Comorbidity of atrial fibrillation and heart failure

E/E′ Is a New Independent Predictor of Recovered Ejection Fraction in Patients With Systolic Heart Failure Undergoing Ablation for Atrial Fibrillation

Aims: Catheter ablation should be considered in patients with atrial fibrillation (AF) and with heart failure (HF) with reduced ejection fraction (EF; HFrEF) to improve survival and reduce heart failure hospitalization. Careful patient selection for AF ablation is key to achieving similar outcome benefits. However, limited data exist regarding predictors of recovered ejection fraction. We aimed to evaluate the predictors of recovered ejection fraction in consecutive patients with HF undergoing AF ablation.

Methods and Results: A total of 156 patients [67.3% men, median age 63 (11)] with AF and HF underwent initial catheter ablation between September 2017 and October 2019 in the First Affiliated Hospital of Dalian Medical University. Overall, the percentage of recovered ejection fractions was 72.3%. Recovered EFs were associated with a 39% reduction in all-cause hospitalization compared to non-recovered EFs at the 1-year follow-up [23.8 vs. 62.8 (odds ratio) OR 2.09 (1.40–3.12), P < 0.001]. Univariate analysis for recovered EFs showed that diabetes (P = 0.083), prevalent HF (P = 0.014), prevalent AF (P = 0.051), LVEF (P = 0.022), and E/E′ (P = 0.001) were associated with EF improvement. Multivariate analysis showed that the only independent predictor of EF recovery was E/E′ [OR 1.13 (1.03–1.24); P = 0.011]. A receiver operating characteristic analysis determined that the suitable cut-off value for E/E′ was 15 (sensitivity 38.7%, specificity 89.2%, the area under curve 0.704).

Conclusions: Ejection fraction (EF) recovery occurred in 72.3% of patients, associated with a 39% reduction in all-cause hospitalization compared to the non-recovered EFs in our cohort. The only independent predictor of recovered EF was E/E′ < 15 in our series.

Risk factors for developing pacing induced LV dysfunction: Experience from a tertiary centre in the UK

INTRODUCTION

The risk factors for developing pacing induced Left Ventricular dysfunction (LVD) in patients with high burden of right ventricular pacing (RVP) is poorly understood. Therefore, in the present study, we aimed to assess the determinants of pacing induced LVD.

METHODS

Our data were retrospectively collected from 146 patients with RVP > 40% who underwent generator change (GC) or cardiac resynchronisation therapy (CRT) upgrade between 2016-2019 who had left ventricular ejection fraction (EF) ≥50% at initial implant.

RESULTS

75 patients had CRT upgrade due to pacing induced LVD (EF<50%) and 71 patients with preserved LV function (EF ≥50%) had a GC. Primary indication for pacing in both groups was complete heart block. Male predominance (p = 0.008), prior myocardial infarction (MI) (p = 0.001), atrial fibrillation (AF) (p = 0.009), chronic kidney disease (CKD) (p = 0.005), and borderline low systolic function (BLSF) (EF 50-55%) (p = 0.04) were more prevalent in the CRT upgrade group. Presence of AF (OR = 3.05, 95% CI 1.42-6.58; p = 0.004), BLSF (OR = 3.8, 95% CI 1.22-11.8; p = 0.02) and male gender (OR = 2.41, 95% CI 1.14-5.08; p = 0.02) were independent predictors for RVP induced LVD. Age (OR = 1.08, 95% CI 1.02-1.14; p = 0.005) and BLSF (OR = 5.33, 95% CI 1.26-22.5; p = 0.023) were independent predictors of earlier development of LVD after implant.

CONCLUSIONS

Our results suggested that AF, BLSF and male gender are predictors for development of pacing induced LVD in patients with high RVP burden. LVD can occur at any time after pacemaker implant with BLSF and increasing age associated with earlier development of LVD. This article is protected by copyright. All rights reserved.

OUP accepted manuscript

Atrial tachyarrhythmias and worsening heart failure frequently coexist and potentially progress to a life threatening condition. Therapeutic approach requires simultaneous management of rapid ventricular response and heart failure symptom relief in order to improve haemodynamic stability and cardiac function. Landiolol is an ultra-short-acting b-adrenergic receptor blocker with high b1 selectivity incorporated in 2020 European Society of Cardiology guidelines for the management of atrial fibrillation. We provide a report of two cases with atrial fibrillation treated with landiolol in the acute setting of pulmonary oedema and cardiogenic shock, respectively. Additionally, we searched the international database PUBMED (MEDLINE, PubMed Central) to retrieve scientific evidence regarding its implementation in the treatment of atrial tachyarrhythmias in patients with cardiac dysfunction. Recent studies support the use of landiolol in patients with acute heart failure and atrial tachyarrhythmias. Compared to digoxin, landiolol proved to be more effective in controlling heart rate, with minimal adverse effects. Moreover, landiolol may be helpful in the conversion of atrial tachyarrhythmia to sinus rhythm. A more potent effect has been reported in patients with heart failure with preserved or mildly reduced ejection fraction, small left ventricular volume and high blood pressure. Likewise, administration of low doses of landiolol in patients with cardiogenic shock and atrial tachyarrhythmias reduced heart rate and pulmonary capillary wedge pressure and improved cardiac contractility without reducing blood pressure. Landiolol seems to be an attractive alternative in the acute management of patients with atrial tachyarrhythmias and cardiac dysfunction, though further clinical trials are needed to establish its role.

