients with chronic heart failure

Diabetes mellitus is a chronic disease requiring lifelong control with hypoglycemic agents that must demonstrate excellent efficacy and safety profiles. In patients taking glucose-lowering drugs, hypoglycemia is a common cause of death associated with arrhythmias, increased thrombus formation, and specific effects of catecholamines due to sympathoadrenal activation. Focus is now shifting from merely glycemic control to multifactorial approach. In the context of individual drugs and classes, this article reviews interdisciplinary strategies evaluating metabolic effects of drugs for treatment of chronic heart failure (CHF) which can mask characteristic hypoglycemia symptoms. Hypoglycemia unawareness and cardiac autonomic neuropathy are discussed. Data suggesting that hypoglycemia modulates immune response are reviewed. The potential role of gut microbiota in improving health of patients with diabetes and CHF is emphasized. Reports stating that nondiabetic CHF patients can have life-threatening hypoglycemia associated with imbalance of thyroid hormones are discussed. Regular glycemic control based on HbA1c measurements and adequate pharmacotherapy remain the priorities in diabetes management. New antihyperglycemic drugs with safer profiles should be preferred in vulnerable CHF patients. Multidrug interactions must be considered. Emerging therapies with reduced hypoglycemia risk, telemedicine, sensor technologies, and genetic testing predicting hypoglycemia risk may help solving the challenges of hypoglycemia in CHF patients with diabetes. Interdisciplinary work may involve cardiologists, diabetologists/endocrinologists, immunologists, gastroenterologists, microbiologists, nutritionists, imaging specialists, geneticists, telemedicine experts, and other relevant specialists. This review emphasizes that systematic knowledge on pathophysiology of hypoglycemia in diabetic patients with CHF is largely lacking and the gaps in our understanding require further discoveries.

Considerations and treatment options for patients with comorbid atrial fibrillation and diabetes mellitus

INTRODUCTION

Atrial fibrillation (AF) and diabetes mellitus (DM) are common worldwide and their incidence is increasing, representing a significant public health and economic burden as well as an increase in individual increased morbidity and mortality risk profiles. Both conditions are closely related, as patients with DM are at increased risk of incident AF, and AF patients with DM are at higher risk of cardiovascular events compared to non-AF patients. Areas covered: This review article aims to provide an overview of the current evidence linking DM and AF, as well as the impact of obesity, weight loss and stroke on these coexisting conditions. Second, the effects of new oral anti hyperglycaemic medications on cardiovascular risk will be considered. Expert opinion: In conclusion, coexisting AF and DM represent a high risk population of patients requiring aggressive risk factor identification and treatment optimisation. The multifactorial interplay between these conditions requires individual assessment of patient risk profiles with the aim of minimising the impact of each modifiable risk factor.

Alogliptin, a Dipeptidyl Peptidase-4 Inhibitor, Alleviates Atrial Remodeling and Improves Mitochondrial Function and Biogenesis in Diabetic Rabbits

Background

There is increasing evidence implicating atrial mitochondrial dysfunction in the pathogenesis of atrial fibrillation. In this study, we explored whether alogliptin, a dipeptidyl peptidase‐4 inhibitor, can prevent mitochondrial dysfunction and atrial remodeling in a diabetic rabbit model.

Methods and Results

A total of 90 rabbits were randomized into 3 groups as follows: control group (n=30), alloxan‐induced diabetes mellitus group (n=30), and alogliptin‐treated (12.5 mg/kg per day for 8 weeks) diabetes mellitus group (n=30). Echocardiographic and hemodynamic assessments were performed in vivo. The serum concentrations of glucagon‐like peptide‐1, insulin, and inflammatory and oxidative stress markers were measured. Electrophysiological properties of Langendorff‐perfused rabbit hearts were assessed. Mitochondrial morphology, respiratory function, membrane potential, and reactive oxygen species generation rate were assessed. The protein expression of transforming growth factor β1, nuclear factor κB p65, and mitochondrial biogenesis–related proteins were measured by Western blot analysis. Diabetic rabbits exhibited left ventricular hypertrophy and left atrial dilation without obvious hemodynamic abnormalities, and all of these changes were attenuated by alogliptin. Compared with the control group, higher atrial fibrillation inducibility in the diabetes mellitus group was observed, and markedly reduced by alogliptin. Alogliptin decreased mitochondrial reactive oxygen species production rate, prevented mitochondrial membrane depolarization, and alleviated mitochondrial swelling in diabetic rabbits. It also improved mitochondrial biogenesis by peroxisome proliferator–activated receptor‐γ coactivator 1α/nuclear respiratory factor‐1/mitochondrial transcription factor A signaling regulated by adiponectin/AMP‐activated protein kinase.

Conclusions

Dipeptidyl peptidase‐4 inhibitors can prevent atrial fibrillation by reversing electrophysiological abnormalities, improving mitochondrial function, and promoting mitochondrial biogenesis.

Atrial conduction times and left atrial mechanical functions and their relation with diastolic function in prediabetic patients

BACKGROUND/AIMS

The aim of this study was to investigate atrial conduction times and left atrial mechanical functions, the noninvasive predictors of atrial fibrillation, in prediabetic patients with impaired fasting glucose (IFG) and impaired glucose tolerance (IGT).

