Influences of autonomic nervous system on atrial arrhythmogenic substrates and the incidence of atrial fibrillation in diabetic heart

Artificial-intelligence-based risk prediction and mechanism discovery for atrial fibrillation using heart beat-to-beat intervals

BACKGROUND

Early diagnosis of atrial fibrillation (AF) is important for preventing stroke and other complications. Predicting AF risk in advance can improve early diagnostic efficiency. Deep learning has been used for disease risk prediction; however, it lacks adherence to evidence-based medicine standards. Identifying the underlying mechanisms behind disease risk prediction is important and required.

METHODS

We developed an explainable deep learning model called HBBI-AI to predict AF risk using only heart beat-to-beat intervals (HBBIs) during sinus rhythm. We proposed a possible AF mechanism based on the model's explainability and verified this conjecture using confirmed AF risk factors while also examining new AF risk factors. Finally, we investigated the changes in clinicians' ability to predict AF risk using only HBBIs before and after learning the model's explainability.

FINDINGS

HBBI-AI consistently performed well across large in-house and external public datasets. HBBIs with large changes or extreme stability were critical predictors for increased AF risk, and the underlying cause was autonomic imbalance. We verified various AF risk factors and discovered that autonomic imbalance was associated with all these factors. Finally, cardiologists effectively understood and learned from these findings to improve their abilities in AF risk prediction.

CONCLUSIONS

HBBI-AI effectively predicted AF risk using only HBBI information through evaluating autonomic imbalance. Autonomic imbalance may play an important role in many risk factors of AF rather than in a limited number of risk factors.

FUNDING

This study was supported in part by the National Key R&D Program and the National Natural Science Foundation of China.

Association of stress hyperglycemia ratio with in-hospital new-onset atrial fibrillation and long-term outcomes in patients with acute myocardial infarction

AIMS

To investigate the predictive value and prognostic impact of stress hyperglycemia ratio (SHR) for new-onset atrial fibrillation (NOAF) complicating acute myocardial infarction (AMI).

MATERIALS AND METHODS

This retrospective study included 2145 AMI patients without AF history between February 2014 and March 2018. SHR was calculated using fasting blood glucose (mmol/L)/[1.59*HbA1c (%)-2.59]. The association between SHR and post-MI NOAF was assessed with multivariable logistic regression analyses. The primary outcome was a composite of cardiac death, heart failure hospitalisation, recurrent MI, and ischaemic stroke (MACE). Cox regression-adjusted hazard ratios with 95% confidence intervals (CI) were estimated for MACE.

RESULTS

A total of 245 (11.4%) patients developed NOAF. In the multivariable logistic regression analyses, SHR (each 10% increase) was significantly associated with increased risks of NOAF in the whole population (OR: 1.05, 95% CI: 1.01-1.10), particularly in non-diabetic individuals (OR:1.08, 95% CI: 1.01-1.17). During a median follow-up of 2.7 years, 370 (18.5%) MACEs were recorded. The optimal cut-off value of SHR for MACE prediction was 1.119. Patients with both high SHR (≥1.119) and NOAF possessed the highest risk of MACE compared to those with neither high SHR nor NOAF after multivariable adjustment (HR: 2.18, 95% CI: 1.39-3.42), especially for diabetics (HR: 2.63, 95% CI: 1.41-4.91). Similar findings were observed using competing-risk models.

CONCLUSIONS

SHR is an independent predictor of post-MI NOAF in non-diabetic individuals. Diabetic patients with both high SHR and NOAF had the highest risk of MACE, suggesting that therapies targeting SHR may be considered in these patients.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03533543.

Impact of diabetes mellitus severity, treatment regimen and glycaemic control on atrial fibrillation prevalence in the Polish population aged ≥ 65

Diabetes mellitus (DM) is a well-known risk factor for atrial fibrillation (AF), but the mechanism(s) by which DM affects AF prevalence remains unclear. This study aims to evaluate the impact of diabetes mellitus severity (expressed as its known duration), antihyperglycemic treatment regimen and glycaemic control on AF prevalence. From the representative sample of 3014 participants (mean age 77.5, 49.1% female) from the cross-sectional NOMED-AF study, 881 participants (mean age 77.6 ± 0.25, 46.4% female) with concomitant DM were involved in the analysis. AF was screened using a telemonitoring vest for a mean of 21.9 ± 9.1 days. The mean DM duration was 12 ± 0.35 years, but no significant impact of DM timespan on AF prevalence was observed. No differences in the treatment pattern (oral medication vs insulin vs both oral + insulin) among the study population with and without AF were shown (p = 0.106). Metabolic control reflected by HbA1c levels showed no significant association with AF and silent AF prevalence (p = 0.635; p = 0.094). On multivariate analyses, age (Odds Ratio (OR) 1.35, 95%CI: 1.18-1.53, p < 0.001), p = 0.042), body mass index (BMI; OR 1.043, 95%CI: 1.01-1.08, p = 0.027) and LDL < 100 mg/dl (OR 0.64, 95%CI: 0.42-0.97, p = 0.037) were independent risk factors for AF prevalence, while age (OR 1.45, 95%CI: 1.20-1.75, p < 0.001), LDL < 100 mg/dl (OR 0.43, 95%CI 0.23-0.82, p = 0.011), use of statins (OR 0.51, 95%CI: 0.28-0.94, p = 0.031) and HbA1c ≤ 6.5 (OR 0.46, 95%CI: 0.25-0.85, p = 0.013) were associated with silent AF prevalence. Diabetes duration, diabetic treatment pattern or metabolic control per se did not significantly impact the prevalence of AF, including silent AF detected by prospective continuous monitoring. Independent predictors of AF were age, BMI and low LDL levels, with statins and HbA1c ≤ 6.5 being additional independent predictors for silent AF.Trial registration: NCT03243474.

The Synergistic Relationship Between Atrial Fibrillation and Diabetes Mellitus: Implications for Cardiovascular and Metabolic Health

Type 2 diabetes mellitus (T2DM) and atrial fibrillation (AF) are widespread chronic conditions that profoundly impact public health. While the intricate mechanisms linking these two diseases remain incompletely understood, this review sets out to comprehensively analyze the current evidence about their pathophysiology, epidemiology, diagnosis, prognosis, and treatment. We reveal that T2DM can influence the electrical and structural properties of the atria through multiple pathways, including oxidative stress, inflammation, fibrosis, connexin remodeling, glycemic variability, and autonomic dysfunction. Moreover, it significantly influences AF's clinical course, elevating the risk of heart failure, stroke, and cardiovascular mortality. Our review also explores treatment options for individuals with T2DM and AF, encompassing antidiabetic and antiarrhythmic drugs and non-pharmacological interventions, such as cardioversion catheter ablation and direct current cardioversion. This review depicts an insight into the clinical interplay between T2DM and AF. It deepens our comprehension of the fundamental mechanisms, potential therapeutic interventions, and their implications for patient care. This comprehensive resource benefits researchers seeking to deepen their knowledge in this domain. Ultimately, our findings pave the way for more effective strategies in managing AF within the context of T2DM.

Dysglycemia and arrhythmias

Disorders in glucose metabolism can be divided into three separate but interrelated domains, namely hyperglycemia, hypoglycemia, and glycemic variability. Intensive glycemic control in patients with diabetes might increase the risk of hypoglycemic incidents and glucose fluctuations. These three dysglycemic states occur not only amongst patients with diabetes, but are frequently present in other clinical settings, such as during critically ill. A growing body of evidence has focused on the relationships between these dysglycemic domains with cardiac arrhythmias, including supraventricular arrhythmias (primarily atrial fibrillation), ventricular arrhythmias (malignant ventricular arrhythmias and QT interval prolongation), and bradyarrhythmias (bradycardia and heart block). Different mechanisms by which these dysglycemic states might provoke cardiac arr-hythmias have been identified in experimental studies. A customized glycemic control strategy to minimize the risk of hyperglycemia, hypoglycemia and glucose variability is of the utmost importance in order to mitigate the risk of cardiac arrhythmias.

Accumulated hypertension burden on atrial fibrillation risk in diabetes mellitus: a nationwide population study

BACKGROUND

Patients with diabetes mellitus have an increased risk of incident atrial fibrillation (AF). The effect of accumulated hypertension burden is a less well-known modifiable risk factor. We explored the relationship between accumulated hypertension burden and incident AF in these patients.