Patient Perspectives on Performance of a Smartphone App for Atrial FibrillationSelf-Management

INTRODUCTION

AF self-care requires patients to perform daily self-monitoring for symptoms, practice decision making to address symptom changes, and adhere to prescribed medication, diet, physical activity, and follow-up care. Technology can facilitate these critical self-care behaviors and ultimately improve patient outcomes. We assessed atrial fibrillation (AF) patients' experiences with a smartphone application (app) for AF self-management.

METHODS

A focus group with 9 AF patients and app users was conducted and analyzed using qualitative research methods. The focus group was recorded, transcribed, and coded using a priori and inductive coding strategies. Participant responses for each code were synthesized to identify primary themes.

RESULTS

We identified four superordinate themes from patients' experiences: (1) disconnect between tool and its intended use; (2) app as acknowledged tool for adherence; (3) knowledge as empowerment; (3) motives: self-interest vs supporting research. Results from this qualitative study underscore the need to clarify the app's intended use and to better accommodate patients with different AF experiences. The disconnect between a tool and its intended use can generate frustration for users.

DISCUSSION

The study reinforces that participants not only see how the app is a tool for adherence; they also see knowledge they gain via the app as empowering, suggesting a correlation between app use and self-efficacy.

Predictors for Early Mortality in Patients with Implantable Cardiac Defibrillator for Heart Failure with Reduced Ejection Fraction

Implantable cardioverter defibrillators (ICD) are recommended in heart failure with reduced ejection fraction (HFrEF) patients to reduce arrhythmic deaths. This study aimed to identify risk factors associated with mortality within one-year following the ICD. The data from our hospital's electronic database system was extracted for patients who were implanted ICD secondary to HFrEF between 2009 and 2019. Overall, 1107 patients were included in the present analysis. Mortality rate at one-year following the device implantation was 4.7%. In multivariate analysis; age, atrial fibrillation, New York Heart Association classification >2, blood urea nitrogen, pro-brain natriuretic peptide and albumin independently predicted one year mortality.

Rate of Heart Failure Following Atrial Fibrillation According to Presence of Family History of Dilated Cardiomyopathy or Heart Failure: A Nationwide Study

Background It is poorly understood why some patients with atrial fibrillation develop heart failure (HF) and others do not. We examined the rate of developing HF in patients with atrial fibrillation with and without first-degree family members with HF or dilated cardiomyopathy (DCM). Methods and Results Using Danish nationwide registries, patients born after 1942 diagnosed with atrial fibrillation in the period 2005 to 2015 were identified and followed for up to 5 years. Patients with pre-existing HF, DCM, and/or ischemic heart disease diagnoses were excluded. Exposure was defined as a first-degree relative with HF or DCM. The rate of developing the composite end point of HF or death, and the components, was estimated with multivariable Cox proportional hazard regression models. We included 10 605 patients. A total of 17% had a family member with DCM/HF. Having a family member with HF/DCM was associated with an increased 5-year risk of the composite of HF/death (cumulative incidence, 9.2% [95% CI, 7.8-10.7] versus 5.6% [95% CI, 5.0-6.1]; adjusted hazard ratio [HR] 1.36 [95% CI, 1.13-1.64]). (HF 8.4% [95% CI, 7.0-9.8] versus 4.5% [95% CI, 4.1-5.0]); (adjusted HR, 1.49 [95% CI, 1.22-1.82]). However, familial HF/DCM was not significantly associated with an increased 5-year risk and rate of death (0.8% [95% CI, 0.4-1.2] versus 1.1% [95% CI, 0.8-1.3]); (adjusted HR, 0.80 [95% CI, 0.46-1.39]). Conclusions In patients with incident atrial fibrillation without prior ischemic heart disease or HF diagnoses, 1 of 6 had a first-degree relative with HF, and having such a family history of HF/DCM was associated with an 87% increase in 5-year incidence of HF compared with those without.

Hierarchical management of chronic heart failure: a perspective based on the latent structure of comorbidities

AIMS

Chronic heart failure (CHF) has an increasing burden of comorbidities, which affect clinical outcomes. Few studies have focused on the clustering and hierarchical management of patients with CHF based on comorbidity. This study aimed to explore the cluster model of CHF patients based on comorbidities and to verify their relationship with clinical outcomes.