METHODS

Study included 59 patients (23 males, 36 females; mean age 52.5 ± 10.6 years) diagnosed with IFG or IGT by the American Diabetes Association criteria, and 43 healthy adults (22 males, 21 females; mean age 48.5 ± 12.1 years). Conventional and tissue Doppler echocardiography were performed. The electromechanical delay parameters were measured from the onset of the P wave on the surface electrocardiogram to the onset of the atrial systolic wave on tissue Doppler imaging from septum, lateral, and right ventricular annuli. The left atrial volumes were calculated by the disk method. Left atrial mechanical functions were calculated.

RESULTS

The mitral E/A and E'/A' ratios measured from the lateral and septal annuli were significantly lower in the prediabetics compared to the controls. The interatrial and left atrial electromechanical delay were significantly longer in prediabetic group compared to the controls. Left atrial active emptying volume (LAAEV) and fraction (LAAEF) were significantly higher in the prediabetics than the controls. LAAEV and LAAEF were significantly correlated with E/A, lateral and septal E'/A'.

CONCLUSIONS

In the prediabetic patients, the atrial conduction times and P wave dispersion on surface electrocardiographic were longer before the development of overt diabetes. In addition, the left atrial mechanical functions were impaired secondary to a deterioration in the diastolic functions in the prediabetic patients.

Association between Atrial Fibrillation and Three-Year Mortality in Nondiabetic Patients with Acute First-Ever Ischemic Stroke

BACKGROUND

Diabetes mellitus (DM) is a risk factor for atrial fibrillation (AF) and is known to be an important risk factor for death from stroke. The influence of AF on long-term outcomes in patients with ischemic stroke remains controversial. To clarify the exact influence of AF on stroke outcome and exclude the effect from DM, we investigated the influence of AF on the 3-year outcomes of nondiabetic patients with acute first-ever ischemic stroke.

METHODS

Five-hundred seventy-four nondiabetic patients with acute first-ever ischemic stroke were enrolled and had been followed for 3 years. Patients were divided into 2 groups according to whether AF was diagnosed or not. Clinical presentations, risk factors for stroke, laboratory data, comorbidities, and outcomes were recorded.

RESULTS

A total of 107 patients (18.6%) had AF. The age was significantly older in patients with AF. Total anterior circulation syndrome occurred more frequently among patients with AF (P < .001). The mean length of stay in the acute ward was significantly higher in patients with AF (P < .001). Furthermore, dependent functional status following discharge was higher in patients with AF (P < .001). Multivariate Cox regression revealed that AF is a significant predictor of 3-year all-cause mortality (hazard ratio = 1.98, 95% confidence interval = 1.07-3.67, P = .022).

CONCLUSIONS

AF is associated with increased risk of 3-year mortality in nondiabetic patients with acute first-ever ischemic stroke. Careful cardiac evaluation and treatment are essential in patients with AF and stroke.

Role of diabetes in heart rhythm disorders

The incidence of diabetes mellitus (DM) is increasing rapidly. DM is the leading cause of cardiovascular diseases, which can lead to varied cardiovascular complications by aggravated atherosclerosis in large arteries and coronary atherosclerosis, thereby grows the risk for macro and microangiopathy such as myocardial infarction, stroke, limb loss and retinopathy. Moreover diabetes is one of the strongest and independent risk factor for cardiovascular morbidity and mortality, which associated frequently rhythm disorders such as atrial fibrillation (AF) and ventricular arrhythmias (VA). The present article provides a concise overview of the association between DM and rhythm disorders such as AF and VA with underlying pathophysiological mechanisms.

Diabetes Alters the Expression and Translocation of the Insulin-Sensitive Glucose Transporters 4 and 8 in the Atria

Although diabetes has been identified as a major risk factor for atrial fibrillation, little is known about glucose metabolism in the healthy and diabetic atria. Glucose transport into the cell, the rate-limiting step of glucose utilization, is regulated by the Glucose Transporters (GLUTs). Although GLUT4 is the major isoform in the heart, GLUT8 has recently emerged as a novel cardiac isoform. We hypothesized that GLUT-4 and -8 translocation to the atrial cell surface will be regulated by insulin and impaired during insulin-dependent diabetes. GLUT protein content was measured by Western blotting in healthy cardiac myocytes and type 1 (streptozotocin-induced, T1Dx) diabetic rodents. Active cell surface GLUT content was measured using a biotinylated photolabeled assay in the perfused heart. In the healthy atria, insulin stimulation increased both GLUT-4 and -8 translocation to the cell surface (by 100% and 240%, respectively, P<0.05). Upon insulin stimulation, we reported an increase in Akt (Th308 and s473 sites) and AS160 phosphorylation, which was positively (P<0.05) correlated with GLUT4 protein content in the healthy atria. During diabetes, active cell surface GLUT-4 and -8 content was downregulated in the atria (by 70% and 90%, respectively, P<0.05). Akt and AS160 phosphorylation was not impaired in the diabetic atria, suggesting the presence of an intact insulin signaling pathway. This was confirmed by the rescued translocation of GLUT-4 and -8 to the atrial cell surface upon insulin stimulation in the atria of type 1 diabetic subjects. In conclusion, our data suggest that: 1) both GLUT-4 and -8 are insulin-sensitive in the healthy atria through an Akt/AS160 dependent pathway; 2) GLUT-4 and -8 trafficking is impaired in the diabetic atria and rescued by insulin treatment. Alterations in atrial glucose transport may induce perturbations in energy production, which may provide a metabolic substrate for atrial fibrillation during diabetes.