METHODS

We evaluated data for 526,384 patients with diabetes who underwent three consecutive health examinations, between 2009 and 2012, from the Korean National Health Insurance Service. Hypertension burden was calculated by assigning points to each stage of hypertension in each health examination: 1 for stage 1 hypertension (systolic blood pressure [SBP] 130-139 mmHg; diastolic blood pressure [DBP] 80-89 mmHg); 2 for stage 2 (SBP 140-159 mmHg and DBP 90-99 mmHg); and 3 for stage 3 (SBP ≥ 160 mmHg or DBP ≥ 100 mmHg). Patients were categorized into 10 hypertensive burden groups (0-9). Groups 1-9 were then clustered into 1-3, 4-6, and 7-9.

RESULTS

During a mean follow-up duration of 6.7 ± 1.7 years, AF was newly diagnosed in 18,561 (3.5%) patients. Compared to patients with hypertension burden 0, those with burden 1 to 9 showed a progressively increasing risk of incident AF: 6%, 11%, 16%, 24%, 28%, 41%, 46%, 57%, and 67% respectively. Clusters 1-3, 4-6, and 7-9 showed increased risks by 10%, 26%, and 45%, respectively, when compared to a hypertension burden of 0.

CONCLUSIONS

Accumulated hypertension burden was associated with an increased risk of incident AF in patients with diabetes. Strict BP control should be emphasized for these patients.

Epidemiology and modifiable risk factors for atrial fibrillation

The global prevalence of atrial fibrillation (AF) has increased substantially over the past three decades and is currently approximately 60 million cases. Incident AF and its clinical consequences are largely the result of risk factors that can be modified by lifestyle changes. In this Review, we provide evidence that the lifetime risk of AF is modified not only by sex and race but also through the clinical risk factor and comorbidity burden of individual patients. We begin by summarizing the epidemiology of AF, focusing on non-modifiable and modifiable risk factors, as well as targets and strategies for the primary prevention of AF. Furthermore, we evaluate the role of modifiable risk factors in the secondary prevention of AF as well as the potential effects of risk factor interventions on the frequency and severity of subsequent AF episodes. We end the Review by proposing strategies that require evaluation as well as global policy changes that are needed for the prevention of incident AF and the management of recurrent episodes in patients already affected by AF.

Correlation of Insulin Resistance With Short-Term Outcome in Nondiabetic Patients With ST-Segment Elevation Myocardial Infarction

BACKGROUND

 Obviously, hyperglycemia and insulin resistance (IR) are common in patients with acute ST-segment elevation myocardial infarction (STEMI). Additionally, IR is a substantial risk factor for cardiovascular diseases. The study aims to evaluate the association between IR and short-term outcomes of acute STEMI patients without diabetes mellitus in the form of reperfusion success, the occurrence of heart failure, the development of arrhythmias, and mortality.

METHOD

 A cross-sectional study was done from August 2021 to December 2021 in two cardiology centers in Al-Sadr Teaching hospital and Basrah Oil hospital in Basrah, Southern Iraq. Sixty-one nondiabetic hospitalized patients with acute STEMI were included in the study. Twenty-five (41%) of them received thrombolytics and 36 (59%) were managed with percutaneous transluminal coronary angioplasty. From each patient, a fasting blood sample was taken for calculation of the Homeostasis Model Assessment for IR (HOMA-IR) and triglyceride glucose index (TyG) index. The patients were evaluated within 1-week for (reperfusion success, echocardiography for calculation of the ejection fraction (EF), arrhythmias, and mortality), and within 4-weeks for mortality.

RESULTS

 Within the tertile 3 of the HOMA-IR and TyG index, significant higher 4-week mortality (35% and 30%, respectively). Pearson correlation also showed significant and negative correlations between both HOMA-IR and TyG index values and EF. While reperfusion success, arrhythmias, and 1-week mortality did not correlate significantly with both HOMA-IR and TyG index.

CONCLUSION

 IR as defined by HOMA-IR and TyG index was significantly associated with poor outcomes in patients with acute STEMI in the form of EF<55 and 4-week mortality.

Burden of Microvascular Disease and Risk of Atrial Fibrillation in Adults with Type 2 Diabetes

BACKGROUND

Epidemiological data on the associations of microvascular disease with atrial fibrillation are scarce. We evaluated the associations of diabetes-related microvascular disease in multiple vascular beds and its burden with incident atrial fibrillation among adults with type 2 diabetes.

METHODS

A total of 7603 participants with type 2 diabetes and without atrial fibrillation were assessed for diabetic kidney disease, retinopathy, or neuropathy at baseline in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study. Incident atrial fibrillation events were adjudicated using follow-up electrocardiograms. Modified Poisson regression was used to generate risk ratios (RRs) and 95% confidence intervals (CIs) for atrial fibrillation.

RESULTS

Of the 7603 participants (mean age 62.5 years, 38.0% women, 63.4% white), 63.3% (n = 4816) had microvascular disease-defined as the presence of ≥1 of: diabetic kidney disease, retinopathy, or neuropathy at baseline. Over a median of 7 years, there were 137 atrial fibrillation events (1.8%). Participants with microvascular disease had a 1.9-fold higher risk of incident atrial fibrillation compared with those without microvascular disease (RR 1.88; 95% CI, 1.20-2.95). Compared with no microvascular disease, the RRs for atrial fibrillation were 1.62 (95% CI, 1.01-2.61) and 2.47 (95% CI, 1.46-4.16) for those with 1 and ≥2 microvascular territories affected, respectively. The RRs for atrial fibrillation by type of microvascular disease were 1.57 (95% CI, 1.09-2.26), 0.95 (95% CI, 0.53-1.70), and 1.67 (95% CI, 1.15-2.44) for neuropathy, retinopathy, and diabetic kidney disease, respectively.

CONCLUSIONS

In a large cohort of adults with type 2 diabetes, the presence of microvascular disease and its burden were independently associated with higher risk of incident atrial fibrillation.

[Rhythm and metabolic control]

Diabetes mellitus and atrial fibrillation show a steady increase in their prevalence. Diabetes mellitus is a relevant risk factor for the development and maintenance of atrial fibrillation, which should not be underestimated. Fluctuations in blood glucose levels occurring in diabetes, inflammatory processes and oxidative stress lead to structural, electromechanical, electrical and autonomic remodelling processes in the myocardium that promote atrial fibrillation. When atrial fibrillation and diabetes mellitus coincide, this is often associated with more pronounced symptoms, lower quality of life, more frequent hospitalization and a higher mortality rate. Can early and consistent euglycemic blood glucose monitoring effectively influence atrial remodelling processes, cardiovascular end points and the occurrence of atrial fibrillation? Are there new and combined drug treatment approaches for diabetes mellitus and atrial fibrillation? What ablation strategy should be adopted for the interventional treatment of atrial fibrillation in patients with diabetes mellitus? This review article attempts to find answers to these questions.

Cardiac Macrophages and Their Effects on Arrhythmogenesis

Cardiac electrophysiology is a complex system established by a plethora of inward and outward ion currents in cardiomyocytes generating and conducting electrical signals in the heart. However, not only cardiomyocytes but also other cell types can modulate the heart rhythm. Recently, cardiac macrophages were demonstrated as important players in both electrophysiology and arrhythmogenesis. Cardiac macrophages are a heterogeneous group of immune cells including resident macrophages derived from embryonic and fetal precursors and recruited macrophages derived from circulating monocytes from the bone marrow. Recent studies suggest antiarrhythmic as well as proarrhythmic effects of cardiac macrophages. The proposed mechanisms of how cardiac macrophages affect electrophysiology vary and include both direct and indirect interactions with other cardiac cells. In this review, we provide an overview of the different subsets of macrophages in the heart and their possible interactions with cardiomyocytes under both physiologic conditions and heart disease. Furthermore, we elucidate similarities and differences between human, murine and porcine cardiac macrophages, thus providing detailed information for researchers investigating cardiac macrophages in important animal species for electrophysiologic research. Finally, we discuss the pros and cons of mice and pigs to investigate the role of cardiac macrophages in arrhythmogenesis from a translational perspective.

Triglyceride-Glucose Index and New-Onset Atrial Fibrillation in ST-Segment Elevation Myocardial Infarction Patients After Percutaneous Coronary Intervention

Background

New-onset atrial fibrillation (NOAF) is associated with worse prognostic outcomes in cases diagnosed with ST-segment elevation myocardial infarction (STEMI) patients after percutaneous coronary intervention (PCI). The triglyceride-glucose (TyG) index, as a credible and convenient marker of insulin resistance, has been shown to be predictive of outcomes for STEMI patients following revascularization. The association between TyG index and NOAF among STEMI patients following PCI, however, has not been established to date.