METHODS AND RESULTS

Electronic health records of patients hospitalized with CHF from January 2014 to April 2019 were collected, and 12 common comorbidities were included in the latent class analysis. The Fruchterman-Reingold layout was used to draw the comorbidity network, and analysis of variance was used to compare the weighted degrees among them. The incidence of clinical outcomes among different clusters was presented on Kaplan-Meier curves and compared using the log-rank test, and the hazard ratio was calculated using the Cox proportional risk model. Sensitivity analysis was performed according to the left ventricular ejection fraction. Four different clinical clusters from 4063 total patients were identified: metabolic, ischaemic, high comorbidity burden, and elderly-atrial fibrillation. Compared with the metabolic cluster, patients in the high comorbidity burden cluster had the highest adjusted risk of combined outcome and all-cause mortality {1.67 [95% confidence interval (CI), 1.40-1.99] and 2.87 [95% CI, 2.17-3.81], respectively}, followed by the elderly-atrial fibrillation and ischaemic clusters. The adjusted readmission risk of patients with ischaemic, high comorbidity burden, and elderly-atrial fibrillation clusters were 1.35 (95% CI, 1.08-1.68), 1.39 (95% CI, 1.13-1.72), and 1.42 (95% CI, 1.14-1.77), respectively. The comorbidity network analysis found that patients in the high comorbidity burden cluster had more and higher comorbidity correlations than those in other clusters. Sensitivity analysis revealed that patients in the high comorbidity burden cluster had the highest risk of combined outcome and all-cause mortality (P < 0.05).

CONCLUSIONS

The difference in adverse outcomes among clusters confirmed the heterogeneity of CHF and the importance of hierarchical management. This study can provide a basis for personalized treatment and management of patients with CHF, and provide a new perspective for clinical decision making.

NETs promote pathogenic cardiac fibrosis and participate in ventricular aneurysm formation after ischemia injury through the facilitation of perivascular fibrosis

Fibrosis has been widely investigated in acute phase of myocardial infarction (MI). However, the mechanism of sustained fibrosis after MI hasn't been elucidated, which eventually gives rise to ventricular aneurysm (VA) formation chronic while lethal. Neutrophil as vital cell facilitating the fibrotic repair after acute MI may not project its effect to chronic phase unless neutrophil extracellular traps (NETs) were secreted and accumulating. The aim of this study was to investigate whether NETs contribute to the sustained fibrosis and VA formation after MI. We identified NETs in ventricular aneurysm of patients. Accordingly, NETs increased in peripheral blood of VA patients. Moreover, in rat VA NETs were also identified. Stimulated by NETs, the migration of fibroblast was enhanced and the differentiation of cardiac myofibroblast was initiated. Smad, MAPK and RhoA signaling pathways were activated by NETs incubation. And additional deposition with DNase I to disrupt NETs and abrogated NETs induced fibrosis both in vivo and vitro. These results collectively demonstrate a novel profibrotic role for NETs in chronic cardiac fibrosis and VA formation.

Quality of life in patients with long-standing persistent atrial fibrillation after surgical ablation and simultaneous coronary artery bypass grafting

Aim. To analyze quality of life (QOL) of patients with coronary artery disease (CAD) in combination with long-standing persistent atrial fibrillation (AF) in the long-term postoperative period, depending on chosen surgical strategy for concomitant pathology.

Material and methods. The analysis of QOL changes in the long-term postoperative period (12 and 24 months) in 116 patients with CAD and concomitant long-term persistent AF who selectively underwent biatrial (BA) or isolated left atrial (LA) ablation with simultaneous on-pump coronary artery bypass grafting. To assess QOL, a non-specific Medical Outcomes Study 36-Item Form Health Status Survey (SF-36) questionnaire was used. Patients were questioned in preoperative and long-term postoperative periods (12 and 24 months).

Results. All SF-36 parameters significantly improve after open surgical treatment in the long-term postoperative period (24 months) with both treatment strategies (BA and LA ablation) for AF. In the BA ablation group, 74% of patients did not have arrhythmia after 12 months, and only 38,5% of patients in the LA ablation group belonged to European Heart Rhythm Association (EHRA) score class 1 (p=0,001). After 24 months, a comparison revealed a significant diff erence between the two groups in arrhythmia symptoms (p=0,014), with maintaining the advantage of the BA ablation group. After 12 and 24 months, none of the patients in both compared groups had severe class IV angina.

Conclusion. SF-36 parameters were improved 24 months after surgical treatment of CAD and long-standing persistent AF, regardless of the ablation strategy. Elimination of angina symptoms and long-term maintenance of sinus rhythm can improve the QOL  of patients in the long-term postoperative period.