Is diabetes a hypercoagulable state? A critical appraisal

Diabetes mellitus (DM), a chronic disease with an increasing incidence and prevalence worldwide, is an established risk factor for arterial cardiovascular, cerebrovascular and peripheral vascular diseases including acute myocardial infarction, stroke and peripheral artery disease. On the other hand, its role as independent risk factor for venous thromboembolism (VTE) and for cardioembolic stroke or systemic embolism (SE) in patients with atrial fibrillation (AF) is more conflicting. Venous and arterial thromboses have traditionally been regarded as separate diseases, but recent studies have documented an association between these vascular complications. Cardiovascular risk factors may contribute to unprovoked VTE, and VTE may be an early symptomatic event in patients at high cardiovascular risk, including diabetic patients. Compelling evidences suggest that DM is associated with a higher risk of development and progression of AF. Furthermore, in AF patients with a coexisting DM the risk of cardioembolic stroke/SE appeared increased. Thus, DM has been included as one of the items of the CHADS2 score and of the subsequent CHA2DS2-VASc score that have been developed to assess the arterial tromboembolic risk of AF patients. Such a high incidence of thromboembolic events observed in these clinical subsets may be attributable to the DM-related prothrombotic state due to a number of changes in primary and secondary hemostasis. Although of potential clinical interest, unfortunately, to date, no study has properly evaluated the effects of drugs used to control blood glucose levels on the risk of venous thromboembolism and arterial cardioembolic events in patients with DM.

High risk factors of atrial fibrillation in type 2 diabetes: results from the Chinese Kailuan study

BACKGROUND

The pathophysiological mechanisms for atrial fibrillation (AF) vulnerability in diabetic patients are largely unclear.

AIM

To investigate the high risk factors of AF in Chinese Kailuan diabetes.

DESIGN

A retrospective review of AF in Chinese Kailuan diabetes.

METHODS

Research and statistic analysis on the clinical data of 9050 diabetic patients from Kailuan Coal Mine Group Corporation who participated in a health survey from July 2006 to October 2007.

RESULTS

Sixty diabetic patients (50 males and 10 females) were diagnosed with AF during the health checkup, with a prevalence of 0.66% (0.67% in males and 0.62% in females). Univariate analysis showed that patients with AF were older and had higher levels of serum uric acid (UA), pulse pressure, serum c-reactive protein and anti-hypertensive medication usage, but lower levels of fasting blood glucose and triglycerides (TG). Multivariate analysis indicated that older age (OR = 1.09; 95% CI: 1.06-1.12), increased UA (OR = 1.01; 95% CI: 1.00-1.01) and decreased TG (OR = 0.71; 95% CI: 0.55-0.92) were independent predictive factors of AF after adjusting for other variables. After gender stratification, age and UA remained as independent predictive factors of AF in both male and female patients. However, TG had an independent inverse association with AF in male patients only.

CONCLUSIONS

Age and UA are independent predictive factors of AF in both male and female diabetic patients. TG is inversely correlated with AF in male diabetic patients only.

Therapeutic targeting of oxidative stress with coenzyme Q10 counteracts exaggerated diabetic cardiomyopathy in a mouse model of diabetes with diminished PI3K(p110α) signaling

Diabetes-induced cardiac complications include left ventricular (LV) dysfunction and heart failure. We previously demonstrated that LV phosphoinositide 3-kinase p110α (PI3K) protects the heart against diabetic cardiomyopathy, associated with reduced NADPH oxidase expression and activity. Conversely, in dominant negative PI3K(p110α) transgenic mice (dnPI3K), reduced cardiac PI3K signaling exaggerated diabetes-induced cardiomyopathy, associated with upregulated NADPH oxidase. The goal was to examine whether chronic supplementation with the antioxidant coenzyme Q(10) (CoQ(10)) could attenuate LV superoxide and diabetic cardiomyopathy in a setting of impaired PI3K signaling. Diabetes was induced in 6-week-old nontransgenic and dnPI3K male mice via streptozotocin. After 4 weeks of diabetes, CoQ(10) supplementation commenced (10 mg/kg ip, 3 times/week, 8 weeks). At study end (12 weeks of diabetes), markers of LV function, cardiomyocyte hypertrophy, collagen deposition, NADPH oxidase, oxidative stress (3-nitrotyrosine), and concentrations of CoQ(9) and CoQ(10) were determined. LV NADPH oxidase (Nox2 gene expression and activity, and lucigenin-enhanced chemiluminescence), as well as oxidative stress, were increased by diabetes, exaggerated in diabetic dnPI3K mice, and attenuated by CoQ(10). Diabetes-induced LV diastolic dysfunction (prolonged deceleration time, elevated end-diastolic pressure, impaired E/A ratio), cardiomyocyte hypertrophy and fibrosis, expression of atrial natriuretic peptide, connective tissue growth factor, and β-myosin heavy chain were all attenuated by CoQ(10). Chronic CoQ(10) supplementation attenuates aspects of diabetic cardiomyopathy, even in a setting of reduced cardiac PI3K protective signaling. Given that CoQ(10) supplementation has been suggested to have positive outcomes in heart failure patients, chronic CoQ(10) supplementation may be an attractive adjunct therapy for diabetic heart failure.

