Cardiac Autonomic Dysfunction and Incidence of Atrial Fibrillation: Results From 20 Years Follow-Up

Heart rate variability in patients with atrial fibrillation of sinus rhythm or atrial fibrillation: chaos or merit?

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia characterized by consistently irregular atrial and ventricular contractions. Heart rate variability (HRV) refers to the changes in the intervals between consecutive ventricular heartbeats. In sinus rhythm, HRV may be subtle and is quantitatively reflecting the dynamic interplay of the cardiac autonomic nervous system, which plays a crucial role in the onset, development, and maintenance of AF. HRV metrics, consisting of time-domain, frequency-domain, and nonlinear parameters, have been verified to vary significantly before and after AF episodes, and AF treatment-related procedures such as electrical cardioversion, ablation, and surgery of AF. Therefore, HRV may serve as a digital biomarker in predicting AF risk in long-term and acute risk period, identification of patients with AF risk in sinus rhythm and recurrence risk stratification after procedures. HRV in AF rhythm, predominantly influenced by dynamic atrioventricular node conduction under the onslaught of irregular atrial impulses, shows a huge disparity compared to that in sinus rhythm. Despite this, HRV in AF rhythm still provides valuable prognostic information, as reduced HRV may indicate a poor heart function and outcomes in patients with AF. Despite being influenced by lots of variables, HRV can still serve as an independent digital biomarker in the clinical management of AF throughout its entire lifecycle.

Neural Mechanisms in Cardiovascular Health and Disease

Although the neurocardiac axis is central to cardiovascular homeostasis, its dysregulation drives heart failure and cardiometabolic diseases. This review examines the bidirectional interplay between the autonomic nervous system and the heart, highlighting the role of this interplay in disease progression and its therapeutic potential. The autonomic nervous system modulates cardiac function and vascular tone through its sympathetic and parasympathetic branches. However, in heart failure, chronic sympathetic overdrive and parasympathetic withdrawal exacerbate myocardial remodeling and metabolic dysfunction, both of which are exacerbated by cardiometabolic conditions such as obesity and diabetes. These conditions are increasingly recognized to impair neurocardiac regulation, thereby promoting inflammation and adverse outcomes. An important emerging area concerns neuroimmune control, in which the brain orchestrates systemic inflammation through circuits involving the bone marrow, spleen, and other organs, thereby amplifying cardiovascular damage. This neuroimmune axis integrates peripheral signals to influence immune responses that contribute to disease progression. Lifestyle factors, such as stress, sleep, exercise, and diet, affect autonomic and immune balance and, thus, cardiovascular disease. Therapeutically, targeting neurocardiac and neuroimmune pathways pharmacologically or via neuromodulation (eg, vagal or splenic nerve stimulation) offers promise although the clinical translation of the latter remains challenging. In this review, we synthesize preclinical and clinical data to highlight the neurocardiac axis as a critical nexus in heart failure and cardiometabolic disease. Harnessing neuroimmune and neurocardiac interactions may inform precision approaches to reduce the burden of these conditions.

The clinical role of closed loop stimulation pacemakers in the treatment of patients with sinus node dysfunction: a review

Sinus bradycardia, sinoatrial block, sinus arrest, and bradycardia-tachycardia syndrome are manifestations of intermittent or persistent sinus node dysfunctions (SNDs). SND is classified as intrinsic, when related to an anatomic disease of sinoatrial cells, or extrinsic, when bradycardia is caused by inappropriate vagal outflow. Chronotropic incompetence is often associated with SND, especially in elderly patients. When symptoms are related to SND, pacemaker implantation is the recommended therapy, and rate-adaptive pacing modes are often preferred in cases of chronotropic incompetence. Closed-Loop Stimulation (CLS) is a rate-adaptive system based on continuous evaluation of contractility and contraction speed through the analysis of right-ventricular unipolar impedance trends during the systole of each cardiac cycle. An increase in contractility or contraction speed modifies the impedance trends, to which the CLS algorithm responds by adapting the pacing rate, and thereby heart rate and cardiac output. Therefore, CLS is integrated into the autonomic mechanisms of cardiac output regulation. This feature has drawn interest in the use of CLS in several forms of SND, from the treatment of intrinsic bradycardias to the prevention of vasovagal syncope and device-detected atrial fibrillation. We will examine the working principle of CLS and review the results of recent clinical investigations.

Assessing heart rate fragmentation to predict atrial fibrillation in the general population aged 65: the PROOF-AF study

Aims

Screening the general population aged 65 for atrial fibrillation (AF) has been proposed as a preventive measure against potential complications. Metrics derived from heart rate variability (HRV) that depict heart rate fragmentation (HRF) have been suggested to reflect autonomic nervous system dysfunction. The aim of the study was to assess the predictive capacity of HRV markers, including HRF, for AF occurrence over an 18-year follow-up and to develop a predictive score for AF onset among the general population aged 65 at the study's inception.

Methods and results

The PROOF prospective cohort consisted of 1011 subjects aged 65 with no history of AF nor history of cardiovascular disease. A 24 h Holter-electrocardiogram was performed at baseline and HRV, from which HRV indices using temporal, frequency, and non-linear methods, and the percentage of inflection points (PIPs) were calculated. The PROOF cohort demonstrated a cumulative incidence of AF of 13.0% during a median follow-up of 17.8 years. Male gender, hypertension, decreased heart rate and α1, and increased premature atrial complex burden, PNN50, and PIP were independent predictors of AF occurrence. Subsequently, the PROOF-AF risk score was developed, ranging from 0 to 7, providing interesting predictive capacity [area under the curve (AUC) = 70.1%, negative predictive value = 92.0%, and accuracy = 72.0%]. The high-risk group (PROOF-AF score from 5 to 7) and the intermediate-risk group (PROOF-AF score from 2 to 4) exhibited a 16.8- and 5.4-fold higher risk, respectively, of developing AF.

Conclusion

Heart rate fragmentation parameters, included in the PROOF-AF score, may be used to identify healthy individuals aged 65 who are at high risk of developing AF and assist population screening.

Actigraphy-based sleep disruption and diurnal biomarkers of autonomic function in paroxysmal atrial fibrillation

INTRODUCTION

Sleep architectural disruption is associated with atrial fibrillation (AF); however, associated autonomic influences remain unclear and it is unknown if this detriment persists during wakefulness. We hypothesize sleep disruption and autonomic dysfunction have diurnal patterning in patients with paroxysmal AF.

METHODS

We analyzed data from the Sleep Apnea and Atrial Fibrillation Biomarkers and Electrophysiologic Atrial Triggers (SAFEBEAT) study designed to examine paroxysmal AF and sleep apnea, including simultaneous collection of continuous electrocardiogram monitoring (Heartrak Telemetry®) and actigraphy (Actiwatch GTX) for 7-21 days. Heart rate variability (HRV) measures in time-domain (standard deviation of normal-to-normal (NN) intervals (SDNN), coefficient of variation (CV)) and frequency-domain (low frequency power (LFP), high frequency power (HFP)) were used as surrogates of autonomic function and averaged per sleep/wake per day. A linear mixed-effects model assuming compound symmetry correlation structure was used to assess the relationship of HRV with actigraphy-derived sleep data.

RESULTS

The analytic sample (age 60.1 ± 12.0 years, body mass index 32.6 ± 6.7 kg/m2, 36% female, 75% White) included 100 participants with paroxysmal AF. Longer sleep latency was associated with lower HFP during wakefulness (coefficient - 0.0501, p = 0.031). Higher sleep efficiency was associated with increased SDNN (coefficient 0.0007, p = 0.014) and CV (coefficient 0.0167, p = 0.047). Higher arousal index was associated with increased CV (coefficient 0.0166, p = 0.007) and LFP (coefficient 0.0232, p = 0.003). During sleep, longer average awakenings duration was associated with increased LFP/HFP ratio (coefficient 0.1977, p < 0.001) and reduced HFP (coefficient - 0.1338, p < 0.001). Significant sleep-wake interactions were observed for sleep latency with HFP (p = 0.024), sleep efficiency with SDNN and CV (both p < 0.01), WASO with SDNN, CV, and LFP (all p < 0.05), and frequency of awakenings with CV and LFP (both p < 0.05).

CONCLUSIONS

Actigraphy-based measures of sleep disruption were associated with autonomic function alterations exhibiting diurnal variability in paroxysmal AF. Greater overall HRV and parasympathetic modulation were related to better sleep quality. Increased sympathetic activation was associated with sleep fragmentation. Results provide insights into differential autonomic dysfunction related to sleep disruption that may contribute to atrial arrhythmogenesis.

Heart rate variability in mental disorders: an umbrella review of meta-analyses

Heart rate variability (HRV) monitoring is increasingly applied in the realm of mental disorders; however, it remains a subject of controversy. This umbrella review summarizes HRV differences between individuals with mental disorders and healthy controls (HCs), as well as changes in HRV before and after treatment in patients with mental disorders. A literature search was conducted using Medline, PubMed, Embase, and the Cochrane Database. Meta-analyses on HRV changes in patients with mental disorders, as well as meta-analyses comparing HCs and patients with mental disorders were included. We computed the summary effect size using random effects models, along with 95% confidence and prediction intervals. We assessed heterogeneity, p value of the largest study, excess significance bias, and small-study effects. Evidence levels were classified as convincing, highly suggestive, suggestive, weak, or not significant. Twenty-one systematic reviews on HRV, covering 19 mental disorders (53 meta-analyses) and 8 treatment modalities (18 meta-analyses), included 442 primary studies and 34,625. For differences between mental disorders and HCs, evidence was suggestive for 7 (13.2%) pooled analyses, indicating decreased HRV in dementia, PTSD, somatic symptom disorders, functional somatic syndromes, and schizophrenia. For other disorders, including autism spectrum disorder, alcohol use disorder, bipolar disorder, generalized anxiety disorder, insomnia, and major depressive disorder, the evidence was weaker and below the suggestive level. For treatment effects, 5 pooled analyses (27.8%) had weak evidence, indicating altered HRV before and after antipsychotic treatment, repetitive transcranial magnetic stimulation treatment, physiotherapy, and psychotherapy. The credibility of HRV evidence in mental disorders varied across HRV variables and diseases. No two diseases exhibited identical altered HRV patterns, highlighting the potential significance of overall HRV profiles in delineating distinct disorders.