The predictive value of high-sensitive troponin I for perioperative risk in patients undergoing gastrointestinal tumor surgery

BACKGROUND

The incidence of cardiovascular events in perioperative period of gastrointestinal tumor surgery cannot be ignored, and studies have shown that level of postoperative troponin is related to the postoperative risk of non-cardiac surgery. However, the relationship between pre-operative troponin levels and perioperative risk of gastrointestinal tumor surgery is unclear. Thus, we aimed to evaluate the value of high-sensitive cardiac troponin I (hs-cTnI) prior to gastrointestinal tumor surgery for perioperative risk assessment.

METHODS

In this retrospective cohort study, 1259 patients who underwent gastrointestinal tumor surgery and had been tested for hs-cTnI on admission within 7 days prior to surgery were retrospectively recruited from January 2018 to June 2020. The primary combined endpoint including in-hospital all-cause mortality, acute myocardial infarction, cardiac arrest or ventricular fibrillation and acute decompensated heart failure. The secondary endpoint included total hospital stay and requirement of intensive care treatment.

FINDINGS

Compared with patients with normal hs-cTnI, those with elevated hs-cTnI (> 0·028 ng/ml) were more likely to experience the combined endpoint (28·2% versus 2·7%, P < 0·001) and there was also an increasing rate of in mortality in elevated hs-cTnI group (2·4% versus 0·3%, P = 0·057). The length of total hospital stay was significantly longer in patients with elevated hs-cTnI (24·8 ± 16·3 versus 19·5 ± 7·9, P = 0·003) and the number of patients requiring intensive care treatment was also higher (22·6% versus 4·2%, P < 0·001). The area under the ROC curve assessing hs-cTnI in predicting in-hospital mortality was 0·787 [95% confidence interval (CI) 0·612-0·963, P = 0·015] and for combined endpoint was 0·822 [95% CI 0·766-0·879, P < 0·001]. Hs-cTnI > 0·028 ng/ml was associated with significantly higher cardiovascular event rate in patients with the revised cardiac index ≤ 1. The positive likelihood ratio of hs-cTnI (> 0·028 ng/ml) for predicting combined endpoint reaches 10.5 in patients with Lee index = 0. In multivariate logistic analyses, hs-cTnI was one of the best predictors for the combined endpoint [odds ratio (OR) 5·924 (95%CI: 2·869-12·233), P < 0·001].

INTERPRETATION

Hs-cTnI provides powerful prognostic information for patients undergoing gastrointestinal tumor surgery, and therefore provides reliable prognostic information incremental to revised cardiac index.

LVS-HARMED Risk Score for Incident Heart Failure in Patients With Atrial Fibrillation Who Present to the Emergency Department: Data from a World-Wide Registry

Background Heart failure (HF) is a common complication to atrial fibrillation (AF), leading to rehospitalization and death. Early identification of patients with AF at risk for HF might improve outcomes. We aimed to derive a score to predict 1-year risk of new-onset HF after an emergency department (ED) visit with AF. Methods and Results The RE-LY AF (Randomized Evaluation of Long-Term Anticoagulant Therapy) registry enrolled patients with AF presenting to an ED in 47 countries, and followed them for a year. The end point was HF hospitalization and/or HF death. Among 15 400 ED patients, 9765 had no prior HF (mean age, 64.9±14.9 years). Within 1 year, new-onset HF developed in 6.8% of patients, of whom 21% died of HF. Independent predictors of HF included left ventricular hypertrophy (odds ratio [OR], 1.47; 95% CI, 1.19-1.82), valvular heart disease (OR, 1.55; 95% CI, 1.18-2.04), smoking (OR, 1.42; 95% CI, 1.12-1.78), height (OR, 0.93; 95% CI, 0.90-0.95 per 3 cm), age (OR, 1.11; 95% CI, 1.07-1.15 per 5 years), rheumatic heart disease (OR, 1.77, 95% CI, 1.24-2.51), prior myocardial infarction (OR, 1.85; 95% CI, 1.45-2.36), remaining in AF at ED discharge (OR, 1.86; 95% CI, 1.46-2.36), and diabetes (OR, 1.33; 95% CI, 1.09-1.64). A continuous risk prediction score (LVS-HARMED [left ventricular, valvular heart disease, smoking or other tobacco use, height, age, rheumatic heart disease, myocardial infarction, emergency department discharge rhythm, and diabetes]) had good discrimination (C statistic, 0.735; 95% CI, 0.716-0.755). Validation was conducted internally using bootstrapping (optimism-corrected C statistic, 0.705) and externally (C statistic, 0.699). The 1-year incidence of HF hospitalization and/or HF death across quartile groups of the score was 1.1%, 4.5%, 6.9%, and 14.4%, respectively. LVS-HARMED also predicted incident stroke (C statistic, 0.753; 95% CI, 0.728-0.778). Conclusions The LVS-HARMED score predicts new-onset HF after an ED visit for AF. Preventative strategies should be considered in patients with high LVS-HARMED HF risk.

