Atrial conduction time and atrial mechanical function in patients with impaired fasting glucose

β-blockades and the risk of atrial fibrillation in patients with cardiovascular diseases

Background

β-blockers have been widely used in patients with extensive cardiovascular disease (CVD) and have provided benefits. However, they are more likely to cause symptomatic bradycardia, hypotension, or glucose metabolism disorders, which may lead to an increased risk of atrial fibrillation (AF), but evidence is lacking.

Aims

This study was to analyze the association between the use of β-blockers and the risk of developing AF.

Methods

This nationwide, prospective cohort study utilized data from the 2013-2020 National Health and Nutrition Examination Survey (NHANES). The patients were stratified into a β-blocker treatment group (n = 2585) and a non-β-blocker treatment group (n = 8525). Univariate and multivariate logistic regression analyses were performed to identify the relationship between β-blockades and the risk of AF. Propensity matching analysis was used to balance patient baseline characteristics and to control for confounders.

Results

A total of 11,110 subjects were included in this study (mean [SD] age, 59.89 [15.07] years; 5657 [49.7%] males). A total of 111/2585 subjects developed AF in the β-blocker treatment group, and 75/8525 developed AF in the non-β-blocker treatment group (incidence rate, 4.2% vs. 0.8%). Compared with the non-β-blocker group, the β-blocker group had an increased risk of incident AF (aOR, 2.339; 95% CI, 1.614-3.410). Some sensitivity analyses also revealed consistent findings of increased AF risk associated with β-blocker treatment.

Conclusion

The findings from this study suggest that β-blocker treatment is associated with an increased risk of incident AF and may help physicians select a modest medication for patients while also assessing the risk of AF.

Unveiling the Role of Endothelial Dysfunction: A Possible Key to Enhancing Catheter Ablation Success in Atrial Fibrillation

Atrial fibrillation, a prevalent type of arrhythmia, is increasingly contributing to the economic burden on healthcare systems. The development of innovative treatments, notably catheter ablation, has demonstrated both impressive and promising outcomes. However, these treatments have not yet fully replaced pharmaceutical approaches, primarily due to the relatively high incidence of atrial fibrillation recurrence post-procedure. Recent insights into endothelial dysfunction have shed light on its role in both the onset and progression of atrial fibrillation. This emerging understanding suggests that endothelial function might significantly influence the effectiveness of catheter ablation. Consequently, a deeper exploration into endothelial dynamics could potentially elevate the status of catheter ablation, positioning it as a primary treatment option for atrial fibrillation.

Metabolic Syndrome and Atrial Fibrillation: Different Entities or Combined Disorders

Obesity, hypertension, insulin resistance, and dyslipidemia are all clusters of an entity called "Metabolic Syndrome". The global trends of this syndrome's incidence/prevalence continue to increase reciprocally, converting it into a massive epidemic problem in the medical community. Observing the risk factors of atrial fibrillation, a medical condition that is also converted to a scourge, almost all parts of the metabolic syndrome are encountered. In addition, several studies demonstrated a robust correlation between metabolic syndrome and the occurrence of atrial fibrillation. For atrial fibrillation to develop, a combination of the appropriate substrate and a trigger point is necessary. The metabolic syndrome affects the left atrium in a multifactorial way, leading to atrial remodeling, thus providing both the substrate and provoking the trigger needed, which possibly plays a substantial role in the progression of atrial fibrillation. Due to the remodeling, treatment of atrial fibrillation may culminate in pernicious sequelae, such as repeated catheter ablation procedures. A holistic approach of the patient, with simultaneous treatment of both entities, is suggested in order to ensure better outcomes for the patients.

Diabetes mellitus and atrial fibrillation-from pathophysiology to treatment

Type 2 diabetes mellitus (T2DM) is a leading risk factor for cardiovascular complications around the globe and one of the most common medical conditions. Atrial fibrillation (AF) is the most common supraventricular arrhythmia, with a rapidly increasing prevalence. T2DM has been closely associated with the risk of AF development, identified as an independent risk factor. Regarding cardio-vascular complications, both AF and T2DM have been linked with high mortality. The underlying pathophysiology has not been fully determined yet; however, it is multifactorial, including structural, electrical, and autonomic pathways. Novel therapies include pharmaceutical agents in sodium-glucose cotransporter-2 inhibitors, as well as antiarrhythmic strategies, such as cardioversion and ablation. Of interest, glucose-lowering therapies may affect the prevalence of AF. This review presents the current evidence regarding the connection between the two entities, the pathophysiological pathways that link them, and the therapeutic options that exist.