Obesity and atrial fibrillation: A comprehensive review of the pathophysiological mechanisms and links

Obesity is a worldwide health problem with epidemic proportions that has been associated with atrial fibrillation (AF). Even though the underlying pathophysiological mechanisms have not been completely elucidated, several experimental and clinical studies implicate obesity in the initiation and perpetuation of AF. Of note, hypertension, diabetes mellitus, metabolic syndrome, coronary artery disease, and obstructive sleep apnea, represent clinical correlates between obesity and AF. In addition, ventricular adaptation, diastolic dysfunction, and epicardial adipose tissue appear to be implicated in atrial electrical and structural remodeling, thereby promoting the arrhythmia in obese subjects. The present article provides a concise overview of the association between obesity and AF, and highlights the underlying pathophysiological mechanisms.

Diabetes mellitus and atrial fibrillation: Pathophysiological mechanisms and potential upstream therapies

Diabetes mellitus (DM) represents one of the most important risk factors for atrial fibrillation (AF) while AF is a strong and independent marker of overall mortality and cardiovascular morbidity in diabetic patients. Autonomic, electrical, electromechanical, and structural remodeling, including oxidative stress, connexin remodeling and glycemic fluctuations seem to be implicated in AF pathophysiology in the setting of DM. The present review highlights the association between DM and AF, provides a comprehensive overview of the responsible pathophysiological mechanisms and briefly discusses potential upstream therapies for DM-related atrial remodeling.

HbA1c levels as predictors of ablation outcome in type 2 diabetes mellitus and paroxysmal atrial fibrillation

AIMS

The aim of this study was to evaluate whether the levels of HbA1c could predict the outcome of ablation in patients with type 2 diabetes mellitus (T2DM) and paroxysmal atrial fibrillation (PAF).

PATIENTS AND METHODS

The study comprised 149 consecutive patients with T2DM and PAF who underwent their first circumferential pulmonary vein isolation. HbA1c levels were measured before ablation. Cox proportional hazards models were constructed to assess the relationship between HbA1c levels and the recurrence of atrial fibrillation (AF).

RESULTS

Of the 149 patients, 60 (40.3 %) developed AF recurrence after a median 12-month follow-up. Multivariate Cox regression analysis revealed that left atrium size and HbA1c were independent predictors of recurrent atrial tachyarrhythmia. Receiver operating characteristic analysis demonstrated that an HbA1c cut-off value of ≥ 6.9 % predicted recurrence with 55.0 % sensitivity and 67.4 % specificity (AUC = 0.634). The success rate of ablation was 69.0 % in patients with an HbA1c value of < 6.9 % compared with 46.8 % in those with an HbA1c value of ≥ 6.9 % (log-rank test, p = 0.004).

CONCLUSION

High levels of HbA1c were associated with an increased risk of recurrence of atrial tachyarrhythmia in patients with T2DM and PAF undergoing catheter ablation.

Mechanism of and therapeutic strategy for atrial fibrillation associated with diabetes mellitus

Diabetes mellitus (DM) is one of the most important risk factors for atrial fibrillation (AF) and is a predictor of stroke and thromboembolism. DM may increase the incidence of AF, and when it is combined with other risk factors, the incidence of stroke and thromboembolism may also be higher; furthermore, hospitalization due to heart failure appears to increase. Maintenance of well-controlled blood glucose and low levels of HbA1c in accordance with guidelines may decrease the incidence of AF. The mechanisms of AF associated with DM are autonomic remodeling, electrical remodeling, structural remodeling, and insulin resistance. Inhibition of the renin-angiotensin system is suggested to be an upstream therapy for this type of AF. Studies have indicated that catheter ablation may be effective for AF associated with DM, restoring sinus rhythm and improving prognosis. Catheter ablation combined with hypoglycemic agents may further increase the rate of maintenance of sinus rhythm and reduce the need for reablation.

Evaluation of Pharmacokinetic Interactions Between Vildagliptin and Digoxin in Healthy Volunteers

Vildagliptin is a novel antidiabetic agent that is an orally active, potent, and selective inhibitor of dipeptidyl peptidase IV, the enzyme responsible for degradation of the incretin hormones. This open-label, randomized, 3-period crossover study investigated the potential for pharmacokinetic interactions in 18 healthy subjects during coadministration of vildagliptin and digoxin. Subjects were randomized to receive each of 3 treatments: vildagliptin 100 mg qd, digoxin (0.5 mg, then 0.25 mg qd on days 2-7), and the combination vildagliptin/digoxin for 7 days. Coadministration of digoxin with vildagliptin had no effect on exposure to vildagliptin (geometric mean ratios [90% confidence interval]: AUC(0-24h), 0.99 [0.95-1.03]; C(max), 0.95 [0.85-1.06]) or to digoxin (AUC(0-24h), 1.02 [0.94-1.12]; C(max), 1.08 [0.97-1.20]). In addition, no changes in t(max), t((1/2)), and CL/F were observed for either drug. These results indicate that no dose adjustment is necessary when vildagliptin and digoxin are coadministered.