Vericiguat in patients with atrial fibrillation and heart failure with reduced ejection fraction: insights from the VICTORIA trial

AIMS

We evaluated the relation between baseline and new-onset atrial fibrillation (AF) and outcomes, and assessed whether vericiguat modified the likelihood of new-onset AF in patients with worsening heart failure (HF) with reduced ejection fraction in VICTORIA.

METHODS AND RESULTS

Of 5050 patients randomized, 5010 with recorded AF status at baseline were analysed. Patients were classified into three groups: no known AF (n = 2661, 53%), history of AF alone (n = 992, 20%), and AF on randomization electrocardiogram (n = 1357, 27%). Compared with those with no AF, those with history of AF alone had a higher risk of cardiovascular death [adjusted hazard ratio (HR) 1.21, 95% confidence interval (CI) 1.01-1.47] without excess myocardial infarction or stroke; neither type of AF was associated with a higher risk of the primary composite outcome (time to cardiovascular death or first HF hospitalization), HF hospitalizations, or all cause-death. The beneficial effect of vericiguat on the primary composite outcome and its components was evident irrespective of AF status at baseline. Over a median follow-up of 10.8 months, new-onset AF occurred in 6.1% of those with no AF and 18.3% with history of AF alone (P < 0.0001). These events were not influenced by vericiguat treatment (adjusted HR 0.93, 95% CI 0.75-1.16; P = 0.51), but were associated with an increase in the hazard of both primary and secondary outcomes.

CONCLUSIONS

Atrial fibrillation was present in nearly half of this high-risk population with worsening HF. A history of AF alone at baseline portends an increased risk of cardiovascular death. Neither type of AF affected the beneficial effect of vericiguat. Development of AF post-randomization was associated with an increase in both cardiovascular death and HF hospitalization which was not influenced by vericiguat.

Expert opinion paper on cardiac imaging after ischemic stroke

This expert opinion paper on cardiac imaging after acute ischemic stroke or transient ischemic attack (TIA) includes a statement of the "Heart and Brain" consortium of the German Cardiac Society and the German Stroke Society. The Stroke Unit-Commission of the German Stroke Society and the German Atrial Fibrillation NETwork (AFNET) endorsed this paper. Cardiac imaging is a key component of etiological work-up after stroke. Enhanced echocardiographic tools, constantly improving cardiac computer tomography (CT) as well as cardiac magnetic resonance imaging (MRI) offer comprehensive non- or less-invasive cardiac evaluation at the expense of increased costs and/or radiation exposure. Certain imaging findings usually lead to a change in medical secondary stroke prevention or may influence medical treatment. However, there is no proof from a randomized controlled trial (RCT) that the choice of the imaging method influences the prognosis of stroke patients. Summarizing present knowledge, the German Heart and Brain consortium proposes an interdisciplinary, staged standard diagnostic scheme for the detection of risk factors of cardio-embolic stroke. This expert opinion paper aims to give practical advice to physicians who are involved in stroke care. In line with the nature of an expert opinion paper, labeling of classes of recommendations is not provided, since many statements are based on expert opinion, reported case series, and clinical experience.

Weekend versus weekday admission and clinical outcomes in heart failure patients with and without atrial fibrillation in Taiwan

PURPOSE

We conduct this study to explore the associations of weekend and weekdays admission with the clinical events among heart failure (HF) patients with and without comorbid atrial fibrillation (AF).

METHODS

In this study, we recruited 57919 HF patients without AF hospitalized in weekends and 57919 HF patients without AF hospitalized in weekdays. There were 21467 and 21467 HF patients with AF admisson in weekends and weekdays, respectively. The outcomes of interest included all-cause mortality, CV death (ICD-9-CM 390-459), and heart failure recurrence. Cox proportional hazard regression model was applied to estimate the hazard ratio. Variables found to be statistically significant in a univariable Cox proportional hazard regression model were further examined in a multivariable Cox proportional hazard regression model. The cumulative incidence curves were obtained by the Kaplan-Meier method and assessed by the Log-rank test.

RESULTS

HF patients with AF and hospitalized in weekends had the highest incidence rates of rehospitalization due to HF (233.8 per1000 person-years), and CV death (23.9 per 1000 person-years) among four groups. Kaplan-Meier method shows that HF patients with AF had the higher cumulative incidence of HF recurrence than that of patients without AF.

CONCLUSION

HF patients with AF and hospitalized in weekends are at highest risk of HF recurrence among these four groups.