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.

P-wave duration and interatrial conduction abnormalities in paroxysmal and persistent typical atrial flutter

Functional and structural changes, the enlargement of the right atrium is the background for the development of typical atrial flutter (AFL). These changes in ECG are manifested in the morphology of the initial part of the P-wave. The aim of the study was to assess the duration and morphology of the P-wave in patients with paroxysmal and persistent AFL. The study population consisted of 131 patients with AFL, 38 women and 93 men aged 66 years (60-72), divided in 62 patients with paroxysmal and 69 with persistent AFL. P-wave duration was measured with an electrophysiological system in all leads at a paper speed of 200 mm/s. The groups did differ in terms of gender (38/24 vs. 55/14, (M/F), p=0.033). Patients with persistent AF had a longer P-wave duration - 175±26.3 ms vs. 159±22.6 ms, p=0.01, and higher creatinine concentration - 1.2±0.60 mg/dl vs. 1.08±0.68 mg/dl, p=0.007. The presence and severity of interatrial conduction block (I-none, II-partial, III-total) was related to age of the patients (60.3±12.1 vs. 64.7±-8.3 vs. 68.9±9.5 years, respectively). Patients with persistent AFL show a longer P-wave compared to paroxysmal AFL, regardless of comorbidities and antiarrhythmic drugs. The arrhythmia-related longer P-wave duration should encourage the clinicians to restore sinus rhythm earlier in order to more effectively maintain it over the long term.

Prediabetes, heart mechanics, and echocardiography: A narrative review

Prediabetes is a dysglycemic state that affects many around the world and is a known risk factor for the occurrence of type 2 diabetes mellitus in the future, accompanied by vascular complications. Evidence abounds regarding myocardial involvement in prediabetes. We herein review studies having applied tissue Doppler imaging or speckle-tracking echocardiography to evaluate myocardial function in subjects with prediabetes to depict a picture of cardiac mechanics in individuals with prediabetes in comparison with patients suffering from diabetes mellitus and individuals in the normoglycemic state. Finally, we present the detrimental effects of prediabetes on cardiac mechanics.

Insulin Treatment Reduces Susceptibility to Atrial Fibrillation in Type 1 Diabetic Mice

Diabetes has been identified as an independent risk factor for atrial fibrillation (AF), the most common chronic cardiac arrhythmia. Whether or not glucose and insulin disturbances observed during diabetes enhance arrhythmogenicity of the atria, potentially leading to AF, is not well-known. We hypothesized that insulin deficiency and impaired glucose transport provide a metabolic substrate for the development and maintenance of AF during diabetes. Transesophageal atrial pacing was used to induce AF in healthy, streptozotocin-induced insulin-deficient type 1 diabetic, and insulin-treated diabetic mice. Translocation of insulin-sensitive glucose transporters (GLUTs) to the atrial cell surface was measured using a biotinylated photolabeling assay in the perfused heart. Fibrosis and glycogen accumulation in the atrium were measured using histological analysis. Diabetic mice displayed mild hyperglycemia, increased duration and frequency of AF episodes vs. age-matched controls (e.g., AF duration: 19.7 ± 6.8 s vs. 1.8 ± 1.1 s, respectively, p = 0.032), whereas insulin-treated diabetic animals did not. The translocation of insulin-sensitive GLUT-4 and -8 to the atrial cell surface was significantly downregulated in the diabetic mice (by 67 and 79%, respectively; p ≤ 0.001), and rescued by insulin treatment. We did not observe fibrosis or glycogen accumulation in the atria of diabetic mice. Therefore, these data suggest that insulin and glucose disturbances were sufficient to induce AF susceptibility during mild diabetes.

Right atrial conduction time for predicting coexistent typical atrial flutter in patients with paroxysmal atrial fibrillation

INTRODUCTION

Screening of coexistent typical atrial flutter (AFL) in patients with atrial fibrillation (AF) is sometimes challenging. This study investigated whether a prolonged right atrial conduction time (RACT) estimated by tissue Doppler imaging (TDI) predicts patients with concomitant AFL and AF.