Objective

To assess the utility of the TyG index as a predictor of NOAF incidence in STEMI patients following PCI, and to assess the relationship between NOAF and long-term all-cause mortality.

Methods

This retrospective cohort research enrolled 549 STEMI patients that had undergone PCI, with these patients being clustered into the NOAF group and sinus rhythm (SR) group. The predictive relevance of TyG index was evaluated through logistic regression analyses and the receiver operating characteristic (ROC) curve. Kaplan-Meier curve was employed to explore differences in the long-term all-cause mortality between the NOAF and SR group.

Results

NOAF occurred in 7.7% of the enrolled STEMI patients after PCI. After multivariate logistic regression analysis, the TyG index was found to be an independent predictor of NOAF [odds ratio (OR): 8.884, 95% confidence interval (CI): 1.570–50.265, P = 0.014], with ROC curve analyses further supporting the predictive value of this parameter, which exhibited an area under ROC curve of 0.758 (95% CI: 0.720–0.793, P < 0.001). All-cause mortality rates were greater for patients in the NOAF group in comparison with the SR group over a median 35-month follow-up period (log-rank P = 0.002).

Conclusions

The TyG index exhibits values as an independent predictor of NOAF during hospitalization, which indicated a poorer prognosis after a relatively long-term follow-up.

The Effect of Obesity, Hypertension, Diabetes Mellitus, Alcohol, and Sleep Apnea on the Risk of Atrial Fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia associated with a two-fold increase in mortality caused by a higher risk of stroke and heart failure. Currently, AF is present in ~ 2 % of the general population, and its incidence and prevalence are increasing. Obesity, hypertension, diabetes mellitus, obstructive sleep apnea, and alcohol consumption increase the risk of AF. Each unit of increase in BMI increases the risk of AF by 3 %, and intensive weight loss is also associated with reduced AF recurrence. Hypertension increases the risk of AF by 50 % in men and by 40 % in women, and explains ≈ 20 % of new AF cases. Patients with obstructive sleep apnea are at four times higher risk of developing AF than subjects without sleep apnea. Higher concentrations of pro-inflammatory cytokines, higher amounts of epicardial adipose tissue, and a higher degree of ventricular diffuse myocardial fibrosis are present in AF patients and patients with the aforementioned metabolic disorders. Several prospective cohort studies and randomized trials have been initiated to show whether weight loss and treatment of other risk factors will be associated with a reduction in AF recurrences.

Pharmacological treatment of type 2 diabetes in elderly patients with heart failure: randomized trials and beyond

Heart failure (HF) and type 2 diabetes mellitus (T2DM) represent two important public health problems, and despite improvements in the management of both diseases, they are responsible for high rates of hospitalizations and mortality. T2DM accelerates physiological cardiac aging through hyperglycemia and hyperinsulinemia. Thus, HF and T2DM are chronic diseases widely represented in elderly people who often are affected by numerous comorbidities with important functional limitations making it difficult to apply the current guidelines. Several antidiabetic drugs should be used with caution in elderly individuals with T2DM. For instance, sulfonylureas should be avoided due to the risk of hypoglycemia associated with its use. Insulin should be used with caution because it is associated with higher risk of hypoglycemia, and may determine fluid retention which can lead to worsening of HF. Thiazolindinediones should be avoided due to the increased risk of fluid retention and HF. Biguanides may lead to a slightly increased risk of lactic acidosis in particular in elderly individuals with impaired renal function. Dipeptidyl peptidase 4 (DPP-4) inhibitors are safe having few side effects, minimal risk of hypoglycemia, and a neutral effect on cardiovascular (CV) outcome, even if it has been reported that saxagliptin treatment is associated with increased risk of hospitalizations for HF (hHF). Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have shown a CV protection without a significant reduction in hHF. On the other hand, sodium-glucose cotransporter 2 (SGLT2) inhibitors have shown a significant improvement in CV outcome, with a strong reduction of hHF and a positive impact on renal damage progression. However, it is necessary to consider the possible some side effects related to their use in elderly individuals including hypotension, bone fractures, and ketoacidosis.It is important to remark that elderly patients, in particular the very elderly, are not sufficiently represented in the trials; thus, the management and treatment of elderly diabetic patients with HF should be mainly based on the integration of scientific evidence with clinical judgment and patients' condition, with respect to the dignity and quality of life.

Impact of BMI on Left Atrial Strain and Abnormal Atrioventricular Interaction in Patients With Type 2 Diabetes Mellitus: A Cardiac Magnetic Resonance Feature Tracking Study

BACKGROUND

Type 2 diabetes mellitus (T2DM) and obesity often coexist and together contribute to left atrial (LA) functional abnormalities. However, little is known about the impact of body mass index (BMI) on LA strains measured using cardiac magnetic resonance feature tracking (MR-FT).

PURPOSE

To investigate the additive effect of BMI on LA functional remodeling using MR-FT as well as to explore abnormal atrioventricular interaction in T2DM patients.

STUDY TYPE

Retrospective.

POPULATION

One hundred and fifty-nine T2DM patients (53, 34, and 72 normal-weight, overweight, and obese individuals) and 105 non-diabetic controls (46, 32, and 27 normal-weight, overweight, and obese individuals).

FIELD STRENGTH/SEQUENCE

3.0 T/balanced steady-state free precession.

ASSESSMENT

LA reservoir strain (ε_s ), conduit strain (ε_e ), and active strain (ε_a ) and their corresponding strain rates (SRs, SRe, SRa) were measured together with left ventricular (LV) radial, circumferential, and longitudinal peak strain, peak systolic strain rate, and peak diastolic strain rate.

STATISTICAL TESTS

Student's t-test or Mann-Whitney U test, one-way ANOVA, univariate and multivariate linear regression. A P value <0.05 was considered statistically significant.

RESULTS

Compared to controls in the same BMI category, T2DM patients had significantly decreased reservoir and conduit function, while pump function was not significantly different (ε_a and SRa: P = 0.757 and 0.583 for normal-weight, P = 0.171 and 0.426 for overweight, P = 0.067 and 0.330 for obese). LA strains were significantly correlated with BMI (r = -0.346 for ε_s , -0.345 for ε_e ) in T2DM patients. Multivariable linear regression analysis indicated that BMI was independently associated with LA ε_s and ε_e , LV global longitudinal strain was independently associated with LA ε_s and ε_a , and LV circumferential peak diastolic strain rate was independently associated with LA ε_e .

DATA CONCLUSION

These findings suggest that the coexistence of increased body weight and T2DM patients can exacerbate the impairment of LA strains and indicate abnormal atrioventricular interactions.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 3.

Association Between Fasting Hyperglycemia and New-Onset Atrial Fibrillation in Patients With Acute Myocardial Infarction and the Impact on Short- and Long-Term Prognosis

Background: The relationship between fasting hyperglycemia (FHG) and new-onset atrial fibrillation (AF) in patients with acute myocardial infarction (AMI) is unclear, and whether their co-occurrence is associated with a worse in-hospital and long-term prognosis than FHG or AF alone is unknown.

Objective: To explore the correlation between FHG and new-onset AF in patients with AMI, and their impact on in-hospital and long-term all-cause mortality.

Methods: We performed a retrospective cohort study comprising 563 AMI patients. The patients were divided into the FHG group and the NFHG group. The incidence of new-onset AF during hospitalization was compared between the two groups and sub-groups under different Killip grades. Logistic regression was used to assess the association between FHG and new-onset AF. In-hospital mortality and long-term all-cause mortality were compared among patients with FHG, AF, and with both FHG and AF according to 10 years of follow-up information.

Results: New-onset AF occurred more frequently in the FHG group than in the NFHG group (21.6 vs. 9.2%, p < 0.001). This trend was observed for Killip grade I (16.6 vs. 6.5%, p = 0.002) and Grade II (17.1 vs. 6.9%, p = 0.005), but not for Killip grade III–IV (40 vs. 33.3%, p = 0.761). Logistic regression showed FHG independently correlated with new-onset AF (OR, 2.56; 95% CI, 1.53–4.30; P < 0.001), and 1 mmol/L increased in fasting glucose was associated with a 5% higher rate of new-onset AF, after adjustment for traditional AF risk factors. AMI patients complicated with both fasting hyperglycemia and AF showed the highest in-hospital mortality and long-term all-cause mortality during an average of 11.2 years of follow-up. Multivariate Cox regression showed FHG combined with AF independently correlated with long-term all-cause mortality after adjustment for other traditional risk factors (OR = 3.13, 95% CI 1.64–5.96, p = 0.001), compared with the group with neither FHG nor new-onset AF.