Managing Atrial Fibrillation in Patients With Heart Failure and Reduced Ejection Fraction: A Scientific Statement From the American Heart Association

Atrial fibrillation and heart failure with reduced ejection fraction are increasing in prevalence worldwide. Atrial fibrillation can precipitate and can be a consequence of heart failure with reduced ejection fraction and cardiomyopathy. Atrial fibrillation and heart failure, when present together, are associated with worse outcomes. Together, these 2 conditions increase the risk of stroke, requiring oral anticoagulation in many or left atrial appendage closure in some. Medical management for rate and rhythm control of atrial fibrillation in heart failure remain hampered by variable success, intolerance, and adverse effects. In multiple randomized clinical trials in recent years, catheter ablation for atrial fibrillation in patients with heart failure and reduced ejection fraction has shown superiority in improving survival, quality of life, and ventricular function and reducing heart failure hospitalizations compared with antiarrhythmic drugs and rate control therapies. This has resulted in a paradigm shift in management toward nonpharmacological rhythm control of atrial fibrillation in heart failure with reduced ejection fraction. The primary objective of this American Heart Association scientific statement is to review the available evidence on the epidemiology and pathophysiology of atrial fibrillation in relation to heart failure and to provide guidance on the latest advances in pharmacological and nonpharmacological management of atrial fibrillation in patients with heart failure and reduced ejection fraction. The writing committee's consensus on the implications for clinical practice, gaps in knowledge, and directions for future research are highlighted.

Meeting the unmet needs of clinicians from AI systems showcased for cardiology with deep-learning-based ECG analysis

Despite their great promise, artificial intelligence (AI) systems have yet to become ubiquitous in the daily practice of medicine largely due to several crucial unmet needs of healthcare practitioners. These include lack of explanations in clinically meaningful terms, handling the presence of unknown medical conditions, and transparency regarding the system's limitations, both in terms of statistical performance as well as recognizing situations for which the system's predictions are irrelevant. We articulate these unmet clinical needs as machine-learning (ML) problems and systematically address them with cutting-edge ML techniques. We focus on electrocardiogram (ECG) analysis as an example domain in which AI has great potential and tackle two challenging tasks: the detection of a heterogeneous mix of known and unknown arrhythmias from ECG and the identification of underlying cardio-pathology from segments annotated as normal sinus rhythm recorded in patients with an intermittent arrhythmia. We validate our methods by simulating a screening for arrhythmias in a large-scale population while adhering to statistical significance requirements. Specifically, our system 1) visualizes the relative importance of each part of an ECG segment for the final model decision; 2) upholds specified statistical constraints on its out-of-sample performance and provides uncertainty estimation for its predictions; 3) handles inputs containing unknown rhythm types; and 4) handles data from unseen patients while also flagging cases in which the model's outputs are not usable for a specific patient. This work represents a significant step toward overcoming the limitations currently impeding the integration of AI into clinical practice in cardiology and medicine in general.

Model Systems for Addressing Mechanism of Arrhythmogenesis in Cardiac Repair

PURPOSE OF REVIEW

Cardiac cell-based therapy represents a promising approach for cardiac repair. However, one of the main challenges is cardiac arrhythmias associated with stem cell transplantation. The current review summarizes the recent progress in model systems for addressing mechanisms of arrhythmogenesis in cardiac repair.

RECENT FINDINGS

Animal models have been extensively developed for mechanistic studies of cardiac arrhythmogenesis. Advances in human induced pluripotent stem cells (hiPSCs), patient-specific disease models, tissue engineering, and gene editing have greatly enhanced our ability to probe the mechanistic bases of cardiac arrhythmias. Additionally, recent development in multiscale computational studies and machine learning provides yet another powerful tool to quantitatively decipher the mechanisms of cardiac arrhythmias. Advancing efforts towards the integrations of experimental and computational studies are critical to gain insights into novel mitigation strategies for cardiac arrhythmias in cell-based therapy.

Atrial fibrillation and risk of incident heart failure with reduced versus preserved ejection fraction

OBJECTIVE

Associations between atrial fibrillation (AF) and heart failure (HF) have been established. We compared the extent to which AF is associated with each primary subtype of HF, with reduced (HFrEF) versus preserved ejection fraction (HFpEF).

METHODS

We included 25 787 participants free of baseline HF from the REGARDS (REasons for Geographic And Racial Differences in Stroke) cohort. Baseline AF was ascertained from ECG and self-reported history of physician diagnosis. Incident HF events were determined from physician-adjudicated review of hospitalisation medical records and HF deaths. Based on left ventricular ejection fraction (LVEF) at the time of HF event, HFrEF, HFpEF, and mid-range HF were defined as LVEF <40%, ≥50% and 40%-49%, respectively. Multivariable Cox proportional-hazards models examined the association between AF and HF. The Lunn-McNeil method was used to compare associations of AF with incident HFrEF versus HFpEF.