Clinical neurocardiology: defining the value of neuroscience-based cardiovascular therapeutics - 2024 update

The intricate role of the autonomic nervous system (ANS) in regulating cardiac physiology has long been recognized. Aberrant function of the ANS is central to the pathophysiology of cardiovascular diseases. It stands to reason, therefore, that neuroscience-based cardiovascular therapeutics hold great promise in the treatment of cardiovascular diseases in humans. A decade after the inaugural edition, this White Paper reviews the current state of understanding of human cardiac neuroanatomy, neurophysiology and pathophysiology in specific disease conditions, autonomic testing, risk stratification, and neuromodulatory strategies to mitigate the progression of cardiovascular diseases.

Linking Cardiovascular Disease and Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD): The Role of Cardiometabolic Drugs in MASLD Treatment

The link between cardiovascular disease (CVD) and metabolic dysfunction-associated steatotic liver disease (MASLD) is well-established at both the epidemiological and pathophysiological levels. Among the common pathophysiological mechanisms involved in the development and progression of both diseases, oxidative stress and inflammation, insulin resistance, lipid metabolism deterioration, hepatokines, and gut dysbiosis along with genetic factors have been recognized to play a pivotal role. Pharmacologic interventions with drugs targeting common modifiable cardiometabolic risk factors, such as T2DM, dyslipidemia, and hypertension, are a reasonable strategy to prevent CVD development and progression of MASLD. Recently, a novel drug for metabolic dysfunction-associated steatohepatitis (MASH), resmetirom, has shown positive effects regarding CVD risk, opening new opportunities for the therapeutic approach of MASLD and CVD. This review provides current knowledge on the epidemiologic association of MASLD to CVD morbidity and mortality and enlightens the possible underlying pathophysiologic mechanisms linking MASLD with CVD. The role of cardiometabolic drugs such as anti-hypertensive drugs, hypolipidemic agents, glucose-lowering medications, acetylsalicylic acid, and the thyroid hormone receptor-beta agonist in the progression of MASLD is also discussed. Metformin failed to prove beneficial effects in MASLD progression. Studies on the administration of thiazolinediones in MASLD suggest effectiveness in improving steatosis, steatohepatitis, and fibrosis, while newer categories of glucose-lowering agents such as GLP-1Ra and SGLT-2i are currently being tested for their efficacy across the whole spectrum of MASLD. Statins alone or in combination with ezetimibe have yielded promising results. The conduction of long-duration, large, high-quality, randomized-controlled trials aiming to assess by biopsy the efficacy of cardiometabolic drugs to reverse MASLD progression is of great importance.

Sex Differences in the Association Between Cardiovascular Autonomic Neuropathy and Mortality in Patients With Type 2 Diabetes: The ACCORD Study

BACKGROUND

Cardiovascular autonomic neuropathy (CAN) is a severe complication of type 2 diabetes. Significant sex-related differences have been observed in type 2 diabetes consequences such as mortality. However, the effect of sex on the association between CAN and mortality in patients with type 2 diabetes is currently unknown.

METHODS AND RESULTS

We assessed 7866 participants in the ACCORD (Action to Control Cardiovascular Risk in Diabetes) trial, including 4730 men and 3136 women. CAN was diagnosed using a combination of heart rate variability and QT interval index, which has 3 different definitions. There were 1364 cases of all-cause mortality and 452 cases of cardiovascular disease mortality during a median follow-up of 9.7 years. We used multivariable Cox regression models to assess the association between different CAN definitions and mortality. In women, various CAN measures were statistically significant associated with an increased risk of all-cause mortality (CAN1: hazard ratio [HR], 1.64 [95% CI, 1.28-2.09]; CAN2: HR, 1.58 [95% CI, 1.17-2.15]; CAN3: HR, 1.78 [95% CI, 1.20-2.65]) and mortality (CAN1: HR, 2.25 [95% CI, 1.44-3.52]; CAN 2: HR, 2.22 [95% CI, 1.28-3.87]; CAN3: HR, 3.31 [95% CI, 1.67-6.57]). CAN was not significantly associated with mortality in men. A significant multiplicative interaction of CAN and sex was observed on both mortality outcomes (P<0.01).

CONCLUSIONS

Significant sex-related differences were observed in CAN and its associated mortality. In terms of mortality risk prevention, CAN should be given greater consideration in women with type 2 diabetes.

Atrial Lesion and Diastolic Dysfunction May Be Associated With Atrial Fibrillation in Patients With Cardiac Amyloidosis

Background

Atrial fibrillation (AF) is a common arrhythmia associated with cardiac amyloidosis (CA). Diastolic dysfunction and atrial lesions have been reported in patients with AF fibrillation. We aimed to evaluate the diastolic function and atrial lesions in patients with CA and AF.

Methods and Results

We included 27 patients (mean age 72 years) with biopsy-confirmed CA. We analyzed the average E/e' as diastolic function using echocardiography and atrial late gadolinium enhancement (LGE) as an atrial lesion using cardiac magnetic resonance imaging (CMRI). We compared these parameters among 20 patients with sinus rhythm (SR) and 7 with AF. Echocardiography examination showed that average E/e' were larger in the AF group than in the SR group (average E/e': AF, 21.3 [14.5-30.3]; SR, 14.2 [10.3-16.9]; P=0.0053). CMRI demonstrated that atrial LGE was more severe in the AF group than in the SR group (AF, 7/7 [100%]; SR, 11/21 [52.4%]; P=0.00228). Univariate logistic regression analysis showed that average E/e' demonstrated significant association with AF in all patients (odds ratio 1.24; [95% confidence interval 1.03-1.51]; P=0.0251).

Conclusions

AF may be associated with atrial lesions and diastolic dysfunction in patients with CA.

Integrating metabolomics and proteomics to identify novel drug targets for heart failure and atrial fibrillation

BACKGROUND

Altered metabolism plays a role in the pathophysiology of cardiac diseases, such as atrial fibrillation (AF) and heart failure (HF). We aimed to identify novel plasma metabolites and proteins associating with cardiac disease.

METHODS

Mendelian randomisation (MR) was used to assess the association of 174 metabolites measured in up to 86,507 participants with AF, HF, dilated cardiomyopathy (DCM), and non-ischemic cardiomyopathy (NICM). Subsequently, we sourced data on 1567 plasma proteins and performed cis MR to identify proteins affecting the identified metabolites as well as the cardiac diseases. Proteins were prioritised on cardiac expression and druggability, and mapped to biological pathways.

RESULTS

We identified 35 metabolites associating with cardiac disease. AF was affected by seventeen metabolites, HF by nineteen, DCM by four, and NCIM by taurine. HF was particularly enriched for phosphatidylcholines (p = 0.029) and DCM for acylcarnitines (p = 0.001). Metabolite involvement with AF was more uniform, spanning for example phosphatidylcholines, amino acids, and acylcarnitines. We identified 38 druggable proteins expressed in cardiac tissue, with a directionally concordant effect on metabolites and cardiac disease. We recapitulated known associations, for example between the drug target of digoxin (AT1B2), taurine and NICM risk. Additionally, we identified numerous novel findings, such as higher RET values associating with phosphatidylcholines and decreasing AF and HF. RET is targeted by drugs such as regorafenib which has known cardiotoxic side-effects. Pathway analysis implicated involvement of GDF15 signalling through RET, and ghrelin regulation of energy homeostasis in cardiac pathogenesis.

CONCLUSIONS

This study identified 35 plasma metabolites involved with cardiac diseases and linked these to 38 druggable proteins, providing actionable leads for drug development.

Resting Heart Rate and Incident Atrial Fibrillation in Black Adults in the Jackson Heart Study

Importance

Resting heart rate (RHR) is a widely available measure of cardiovascular fitness that has been associated with several cardiovascular outcomes. RHR has previously been associated with the risk of atrial fibrillation (AF) among individuals of European ancestry, but little is known about this association in Black adults.

Objective

To evaluate the association between RHR and incident AF in a large community-based sample of Black adults, independently of established risk factors.

Design, Setting, and Participants

This cohort study uses data from the Jackson Heart Study, a prospective community-based cohort in Jackson, Mississippi. Participants without prevalent AF were included and were monitored for new-onset AF during follow-up, from 2000 through 2016. Data analysis was performed from August 1 to December 11, 2023.

Exposure

RHR was assessed from resting 12-lead electrocardiograms performed at examination 1 (2000-2004) and examination 3 (2009-2013).

Main Outcomes and Measures

AF was identified from study electrocardiograms, hospitalization discharge diagnosis codes, and Medicare claims diagnosis codes. Cox regression was used to evaluate the association between baseline (examination 1) RHR and incident AF, adjusting for established AF risk factors.