METHODS AND RESULTS

We retrospectively analyzed 398 patients (mean age: 61.6 years, 73.4% men) undergoing catheter ablation of paroxysmal AF. The patients were classified into two groups according to whether they had evidence of AFL (N = 122, 30.7%) determined by a clinical observation (N = 68), induction during procedures (N = 33), or AFL recurrence after procedures (N = 21) or not (N = 276, 69.3%). The preoperative RACT, defined as a longer duration between the onset of the P-wave and peak A'-wave on the right atrial lateral wall or septal wall, and total atrial conduction time (TACT), defined as the same time duration on the left atrial lateral wall, were evaluated in all patients. Patients with evidence of AFL had a significantly longer RACT than those without AFL (p < .001). A multiple logistic regression and receiver operator characteristics curve analysis revealed the ratio of the RACT and TACT (RACT/TACT) was the independent and most superior accurate cofounder for predicting evidence of AFL (area under the curve: 0.867). When adding a discriminator of an RACT/TACT ≧ 93% into the conventional screening, 98.4% of the patients with evidence of AFL were estimated to be treated during the initial procedures.

CONCLUSION

The estimated RACT/TACT using the TDI may be useful for predicting patients with concomitant AFL in patients with AF.

Atrial Fibrillation and Diabetes Mellitus: JACC Review Topic of the Week

Diabetes mellitus is one of the most common chronic medical conditions, and is a risk factor for the development of atrial fibrillation (AF). The presence of diabetes in patients with AF is associated with increased symptom burden and increased cardiovascular and cerebrovascular mortality. The pathophysiology of diabetes-related AF is not fully understood, but is related to structural, electrical, electromechanical, and autonomic remodeling. This paper reviews the complex interaction between diabetes and AF, and explores its effect on the prevention and treatment of AF.

Chronic kidney disease predicts atrial fibrillation in patients with ST-segment elevation myocardial infarction treated by primary percutaneous coronary intervention

Background: Atrial fibrillation (AF) often complicates ST-segment elevation myocardial infarction (STEMI). Predictors of AF in this setting include factors related to the acute phase of STEMI and pre-existing conditions. More recently, novel AF predictors have been identified in the general population. We aimed to assess the ability of such novel factors to predict STEMI-related AF.Methods: Data were collected from STEMI patients treated by primary PCI. Factors related to the acute phase of STEMI (Killip class, heart rate, blood pressure on admission, post-PCI TIMI flow), classic (age, hypertension, heart failure, previous myocardial infarction), and more novel (body mass index [BMI], diabetes, chronic kidney disease [CKD], chronic obstructive pulmonary disease [COPD]) AF predictors were evaluated. The ability of these novel factors to predict STEMI-related AF was assessed.Results: Of the 629 studied patients, 10.5% presented STEMI-related AF. AF patients had higher Killip class on admission (p < .0001) and lower post-PCI TIMI flow (p < .01), they were older (p < .0001) and more likely to have a history of heart failure (p = .02) and myocardial infarction (p = .04). BMI, history of diabetes and COPD were similar between patients with and without AF (all p > .05), but CKD was more common in AF patients (p < .0001). In multiple regression analysis, CKD remained a strong independent predictor of STEMI-related AF (p < .0001).Conclusion: Irrespective of other factors, CKD was associated with increased risk of STEMI-related AF. CKD could be used to identify patients who will develop AF in this setting and who would benefit from closer follow-up and more intensive prophylactic strategies.

Data Linking Diabetes Mellitus and Atrial Fibrillation-How Strong Is the Evidence? From Epidemiology and Pathophysiology to Therapeutic Implications

According to estimates, around 5% of the world population has hazel eyes. And there are about as many people with diabetes mellitus (DM). Red hair occurs naturally in up to 2% of the human population. And about as many people are estimated to have atrial fibrillation (AF). If a hazel eyed person with red hair does not surprise us, should a diabetic patient with AF? Accumulating epidemiologic data suggest, however, that the DM-AF association may be more than a simple coincidence. But, how strong is this evidence? Experimental studies bring evidence for a DM-induced atrial proarrhythmic remodelling. But how relevant are these data for the clinical setting? In this review, we aim to provide a critical analysis of the existing clinical and experimental, epidemiologic, and mechanistic data that bridge DM and AF, we emphasize a number of questions that remain to be answered, and we identify hotspots for future research. The therapeutic implications of the DM-AF coexistence are also discussed, with a focus on rhythm control and on conventional and DM-specific upstream therapies for AF management.

Diabetes mellitus, blood glucose and the risk of atrial fibrillation: A systematic review and meta-analysis of cohort studies

BACKGROUND

Diabetes and elevated blood glucose have been associated with increased risk of atrial fibrillation in a number of epidemiological studies, however, the findings have not been entirely consistent. We conducted a systematic review and meta-analysis to clarify the association.