Conclusion: FHG was an independent risk factor for new-onset AF in patients with AMI. AMI patients complicated with both FHG and new-onset AF showed worse in-hospital and long-term all-cause mortality than with FHG or AF alone.

Exercise and Stevia Rebaudiana (R) Extracts Attenuate Diabetic Cardiomyopathy in Type 2 Diabetic Rats: Possible Underlying Mechanisms

BACKGROUND AND AIMS

In the current work, we studied the effects of exercise and stevia rebaudiana (R) extracts on diabetic cardiomyopathy (DCM) in type 2 diabetic rats and their possible underlying mechanisms.

METHODS

Thirty-two male Sprague Dawley rats were randomly allocated into 4 equal groups; a) normal control group, b) DM group, type 2 diabetic rats received 2 ml oral saline daily for 4 weeks, c) DM+ Exercise, type 2 diabetic rats were treated with exercise for 4 weeks and d) DM+ stevia R extracts: type 2 diabetic rats received methanolic stevia R extracts. By the end of the experiment, serum blood glucose, HOMA-IR, insulin and cardiac enzymes (LDH, CK-MB), cardiac histopathology, oxidative stress markers (MDA, GSH and CAT), myocardial fibrosis by Masson trichrome, the expression of p53, caspase-3, α-SMA and tyrosine hydroxylase (TH) by immunostaining in myocardial tissues were measured.

RESULTS

T2DM caused a significant increase in blood glucose, HOMA-IR index, serum CK-MB and LDH, myocardial damage and fibrosis, myocardial MDA, myocardial α-SMA, p53, caspase-3, Nrf2 and TH density with a significant decrease in serum insulin and myocardial GSH and CAT (p< 0.05). On the other hand, treatment with either exercise or stevia R extracts significantly improved all studied parameters (p< 0.05). Moreover, the effects of stevia R was more significant than exercise (p< 0.05).

CONCLUSION

Both exercise and methanolic stevia R extracts showed cardioprotective effects against DCM and Stevia R offered more cardioprotective than exercise. This cardioprotective effect of these lines of treatment might be due to attenuation of oxidative stress, apoptosis, sympathetic nerve density and fibrosis and upregulation of the antioxidant transcription factor, Nrf2.

Alcohol Abstinence and the Risk of Atrial Fibrillation in Patients With Newly Diagnosed Type 2 Diabetes Mellitus: A Nationwide Population-Based Study

OBJECTIVE

To investigate the effects of alcohol abstinence on prevention of new-onset atrial fibrillation (AF) in patients with type 2 diabetes mellitus (T2DM).

RESEARCH DESIGN AND METHODS

A total of 1,112,682 patients newly diagnosed with T2DM between 2011 and 2014 were identified from the Korean National Health Insurance Service database. After excluding those with a history of AF, 175,100 patients were included. The primary outcome was new-onset AF.

RESULTS

During a mean follow-up of 4.0 years, AF occurred in 4,174 patients. Those with heavy alcohol consumption (alcohol intake ≥40 g/day) before T2DM diagnosis had a higher risk of AF (adjusted hazard ratio [aHR] 1.22; 95% CI 1.06-1.41) compared with patients with no alcohol consumption. After T2DM diagnosis, those with moderate to heavy alcohol consumption (alcohol intake ≥20 g/day) who abstained from alcohol had a lower risk of AF (aHR 0.81; 95% CI 0.68-0.97) compared with constant drinkers. Alcohol abstinence showed consistent trends toward lower incident AF in all subgroups and was statistically significant in men (aHR 0.80; 95% CI 0.67-0.96), those aged >65 years (aHR 0.69; 95% CI 0.52-0.91), those with CHA₂DS₂-VASc score <3 points (aHR 0.71; 95% CI 0.59-0.86), noninsulin users (aHR 0.77; 95% CI 0.63-0.94), and those with BMI <25 kg/m² (aHR 0.68; 95% CI 0.53-0.88).

CONCLUSIONS

In patients with newly diagnosed T2DM, alcohol abstinence was associated with a low risk of AF development. Lifestyle modifications, such as alcohol abstinence, in patients newly diagnosed with T2DM should be recommended to reduce the risk of AF.

Effects of respiratory muscle training on parasympathetic activity in diabetes mellitus

This study verified the effects of respiratory muscle training (RMT) on hemodynamics, heart rate (HR) variability, and muscle morphology in rats with streptozotocin-induced diabetes mellitus (DM). Thirty-six male Wistar rats were randomized into 4 groups and 34 completed the study: i) sham-sedentary (Sham-ST; n=9); ii) sham-RMT (Sham-RMT; n=9); iii) DM-sedentary (DM-ST; n=8); and iv) DM-RMT (DM-RMT; n=8). Hemodynamics were assessed by central cannulation, and R-R intervals were measured by electrocardiogram. In addition, the effects of RMT on the cross-sectional area of the diaphragm, anterior tibial, and soleus muscles were analyzed. The induction of DM by streptozotocin resulted in weight loss, hyperglycemia, reduced blood pressure, and attenuated left ventricular contraction and relaxation (P<0.05). We also observed a decrease in root mean square of successive differences between adjacent RR intervals (RMSSD) index and in the cross-sectional area of the muscles assessed, specifically the diaphragm, soleus, and anterior tibial muscles in diabetic rats (P<0.05). Interestingly, RMT led to an increase in RMSSD in rats with DM (P<0.05). The induction of DM produced profound deleterious changes in the diaphragmatic and peripheral muscles, as well as impairments in cardiovascular hemodynamics and autonomic control. Nevertheless, RMT may beneficially attenuate autonomic changes and improve parasympathetic modulation.

Impaired left atrial strain in the presence of interatrial block in patients with type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is one of the most common chronic diseases, and is a risk factor for atrial cardiomyopathy. Interatrial block (IAB), as a predictor of AF, is correlated with the extent of LA fibrosis in the process of atrial cardiomyopathy. We have not encountered any study evaluating LA and LV functions with 3D-STE in the presence of IAB in the T2DM patients. The purpose of the present study was to compare the LA and LV myocardial functions in patients with T2DM with and without IAB by 3D-STE. A total of 175 consecutive patients with T2DM who were examined at outpatient clinics were enrolled in the study (85 patients with IAB and 90 patients without IAB). Surface 12-lead standard electrocardiograms (ECGs) were recorded. Clinical characteristics and laboratory values of the patients were obtained. Conventional 2D echocardiographic and 3D-STE analyses were performed. The mean age of the patients was 59 ± 8.7 years, and 112 (64%) of the patients were female. The LAS-r and LAS-active were significantly decreased in the IAB (+) group than in the IAB (-) group. Statistically significant strong negative linear correlations were observed between P-wave duration and 3D-LA strain values. Our results indicate that there is an impairment in LA myocardial dynamics in the presence of IAB in T2DM patients. According to these findings, we can say that it will be useful to evaluate the LA functions at the preclinical stage in the presence of IAB in patients with T2DM, when considering ischemic cardiovascular and cerebral events.

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.

Meta-analysis of metabolic syndrome and its individual components with risk of atrial fibrillation in different populations

Background

Recent studies have reported the effects of metabolic syndrome (MetS) and its components on atrial fibrillation (AF), but the results remain controversial. Therefore, we performed a meta-analysis to evaluate the relationship between MetS and AF risk.

Methods

Studies were searched from the Cochrane library, PubMed, and Embase databases through May 2020. Adjusted hazard ratios (HRs) and its corresponding 95% confidence intervals (CIs) were extracted and then pooled by using a random effects model.

Results

A total of 6 observational cohort studies were finally included. In the pooled analysis, MetS was associated with an increased risk of AF (HR 1.57; 95% CI 1.40–1.77; P < 0.01). And the components of MetS including abdominal obesity (HR 1.37; 95% CI 1.36–1.38; P < 0.01), elevated blood pressure (HR 1.56; 95% CI 1.46–1.66; P < 0.01), elevated fasting glucose (HR 1.18; 95% CI 1.15–1.21; P < 0.01) and low high density cholesterol (HDL) (HR 1.18; 95% CI 1.06–1.32; P < 0.01) was also associated with an increased risk of AF, while high triglyceride (HR 0.99; 95% CI 0.87–1.11, P = 0.82) was not.