Clinical pharmacokinetics and pharmacodynamics of vildagliptin

Vildagliptin is an orally active, potent and selective dipeptidyl peptidase-4 (DPP-4) inhibitor, shown to be effective and well tolerated in patients with type 2 diabetes mellitus (T2DM) as either monotherapy or in combination with other anti-diabetic agents. Vildagliptin possesses several desirable pharmacokinetic properties that contribute to its lower variability and low potential for drug interaction. Following oral administration, vildagliptin is rapidly and well absorbed with an absolute bioavailability of 85%. An approximately dose-proportional increase in exposure to vildagliptin over the dose range of 25-200 mg has been reported. Food does not have a clinically relevant impact on the pharmacokinetics of vildagliptin, and it can be taken without regard to food. Vildagliptin is minimally bound to plasma proteins (9.3%) and, on the basis of a volume of distribution of 71 L, it is considered to distribute extensively into extravascular spaces. Renal clearance of vildagliptin (13 L/h) accounts for 33% of the total body clearance after intravenous administration (41 L/h). The primary elimination pathway is hydrolysis by multiple tissues/organs. The DPP-4 enzyme contributes to the formation of the major hydrolysis metabolite, LAY151; therefore, vildagliptin is also a substrate of DPP-4. Vildagliptin has a low potential for drug interactions, as cytochrome P450 (CYP) enzymes are minimally (<1.6%) involved in the overall metabolism. Clinical pharmacokinetic studies have reported the lack of drug interaction with several drugs (metformin, pioglitazone, glyburide, simvastatin, amlodipine, valsartan, ramipril, digoxin and warfarin) that are likely to be frequently co-administered to patients with T2DM. In particular, vildagliptin does not affect the pharmacokinetics of pioglitazone, glyburide, warfarin and simvastatin; therefore, it is not expected to affect the pharmacokinetics of a drug that is a substrate for CYP2C8, CYP2C9 or CYP3A4. In the elderly, vildagliptin exposure increases by approximately 30%, which is considered to be mostly attributable to compromised renal function in the elderly population and is not considered to be clinically relevant. Vildagliptin has been demonstrated to be efficacious, safe and well tolerated in elderly patients with T2DM without dose adjustment. In subjects with varying degrees of renal impairment, vildagliptin exposure increases by approximately 2-fold; however, the increase in the exposure does not correlate with the severity of renal impairment. The lack of a clear correlation between the increased exposure and the severity of renal impairment is considered to be attributable to the fact that the kidneys contribute to both the excretion and the hydrolysis metabolism of vildagliptin. Hepatic impairment, gender, body mass index (BMI) and ethnicity do not have an influence on the pharmacokinetics of vildagliptin. These findings suggest that vildagliptin can be used in a diverse patient population without dose adjustment. Oral administration of vildagliptin to patients with T2DM completely inhibits DPP-4 activity at a variety of doses. The onset of DPP-4 inhibition is rapid, and the duration of DPP-4 inhibition is dose dependent. Vildagliptin is a potent inhibitor of the DPP-4 enzyme, with a concentration required to achieve 50% DPP-4 inhibition (IC(50)) of 4.5 nmol/L in patients with T2DM. Similar potency of DPP-4 inhibition by vildagliptin has been reported in different ethnic groups, indicating that ethnicity does not affect the pharmacodynamics of vildagliptin. Vildagliptin significantly increases the active glucagon-like peptide 1 (GLP-1) levels by approximately 2- to 3-fold and glucose-dependent insulinotropic polypeptide (GIP) levels by approximately 5-fold, and significantly suppresses the postprandial glucagon levels in response to a meal or following an oral glucose tolerance test (OGTT) in patients with T2DM. Vildagliptin significantly reduces both fasting and postprandial glucose levels over the dose range of 50-100 mg daily (administered either once daily or twice daily), and there are no substantial additional benefits of doses greater than 50 mg twice daily. The primary clinical dosing regimen is 50 mg twice daily as monotherapy or in combination with metformin. Vildagliptin increases the insulin levels following an OGTT and an intravenous glucose tolerance test (IVGTT), and the stimulation of insulin secretion is glucose dependent. Vildagliptin has been shown to improve beta-cell function on the basis of pharmacodynamic modelling taking the reduced glucose levels into account. The improvement of beta-cell function by vildagliptin has been confirmed after chronic treatment with vildagliptin for up to 2 years. Reduction of the endogenous glucose production appears to contribute to the glucose-lowering effects. Unlike the GLP-1 receptor agonists, vildagliptin does not affect gastric emptying, and this is consistent with the favourable gastrointestinal safety profile. Vildagliptin improves the sensitivity of the alpha cell to glucose in patients with T2DM by enhancing the alpha-cell responsiveness to both suppressive effects of hyperglycaemia and stimulatory effects of hypoglycaemia. Consistently, a lower incidence of hypoglycaemic events with vildagliptin is reported when it is used as either monotherapy or in combination with other anti-diabetic agents, such as metformin or insulin, as compared with a sulphonylurea. Numerous long-term clinical trials of up to 2 years have demonstrated that vildagliptin 50 mg once daily or twice daily is effective, safe and well tolerated in patients with T2DM as either monotherapy or in combination with a variety of other anti-diabetic agents.

Insulin resistance and atrial fibrillation (from the Framingham Heart Study)

Diabetes mellitus and obesity are increasing in prevalence and are associated with an elevated risk of atrial fibrillation (AF). Given the aging of the United States population, AF is projected to concomitantly increase in prevalence in the upcoming decades. Both diabetes and obesity are associated with insulin resistance. Whether insulin resistance is an intermediate step for the development of AF is uncertain. We hypothesized that insulin resistance is associated with an increased risk of incident AF. We examined the association of insulin resistance with incident AF using multivariate Cox proportional hazards regression analysis adjusting for the established AF risk factors (i.e., age, gender, systolic blood pressure, hypertension treatment, PR interval, significant heart murmur, heart failure, and body mass index). Of the 3,023 eligible participants (55% women; mean age 59 years) representing 4,583 person-examinations (Framingham Offspring fifth and seventh examination cycles), 279 participants developed AF (9.3%) within ≤10 years of follow-up. With multivariate modeling, insulin resistance was not significantly associated with incident AF (hazard ratio comparing top quartile to other 3 quartiles of homeostatic model assessment index 1.18, 95% confidence interval 0.84 to 1.65, p = 0.34). In a community-based cohort with ≤10 years of follow-up, no significant association was observed between insulin resistance and incident AF.