RESULTS

Over a median of 9 years of follow-up, 1109 HF events occurred (356 HFpEF, 388 HFrEF, 77 mid-range and 288 unclassified). In a model adjusted for sociodemographics, cardiovascular risk factors, and incident coronary heart disease, AF was associated with increased risk of all HF events (HR 1.67, 95% CI 1.38 to 2.01). The associations of AF with HFrEF versus HFpEF events did not differ significantly (HR 1.87 (95% CI 1.38 to 2.54) and HR 1.65 (95% CI 1.20 to 2.28), respectively; p value for difference=0.581). These associations were consistent in sex and race subgroups.

CONCLUSIONS

AF is associated with both HFrEF and HFpEF events, with no significant difference in the strength of association among these subtypes.

Metabolism and Chronic Inflammation: The Links Between Chronic Heart Failure and Comorbidities

Heart failure (HF) patients often suffer from multiple comorbidities, such as diabetes, atrial fibrillation, depression, chronic obstructive pulmonary disease, and chronic kidney disease. The coexistance of comorbidities usually leads to multi morbidity and poor prognosis. Treatments for HF patients with multi morbidity are still an unmet clinical need, and finding an effective therapy strategy is of great value. HF can lead to comorbidity, and in return, comorbidity may promote the progression of HF, creating a vicious cycle. This reciprocal correlation indicates there may be some common causes and biological mechanisms. Metabolism remodeling and chronic inflammation play a vital role in the pathophysiological processes of HF and comorbidities, indicating metabolism and inflammation may be the links between HF and comorbidities. In this review, we comprehensively discuss the major underlying mechanisms and therapeutic implications for comorbidities of HF. We first summarize the potential role of metabolism and inflammation in HF. Then, we give an overview of the linkage between common comorbidities and HF, from the perspective of epidemiological evidence to the underlying metabolism and inflammation mechanisms. Moreover, with the help of bioinformatics, we summarize the shared risk factors, signal pathways, and therapeutic targets between HF and comorbidities. Metabolic syndrome, aging, deleterious lifestyles (sedentary behavior, poor dietary patterns, smoking, etc.), and other risk factors common to HF and comorbidities are all associated with common mechanisms. Impaired mitochondrial biogenesis, autophagy, insulin resistance, and oxidative stress, are among the major mechanisms of both HF and comorbidities. Gene enrichment analysis showed the PI3K/AKT pathway may probably play a central role in multi morbidity. Additionally, drug targets common to HF and several common comorbidities were found by network analysis. Such analysis has already been instrumental in drug repurposing to treat HF and comorbidity. And the result suggests sodium-glucose transporter-2 (SGLT-2) inhibitors, IL-1β inhibitors, and metformin may be promising drugs for repurposing to treat multi morbidity. We propose that targeting the metabolic and inflammatory pathways that are common to HF and comorbidities may provide a promising therapeutic strategy.

Optimizing indices of AF susceptibility and burden to evaluate AF severity, risk and outcomes

Atrial fibrillation (AF) has heterogeneous patterns of presentation concerning symptoms, duration of episodes, AF burden, and the tendency to progress towards the terminal step of permanent AF. AF is associated with a risk of stroke/thromboembolism traditionally considered dependent on patient-level risk factors rather than AF type, AF burden, or other characterizations. However, the time spent in AF appears related to an incremental risk of stroke, as suggested by the higher risk of stroke in patients with clinical AF vs. subclinical episodes and in patients with non-paroxysmal AF vs. paroxysmal AF. In patients with device-detected atrial tachyarrhythmias, AF burden is a dynamic process with potential transitions from a lower to a higher maximum daily arrhythmia burden, thus justifying monitoring its temporal evolution. In clinical terms, the appearance of the first episode of AF, the characterization of the arrhythmia in a specific AF type, the progression of AF, and the response to rhythm control therapies, as well as the clinical outcomes, are all conditioned by underlying heart disease, risk factors, and comorbidities. Improved understanding is needed on how to monitor and modulate the effect of factors that condition AF susceptibility and modulate AF-associated outcomes. The increasing use of wearables and apps in practice and clinical research may be useful to predict and quantify AF burden and assess AF susceptibility at the individual patient level. This may help us reveal why AF stops and starts again, or why AF episodes, or burden, cluster. Additionally, whether the distribution of burden is associated with variations in the propensity to thrombosis or other clinical adverse events. Combining the improved methods for data analysis, clinical and translational science could be the basis for the early identification of the subset of patients at risk of progressing to a longer duration/higher burden of AF and the associated adverse outcomes.

Left Atrial Myopathy in Atrial Fibrillation and Heart Failure: Clinical Implications, Mechanisms, and Therapeutic Targets

PURPOSE OF REVIEW

This review discusses the mechanisms, clinical implications, and treatments of left atrial (LA) myopathy in comorbid atrial fibrillation (AF) and heart failure (HF) across the spectrum of ejection fraction.