Conclusions

Our present meta-analysis suggested that MetS, as well as its components including abdominal obesity, elevated blood pressure, elevated fasting glucose and low HDL cholesterol were associated with an increase in the risk of AF.

2021 ISHNE/HRS/EHRA/APHRS Expert Collaborative Statement on mHealth in Arrhythmia Management: Digital Medical Tools for Heart Rhythm Professionals: From the International Society for Holter and Noninvasive Electrocardiology/Heart Rhythm Society/European Heart Rhythm Association/Asia-Pacific Heart Rhythm Society

Supplemental Digital Content is available in the text.

This collaborative statement from the International Society for Holter and Noninvasive Electrocardiology/Heart Rhythm Society/European Heart Rhythm Association/Asia-Pacific Heart Rhythm Society describes the current status of mobile health technologies in arrhythmia management. The range of digital medical tools and heart rhythm disorders that they may be applied to and clinical decisions that may be enabled are discussed. The facilitation of comorbidity and lifestyle management (increasingly recognized to play a role in heart rhythm disorders) and patient self-management are novel aspects of mobile health. The promises of predictive analytics but also operational challenges in embedding mobile health into routine clinical care are explored.

2021 ISHNE/HRS/EHRA/APHRS Collaborative Statement on mHealth in Arrhythmia Management: Digital Medical Tools for Heart Rhythm Professionals

This collaborative statement from the International Society for Holter and Noninvasive Electrocardiology/Heart Rhythm Society/European Heart Rhythm Association/Asia Pacific Heart Rhythm Society describes the current status of mobile health ("mHealth") technologies in arrhythmia management. The range of digital medical tools and heart rhythm disorders that they may be applied to and clinical decisions that may be enabled are discussed. The facilitation of comorbidity and lifestyle management (increasingly recognized to play a role in heart rhythm disorders) and patient self-management are novel aspects of mHealth. The promises of predictive analytics but also operational challenges in embedding mHealth into routine clinical care are explored.

2021 ISHNE/ HRS/ EHRA/ APHRS collaborative statement on mHealth in Arrhythmia Management: Digital Medical Tools for Heart Rhythm Professionals: From the International Society for Holter and Noninvasive Electrocardiology/Heart Rhythm Society/European Heart Rhythm Association/Asia Pacific Heart Rhythm Society

This collaborative statement from the International Society for Holter and Noninvasive Electrocardiology/ Heart Rhythm Society/ European Heart Rhythm Association/ Asia Pacific Heart Rhythm Society describes the current status of mobile health ("mHealth") technologies in arrhythmia management. The range of digital medical tools and heart rhythm disorders that they may be applied to and clinical decisions that may be enabled are discussed. The facilitation of comorbidity and lifestyle management (increasingly recognized to play a role in heart rhythm disorders) and patient self‐management are novel aspects of mHealth. The promises of predictive analytics but also operational challenges in embedding mHealth into routine clinical care are explored.

2021 ISHNE/HRS/EHRA/APHRS collaborative statement on mHealth in Arrhythmia Management: Digital Medical Tools for Heart Rhythm Professionals: From the International Society for Holter and Noninvasive Electrocardiology/Heart Rhythm Society/European Heart Rhythm Association/Asia Pacific Heart Rhythm Society

This collaborative statement from the International Society for Holter and Noninvasive Electrocardiology/Heart Rhythm Society/European Heart Rhythm Association/Asia Pacific Heart Rhythm Society describes the current status of mobile health (“mHealth”) technologies in arrhythmia management. The range of digital medical tools and heart rhythm disorders that they may be applied to and clinical decisions that may be enabled are discussed. The facilitation of comorbidity and lifestyle management (increasingly recognized to play a role in heart rhythm disorders) and patient self‐management are novel aspects of mHealth. The promises of predictive analytics but also operational challenges in embedding mHealth into routine clinical care are explored.

2021 ISHNE / HRS / EHRA / APHRS Collaborative Statement on mHealth in Arrhythmia Management: Digital Medical Tools for Heart Rhythm Professionals: From the International Society for Holter and Noninvasive Electrocardiology / Heart Rhythm Society / European Heart Rhythm Association / Asia Pacific Heart Rhythm Society

This collaborative statement from the International Society for Holter and Noninvasive Electrocardiology / Heart Rhythm Society / European Heart Rhythm Association / Asia Pacific Heart Rhythm Society describes the current status of mobile health ("mHealth") technologies in arrhythmia management. The range of digital medical tools and heart rhythm disorders that they may be applied to and clinical decisions that may be enabled are discussed. The facilitation of comorbidity and lifestyle management (increasingly recognized to play a role in heart rhythm disorders) and patient self-management are novel aspects of mHealth. The promises of predictive analytics but also operational challenges in embedding mHealth into routine clinical care are explored.

Diabetes and Endocrine Disorders (Hyperthyroidism/Hypothyroidism) as Risk Factors for Atrial Fibrillation

Risk factors including cardiometabolic and endocrine disorders have a significant impact on atrial remodeling causing atrial fibrillation (AF). Diabetes mellitus and hyperthyroidism are strong independent risk factors for AF and worsen outcomes of rhythm control strategies. An early diagnosis and intervention for these risk factors combined with rhythm control strategies may improve the overall cardiovascular mortality and morbidity. This review summarizes the current state of knowledge about the AF risk factors diabetes mellitus and thyroid disease, and discusses the impact of the modification of these risk factors on primary and secondary prevention of AF.

Association of type 2 diabetes mellitus with the development of new-onset atrial fibrillation in patients with non-ischemic dilated cardiomyopathy: impact of SGLT2 inhibitors

The aim of this study was to investigate the association of type 2 diabetes mellitus (T2DM) with the development of new-onset atrial fibrillation (AF) for non-ischemic dilated cardiomyopathy (DCM) patients. We also tested the hypothesis that sodium glucose cotransporter type 2 (SGLT2) inhibitors reduce the risk of development of new-onset AF for non-ischemic DCM patients. We retrospectively studied 210 patients with non-ischemic DCM and sinus rhythm, mean age of 59.0 ± 16.7 years and left ventricular ejection fraction of 31.0 ± 8.2% (all < 45%). T2DM was identified in 60 patients (28.6%), and the remaining 150 patients (71.4%) were classified as non-T2DM patients. New-onset AF occurred in 21 patients (10.0%) over a median follow-up of 6.1 years. Kaplan-Meier curve analysis showed that non-ischemic DCM patients without T2DM experienced fewer occurrences of the development of new-onset AF compared with those with T2DM (log-rank p = 0.0003). Furthermore, global longitudinal strain in patients who showed development of new-onset AF was significantly lower than that in those whose sinus rhythm was preserved (6.4 ± 1.4% vs. 7.7 ± 2.2%, p = 0.01). Of the 60 non-ischemic DCM patients with T2DM, those treated with SGLT2 inhibitors experienced fewer occurrences of the development of new-onset AF than did those not treated with SGLT2 inhibitors (log-rank p = 0.040). T2DM is associated with the development of new-onset AF in non-ischemic DCM patients, and treatment with SGLT2 inhibitors can significantly reduce the development of new-onset AF. Our findings may thus offer a new insight into the management of non-ischemic DCM patients with T2DM.

Blockade of Renin Angiotensin System Ameliorates the Cardiac Arrhythmias and Sympathetic Neural Remodeling in Hearts of Type 2 DM Rat Model

OBJECTIVE

The present study was designed to investigate the effects of renin angiotensin system (RAS) blockade on cardiac arrhythmias and sympathetic nerve remodelling in heart tissues of type 2 diabetic rats.

METHODS

Thirty-two male Sprague Dawley rats were randomly allocated into 4 equal groups; a) normal control group: normal rats, b) DM group; after type 2 diabetes induction, rats received 2ml oral saline daily for 4 weeks, c) DM+ ACEi: after type 2 diabetes induction, rats were treated with enalapril (10 mg/kg, orally for 4 weeks) and d) DM+ ARBs: after type 2 diabetes induction, rats were treated with losartan (30 mg/kg, orally for 4 weeks).

RESULTS

In type 2 diabetic rats, the results demonstrated significant prolongation in Q-T interval and elevation of blood sugar, HOMA-IR index, TC, TGs, LDL, serum CK-MB, myocardial damage, myocardial MDA, myocardial norepinephrine and tyrosine hydroxylase (TH) density with significant reduction in serum HDL, serum insulin and myocardial GSH and CAT. On the other hand, blockade of RAS at the level of either ACE by enalapril or angiotensin (Ag) receptors by losartan resulted in significant improvement in ECG parameters (Q-T), cardiac enzymes (CK-MB), cardiac morphology, myocardial oxidative stress (low MDA, high CAT and GSH) and myocardial TH density.