Diabetes mellitus, glycemic control, and risk of atrial fibrillation

BACKGROUND

Diabetes may be an independent risk factor for atrial fibrillation. However, results from prior studies are in conflict, and no study has examined diabetes duration or glycemic control.

OBJECTIVE

To examine the association of diabetes with risk of atrial fibrillation and to describe risk according to diabetes duration and glycemic control.

DESIGN

A population-based case-control study.

PARTICIPANTS

Within a large, integrated healthcare delivery system, we identified 1,410 people with newly-recognized atrial fibrillation from ICD-9 codes and validated cases by review of medical records. 2,203 controls without atrial fibrillation were selected from enrollment lists, stratified on age, sex, hypertension, and calendar year.

MAIN MEASURES

Information on atrial fibrillation, diabetes and other characteristics came from medical records. Diabetes was defined based on physician diagnoses recorded in the medical record, and pharmacologically treated diabetes was defined as receiving antihyperglycemic medications. Information about hemoglobin A1c levels came from computerized laboratory data.

KEY RESULTS

Among people with atrial fibrillation, 252/1410 (17.9%) had pharmacologically treated diabetes compared to 311/2203 (14.1%) of controls. The adjusted OR for atrial fibrillation was 1.40 (95% CI 1.15-1.71) for people with treated diabetes compared to those without diabetes. Among those with treated diabetes, the risk of developing atrial fibrillation was 3% higher for each additional year of diabetes duration (95% CI 1-6%). Compared to people without diabetes, the adjusted OR for people with treated diabetes with average hemoglobin A1c <or=7 was 1.06 (95% CI 0.74-1.51); for A1c >7 but <or=8, 1.48 (1.09-2.01); for A1c >8 but <or=9, 1.46 (1.02-2.08); and for A1c >9, 1.96 (1.22-3.14).

CONCLUSIONS

Diabetes was associated with higher risk of developing atrial fibrillation, and risk was higher with longer duration of treated diabetes and worse glycemic control. Future research should identify and test approaches to reduce the risk of atrial fibrillation in people with diabetes.

Reduced phosphoinositide 3-kinase (p110alpha) activation increases the susceptibility to atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia presenting at cardiology departments. A limited understanding of the molecular mechanisms responsible for the development of AF has hindered treatment strategies. The purpose of this study was to assess whether reduced activation of phosphoinositide 3-kinase (PI3K, p110alpha) makes the compromised heart susceptible to AF. Risk factors for AF, including aging, obesity, and diabetes, have been associated with insulin resistance that leads to depressed/defective PI3K signaling. However, to date, there has been no link between PI3K(p110alpha) and AF. To address this question, we crossed a cardiac-specific transgenic mouse model of dilated cardiomyopathy (DCM) with a cardiac-specific transgenic mouse expressing a dominant negative mutant of PI3K (dnPI3K; reduces PI3K activity). Adult ( approximately 4.5 months) double-transgenic (dnPI3K-DCM), single-transgenic (DCM-Tg, dnPI3K-Tg), and nontransgenic mice were subjected to morphological, functional/ECG, microarray, and biochemical analyses. dnPI3K-DCM mice developed AF and had depressed cardiac function as well as greater atrial enlargement and fibrosis than DCM-Tg mice. AF was not detected in other groups. Aged DCM-Tg mice ( approximately 15 months) with a similar phenotype to dnPI3K-DCM mice (4.5 months) did not develop AF, suggesting loss of PI3K activity directly contributed to the AF phenotype. Furthermore, increasing PI3K activity reduced atrial fibrosis and improved cardiac conduction in DCM-Tg mice. Finally, in atrial appendages from patients with AF, PI3K activation was lower compared with tissue from patients in sinus rhythm. These results suggest a link between PI3K(p110alpha) and AF.

Prevalence of atrial fibrillation in the general population of Japan: an analysis based on periodic health examination

BACKGROUND

The mortality and morbidity rates of various cardiovascular diseases differ between Western countries and Japan. The age- and gender-specific prevalence rate of atrial fibrillation (AF) in the general population of Japan was determined using the data from periodic health examinations in 2003.

METHODS

Data of 630,138 subjects aged 40 years or more (47% were men and 34% were employees of companies and local governments) were collected from northern to southern Japan. The prevalence of diagnosed AF in each 10-year age group of both men and women was determined. Based on these prevalence rates and the Registry of Residents, the number of people having AF in Japan was estimated.

RESULTS

The prevalence rate of AF increased as both male and female subjects aged, and it was 4.4% for men but only 2.2% for women aged 80 years or more (p<0.0001). As a whole, the AF prevalence of men was three times that of women (1.35 versus 0.43%, p<0.0001). There may be approximately 716,000 people (95% confidence interval (CI), 711,000-720,000) with AF in Japan, an overall prevalence of 0.56%. The number of people having AF was projected to be 1.034 (95% CI, 1.029-1.039) million, an overall prevalence of 1.09%, in 2050.