Results

Among 4965 Black adults eligible for analysis, the mean (SD) age was 55 (13) years, 1830 (37%) were male, and the mean (SD) RHR at baseline was 65 (11) beats per minute (bpm). During a median (IQR) 14 (12-15) years of follow-up, there were 458 incident AF events, resulting in an incident rate of 7.5 per 1000 person-years (95% CI, 6.8-8.2 incidents per 1000 person-years). Each 10-bpm higher RHR was associated with a 9% higher risk of incident AF after adjustment for AF risk factors (hazard ratio, 1.09; 95% CI, 1.00-1.19). In a sensitivity analysis that excluded individuals with prior heart failure, prior myocardial infarction, and antiarrhythmic medication use at baseline, the hazard ratio was 1.14 (95% CI, 1.02-1.28). There was little evidence of effect modification of these associations by age, sex, body mass index, hypertension, or physical activity level.

Conclusions and Relevance

In this large prospective cohort study of Black adults, elevated baseline RHR was associated with increased risk of incident AF, consistent with findings from previous studies of European ancestry populations. Future research should focus on determining whether RHR can be used to screen patients at high risk of AF.

Restoring the Autonomic Balance in an Atrial Fibrillation Rat Model by Electroacupuncture at the Neiguan Point

OBJECTIVES

Autonomic nervous activity imbalance plays an important role in atrial fibrillation (AF). AF can be treated by acupuncture at the Neiguan point (PC6), but the mechanism remains elusive. Here, we investigated autonomic nervous system activity in electroacupuncture (EA) at PC6 in a rat AF model.

MATERIAL AND METHODS

In this study, we established a rat AF model via tail vein injection with ACh-CaCl2 for ten consecutive days with or without EA at PC6. AF inducibility and heart rate variability (HRV) were assessed by electrocardiogram. Next, we completed in vivo recording of the activity of cervical sympathetic and vagal nerves, respectively. Finally, the activities of brain regions related to autonomic nerve regulation were assessed by c-Fos immunofluorescence and multichannel recording.

RESULTS

EA at PC6 decreased AF inducibility and prevented changes in HRV caused by ACh-CaCl2 injection. Meanwhile, EA at PC6 reversed the increased sympathetic and decreased vagal nerve activity in AF rats. Furthermore, EA treatment downregulated increased c-Fos expression in brain regions, including paraventricular nucleus, rostral ventrolateral medulla, and dorsal motor nucleus of the vagus in AF, while c-Fos expression in nucleus ambiguus was upregulated with EA.

CONCLUSION

The protective effect of EA at PC6 on AF is associated with balance between sympathetic and vagal nerve activities.

Atrial fibrillation in the setting of cardiac amyloidosis - A review of the literature

Cardiac amyloidosis (CA) is related to the aggregation of insoluble fibrous deposits of misfolded proteins within the myocardium. Transthyretin amyloidosis (ATTR) and immunoglobulin light-chain amyloidosis are the main forms of CA. Atrial fibrillation (AF) is a common arrhythmia in CA patients, especially in those with ATTR amyloidosis. Increased atrial preload and afterload, atrial enlargement, enhanced atrial wall stress, and autonomic dysfunction are the main mechanisms of AF in CA patients. CA is associated with the formation of endocardial thrombi and systemic embolism. The promoters of thrombogenesis include endomyocardial damage, blood stasis, and hypercoagulability. The prevalence of thrombi in patients with AF remains elevated despite long-term anticoagulation. Consequently, transesophageal ultrasound examinations before cardioversion should be performed to exclude endocardiac thrombi despite anticoagulation. Furthermore, the CHA2DS2-VASc score should not be used to assess the thromboembolic risk in CA patients with AF. Rate control is challenging in patients with CA, while rhythm control is the preferred treatment option, especially in the early stages of the disease process. Although catheter ablation is an effective treatment option, more data are needed to explore the role of the procedure in CA patients.

The Role of the Autonomic Nervous System as Both "Trigger and "Substrate" in Atrial Fibrillation

Several complex mechanisms, working alone, or together, initiate and maintain atrial fibrillation (AF). At disease onset, pulmonary vein-atrial triggers, producing ectopy, predominate. Then, as AF progresses, a shift toward substrate occurs, which AF also self-perpetuates. The autonomic nervous system (ANS) plays an important role as trigger and substrate. Although the efferent arm of the ANS as AF trigger is well-established, there is emerging evidence to show that (1) the ANS is a substrate for AF and (2) afferent or regulatory ANS dysfunction occurs in AF patients. These findings could represent a mechanism for the progression of AF.

Exploring the impact of electrocardiographic parameters on the risk of common arrhythmias: a two-sample Mendelian randomization study

Background

Observational studies have shown that heart rate (HR), heart rate variability (HRV), P-wave terminal force, P-wave duration, T-wave amplitude and PR interval are associated with risk factors for atrial fibrillation (AF) or bradycardia. Arrhythmias are associated with many causes of hospitalization. However, observational studies are susceptible to confounding factors that have not yet been identified. The objective of this study was to clarify the causal relationships by Mendelian randomization analysis.

Methods

We conducted a two-sample and multivariate Mendelian randomization (MVMR) analysis using genome-wide association study (GWAS) data from a European population to assess the total and direct causal effects of HR, three HRV traits, P-wave terminal force, P-wave duration, T-wave top amplitude in five-lead modes, and the PR interval on the risk of AF (N=191,205), bradycardia (N=463,010), and supraventricular tachycardia (SVT) (N=463,010).

Results

The results of the univariate MR analysis revealed the following significant causal effects: the higher the genetically predicted PR interval, the lower the risk of AF; the higher the HR and T-wave top amplitude (aVR leads and V3 + V4 + aVL leads), the lower the risk of bradycardia; and the higher HR and the lower PR interval, the higher the risk of SVT. The multivariate MR results indicated that the HRV_standard deviation of the normal-to-normal (SDNN) interval had an independent causal effect on the risk of AF [odds ratio (OR): 0.515; 95% confidence interval (CI): 0.278-0.954; P=0.03], and the T-wave top amplitude in the aVR leads (OR: 0.998; 95% CI: 0.996-0.999; P<0.001) and the HRV_SDNN (OR: 0.988; 95% CI: 0.976-1.000; P=0.045) had independent causal effects on the risk of bradycardia.

Conclusions

The HRV_SDNN had an independent causal effect on AF, while the HRV_SDNN and T-wave top amplitude in the aVR leads had independent causal effects on bradycardia, which suggests that some of the electrocardiographic parameters have preventive effects on the incidence of AF and bradycardia.

Arrhythmic Risk Stratification in Cardiac Amyloidosis: A Review of the Current Literature

Cardiac amyloidosis is the most frequent infiltrative disease caused by the deposition of misfolded proteins in the cardiac tissue, leading to heart failure, brady- and tachyarrhythmia and death. Conduction disorders, atrial fibrillation (AF) and ventricular arrhythmia (VA) significantly impact patient outcomes and demand recognition. However, several issues remain unresolved regarding early diagnosis and optimal management. Extreme bradycardia is the most common cause of arrhythmic death, while fast and sustained VAs can be found even in the early phases of the disease. Risk stratification and the prevention of sudden cardiac death are therefore to be considered in these patients, although the time for defibrillator implantation is still a subject of debate. Moreover, atrial impairment due to amyloid fibrils is associated with an increased risk of AF resistant to antiarrhythmic therapy, as well as recurrent thromboembolic events despite adequate anticoagulation. In the last few years, the aging of the population and progressive improvements in imaging methods have led to increases in the diagnosis of cardiac amyloidosis. Novel therapies have been developed to improve patients' functional status, quality of life and mortality, without data regarding their effect on arrhythmia prevention. In this review, we consider the latest evidence regarding the arrhythmic risk stratification of cardiac amyloidosis, as well as the available therapeutic strategies.

Circulating neuropeptide Y as a biomarker in postoperative atrial fibrillation cases administered off-pump coronary bypass Graft surgery

Background and aims

Postoperative atrial fibrillation (POAF) is considered the most prevalent irregular heart rhythm after heart surgery. The cardiac autonomic nervous system significantly affects POAF, and neuropeptide Y (NPY), an abundant neuropeptide in the cardiovascular system, is involved in this autonomic regulation. The current work aimed to examine the potential association of NPY with POAF in individuals administered isolated off-pump coronary artery bypass grafting.

Methods

From January 1 to May 31, 2020, we examined consecutive cases administered successful isolated off-pump coronary artery bypass grafting with no previously diagnosed atrial fibrillation (AF). Clinical characteristics and plasma samples were collected before surgery. NPY was quantified by enzyme-linked immunosorbent assay (ELISA) in peripheral blood, and POAF cases were identified through a 7-day Holter monitoring.

Results

Among 120 cases with no previously diagnosed AF, 33 (27.5 %) developed POAF during hospitalization. Median NPY levels were markedly elevated in the POAF group in comparison with the sinus rhythm group (31.72 vs. 27.95, P = 0.014). Multivariable logistic regression analysis revealed age (OR = 1.135, 95%CI 1.054-1.223; P = 0.001), left atrial size (OR = 1.136, 95%CI 1.004-1.285; P = 0.043), and NPY levels in peripheral blood (OR = 1.055, 95%CI 1.002-1.111; p = 0.041) independently predicted POAF. Additionally, NPY levels were positively correlated with high-frequency (HF) (r = 0.2774, P = 0.0022) and low-frequency (LF) (r = 0.2095, P = 0.0217) components of heart rate variability.