CONCLUSION

RAS plays a role in the cardiac sympathetic nerve sprouting and cardiac arrhythmias induced by type 2 DM and its blockade might have a cardioprotective effect via attenuation of sympathetic nerve fibres remodelling, myocardial norepinephrine contents and oxidative stress.

The risk of new-onset atrial fibrillation in patients with type 2 diabetes mellitus treated with sodium glucose cotransporter 2 inhibitors versus dipeptidyl peptidase-4 inhibitors

Background

Sodium glucose cotransporter 2 inhibitor (SGLT2i) reduces the risk of hard cardiovascular endpoints in type 2 diabetes mellitus (T2DM) patients with/without established cardiovascular diseases. Whether SGLT2i is associated with a lower risk of new-onset atrial fibrillation (AF) in T2DM patients is unclear. We aimed to evaluate the risk of new-onset AF associated with the use of SGLT2i compared to dipeptidyl peptidase-4 inhibitor (DPP4i) among a longitudinal cohort of diabetic patients.

Methods

We used medical data from a multi-center healthcare provider in Taiwan, which included a total of 15,606 and 12,383 patients treated with SGLT2i and DPP4i, respectively, from June 1, 2016 to December 31, 2018. We used propensity-score weighting to balance covariates across study groups. Patients were followed up from the drug index date until the occurrence of new-onset AF, discontinuation of the index drug, or the end of the study period, whichever occurred first.

Results

Overall, 55%, 45%, and 0% of the patients were treated with empagliflozin, dapagliflozin, and canagliflozin, respectively. Most patients in the DPP4i group were prescribed with linagliptin (51%), followed by sitagliptin (24%), saxagliptin (13%), vildagliptin (8%) and alogliptin (5%). The use of SGLT2i was associated with a lower risk of new-onset AF compared with DPP4i after propensity-score weighting [hazard ratio: 0.61; 95% confidential interval: 0.50–0.73; P < 0.001]. Subgroup analysis revealed that the use of SGLT2i was associated with a lower risk of new-onset AF compared with DPP4i across several subgroups including old age, female in gender, the presence of cardiovascular disease, hemoglobin A1c \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\ge$$\end{document}≥ 8%, and chronic kidney disease. The advantage of SGLT2i over DPP4i persisted with different SGLT2i (dapagliflozin or empagliflozin) and either low- or standard-dose SGLT2i.

Conclusions

SGLT2i was associated with a lower risk of new-onset AF compared with DPP4i among T2DM patients in real-world practice.

The "Road" to Atrial Fibrillation: The Role of the Cardiac Autonomic Nervous System

At the population level, there is a parallel escalation in the healthcare burden of both, atrial fibrillation (AF) as well its risk factors. Compounding this relationship, AF is associated with escalating burden at an individual level, due its self-perpetuating and progressive nature. The mechanisms by which these risk factors interact to produce atrial remodelling and subsequent AF are unclear. This intersection is critical to the development of strategies to combat this disease at both the individual and population-level. It is well known that AF can manifest from disturbances in autonomic activity. At the population level, there is growing data to suggest a role of the autonomic nervous system in the future incidence of AF. Here, we provide an overview of the association of cardiac autonomic dysfunction with the incidence of AF, review the role of the autonomic nervous system (ANS) as an intermediary between risk factors and the development of AF and finally, we discuss the bidirectional relationship between AF and cardiac autonomic nervous system dysfunction; to determine whether this is implicated in the progression of AF.

Predictors of Recurrence after Catheter Ablation of Paroxysmal Atrial Fibrillation in Different Follow-Up Periods

Background and objectives: Pulmonary vein (PV) reconnection is a major reason for recurrence after catheter ablation of paroxysmal atrial fibrillation (PAF). However, the timing of the recurrence varies between patients, and recurrence >1 year after ablation is not uncommon. We sought to elucidate the characteristics of atrial fibrillation (AF) that recurred in different follow-up periods. Materials and Methods: Study subjects comprised 151 consecutive patients undergoing initial catheter ablation of PAF. Left atrial volume index (LAVi) and atrial/brain natriuretic peptide (ANP/BNP) levels were systematically measured annually over 3 years until AF recurred. Results: Study subjects were classified into four groups: non-recurrence group (n = 84), and short-term- (within 1 year) (n = 30), mid-term- (1–3 years) (n = 26), and long-term-recurrence group (>3 years) (n = 11). The short-term-recurrence group was characterized by a higher prevalence of diabetes mellitus (hazard ratio 2.639 (95% confidence interval, 1.174–5.932), p = 0.019 by the Cox method), frequent AF episodes (≥1/week) before ablation (4.038 (1.545–10.557), p = 0.004), and higher BNP level at baseline (per 10 pg/mL) (1.054 (1.029–1.081), p < 0.0001). The mid-term-recurrence group was associated with higher BNP level (1.163 (1.070–1.265), p = 0.0004), larger LAVi (mL/m²) (1.033 (1.007–1.060), p = 0.013), and longer AF cycle length at baseline (per 10 ms) (1.194 (1.058–1.348), p = 0.004). In the long-term-recurrence group, the ANP and BNP levels were low throughout follow-up, as with those in the non-recurrence group, and AF cycle length was shorter (0.694 (0.522–0.924), p = 0.012) than those in the other recurrence groups. Conclusions: Distinct characteristics of AF were found according to the time to first recurrence after PAF ablation. The presence of secondary factors beyond PV reconnections could be considered as mechanisms for the recurrence of PAF in each follow-up period.

COVID-19 associated atrial fibrillation: Incidence, putative mechanisms and potential clinical implications

Coronavirus disease 2019 (COVID-19) is a novel, highly transmittable and severe strain disease, which has rapidly spread worldwide. Despite epidemiological evidence linking COVID-19 with cardiovascular diseases, little is known about whether and how COVID-19 influences atrial fibrillation (AF), the most prevalent arrhythmia in clinical practice. Here, we review the available evidence for prevalence and incidence of AF in patients infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and discuss disease management approaches and potential treatment options for COVID-19 infected AF patients.

Association of P-Wave Axis With Incident Atrial Fibrillation in Diabetes Mellitus (from the ACCORD Trial)

Abnormal P-wave axis may reflect preclinical atrial dysfunction and has been associated with an increased risk of incident atrial fibrillation (AF) in the general population. Patients with diabetes mellitus (DM) have a higher prevalence of AF, but the association of abnormal P-wave axis and the risk of incident AF in those with diabetes has not been previously explored. For this analysis, we included 8,965 eligible participants from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. P-wave axis was automatically measured on study electrocardiogram and visually confirmed, with the normal range being between 0° and 75°. At baseline, 8% of the study population had an abnormal P-wave axis. During 43,856 person-years of follow-up, there were 145 cases of incident AF. Using multivariable-adjusted Cox proportional hazards models, participants with abnormal P-wave axis had an increased risk of incident AF (hazard ratio 2.65, 95% confidence interval 1.76 to 3.99, p < 0.0001). Findings were similar in prespecified subgroups, without evidence of effect modification. Both left- and right-axis deviation of the P-wave were associated with incident AF. Our results suggest that abnormal P-wave axis is associated with incident AF in those with DM and that this relation is conserved in prespecified subgroups. There may be utility in considering P-wave axis values from routine ECGs in these patients.

Acute hyperglycaemia is not associated with the development of atrial fibrillation in healthy pigs

Development and progression of atrial fibrillation (AF) is driven by comorbidities such as arterial hypertension and diabetes mellitus. In animal models of chronic hyperglycaemia, progression of AF has been proposed to be triggered by oxidative stress, apoptosis and fibrosis. Acute glycosylation of CaMKII has been associated with increased susceptibility to arrhythmias in acute hyperglycaemia. However, the proarrhythmogenic effect of acute hyperglycaemia has not been investigated. Nine healthy, anesthetized pigs (54 ± 6 kg) were instrumented with electrophysiologic catheters and a multielectrode array on the epicardium of the left atrial anterior wall. Left and right atrial effective refractory periods (AERP), inducibility of AF and left atrial epicardial conduction velocities (CV) were measured at baseline (BL), increasing steps of blood glucose (200-500 mg/dL in steps of 100 mg/dL by glucose infusion) and repeated after normalisation of blood glucose levels (recovery). Serum electrolytes were kept constant during measurements by means of sodium and potassium infusion. There were no significant differences in AERP, CV or AF inducibility between BL and recovery. Heart rate remained constant regardless of blood glucose levels (BL: 103 ± 18 bpm, 500 mg/dL: 103 ± 18 bpm, r = 0.02, p = 0.346). Mean left as well as right AERP increased with higher glucose levels. CV increased with glucose levels (1.25 (1.04, 1.67) m/s at BL vs. 1.53 (1.22, 2.15) m/s at 500 mg/dL, r = 0.85, p = 0.034). Rate of AF inducibility in the left atrium remained constant throughout the whole protocol (AF episodes > 10 s: mean inducibility of 80% at BL vs. 69% at 500 mg/dL, p = 0.32, episodes > 30 s: 0% at BL vs. 0% at 500 mg/dL, p = 0.17). Our data imply that acute hyperglycaemia is associated with lower arrhythmogenic substrate and does not promote AF inducibility.