CONCLUSIONS

The prevalence of AF increased in Japan as the population aged, as in Western countries. The overall prevalence of AF in Japan is approximately two-thirds of that in the USA. The projected increase in the number of people having AF is modest in Japan in 2050.

P-wave duration and dispersion in obese subjects

BACKGROUND

Although previous studies have documented a variety of electrocardiogram (ECG) abnormalities in obesity, P-wave alterations, which represent an increased risk for atrial arrhythmia, have not been studied very well in these patients. The aim of the present study was to evaluate P-wave duration and P dispersion (Pd) in obese subjects, and to investigate the relationship between P-wave measurements, and the clinical and echocardiographic variables.

METHODS

The study population consisted of 52 obese and 30 normal weight control subjects. P-wave duration and P-wave dispersion were calculated on the 12-lead ECG. As echocardiographic variables, left atrial diameter (LAD), left ventricular end-diastolic, and end-systolic diameters (LVDD and LVSD), left ventricular ejection fraction (LVEF), interventricular septum thickness (IVST), left ventricular posterior wall thickness (LVPWT), and left ventricular mass (LVM) of the obese and the control subjects were measured by means of transthoracic echocardiography.

RESULTS

There were statistically significant differences between obese and controls as regards to Pmax (maximum P-wave duration) and Pd (P dispersion) (P < 0.001 and P < 0.001, respectively). Pmin (minimum P wave duration) was similar in both groups. Correlation analysis showed that Pd in the obese patients was related to any the clinical and echocardiographic parameters including BMI, LAD, LVDD, IVST, LVPWT, and LVM.

CONCLUSION

Our data suggest that obesity affects P-wave dispersion and duration, and changes in P dispersion may be closely related to the clinical and the echocardiographic parameters such as BMI, LAD, IVST, LVPWT, and LVM.

Impact of new-onset diabetes mellitus on development of atrial fibrillation and heart failure in high-risk hypertension (from the VALUE Trial)

Hypertension and diabetes mellitus (DM) are known risk factors for atrial fibrillation (AF). We investigated the influence of new-onset DM on developing AF in the VALUE trial population of high-risk hypertensive patients. Five thousand two hundred fifty patients of the 15,245 participants in the VALUE trial had DM at baseline and 1,298 of the initially nondiabetic patients developed DM during the average 4.2-year follow-up. The presence of AF was determined by central analyzed electrocardiograms at baseline and changes were assessed yearly. Patients without AF at baseline and with any AF by later electrocardiograms were defined as patients with new-onset AF. Patients with new-onset and baseline DM were compared with patients without DM by a Cox regression model with adjustment for prespecified covariates. Five hundred fifty-one patients developed new-onset AF during the trial. Patients with new-onset DM had a significantly higher event rate of new-onset AF with a hazard ratio of 1.49 (1.14 to 1.94, p = 0.0031) compared with patients without DM, and there was a trend toward more AF in patients with DM at baseline. Patients with new-onset DM had also more persistent AF (hazard ratio 1.87, 1.28 to 2.74, p = 0.0014). Patients with new-onset DM and AF had a hazard ratio of 3.56 for heart failure (2.86 to 4.44, p <0.0001) compared with patients with new-onset DM without AF. In conclusion, hypertensive patients who developed DM during the VALUE trial had more AF than did patients without DM, and this may explain some of their concomitant high risk of hospitalization for heart failure.

AGEs-RAGE system mediates atrial structural remodeling in the diabetic rat

BACKGROUND

Diabetes mellitus (DM) is one of the independent risk factors for atrial fibrillation (AF). Our previous study has indicated that DM causes atrial structural remodeling with intraatrial conduction disturbances. We tested the hypothesis that the advanced glycation end products (AGEs) and the receptor for AGE (RAGE), which have been implicated in diabetic complications, are responsible for the atrial structural remodeling.

METHODS AND RESULTS

Diabetes was induced by streptozotocin (65 mg/kg i.p.) in 8-week-old female Sprague-Dawley rats. When 24 weeks old, their atria were subjected to histology, Western blotting, and immunohistochemistry. The HbA(1c) value of induced-DM rats was significantly higher than that of control rats. Histological and immunohistochemical examinations revealed that the atria of diabetic rats showed remarkable structural changes characterized by diffuse interstitial fibrosis with abundant expressions of RAGE and connective tissue growth factor (CTGF), which findings were also confirmed by Western blotting analysis. This diabetes-induced atrial fibrosis was remarkably prevented by administration of an inhibitor of AGEs formation, OPB-9195, along with reduction of CTGF expression.

CONCLUSIONS

DM promoted atrial structural remodeling via the activation of the AGEs-RAGE system with upregulating CTGF. The inhibition of AGEs formation could be a novel upstream therapeutic approach for diabetes-related atrial fibrosis.

[Prognostic factors in patients admitted with type 2 diabetes in Internal Medicine Services: hospital mortality and readmission in one year (DICAMI study)]

INTRODUCTION

Type II diabetes mellitus (T2DM) is a prevalent Public Health Care problem that causes an increase in morbidity, mortality and number of hospital admissions as well as increased costs in care services in this population group. The clinical indicator that determine readmission and/or death are analyzed in a 12 month follow-up period.