Conclusion

In summary, this study demonstrates an association between elevated NPY levels in peripheral blood before surgery and POAF occurrence.

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.

The Role of Ferroptosis in Atrial Fibrillation: A Promising Future

Atrial fibrillation (AF) is one of the most common cardiac arrhythmias, with its diagnosis being closely tied to higher rates of cardiovascular morbidity and mortality. AF is associated with a range of dangerous complications including stroke and heart failure, making it a key driver of healthcare spending and a major threat to global public health. The precise mechanisms that govern AF incidence and the onset of related complications, however, remain uncertain. Ferroptotic cell death has been the focus of rising interest in the cardiac arrhythmias, and there is recent evidence supporting a role for atrial ferroptosis as a mediator of AF development. Interventional strategies focused on ferroptotic activity, such as novel ferroptosis inhibitors, have also shown promise as a means of protecting against AF through their ability to reduce iron overload. In this review, we provide a summary of the proposed mechanisms whereby ferroptosis contributes to the pathophysiology of AF and their therapeutic implications.

Effect of an intensive lifestyle intervention on the structural and functional substrate for atrial fibrillation in people with metabolic syndrome

AIMS

To evaluate the effect of an intensive lifestyle intervention (ILI) on the structural and functional cardiac substrate of atrial fibrillation (AF) in overweight or obese people with metabolic syndrome (Mets).

METHODS AND RESULTS

Participants of the PREvención con DIeta MEDiterranea-Plus trial (n = 6874) were randomized 1:1 to an ILI programme based on an energy-reduced Mediterranean diet, increased physical activity, and cognitive-behavioural weight management or to a control intervention of low-intensity dietary advice. A core echocardiography lab evaluated left atrial (LA) strain, function, and volumes in 534 participants at baseline, 3-year, and 5-year follow-ups. Mixed models were used to evaluate the effect of the ILI on LA structure and function. In the subsample, the baseline mean age was 65 years [standard deviation (SD) 5 years], and 40% of the participants were women. The mean weight change after 5 years was -3.9 kg (SD 5.3 kg) in the ILI group and -0.3 kg (SD 5.1 kg) in the control group. Over the 5-year period, both groups experienced a worsening of LA structure and function, with increases in LA volumes and stiffness index and decreases in LA longitudinal strain, LA function index, and LA emptying fraction over time. Changes in the ILI and control groups were not significantly different for any of the primary outcomes {LA emptying fraction: -0.95% [95% confidence interval (CI) -0.93, -0.98] in the control group, -0.97% [95% CI -0.94, -1.00] in the ILI group, Pbetween groups = 0.80; LA longitudinal strain: 0.82% [95% CI 0.79, 0.85] in the control group, 0.85% [95% CI 0.82, 0.89] in the ILI group, Pbetween groups = 0.24} or any of the secondary outcomes.

CONCLUSION

In overweight or obese people with Mets, an ILI had no impact on the underlying structural and functional LA substrate measurements associated with AF risk.

Interplay of heart rate variability and resting heart rate on mortality in type 2 diabetes

AIMS

Heart rate variability (HRV) and resting heart rate (RHR) are usually analyzed and interpreted separately. We aimed to assess the interplay of HRV and RHR on mortality in type 2 diabetes.

METHODS

The study included 7,529 participants from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. HRV metrics included standard deviation of all normal-to-normal intervals (SDNN) and root mean square of successive differences between normal-to-normal intervals (rMSSD). Abnormal values were defined based on <25th percentile for HRV and >75th percentile for RHR. Interactions of HRV status and RHR status were tested on multiplicative and additive scales. Results were validated in a subset of patients with type 2 diabetes (n = 745) from the Multi-Ethnic Study of Atherosclerosis.

RESULTS

Low SDNN was associated with increased all-cause mortality in the high RHR group (HR 1.60; 95% CI 1.29-1.97), but not in the normal RHR group. Compared with those who had neither low SDNN nor high RHR, the presence of either low SDNN or high RHR was not significantly associated with an increased risk of all-cause mortality. In contrast, the combination of low SDNN and high RHR was associated with a significantly increased risk of all-cause mortality (HR 1.68; 95% CI 1.43-1.97). Significant multiplicative and additive interactions were found between HRV status and RHR status on risk of all-cause mortality (all Pinteraction < 0.05). Similar findings were observed for cardiovascular mortality, in analyses using rMSSD, and in the Multi-Ethnic Study of Atherosclerosis.

CONCLUSIONS

The association between HRV and mortality risk is modified by RHR levels. Furthermore, low HRV and high RHR have interdependent and synergistic associations with mortality risk.

Intensive Glycemic Therapy in Type 2 Diabetes Patients With Cardiac Autonomic Dysfunction: The ACCORD Trial

OBJECTIVE

To assess whether the presence of cardiac autonomic dysfunction denoted by low heart rate variability (HRV) modifies the effect of intensive glycemic therapy on outcomes in patients with type 2 diabetes.

PATIENTS AND METHODS

This study included 7946 participants in the ACCORD (Action to Control Cardiovascular Risk in Diabetes) trial from January 2001 through June 2009. Heart rate variability measures included standard deviation of all normal-to-normal intervals (SDNN) and root mean square of successive differences between normal-to-normal intervals (rMSSD). Abnormal values were defined based on less than the 10th percentile for SDNN and rMSSD.

RESULTS

Compared with standard therapy, intensive therapy was associated with improved primary outcome (composite of cardiovascular events) in the low-HRV group (SDNN: HR, 0.57; 95% CI, 0.39 to 0.84; rMSSD: HR, 0.57; 95% CI, 0.38 to 0.84), but not in the normal-HRV group (SDNN: HR, 0.90; 95% CI, 0.77 to 1.05; rMSSD: HR, 0.90; 95% CI, 0.77 to 1.05). A similar pattern was found for coronary heart disease. Conversely, intensive therapy had a neutral effect on all cause death in the low-HRV group (SDNN: HR, 0.88; 95% CI, 0.54 to 1.41; rMSSD: HR, 0.71; 95% CI, 0.43 to 1.17;), but increase risk of all-cause death in the normal-HRV group (SDNN: HR, 1.21; 95% CI, 1.00 to 1.46; rMSSD: HR, 1.25; 95% CI, 1.03 to 1.51). Intensive therapy induced a greater risk of hypoglycemia in the normal-HRV group than that in the low-HRV group.

CONCLUSION

Cardiac autonomic dysfunction expressed as low HRV identified subpopulations in ACCORD with more benefits and less harms from intensive therapy.

Characteristics of cardiac arrhythmia and heart rate variability in Chinese patients with primary aldosteronism

We applied 24-h Holter monitoring to analyze the characteristics of arrhythmias and heart rate variability in Chinese patients with primary aldosteronism (PA) and compared them with age-, sex-, and blood pressure-matched primary hypertension (PH) patients. A total of 216 PA patients and 261 PH patients were enrolled. The nonstudy data were balanced using propensity score matching (PSM), and the risk variables for developing arrhythmias were then analyzed using logistic regression analysis. Before PSM, the proportion of PA patients with combined atrial premature beats and prolonged QT interval was higher than the corresponding proportion in the PH group. After PSM, the PA group had a larger percentage of transient atrial tachycardia and frequent atrial premature beats, and it had higher heart rate variability metrics. The proportion of unilateral PA combined with multiple ventricular premature beats was higher than that of bilateral PA. Older age, grade 3 hypertension, and hypokalemia were independent risk factors for the emergence of arrhythmias in PA patients. PA patients suffer from a greater prevalence of arrhythmias than well-matched PH patients.

Development and Validation of a Predictive Model Based on LASSO Regression: Predicting the Risk of Early Recurrence of Atrial Fibrillation after Radiofrequency Catheter Ablation

BACKGROUND

Although recurrence rates after radiofrequency catheter ablation (RFCA) in patients with atrial fibrillation (AF) remain high, there are a limited number of novel, high-quality mathematical predictive models that can be used to assess early recurrence after RFCA in patients with AF.

PURPOSE

To identify the preoperative serum biomarkers and clinical characteristics associated with post-RFCA early recurrence of AF and develop a novel risk model based on least absolute shrinkage and selection operator (LASSO) regression to select important variables for predicting the risk of early recurrence of AF after RFCA.

METHODS

This study collected a dataset of 136 atrial fibrillation patients who underwent RFCA for the first time at Peking University Shenzhen Hospital from May 2016 to July 2022. The dataset included clinical characteristics, laboratory results, medication treatments, and other relevant parameters. LASSO regression was performed on 100 cycles of data. Variables present in at least one of the 100 cycles were selected to determine factors associated with the early recurrence of AF. Then, multivariable logistic regression analysis was applied to build a prediction model introducing the predictors selected from the LASSO regression analysis. A nomogram model for early post-RFCA recurrence in AF patients was developed based on visual analysis of the selected variables. Internal validation was conducted using the bootstrap method with 100 resamples. The model's discriminatory ability was determined by calculating the area under the curve (AUC), and calibration analysis and decision curve analysis (DCA) were performed on the model.

RESULTS

In a 3-month follow-up of AF patients (n = 136) who underwent RFCA, there were 47 recurrences of and 89 non-recurrences of AF after RFCA. P, PLR, RDW, LDL, and CRI-II were associated with early recurrence of AF after RFCA in patients with AF (p < 0.05). We developed a predictive model using LASSO regression, incorporating four robust factors (PLR, RDW, LDL, CRI-II). The AUC of this prediction model was 0.7248 (95% CI 0.6342-0.8155), and the AUC of the internal validation using the bootstrap method was 0.8403 (95% CI 0.7684-0.9122). The model demonstrated a strong predictive capability, along with favorable calibration and clinical applicability. The Hosmer-Lemeshow test indicated that there was good consistency between the predicted and observed values. Additionally, DCA highlighted the model's advantages in terms of its clinical application.