Disrupting the Electrical Circuit: New Onset Atrial Fibrillation in a Patient With Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)

In December 2019, an outbreak of pneumonia cases in Wuhan, China was attributed to a novel coronavirus that was eventually recognized as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently identified as coronavirus disease 2019 (COVID-19), it has been declared a pandemic by the World Health Organization given its rapid global transmission. Various cardiovascular complications have been reported, including heart failure, myocarditis, acute coronary syndrome and arrhythmias, both atrial and ventricular. Regarding arrhythmias, onset from time of infection is variable but usually ranges from several days to a week. We hereby present a case of a COVID-19 positive patient presenting with new onset atrial fibrillation.

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.

Atrial Arrhythmias in a Patient Presenting With Coronavirus Disease-2019 (COVID-19) Infection

The coronavirus disease-2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) that has significant potential cardiovascular implications for patients. These include myocarditis, acute coronary syndromes, cardiac arrhythmias, cardiomyopathies with heart failure and cardiogenic shock, and venous thromboembolic events. We describe a Caribbean-Black gentleman with COVID-19 infection presenting with atrial arrhythmias, namely, atrial flutter and atrial fibrillation, which resolved with rate and rhythm control strategies, and supportive care.

Electrocardiological effects of ranolazine and lidocaine on normal and diabetic rat atrium

PURPOSE

Cellular changes occurring in diabetic cardiomyopathy include disturbances of calcium and sodium homeostasis. Voltage-gated sodium channels are responsible for the initiation of cardiac action potentials, and the excitability would create relevance. The effect of ranolazine as a sodium channel blocker on atrium electromechanical parameters is investigated and compared with lidocaine in streptozocin-treated diabetic rats.

METHODS

After an 8-week induction of diabetes type I, the effect of cumulative concentrations of ranolazine and lidocaine on the electrophysiology of isolated atrium was studied. Ranolazine's effects were evaluated on cardiac sodium current in normal- and high-glucose medium, with whole-cell patch-clamp technique.

RESULTS

Ranolazine at therapeutic concentrations had no significant statistical effect on refractory period in normal and diabetic isolated heart. Ranolazine (10 μM) caused a hyperpolarizing shift of V_1/2 for steady-state inactivation in normal media, while it significantly elicited a depolarizing shift in high-glucose media (p < 0.05).

CONCLUSION

It is concluded that in the isolated rat atrium preparation, ranolazine and lidocaine have no beneficial on diabetic cardiomyopathy. Although refractoriness and contractility were not much different in normal and diabetic atria, there was a definite effect of ranolazine and lidocaine on sodium current in varying concentrations. This may have significance in future therapeutics.

Lifestyle and Risk Factor Modification for Reduction of Atrial Fibrillation: A Scientific Statement From the American Heart Association

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, is associated with substantial morbidity, mortality, and healthcare use. Great strides have been made in stroke prevention and rhythm control strategies, yet reducing the incidence of AF has been slowed by the increasing incidence and prevalence of AF risk factors, including obesity, physical inactivity, sleep apnea, diabetes mellitus, hypertension, and other modifiable lifestyle-related factors. Fortunately, many of these AF drivers are potentially reversible, and emerging evidence supports that addressing these modifiable risks may be effective for primary and secondary AF prevention. A structured, protocol-driven multidisciplinary approach to integrate lifestyle and risk factor management as an integral part of AF management may help in the prevention and treatment of AF. However, this aspect of AF management is currently underrecognized, underused, and understudied. The purpose of this American Heart Association scientific statement is to review the association of modifiable risk factors with AF and the effects of risk factor intervention. Implementation strategies, care pathways, and educational links for achieving impactful weight reduction, increased physical activity, and risk factor modification are included. Implications for clinical practice, gaps in knowledge, and future directions for the research community are highlighted.

Cardiac Arrhythmias in Autoimmune Diseases

Autoimmune diseases (ADs) affect approximately 10% of the world's population. Because ADs are frequently systemic disorders, cardiac involvement is common. In this review we focus on typical arrhythmias and their pathogenesis, arrhythmia-associated mortality, and possible treatment options among selected ADs (sarcoidosis, systemic lupus erythematosus, scleroderma, type 1 diabetes, Graves' disease, rheumatoid arthritis, ankylosing spondylitis [AS], psoriasis, celiac disease [CD], and inflammatory bowel disease [IBD]). Rhythm disorders have different underlying pathophysiologies; myocardial inflammation and fibrosis seem to be the most important factors. Inflammatory processes and oxidative stress lead to cardiomyocyte necrosis, with subsequent electrical and structural remodeling. Furthermore, chronic inflammation is the pathophysiological basis linking AD to autonomic dysfunction, including sympathetic overactivation and a decline in parasympathetic function. Autoantibody-mediated inhibitory effects of cellular events (i.e., potassium or L-type calcium currents, M₂muscarinic cholinergic or β₁-adrenergic receptor signaling) can also lead to cardiac arrhythmia. Drug-induced arrhythmias, caused, for example, by corticosteroids, methotrexate, chloroquine, are also observed among AD patients. The most common arrhythmia in most AD presentations is atrial arrhythmia (primarily atrial fibrillation), expect for sarcoidosis and scleroderma, which are characterized by a higher burden of ventricular arrhythmia. Arrhythmia-associated mortality is highest among patients with sarcoidosis and lowest among those with AS; there are scant data related to mortality in patients with psoriasis, CD, and IBD.

Comparative Study of the Effects of GLP1 Analog and SGLT2 Inhibitor against Diabetic Cardiomyopathy in Type 2 Diabetic Rats: Possible Underlying Mechanisms

The present study investigated the possible cardioprotective effects of GLP1 and SGLT2i against diabetic cardiomyopathy (DCM) in type 2 diabetic rats and the possible underlying mechanisms.

METHODS

Thirty-two male Sprague Dawley rats were randomly subdivided into 4 equal groups: a) control group, b) DM group, type 2 diabetic rats with saline daily for 4 weeks, c) DM+ GLP1, as DM group with GLP1 analogue (liraglutide) at a dose of 75 µg/kg for 4 weeks, and d) DM+ SGLT2i as DM group with SGLT2 inhibitor (dapagliflozin) at a dose of 1mg/kg for 4 weeks. By the end of treatment (4 weeks), serum blood glucose, homeostasis model assessment insulin resistance (HOMA-IR), insulin, and cardiac enzymes (LDH, CK-MB) were measured. Also, the cardiac histopathology, myocardial oxidative stress markers (malondialdehyde (MDA), glutathione (GSH) and CAT) and norepinephrine (NE), myocardial fibrosis, the expression of caspase-3, TGF-β, TNF-α, and tyrosine hydroxylase (TH) in myocardial tissues were measured.

RESULTS

T2DM caused significant increase in serum glucose, HOMA-IR, serum CK-MB, and LDH (p < 0.05). Also, DM caused significant myocardial damage and fibrosis; elevation of myocardial MDA; NE with upregulation of myocardial caspase-3, TNF-α, TGF-β, and TH; and significant decrease in serum insulin and myocardial GSH and CAT (p < 0.05). Administration of either GLP1 analog or SGLT2i caused a significant improvement in all studied parameters (p < 0.05).

CONCLUSION

We concluded that both GLP1 and SGLT2i exhibited cardioprotective effects against DCM in T2DM, with the upper hand for SGLT2i. This might be due to attenuation of fibrosis, oxidative stress, apoptosis (caspase-3), sympathetic nerve activity, and inflammatory cytokines (TNF-α and TGF-β).