MATERIAL AND METHODS

We searched the PubMed and Embase databases for studies of diabetes and blood glucose and atrial fibrillation up to July 18th 2017. Cohort studies were included if they reported relative risk (RR) estimates and 95% confidence intervals (CIs) of atrial fibrillation associated with a diabetes diagnosis, prediabetes or blood glucose. Summary RRs were estimated using a random effects model.

RESULTS

Thirty four studies were included in the meta-analysis of diabetes, pre-diabetes or blood glucose and atrial fibrillation. Thirty two cohort studies (464,229 cases, >10,244,043 participants) were included in the analysis of diabetes mellitus and atrial fibrillation. The summary RR for patients with diabetes mellitus versus patients without diabetes was 1.30 (95% CIs: 1.03-1.66), however, there was extreme heterogeneity, I² = 99.9%) and evidence of publication bias with Begg's test, p < 0.0001. After excluding a very large and outlying study the summary RR was 1.28 (95% CI: 1.22-1.35, I² = 90%, n = 31, 249,772 cases, 10,244,043 participants). The heterogeneity was mainly due to differences in the size of the association between studies and the results persisted in a number of subgroup and sensitivity analyses. The summary RR was 1.20 (95% CI: 1.03-1.39, I² = 30%, n = 4, 2392 cases, 58,547 participants) for the association between prediabetes and atrial fibrillation. The summary RR was 1.11 (95% CI: 1.04-1.18, I² = 61%, n = 4) per 20 mg/dl increase of blood glucose in relation to atrial fibrillation (3385 cases, 247,447 participants) and there was no evidence of nonlinearity, p_nonlinearity = 0.34.

CONCLUSIONS

This meta-analysis suggest that prediabetes and diabetes increase the risk of atrial fibrillation by 20% and 28%, respectively, and there is a dose-response relationship between increasing blood glucose and atrial fibrillation. Any further studies should clarify whether the association between diabetes and blood glucose and atrial fibrillation is independent of adiposity.

Plasma lipids affect dabigatran etexilate anticoagulation in rats with unbalanced diabetes mellitus

BACKGROUND

Dabigatran etexilate (DE) has similar stroke prevention efficacy in patients with and without diabetes mellitus (DM). However, the benefit of reducing major bleeding was not seen in diabetics. Thus, this study investigated anticoagulant responses to DE and the biological predictors of this response in a DM model.

METHODS

Experiments were performed in six control (C), eight DE-treated control (CD), five diabetic (D), and eight DE-treated diabetic (DD) rats. Dabigatran etexilate (50 mg/kg/day) was administered in chow for 12 weeks. At the end of the study, plasma glucose, triglycerides, total cholesterol (TC), high-density lipoprotein cholesterol, low-density lipoprotein cholesterol (LDL-C), and plasma creatinine were measured. Correlations were ascertained with the diluted thrombin time (dTT).

RESULTS

When corrected for similar DE intake, dTT was significantly higher in DD than CD rats (P < 0.001). There was a significant negative correlation between creatinine clearance (CCr) and dTT (r = -0.91, P < 0.01) in DD rats. In addition, dTT was positively correlated with TC (r = 0.96, P < 0.01), LDL-C (r = 0.75, P = 0.04), and glucose (r = 0.83, P = 0.02). In multiple regression analysis, CCr (r = -0.81, P = 0.01), TC (r = 0.93, P < 0.001), and LDL-C (r = 0.74, P < 0.01) remained the only independent predictors of dTT.

CONCLUSIONS

The results show a significantly more intense DE-induced anticoagulation in diabetic rats that does not seem to be solely related to altered kidney function, and demonstrate that plasma cholesterol can significantly affect DE anticoagulation in this setting.

Assessment of atrial conduction times in prediabetic patients with coronary artery disease

Objective:

Prediabetes is a dysglycemic state and is associated with subtle myocardial injury and dysfunction. We evaluated atrial conduction times (ACTs) and atrial electromechanical delays (EMDs) in prediabetic patients with coronary artery disease (CAD).

Methods:

In the present study, we recruited 128 consecutive patient candidates (40 euglycemic, 48 prediabetic, and 40 diabetic patients) for coro- nary artery bypass grafting. ACTs were measured using tissue Doppler imaging (TDI). The time intervals between the beginning of the P wave in the surface electrocardiogram and the peak of the a¢ wave in TDI (PA) in the septal and lateral mitral annuli and the lateral tricuspid annulus were measured and termed as “septal PA,” “lateral PA,” and “right ventricular (RV) PA,” respectively. The differences between lateral and septal PA, septal and RV PA, and lateral and RV PA were termed as “left intra-atrial EMD,” “right intra-atrial EMD,” and “inter-atrial EMD” respectively.