CONCLUSIONS

We have developed and validated a risk prediction model for the early recurrence of AF after RFCA, demonstrating strong clinical applicability and diagnostic performance. This model plays a crucial role in guiding physicians in preoperative assessment and clinical decision-making. This novel approach also provides physicians with personalized management recommendations.

Research on atrial fibrillation mechanisms and prediction of therapeutic prospects: focus on the autonomic nervous system upstream pathways

Atrial fibrillation (AF) is the most common clinical arrhythmia disorder. It can easily lead to complications such as thromboembolism, palpitations, dizziness, angina, heart failure, and stroke. The disability and mortality rates associated with AF are extremely high, significantly affecting the quality of life and work of patients. With the deepening of research into the brain-heart connection, the link between AF and stroke has become increasingly evident. AF is now categorized as either Known Atrial Fibrillation (KAF) or Atrial Fibrillation Detected After Stroke (AFDAS), with stroke as the baseline. This article, through a literature review, briefly summarizes the current pathogenesis of KAF and AFDAS, as well as the status of their clinical pharmacological and non-pharmacological treatments. It has been found that the existing treatments for KAF and AFDAS have limited efficacy and are often associated with significant adverse reactions and a risk of recurrence. Moreover, most drugs and treatment methods tend to focus on a single mechanism pathway. For example, drugs targeting ion channels primarily modulate ion channels and have relatively limited impact on other pathways. This limitation underscores the need to break away from the "one disease, one target, one drug/measurement" dogma for the development of innovative treatments, promoting both drug and non-drug therapies and significantly improving the quality of clinical treatment. With the increasing refinement of the overall mechanisms of KAF and AFDAS, a deeper exploration of physiological pathology, and comprehensive research on the brain-heart relationship, it is imperative to shift from long-term symptom management to more precise and optimized treatment methods that are effective for almost all patients. We anticipate that drugs or non-drug therapies targeting the central nervous system and upstream pathways can guide the simultaneous treatment of multiple downstream pathways in AF, thereby becoming a new breakthrough in AF treatment research.

Long-term association of ultra-short heart rate variability with cardiovascular events

Heart rate variability (HRV) is a cardiac autonomic marker with predictive value in cardiac patients. Ultra-short HRV (usHRV) can be measured at scale using standard and wearable ECGs, but its association with cardiovascular events in the general population is undetermined. We aimed to validate usHRV measured using ≤ 15-s ECGs (using RMSSD, SDSD and PHF indices) and investigate its association with atrial fibrillation, major adverse cardiac events, stroke and mortality in individuals without cardiovascular disease. In the National Survey for Health and Development (n = 1337 participants), agreement between 15-s and 6-min HRV, assessed with correlation analysis and Bland-Altman plots, was very good for RMSSD and SDSD and good for PHF. In the UK Biobank (n = 51,628 participants, 64% male, median age 58), after a median follow-up of 11.5 (11.4-11.7) years, incidence of outcomes ranged between 1.7% and 4.3%. Non-linear Cox regression analysis showed that reduced usHRV from 15-, 10- and 5-s ECGs was associated with all outcomes. Individuals with low usHRV (< 20th percentile) had hazard ratios for outcomes between 1.16 and 1.29, p < 0.05, with respect to the reference group. In conclusion, usHRV from ≤ 15-s ECGs correlates with standard short-term HRV and predicts increased risk of cardiovascular events in a large population-representative cohort.

Associations of polyneuropathy with risk of all-cause and cardiovascular mortality, cardiovascular disease events stratified by diabetes status

AIMS/INTRODUCTION

We investigated the association of polyneuropathy (PN) with all-cause and cardiovascular (CV) mortality and with cardiovascular disease (CVD) events stratified by diabetes status.

MATERIALS AND METHODS

This prospective cohort study used the UK Biobank. Polyneuropathy was defined based on nurse-led interviews or ICD codes for polyneuropathy. Cox proportional hazards models were used to investigate the association of polyneuropathy with clinical outcomes.

RESULTS

A total of 459,127 participants were included in the analysis. Polyneuropathy was significantly associated with all-cause and cardiovascular mortality, and with CVD events even after adjusting for CVD risk factors across all diabetes statuses. Metabolic parameters HbA1c , waist circumference, BMI and the inflammatory parameter C-reactive protein showed significant mediation effects for the association between polyneuropathy and CVD. Adherence to a favorable lifestyle was associated with a lower risk of all-cause and cardiovascular mortality regardless of polyneuropathy status.

CONCLUSIONS

Polyneuropathy was associated with all-cause and cardiovascular mortality, and with CVD events in subjects with diabetes or prediabetes, even those having normal glucose tolerance. This study suggests the importance of polyneuropathy as a risk factor for death and highlights the necessity of early diagnosis and lifestyle intervention for those with type 2 diabetes and polyneuropathy.

Insomnia and Early Incident Atrial Fibrillation: A 16-Year Cohort Study of Younger Men and Women Veterans

Background There is growing consideration of sleep disturbances and disorders in early cardiovascular risk, including atrial fibrillation (AF). Obstructive sleep apnea confers risk for AF but is highly comorbid with insomnia, another common sleep disorder. We sought to first determine the association of insomnia and early incident AF risk, and second, to determine if AF onset is earlier among those with insomnia. Methods and Results This retrospective analysis used electronic health records from a cohort study of US veterans who were discharged from military service since October 1, 2001 (ie, post-9/11) and received Veterans Health Administration care, 2001 to 2017. Time-varying, multivariate Cox proportional hazard models were used to examine the independent contribution of insomnia diagnosis to AF incidence while serially adjusting for demographics, lifestyle factors, clinical comorbidities including obstructive sleep apnea and psychiatric disorders, and health care utilization. Overall, 1 063 723 post-9/11 veterans (Mean age=28.2 years, 14% women) were followed for 10 years on average. There were 4168 cases of AF (0.42/1000 person-years). Insomnia was associated with a 32% greater adjusted risk of AF (95% CI, 1.21-1.43), and veterans with insomnia showed AF onset up to 2 years earlier. Insomnia-AF associations were similar after accounting for health care utilization (adjusted hazard ratio [aHR], 1.27 [95% CI, 1.17-1.39]), excluding veterans with obstructive sleep apnea (aHR, 1.38 [95% CI, 1.24-1.53]), and among those with a sleep study (aHR, 1.26 [95% CI, 1.07-1.50]). Conclusions In younger adults, insomnia was independently associated with incident AF. Additional studies should determine if this association differs by sex and if behavioral or pharmacological treatment for insomnia attenuates AF risk.

Risk of atrial fibrillation in individuals with dysglycemia and diabetes

OBJECTIVE

Diabetes is a risk factor for atrial fibrillation (AF), and increases the risk of thromboembolic events in persons with AF. However, the link between the two conditions is not fully elucidated. Few studies have investigated the association of dysglycemia and incident AF. We investigated the risk of incident AF and prognosis according to diabetes status.

RESEARCH DESIGN AND METHODS

The Copenhagen Primary Care Laboratory Database was merged with data on medical prescriptions, in- and outpatient contacts and vital status. The risk of AF according to diabetes status was investigated by use of Cox regression models.

RESULTS

Of 354.807 individuals with a hemoglobin A1c (HbA1c) measurement, 28.541 (8 %) had known diabetes, 13.038 (4 %) had new onset diabetes and 27.754 (8 %) had prediabetes (HbA1c 42-47 mmol/mol). Persons with dysglycemia (HbA1c > 42 mmol/mol) and diabetes were older, more were men, they had lower level of education and were more likely to be living alone. We observed a gradual increase in risk of developing AF from HbA1c levels of 40 to 60 mmol/mol. In adjusted analyses we found a stepwise increase in hazard of AF from normoglycemia over prediabetes to persons with diabetes (no diabetes: 1.00 [ref.]; prediabetes: 1.12 [1.08-1.16]; new-onset diabetes: 1.16 [1.10-1.22]; known diabetes: 1.15 [1.11-1.20]). Persons with known diabetes had a significant higher hazard of stroke, cardiovascular and all-cause mortality.

CONCLUSION

Increasing levels of HbA1c were associated with an increased hazard of developing AF. Persons with new onset of diabetes and those with known diabetes had similar hazard of developing AF, however persons with known diabetes had a significant higher hazard of stroke, cardiovascular- and all-cause mortality.