The impact of body weight and diabetes on new-onset atrial fibrillation: a nationwide population based study

Background

Being obese or underweight, and having diabetes are important risk factors for new-onset atrial fibrillation (AF). However, it is unclear whether there is any interaction between body weight and diabetes in regard to development of new-onset AF. We aimed to evaluate the role of body weight status and various stage of diabetes on new-onset AF.

Methods

This was a nationwide population based study using National Health Insurance Service (NHIS) data. A total of 9,797,418 patients who underwent national health check-ups were analyzed. Patients were classified as underweight [body mass index (BMI) < 18.5], normal reference group (18.5 ≤ BMI < 23.0), upper normal (23.0 ≤ BMI < 25.0), overweight (25.0 ≤ BMI < 30.0), or obese (BMI ≥ 30.0) based on BMI. Diabetes were categorized as non-diabetic, impaired fasting glucose (IFG), new-onset diabetes, diabetes < 5 years, and diabetes ≥ 5 years. Primary outcome end point was new-onset AF. New-onset AF was defined as one inpatient or two outpatient records of International Classification of Disease, Tenth Revision (ICD-10) codes in patients without prior AF diagnosis.

Results

During 80,130,161 patient*years follow-up, a total of 196,136 new-onset AF occurred. Obese [hazard ration (HR) = 1.327], overweight (HR = 1.123), upper normal (HR = 1.040), and underweight (HR = 1.055) patients showed significantly increased risk of new-onset AF compared to the normal reference group. Gradual escalation in the risk of new-onset AF was observed along with advancing diabetic stage. Body weight status and diabetes were independently associated with new-onset AF and at the same time, had synergistic effects on the risk of new-onset AF with obese diabetic patients having the highest risk (HR = 1.823).

Conclusions

Patients with obesity, overweight, underweight, and diabetes had significantly increased risk of new-onset AF. Body weight status and diabetes had synergistic effects on the risk of new-onset AF. The risk of new-onset AF increased gradually with advancing diabetic stage. This study suggests that maintaining optimal body weight and glucose homeostasis might prevent new-onset AF.

Atrial fibrillation and its arrhythmogenesis associated with insulin resistance

Background

Insulin resistance (IR) is considered as a risk factor for atrial fibrillation (AF) even before diabetes develops. The pathophysiology and underlying mechanism are largely unclear.

Methods

We investigated the corresponding mechanism in two IR models of rats fed 15-week high-fat (HFa) and high-fructose/cholesterol (HFr) diets. AF was evaluated and induced by burst atrial pacing. Isolated atrial myocytes were used for whole-cell patch clamp and calcium assessment. Ex vivo whole heart was used for optical mapping. Western blot and immunofluorescence were used for quantitative protein evaluation.

Results

Both HFa and HFr rat atria were vulnerable to AF evaluated by burst atrial pacing. Isolated atrial myocytes from HFa and HFr rats revealed significantly increased sarcoplasmic reticulum calcium content and diastolic calcium sparks. Whole-heart mapping showed prolonged calcium transient duration, conduction velocity reduction, and repetitive ectopic focal discharge in HFa and HFr atria. Protein analysis revealed increased TGF-β1 and collagen expression; increased superoxide production; abnormal upregulation of calcium-homeostasis-related proteins, including oxidized CaMKIIδ, phosphorylated-phospholamban, phosphorylated-RyR-2, and sodium-calcium exchanger; and increased Rac1 activity in both HFa and HFr atria. We observed that inhibition of CaMKII suppressed AF in both HF and HFr diet-fed rats. In vitro palmitate-induced IR neonatal cardiomyocytes and atrial fibroblasts expressed significantly more TGF-β1 than did controls, suggesting paracrine and autocrine effects on both myocytes and fibroblasts.

Conclusions

IR engenders both atrial structural remodeling and abnormal intracellular calcium homeostasis, contributing to increased AF susceptibility. The inhibition of CaMKII may be a potential therapeutic target for AF in insulin resistance.

Atrial Fibrillation – An Orchestra of Classic and Modern Risk Factors

Over the past years, prevention and control of risk factors has begun to play an important role in the management of patients prone to develop atrial fibrillation (AF). A considerable number of risk factors that contribute to the creation of a predisposing substrate for AF has been identified over the years. Although certain AF risk factors such as age, gender, genetic predisposition, or race are unmodifiable, controlling modifiable risk factors may represent an invaluable tool in the management of AF patients. In the recent decades, numerous studies have evaluated the mechanisms linking different risk factors to AF, but the exact degree of atrial remodeling induced by each factor remains unknown. Elucidating these mechanisms is essential for initiating personalized therapies in patients prone to develop AF. The present review aims to provide an overview of the most relevant modifiable risk factors involved in AF occurrence, with a focus on the mechanisms by which these factors lead to AF initiation and perpetuation.

Metformin Regulates the Expression of SK2 and SK3 in the Atria of Rats With Type 2 Diabetes Mellitus Through the NOX4/p38MAPK Signaling Pathway

We previously found that metformin regulates the ion current conducted by the small conductance calcium-activated potassium channels (SK channels) in the atria of rats with type 2 diabetes mellitus (T2DM) as well as the mRNA and protein expression of the SK2 and SK3 subtypes of SK channels. In this study, we hypothesized that the nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4)/p38 mitogen-activated protein kinase (p38MAPK) signaling pathway was involved in the metformin-mediated regulation of SK2 and SK3 expression in the atria of rats with T2DM. We randomly divided Wistar rats into the control group, the untreated T2DM group, the metformin-treated group, the group receiving subcutaneous injections of the nicotinamide adenine dinucleotide phosphate oxidase (NOX) inhibitor diphenyleneiodonium (DPI), and the group receiving tail vein injections of the p38MAPK agonist anisomycin. Real-time polymerase chain reaction, Western blot, and immunohistochemistry were applied to examine the expression levels of SK2, SK3, NOX4, and phospho-p38MAPK (p-p38MAPK) mRNAs and proteins in the atrial tissue of relevant groups. We observed that the expression levels of NOX4 mRNA and protein and p-p38MAPK protein were significantly elevated in the atria of rats with T2DM compared with the control group. In addition, SK2 protein expression was reduced, whereas SK3 protein expression was increased. The 8-week treatment with metformin markedly reduced the expression levels of NOX4 mRNA and protein and p-p38MAPK protein, upregulated the SK2 expression, and downregulated the SK3 expression. Tail vein injection with anisomycin significantly increased the p-p38MAPK expression while further inhibiting the expression of SK2 and enhancing the expression of SK3. Subcutaneous injection with DPI considerably inhibited the expression of NOX4, further enhanced the expression of SK2 and suppressed the expression of SK3. In addition, subcutaneous injection with DPI significantly suppressed the phosphorylation of p38MAPK. In conclusion, the NOX4/p38MAPK signaling pathway mediates the downregulation of SK2 and the upregulation of SK3 in the atria of rats with T2DM. Long-term metformin treatment upregulates SK2 protein expression and downregulates SK3 protein expression by inhibiting the NOX4/p38MAPK signaling pathway.

Increase of late sodium current contributes to enhanced susceptibility to atrial fibrillation in diabetic mice

Studies demonstrated that the incidence of atrial fibrillation is significantly increased in patients with diabetes mellitus. Increase of late sodium current (I_NaL) has been associated with atrial arrhythmias. However, the role of I_NaL in the setting of atrial fibrillation in diabetes mellitus remained unknown. In this study, we investigated the alteration of I_NaL in the atria of diabetic mice and the therapeutic effect of its inhibitor (GS967) on the susceptibility of atrial fibrillation. The whole-cell patch-clamp technique was used to detect single cell electrical activities. The results showed that the density of I_NaL in diabetic cardiomyocytes was larger than that of the control cells at the holding potential of -100 mV. The action potential duration at both 50% and 90% repolarization, APD₅₀ and APD₉₀, respectively, was markedly increased in diabetic mice than in controls. GS967 application inhibited I_NaL and shortened APD of diabetic mice. High-frequency electrical stimuli were used to induce atrial arrhythmias. We found that the occurrence rate of atrial fibrillation was significantly increased in diabetic mice, which was alleviated by the administration of GS967. In GS967-treated diabetic mice, the I_NaL current density was reduced and APD was shortened. In conclusion, the susceptibility to atrial fibrillation was increased in diabetic mice, which is associated with the increased late sodium current and the consequent prolongation of action potential. Inhibition of I_NaL by GS967 is beneficial against the occurrence of atrial fibrillation in diabetic mice.