METHODS

All T2DM patients admitted in Spanish Internal Medicine Services between two different periods (june 1-15, 2003 and november 1-15) were enrolled in a prospective cohort study. Primary endpoint were readmission and/or death in the year following the first admission.

RESULTS

Population of the study (n = 482) was distributed in 229 males (47.5%) and 253 females (52.5%). Mean age was 73.48 +/- 8.86 years. A total of 210 (43.6%) were not readmitted to the hospital and/or died in the follow-up and 272 (56.4%) were readmitted and/or died. The latter 272 patients had a significantly greater percentage of heart failure (odds ratio [OR] 1.760; 1.073-2.886), atrial fibrillation (OR 1.747; 1.010- 3.022) and previous history of systolic blood pressure (OR 0.400; 0.241-0.666). They also showed increased levels of plasma glucose (OR 1.004; 1.001-1.007), and lower concentration of plasma hemoglobin (OR 0.756; 0.677-0.845) and creatinine clearance (OR 0.985; 0.976-0.994).

CONCLUSIONS

T2DM patients who are admitted to the Internal Medicine Services in Spain are elderly patients with elevated indices of readmission and death in a short follow-up period (one year). The coexistence of heart failure, atrial fibrillation, renal dysfunction deterioration and decrease in hemoglobin levels may predict this worse outcome.

Regression of paroxysmal atrial fibrillation associated with thiazolidinedione therapy

Thiazolidinediones (TZDs) represent insulin-sensitizing agents that have several pleiotropic properties, possibly related to their favorable effects on cardiovascular remodeling. We briefly describe 2 diabetic patients who experienced a remarkable improvement in their paroxysmal atrial fibrillation (AF) after treatment with rosiglitazone. Current evidence suggests that atrial remodeling represents a prominent mechanism of AF development and perpetuation while inflammation and oxidative stress are possibly implicated in this process. It could therefore be speculated that the pleiotropic effects of TZDs favorably affect atrial remodeling reducing the arrhythmia burden. Further studies are needed in order to elucidate the merit of this pharmacological approach in AF.

Safety and efficacy of catheter ablation of atrial fibrillation in patients with diabetes mellitus—single center experience

BACKGROUND AND OBJECTIVE

Little is known about the outcome of catheter ablation of atrial fibrillation (AF) in patients with diabetes mellitus (DM). We investigated the safety and efficacy of catheter ablation of AF in patients with DM.

MATERIALS AND METHODS

Thirty one patients with DM from a group of 263 consecutive patients undergoing a first-time catheter ablation of AF procedure were enrolled in a prospective study. The ablation protocol (guided by CARTO system) consisted in two continuous circular lesions around ipsilateral pulmonary veins.

RESULTS

The following clinical characteristics differed between DM and no-DM patients: age (62.0 +/- 10.8 vs. 56.1 +/- 10.6 years, P = 0.004), longer AF history (9.6 +/- 9.3 vs. 6.7 +/- 6.3 years, P = 0.024), significantly larger left atrium size (41.1 +/- 7.8 vs. 38.3 +/- 5.8 mm, P = 0.021), hypertension (58.1 vs. 35.8%, P = 0.018) and structural heart disease (67.7 vs. 43.5%, P = 0.011). Despite a similar AF recurrence rate in DM and no-DM patients (32.3 vs. 22.4%, P = 0.240), the ablation procedure was complicated in 28 patients (11 hematomas, three cardiac tamponades and three strokes) and the incidence of complications was significantly higher in DM than in no-DM patients (29.0 vs. 8.2%, respectively, P = 0.002). Multivariate analysis showed that DM was an independent risk factor for complications occurrence (odd ratio 5.936, 95% confidence interval 2.059 to 17.112, P = 0.001).

CONCLUSIONS

First catheter ablation of AF procedure in DM patients was equally efficacious than in no-DM patients. However, DM patients had a higher incidence of complications, mostly thrombotic or hemorrhagic.

Development of a Contemporary Bleeding Risk Model for Elderly Warfarin Recipients

BACKGROUND AND PURPOSE

Develop and validate a contemporary bleeding risk model to guide the clinical use of warfarin in the elderly atrial fibrillation (AF) population.

METHODS

Chart-abstracted data from the National Registry of Atrial Fibrillation was combined with Medicare part A claims to identify major bleeding events requiring hospitalization. Using a split-sample technique, candidate variables that provided statistically stable relationships with major bleeding events were selected for model development. Three risk categories were created and validated. The new model was compared to existing bleeding risk models using c-statistics and Kaplan-Meier curves.

RESULTS

Model development and validation was conducted on 26,345 AF patients who were > 65 years of age and had been discharged from the hospital while receiving warfarin therapy. The following eight variables were included in the final risk score model: age > or = 70 years; gender; remote bleeding; recent (ie, during index hospitalization) bleeding; alcohol/drug abuse; diabetes; anemia; and antiplatelet use. Bleeding rates were 0.9%, 2.0%, and 5.4%, respectively, for the groups with low, moderate, and high risk, compared to the bleeding rates for groups with moderate risk (1.5% and 1.0%) and high risk (1.8% and 2.5%) from other models.

CONCLUSIONS

Using a nationally derived data set, we developed a model based on contemporary practice standards for determining major bleeding risk among AF patients receiving warfarin therapy. The larger sample size afforded the opportunity to incorporate additional risk factors. In addition, since the majority of our population was > 65 years of age, we had greater ability to stratify risk among the elderly.