A randomized clinical trial of omega-3 fatty acid and vitamin D supplementation on electrocardiographic risk profiles

Beneficial and adverse associations with arrhythmias have been reported for omega-3 fatty acids (omega-3 FA) and Vitamin D. The 12 lead electrocardiogram (ECG) contains quantitative measures reflecting diverse aspects of electrophysiology that might provide insights into mechanisms underlying these associations. In a pre-specified ancillary study of the VITaminD and omegA-3 (VITAL) trial, we examined the effect of 1 g of marine omega-3 FA per day, comprised of 460 mg eicosapentanoic acid and 380 mg of docosahexaenoic acid, and 2000 IU VitaminD3 per day on ECG characteristics associated with atrial and ventricular arrhythmias among individuals age 50 years or greater. A total of 911 study participants underwent ECGs at baseline and again at 2 years after the randomization. Individuals randomized to active omega-3 FA demonstrated significant net increase in PR-interval duration (p = 0.005) and P-wave duration (p = 0.03) as well significant net decrease in P-wave amplitude (p = 0.037) as compared to placebo. RMSSD increased to a greater extent in the omega-3 FA arm compared to placebo (p = 0.040). For Vitamin D3, the Cornell voltage increased to a lesser extent in the participants assigned to active treatment as compared to placebo (p = 0.044). There were no other significant differences in QRS, QTc, Cornell voltage or heart rate. Thus, randomized treatment with omega-3 FA supplements resulted in changes on the ECG that are potentially reflective of heightened vagal tone and/or slowing of intraatrial and AV conduction. Vitamin D3 supplementation resulted in modest reductions in progressive LV voltage suggestive of a potential antihypertrophic effect.Trial registration ClinicalTrials.gov Identifiers: NCT01169259, NCT02178410 (06/26/2010 and 06/30/2014).

A systematic review and meta-analysis of cohort studies on the potential association between NAFLD/MAFLD and risk of incident atrial fibrillation

Background and objective

The association between atrial fibrillation (AF) and non-alcoholic fatty liver disease (NAFLD) or metabolic-associated fatty liver disease (MAFLD) has been explored in recent cohort studies, however, the results have been controversial and inconclusive. This meta-analysis aimed to explore this potential association.

Methods

We systematically searched PubMed, Embase, and Web of Science databases to identify all relevant cohort studies investigating the association between NAFLD/MAFLD and AF published from database inception to October 30, 2022. Random-effects models were utilized to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for summary purposes. Additionally, subgroup and sensitivity analyses were performed.

Results

A total of 13 cohort studies with 14 272 735 participants were included. Among these, 12 cohort studies with 14 213 289 participants (median follow-up of 7.8 years) showed a significant association between NAFLD and an increased risk of incident AF (HR = 1.18, 95% CI: 1.12-1.23, P < 0.00001). Our subgroup analyses mostly yielded similar results, and the results of sensitivity analyses remained unchanged. However, meta-analysis of data from 2 cohort studies with 59 896 participants (median follow-up of 2.15 years) showed that MAFLD was not linked to incident AF (HR = 1.36, 95% CI: 0.63-2.92, P = 0.44).

Conclusion

Current evidence shows that NAFLD may be linked to a slightly higher risk of developing AF, particularly among Asian populations and those diagnosed with NAFLD using FLI criteria. Nevertheless, there is not enough evidence to support the proposed association between MAFLD and an increased risk of AF. To better understand this relationship, future studies should consider factors such as specific population, the severity of NAFLD/MAFLD, diagnostic methods of NAFLD and AF, and cardiometabolic risk factors.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero, identifier CRD42022371503.

Blood Pressure Variability and Risk of Atrial Fibrillation in Adults With Type 2 Diabetes

BACKGROUND

There is a paucity of epidemiological data on the association between long-term variability of blood pressure (BP) and incident atrial fibrillation (AF).

OBJECTIVES

The purpose of this study was to evaluate the association of BP variability with incident AF in a large sample of adults with type 2 diabetes.

METHODS

We included participants who had ≥5 BP measurements in the first 24 months of action to control cardiovascular risk in diabetes. The visit-to-visit variability of systolic blood pressure (SBP) and diastolic blood pressure (DBP) was estimated using the coefficient of variation, SD, and variability independent of the mean. Incident AF was recorded using follow-up electrocardiograms. Modified Poisson regression was used to generate risk ratios (RRs) and 95% CI for AF.

RESULTS

A total of 8,399 participants were included (average age 62.6 ± 6.5 years, 38.8% women, 63.2% White). Over a median follow-up of 5 years, 155 developed AF. Compared to the lowest quartile, the highest quartile of BP variability was associated with an increased risk of AF (RR: 1.85 [95% CI: 1.13-3.03] and 1.63 [95% CI: 1.01-2.65] for coefficient of variation of SBP and DBP, respectively). Participants in the highest quartile of both SBP and DBP had a 2-fold higher risk of AF compared to those in the lowest 3 quartiles of both SBP and DBP (RR: 1.94; 95% CI: 1.29-2.93).

CONCLUSIONS

In a large cohort of adults with type 2 diabetes, higher variability in SBP and DBP was independently associated with an increased risk of AF.

Epidemiology, Mechanisms, and Management of Atrial Fibrillation in Cardiac Amyloidosis

Cardiac amyloidosis (CA) is a restrictive disease that results from intramyocardial amyloid deposition due to immunoglobulin light chain or transthyretin proteins. Up to two-third of CA patients have atrial fibrillation (AF) due to electromechanical, autonomic, and hemodynamic disturbances. AF in CA carries particularly increased risk of thromboembolism, prompting anticoagulation therapy irrespective of CHA₂DS₂VASc score. However, CA is also associated with enhanced bleeding risk that warrants thorough assessment of bleeding profile before initiation of anticoagulation. Management of AF in CA is challenging because these patients poorly tolerate rate control agents, while cardiomyopathy precludes most antiarrhythmic agents, leaving amiodarone as the preferred antiarrhythmic drug. The effectiveness of direct current cardioversion in restoring sinus rhythm in CA is comparable with that in the general population, although intraprocedural complication rates could be higher. Transesophageal echocardiogram should be performed prior to direct current cardioversion, given high incidence of intracardiac thrombus in these patients. Finally, the data on catheter ablation is limited.

Prognostic value of heart rate variability in atrial fibrillation recurrence following catheter ablation: A systematic review and meta-analysis

Background

Atrial fibrillation (AF) has been a worldwide health issue with increasing prevalence and mortality. Recently, increasing attention has been gained to the relationship between heart rate variability (HRV) and the clinical prognosis of AF catheter ablation. We aimed to evaluate the prognostic value of HRV in AF recurrence.

Methods

We systematically searched Web of Science, PubMed, and Embase from inception until 17 August 2022 to conduct the systematic review and meta-analysis. We included the studies reporting the predictive value of HRV parameters for AF recurrence or in which HRV parameters in AF recurrence and non-recurrence groups were individually reported.

Results

Finally, we enrolled 16 studies, including 2,352 patients. Higher rMSSD could independently predict AF recurrence following catheter ablation (OR: 1.02, 95% CI: 1.00-1.04; p = 0.03). Higher HF (OR: 1.55, 95% CI: 1.05-2.28; p = 0.03) and lower LF/HF (OR: 1.12, 95% CI: 1.03-1.20; p = 0.004) could independently predict AF recurrence within 1 year. Higher SDNN (OR: 1.02, 95% CI: 101-1.02; p = 0.0006) could independently predict AF recurrence among patients with paroxysmal AF. Almost all HRV parameters within 3 days after catheter ablation and lnHF, lnLF, and rMSSD at 3 months after catheter ablation performed significant differences in AF recurrence and non-recurrence groups.

Conclusion

Heart rate variability, especially higher rMSSD (within short-term and long-term periods), was closely related to recurrent AF following catheter ablation, highlighting the clinical importance of HRV in the prognosis of AF following catheter ablation.

Stroke in Parkinson's disease: a review of epidemiological studies and potential pathophysiological mechanisms

Parkinson's disease (PD) is the fastest growing neurological disorder and one of the leading neurological causes of disability worldwide following stroke. An overall aging global population, as well as general changes in lifestyle associated with mass industrialization in the last century, may be linked to both increased incidence rates of PD and an increase in cumulative cardiovascular risk. Recent epidemiological studies show an increased risk of stroke, post-stroke complications, and subclinical ischemic insults in PD. PD patients have a host of characteristics that might contribute to increasing the risk of developing ischemic stroke including motor impairment, dysautonomia, and sleep disorders. This increases the urgency to study the interplay between PD and other neurological disorders, and their combined effect on mortality, morbidity, and quality of life. In this review, we provide a comprehensive overview of the studied etiological factors and pathological processes involved in PD, specifically with regard to their relationship to stroke. We hope that this review offers an insight into the relationship between PD and ischemic stroke and motivates further studies in this regard.

Initial In-Hospital Visit-to-Visit Heart Rate Variability Is Associated with Higher Risk of Atrial Fibrillation in Patients with Acute Ischemic Stroke

BACKGROUND

To evaluate the association between the visit-to-visit heart rate variability and the risk of atrial fibrillation (AF) in acute ischemic stroke (AIS).

METHODS

We analyzed the data of 8179 patients with AIS. Patients without AF on 12-lead electrocardiography underwent further 24 h Holter monitoring. They were categorized into four subgroups according to the visit-to-visit heart rate variability expressed as the coefficient of variation in heart rate (HR-CV). Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using the HR-CV < 0.08 subgroup as a reference.

RESULTS

The adjusted OR of paroxysmal AF was 1.866 (95% CI = 1.205-2.889) for the HR-CV ≥ 0.08 and <0.10 subgroup, 1.889 (95% CI = 1.174-3.038) for the HR-CV ≥ 0.10 and <0.12 subgroup, and 5.564 (95% CI = 3.847-8.047) for the HR-CV ≥ 0.12 subgroup. The adjusted OR of persistent AF was 2.425 (95% CI = 1.921-3.062) for the HR-CV ≥ 0.08 and <0.10 subgroup, 4.312 (95% CI = 3.415-5.446) for the HR-CV ≥ 0.10 and <0.12 subgroup, and 5.651 (95% CI = 4.586-6.964) for the HR-CV ≥ 0.12 subgroup.