Results:

Septal PA, lateral PA, RV PA, left and right intra-atrial EMDs, and inter-atrial EMD were not statistically different between these three groups. Furthermore, multivariable linear regression models, adjusted for potential confounders, showed that glycemic state was not associated with ACTs, left and right intra-atrial EMDs, and inter-atrial EMD.

Conclusion:

There were no significant differences between the euglycemic, prediabetic, and diabetic patients with CAD regarding ACTs and atrial EMDs.

Diabetes mellitus and atrial remodeling: mechanisms and potential upstream therapies

Atrial fibrillation (AF) is the most common cardiac arrhythmia in clinical practice, and its prevalence has increasing substantially over the last decades. Recent data suggest that there is an increased risk of AF among the patients with diabetes mellitus (DM). However, the potential molecular mechanisms regarding DM-related AF and diabetic atrial remodeling are not fully understood. In this comprehensive review, we would like to summarize the potential relationship between diabetes and atrial remodeling, including structural, electrical, and autonomic remodeling. Also, some upstream therapies, such as thiazolidinediones, probucol, ACEI/ARBs, may play an important role in the prevention and treatment of AF. Therefore, large prospective randomized, controlled trials and further experimental studies should be challengingly continued.

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.

Metabolic syndrome is associated with atrial electrical and mechanical dysfunction

OBJECTIVE

In this study, we aimed to investigate the left atrial (LA) electrical and mechanical functions in patients with metabolic syndrome (MetS).

SUBJECTS AND METHODS

The study population consisted of 87 patients with MetS and 67 controls. Intra-atrial and interatrial electromechanical delays (EDs) were measured with tissue Doppler imaging. P-wave dispersion (Pd) was calculated from the 12-lead electrocardiograms. LA volumes were measured echocardiographically by the biplane area-length method.

RESULTS

Intra-atrial and interatrial EDs and Pd were significantly higher in patients with MetS (10.3 ± 6.3, 21.0 ± 11.5 and 41.7 ± 10.8) than in controls (7.4 ± 5.5, 12.3 ± 10.4 and 29.2 ± 7.4; p = 0.003, p < 0.001 and p < 0.001, respectively). The LA preatrial contraction volume and active emptying volumes were higher in this population, but the LA passive emptying fraction was lower. In the multivariate linear regression analysis, the presence of MetS, LA active emptying volume and left ventricular early diastolic (E) wave velocity/late diastolic (A) wave velocity (E/A) ratios were independent correlates of interatrial ED (p = 0.002, p = 0.001 and p = 0.025, respectively).

CONCLUSIONS

This study showed that intra-atrial and interatrial EDs and Pd were prolonged and LA mechanical functions were impaired in patients with MetS.

Assessment of atrial electromechanical delay in patients with migraine

Evidence suggests that symptoms of migraine are related to the involvement of the autonomic nervous system. Data on atrial conduction system are limited in migraineurs. We aimed to assess atrial electromechanical delay using tissue Doppler imaging (TDI) in patients with migraine. Forty-five migraine patients and age- and sex-matched 26 control subjects were enrolled in the study. All the patients and controls underwent resting surface electrocardiogram (ECG) and TDI. The maximum P-wave duration (Pmax), minimum P-wave duration (Pmin) and P-wave dispersion (Pd) were measured from the 12-lead ECG. Atrial conduction time was determined from the lateral mitral annulus (PA lateral), septal mitral annulus (PA septal), and lateral tricuspid annulus (PA tricuspid) by TDI. Interatrial (PA lateral-PA tricuspid) and intraatrial (PA septal-PA tricuspid) electromechanical delays were calculated. Pd was significantly higher in migraine patients than in controls (p < 0.05), whereas Pmax and Pmin were not different between both groups (p > 0.05). PA lateral and PA septal durations were significantly higher in migraine patients than in controls (p < 0.001 and p < 0.05, respectively). However, PA tricuspid duration was similar between the groups (p > 0.05). Both interatrial and intraatrial conduction times were delayed in migraineurs as compared to the controls (p < 0.001). Interatrial delay and intraatrial delay variables were found as an independent risk factors separately on predicting atrial conduction abnormalities in migraineurs. An interatrial delay of 18 ms and an intraatrial delay of 5 ms were found to be cutoff values in ROC analysis (p < 0.001). This is the first report to provide a hypothetical suggestion that there is an atrial electromechanical delay in patients with migraine.