CONCLUSIONS

HR-CV can facilitate the identification of patients with AIS at a high risk of paroxysmal AF.

Neuromodulation therapy for atrial fibrillation

Atrial fibrillation has a multifactorial pathophysiology influenced by cardiac autonomic innervation. Both sympathetic and parasympathetic influences are profibrillatory. Innovative therapies targeting the neurocardiac axis include catheter ablation or pharmacologic suppression of ganglionated plexi, renal sympathetic denervation, low-level vagal stimulation, and stellate ganglion blockade. To date, these therapies have variable efficacy. As our understanding of atrial fibrillation and the cardiac nervous system expands, our approach to therapeutic neuromodulation will continue evolving for the benefit of those with AF.

Autonomic Nervous System Regulation of Epicardial Adipose Tissue: Potential Roles for Regulator of G Protein Signaling-4

The epicardial adipose tissue (EAT) or epicardial fat is a visceral fat depot in the heart that contains intrinsic adrenergic and cholinergic nerves, through which it interacts with the cardiac sympathetic (adrenergic) and parasympathetic (cholinergic) nervous systems. These EAT nerves represent a significant source of several adipokines and other bioactive molecules, including norepinephrine, epinephrine, and free fatty acids. The production of these molecules is biologically relevant for the heart, since abnormalities in EAT secretion are implicated in the development of pathological conditions, including coronary atherosclerosis, atrial fibrillation, and heart failure. Sympathetic hyperactivity and parasympathetic (cholinergic) derangement are associated with EAT dysfunction, leading to a variety of adverse cardiac conditions, such as heart failure, diastolic dysfunction, atrial fibrillation, etc.; therefore, several studies have focused on exploring the autonomic regulation of EAT as it pertains to heart disease pathogenesis and progression. In addition, Regulator of G protein Signaling (RGS)-4 is a protein with significant regulatory roles in both adrenergic and muscarinic receptor signaling in the heart. In this review, we provide an overview of the autonomic regulation of EAT, with a specific focus on cardiac RGS4 and the potential roles this protein plays in this regulation.

Development and validation of a novel risk model for predicting atrial fibrillation recurrence risk among paroxysmal atrial fibrillation patients after the first catheter ablation

AIMS

Several models have been developed to predict the risk of atrial fibrillation (AF) recurrence after radiofrequency catheter ablation (RFCA). However, these models are of poor quality from the start. We, therefore, aimed to develop and validate a predictive model for post-operative recurrence of AF.

MATERIALS AND METHODS

In a study including 433 patients undergoing the first circumferential pulmonary vein isolation (CPVI) procedure, independent predictors of AF recurrence were retrospectively identified. Using the Cox regression of designated variables, a risk model was developed in a random sample of 70% of the patients (development cohort) and validated in the remaining (validation cohort) 30%. The accuracy and discriminative power of the predictive models were evaluated in both cohorts.

RESULTS

During the established 12 months follow-up, 134 patients (31%) recurred. Six variables were identified in the model including age, coronary artery disease (CAD), heart failure (HF), hypertension, transient ischemic attack (TIA) or cerebrovascular accident (CVA), and left atrial diameter (LAD). The model showed good discriminative power in the development cohort, with an AUC of 0.77 (95% confidence interval [CI], 0.69-0.86). Furthermore, the model shows good agreement between actual and predicted probabilities in the calibration curve. The above results were confirmed in the validation cohort. Meanwhile, decision curve analysis (DCA) for this model also demonstrates the advantages of clinical application.

CONCLUSION

A simple risk model to predict AF recurrence after ablation was developed and validated, showing good discriminative power and calibration.

Neurogenic cardiac outcome in patients after acute ischemic stroke: The brain and heart connection

BACKGROUND

Neurogenic cardiac impairment can occur after acute ischemic stroke (AIS), but the mapping of the neuroanatomic correlation of stroke-related myocardial injury remains uncertain. This study aims to identify the association between cardiac outcomes and middle cerebral artery (MCA) ischemic stroke, with or without insular cortex involvement, as well as the impact of new-onset atrial fibrillation (AF) after AIS on recurrent stroke.

METHODS

Serial measurements of high sensitivity troponin T (TnT), brain natriuretic peptide (BNP), electrocardiography (ECG), echocardiogram, and cardiac monitoring were performed on 415 patients with imaging confirmed MCA stroke, with or without insular involvement. Patients with renal failure, recent cardiovascular events, or congestive heart failure were excluded.

RESULTS

One hundred fifteen patients (28%) had left MCA infarcts with insular involvement, 122 (29%) had right MCA infarcts involving insular cortex, and 178 (43%) had no insular involvement. Patients with left MCA stroke with insular involvement tended to exhibit higher BNP and TnI, and transient cardiac dysfunction, which mimicked Takotsubo cardiomyopathy in 10 patients with left ventricular ejection fraction (LVEF) of 20-40%. Incidence of new-onset AF was higher in right MCA stroke involving insula (39%) than left MCA involving insula (4%). Nine out of fifty-three patients with new-onset AF were not on anticoagulant therapy due to various reasons; none of them experienced recurrent AF or stroke during up to a 3-year follow-up period. Statistically significant correlations between BNP or TnT elevation and left insular infarcts, as well as the incidence of AF and right insular infarcts, were revealed using linear regression analysis.

CONCLUSIONS

The present study demonstrated that acute left MCA stroke with insular involvement could cause transient cardiac dysfunction and elevated cardiac enzymes without persistent negative outcomes in the setting of health baseline cardiac condition. The incidence of new-onset AF was significantly higher in patients with right MCA stroke involving the insula. There was no increased risk of recurrent ischemic stroke in nine patients with newly developed AF who were not on anticoagulant therapy, which indicated a need for further research on presumed neurogenic AF and its management.

Comprehensive Review of Cardiovascular Disease Risk in Nonalcoholic Fatty Liver Disease

Nonalcoholic Fatty Liver Disease (NAFLD) is a growing global phenomenon, and its damaging effects in terms of cardiovascular disease (CVD) risk are becoming more apparent. NAFLD is estimated to affect around one quarter of the world population and is often comorbid with other metabolic disorders including diabetes mellitus, hypertension, coronary artery disease, and metabolic syndrome. In this review, we examine the current evidence describing the many ways that NAFLD itself increases CVD risk. We also discuss the emerging and complex biochemical relationship between NAFLD and its common comorbid conditions, and how they coalesce to increase CVD risk. With NAFLD's rising prevalence and deleterious effects on the cardiovascular system, a complete understanding of the disease must be undertaken, as well as effective strategies to prevent and treat its common comorbid conditions.

Cardiac autonomic dysfunction and risk of incident stroke among adults with type 2 diabetes

Introduction:

There is a dearth of data on the association between cardiac autonomic neuropathy (CAN) with incident stroke among individuals with diabetes mellitus. We evaluated this association in a large sample of adults with type 2 diabetes.

Patients and methods:

Participants with type 2 diabetes from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study without atherosclerotic cardiovascular disease at baseline were included. CAN was assessed at baseline by heart rate variability (HRV) indices and QT index (QTI) calculated from 10-s resting electrocardiograms. HRV was assessed using standard deviation of all normal-to-normal R-Rs intervals (SDNN) and root mean square of successive differences between normal-to-normal R-R intervals (rMSSD). CAN was defined based on several composite measures of SDNN, QTI, resting heart rate and peripheral neuropathy. We used Cox proportional hazards regression to generate hazard ratios (HR) and 95% confidence intervals (CI) for incident stroke in relation to CAN.

Results:

A total of 3493 participants (mean age 62.2 years, 44.5% women, 62.9% White) were included. Over a median follow-up of 5.0 years, 50 stroke cases occurred (incidence rate 3.0/1000 person-years [95% CI 2.2–3.9]). After adjusting for confounders, low HRV was associated with a higher risk of stroke (HR of 2.20 [95% CI 1.23–3.93] and 1.88 [95% CI 1.04–3.41] for low SDNN and rMSSD, respectively). Participants with CAN (defined as lowest quartile of SDNN and highest quartiles of QTI and heart rate) had a 5.7-fold greater risk of stroke (HR 5.70, 95% CI 2.49–13.08).

Discussion and conclusion:

CAN was independently associated with an increased risk of incident stroke in a large cohort of adults with type 2 diabetes.

Risk factors for new-onset atrial fibrillation during critical illness: A Delphi study

Background

New-onset atrial fibrillation (NOAF) is common during critical illness and is associated with poor outcomes. Many risk factors for NOAF during critical illness have been identified, overlapping with risk factors for atrial fibrillation in patients in community settings. To develop interventions to prevent NOAF during critical illness, modifiable risk factors must be identified. These have not been studied in detail and it is not clear which variables warrant further study.

Methods

We undertook an international three-round Delphi process using an expert panel to identify important predictors of NOAF risk during critical illness.

Results

Of 22 experts invited, 12 agreed to participate. Participants were located in Europe, North America and South America and shared 110 publications on the subject of atrial fibrillation. All 12 completed the three Delphi rounds. Potentially modifiable risk factors identified include 15 intervention-related variables.

Conclusions

We present the results of the first Delphi process to identify important predictors of NOAF risk during critical illness. These results support further research into modifiable risk factors including optimal plasma electrolyte concentrations, rates of change of these electrolytes, fluid balance, choice of vasoactive medications and the use of preventative medications in high-risk patients. We also hope our findings will aid the development of predictive models for NOAF.

Characteristics of patients with autonomic dysfunction in the Transthyretin Amyloidosis Outcomes Survey (THAOS)

BACKGROUND

Autonomic dysfunction is common in transthyretin amyloidosis (ATTR amyloidosis), but its frequency, characteristics, and quality-of-life (QoL) impact are not well understood.

METHODS

The Transthyretin Amyloidosis Outcomes Survey (THAOS) is an ongoing, global, longitudinal survey of patients with ATTR amyloidosis, including patients with inherited (ATTRv) and wild-type (ATTRwt) disease and asymptomatic patients with TTR mutations (ClinicalTrials.gov: NCT00628745). In a descriptive analysis, characteristics and Norfolk QoL-DN total (TQoL) scores at enrolment were compared in patients with vs without autonomic dysfunction (analysis cut-off: 1 August 2020).

RESULTS

Autonomic dysfunction occurred in 1181/2922 (40.4%) symptomatic patients, and more commonly in ATTRv (1107/1181 [93.7%]) than ATTRwt (74/1181 [6.3%]) amyloidosis. Time (mean [SD]) from ATTR amyloidosis symptom onset to first autonomic dysfunction symptom was shorter in ATTRv (3.4 [5.7] years) than ATTRwt disease (9.7 [10.4]). In ATTRv disease, patients with vs without autonomic dysfunction had worse QoL (TQoL, 47.3 [33.2] vs 16.1 [18.1]); in ATTRwt disease, those with vs without autonomic dysfunction had similar QoL (23.0 [18.2] vs 19.9 [20.5]).

CONCLUSIONS

Autonomic dysfunction was more common and presented earlier in symptomatic ATTRv than ATTRwt amyloidosis and adversely affected QoL in ATTRv disease. These THAOS findings may aid clinicians in diagnosing and treating patients with ATTR amyloidosis. Trial registration: ClinicalTrials.gov: NCT00628745.

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.

Shift work is associated with 10-year incidence of atrial fibrillation in younger but not older individuals from the general population: results from the Tromsø Study

OBJECTIVES

Shift work is associated with myocardial infarction and stroke. We studied if shift work is also associated with incident atrial fibrillation (AF) and if this association differs, depending on sex and age.

METHODS

We studied 22 339 participants (age 37.0±9.8 years, 49% women) with paid work from the third (1986-1987), fourth (1994-1995), fifth (2001) and sixth (2007-2008) surveys of the population-based Tromsø Study, Norway. Participants were followed up for ECG-confirmed AF through 2016. Shift work was assessed by questionnaire at each survey. We used unadjusted and multivariable-adjusted Cox regression models to study the association of shift work with 10-year incident AF and incident AF during extensive follow-up up to 31 years. Interactions with sex and age were tested in the multivariable model.

RESULTS

Shift work was reported by 21% of participants at the first attended survey. There was an interaction between shift work and age for 10-year incident AF (p=0.069). When adjusted for AF risk factors, shift work was significantly associated with 10-year incident AF in participants <40 years (HR 2.90, 95% CI 1.12 to 7.49) but not≥40 years of age (HR 0.90, 95% CI 0.53 to 1.51). Shift work was not associated with incident AF during extensive follow-up (HR 1.03, 95% CI 0.89 to 1.20). There was no interaction between shift work and sex.

CONCLUSIONS

Shift work was associated with 10-year incident AF in individuals <40 years but not ≥40 years of age. Shift work was not associated with incident AF during extensive follow-up up to 31 years, and there were no sex differences.

Heart rate variability and atrial fibrillation in the general population: a longitudinal and Mendelian randomization study

BACKGROUND

Sex differences and causality of the association between heart rate variability (HRV) and atrial fibrillation (AF) in the general population remain unclear.

METHODS

12,334 participants free of AF from the population-based Rotterdam Study were included. Measures of HRV including the standard deviation of normal RR intervals (SDNN), SDNN corrected for heart rate (SDNNc), RR interval differences (RMSSD), RMSSD corrected for heart rate (RMSSDc), and heart rate were assessed at baseline and follow-up examinations. Joint models, adjusted for cardiovascular risk factors, were used to determine the association between longitudinal measures of HRV with new-onset AF. Genetic variants for HRV were used as instrumental variables in a Mendelian randomization (MR) analysis using genome-wide association studies (GWAS) summary-level data.

RESULTS

During a median follow-up of 9.4 years, 1302 incident AF cases occurred among 12,334 participants (mean age 64.8 years, 58.3% women). In joint models, higher SDNN (fully-adjusted hazard ratio (HR), 95% confidence interval (CI) 1.24, 1.04-1.47, p = 0.0213), and higher RMSSD (fully-adjusted HR, 95% CI 1.33, 1.13-1.54, p = 0.0010) were significantly associated with new-onset AF. Sex-stratified analyses showed that the associations were mostly prominent among women. In MR analyses, a genetically determined increase in SDNN (odds ratio (OR), 95% CI 1.60, 1.27-2.02, p = 8.36 × 10^-05), and RMSSD (OR, 95% CI 1.56, 1.31-1.86, p = 6.32 × 10^-07) were significantly associated with an increased odds of AF.

CONCLUSION

Longitudinal measures of uncorrected HRV were significantly associated with new-onset AF, especially among women. MR analyses supported the causal relationship between uncorrected measures of HRV with AF. Our findings indicate that measures to modulate HRV might prevent AF in the general population, in particular in women. AF; atrial fibrillation, GWAS; genome-wide association study, IVW; inverse variance weighted, MR; Mendelian randomization, MR-PRESSO; MR-egger and mendelian randomization pleiotropy residual sum and outlier, RMSSD; root mean square of successive RR interval differences, RMSSDc; root mean square of successive RR interval differences corrected for heart rate, SDNN; standard deviation of normal to normal RR intervals, SDNNc; standard deviation of normal to normal RR intervals corrected for heart rate, WME; weighted median estimator. ^aRotterdam Study n=12,334 ^bHRV GWAS n=53,174 ^cAF GWAS n=1,030,836.

Association of heart rate variability with progression of retinopathy among adults with type 2 diabetes

AIM

We evaluated the associations of heart rate variability (HRV) with incident vision-threatening retinopathy and retinopathy progression among adults with type 2 diabetes.

METHODS

Participants recruited to the ACCORD (Action to Control Cardiovascular Risk in Diabetes) study with HRV measures at baseline were analysed. HRV measures included standard deviation of all normal-to-normal intervals (SDNN) and root mean square of successive differences between normal-to-normal intervals (rMSSD). Low SDNN was defined as SDNN <8.2 ms; low rMSSD as rMSSD <8.0 ms. We used multivariable adjusted Cox proportional hazards and modified Poisson regression models to generate risk estimates for incident vision-threatening retinopathy and retinopathy progression, respectively.

RESULTS

A total of 5810 participants without incident vision-threatening retinopathy at baseline (mean age 62 years, 40.5% women, 63.5% White) were included. Over a median of 4.7 years, 280 incident vision-threatening retinopathy cases requiring treatment occurred. Low HRV (vs. normal HRV) was associated with higher risk of incident vision-threatening retinopathy (adjusted hazard ratio 1.32 [95%CI 1.03-1.71] and 1.14 [95%CI 1.01-1.28] for low SDNN and rMSSD, respectively). In the subset of 2184 participants with complete eye examinations at baseline and 4 years, 191 experienced retinopathy progression, and low HRV (vs. normal HRV) was associated with a higher risk of retinopathy progression (adjusted relative risks 1.36 [95%CI 1.01-1.83] and 1.36 [95%CI 1.01-1.84] for low SDNN and rMSSD, respectively).

CONCLUSIONS

Cardiac autonomic neuropathy, as assessed by low HRV, was independently associated with increased risks of incident vision-threatening retinopathy and overall retinopathy progression in a large cohort of adults with type 2 diabetes.

Predicting Late Recurrence of Atrial Fibrillation After Radiofrequency Ablation in Patients With Atrial Fibrillation: Comparison of C2HEST and HATCH Scores

Objective

This study was aimed to investigate the risk of recurrence in patients with atrial fibrillation (AF) after radiofrequency ablation and predict risk of recurrence using C2HEST and HATCH scores.

Methods

We retrospectively included 322 patients with AF from Second Hospital of Lanzhou University, and 261 patients were included in the analysis finally. They had AF and were admitted for radiofrequency catheter ablation. We compared the ability of C2HEST and HATCH scores to predict recurrence after radiofrequency ablation of AF. The predictive ability of C2HEST and HATCH scores for AF recurrence was estimated by the area under the receiver operating characteristic curve (AUROC). The difference in receiver operating characteristic curve between the two models was compared using the DeLong test.

Results

Of the 261 patients included in the analysis, 83 (31.6%) patients suffered a late recurrence of AF after radiofrequency ablation. The risk of postoperative recurrence of AF increased with increasing C2HEST and HATCH scores. The AUROC of C2HEST and HATCH scores in predicting postoperative recurrence of AF was 0.773 (95%CI, 0.713–0.833) and 0.801 (95% CI, 0.740–0.861), respectively. There was no significant difference between the two models in their ability to evaluate patients for postoperative recurrence of AF (DeLong test p-value = 0.36). Among the risk factors in both models, hypertension and heart failure (HF) contributed the most to postoperative recurrence after AF, and higher blood pressure and lower cardiac ejection fraction (EF) were associated with a higher risk of recurrence.

Conclusion

Both C2HEST and HATCH scores were significantly associated with the risk of late recurrence after radiofrequency ablation of AF. Besides hypertension and HF contributed the most to postoperative recurrence after AF.