RECENT FINDINGS

AF and HF are highly comorbid conditions. Left atrial (LA) myopathy, characterized by impairments in LA structure, function, or electrical conduction, plays a fundamental role in the development of both AF and HF with preserved ejection fraction (AF-HFpEF) along with AF and HF with reduced ejection fraction (AF-HFrEF). While the nature of LA myopathy in AF-HFpEF is unique from that of AF-HFrEF, LA myopathy also leads to progression of both of these conditions. There may be a vulnerable cohort of AF-HF patients who have a disproportionate degree of LA myopathy compared with left ventricular (LV) dysfunction. Further investigations are required to identify therapies to improve LA function in this cohort.

Catheter ablation for atrial fibrillation in patients with end-stage heart failure and eligibility for heart transplantation

AIMS

Timely referrals for transplantation and left ventricular assist device (LVAD) play a key role in favourable outcomes in patients with advanced heart failure (HF). The purpose of the Catheter Ablation for atrial fibrillation in patientS with end-sTage heart faiLure and Eligibility for Heart Transplantation (CASTLE-HTx) trial is to test the hypothesis that atrial fibrillation (AF) ablation has beneficial effects on mortality and morbidity during 'waiting time' for heart transplantation (HTx) or to prolong the time span until LVAD implantation.

METHODS AND RESULTS

CASTLE-HTx is a randomized evaluation of ablative treatment of AF in patients with severe left ventricular dysfunction who are candidates and eligible for HTx. The primary endpoint is the composite of all-cause mortality, worsening of HF requiring a high urgent transplantation, or LVAD implantation. The secondary study endpoints are all-cause mortality, cardiovascular mortality, cerebrovascular accidents, worsening of HF requiring unplanned hospitalization, AF burden reduction, unplanned hospitalization due to cardiovascular reason, all-cause hospitalization, quality of life, number of delivered implantable cardioverter defibrillator therapies, time to first implantable cardioverter defibrillator therapy, number of device-detected ventricular tachycardia/ventricular fibrillation episodes, left ventricular function, exercise tolerance, and percentage of right ventricular pacing. Ventricular myocardial tissue will be obtained from patients who will undergo LVAD implantation or HTx to assess the effect of catheter ablation on human HF myocardium. CASTLE-HTx will randomize 194 patients over a minimum time period of 2 years.

CONCLUSIONS

CASTLE-HTx will determine if AF ablation has beneficial effects on mortality in patients with end-stage HF who are eligible for HTx.

The impact of malnutrition on atrial fibrillation recurrence post ablation

BACKGROUND AND AIMS

Both malnutrition and atrial fibrillation (AF) are the major health problems in modern society. Only a few studies focused on the relationship between malnutrition and recurrence of atrial arrhythmias post AF ablation (AF recurrence), which used body mass index (BMI) as nutrition assessment tool. However, BMI can't credibly reflect body composition and has limitation in patients with water-sodium retention. In this study, we used controlling nutritional status score (CONUT score) and geriatric nutritional risk index (GNRI) to identify the malnutrition patients and explored the effect of malnutrition on AF recurrence.

METHODS AND RESULTS

This retrospective study included 246 patients who underwent AF ablation. During a median 11-month follow-up, 77 patients (31.3%) experienced AF recurrence. The recurrence group had higher CONUT score (2.3 ± 1.5 vs. 0.9 ± 1.0, P < 0.001) and lower GNRI (99.9 ± 7.6 vs. 103.9 ± 5.6, P < 0.001). After balancing the traditional risk factors, both CONUT score (OR: 2.614, 95%CI: 1.831-3.731, P < 0.001) and GNRI (OR: 0.884, 95%CI: 0.828-0.944, P < 0.001) were the independent predictors for AF recurrence. Pre-ablation CONUT score ≥1 and GNRI≥95.66 are indicative of AF recurrence. Adding CONUT score or GNRI to the base prediction model for AF recurrence significantly improved the discrimination and calibration. However, adding BMI to the base prediction model did not improve the model performance.

CONCLUSIONS

CONUT score and GNRI are ideal tools to evaluate the nutrition status of AF patients. Undernourished patients are more likely to suffer from AF recurrence. Improving nutrition status may be a potential target for reducing the postoperative recurrence rate.

Sex Differences in the Association between Atrial Fibrillation and 90-Day Adverse Outcomes among Older Adults with Heart Failure: A Retrospective Cohort Study

Sex differences in the prognostic impact of coexisting atrial fibrillation (AF) in older patients with heart failure (HF) have not been well-studied. This study, therefore, compared sex differences in the association between AF and its 90-day adverse outcomes (hospital readmissions and emergency room (ER) visits) among older adults with HF. Of the 250 older adult patients, the prevalence rates of coexisting AF between male and female HF patients were 46.0% and 31.0%, respectively. In both male and female older patients, patients with AF have a significantly higher readmission rate (male 46.0%, and female 34.3%) than those without AF (male 6.8%, and female 12.8%). However, there are no significant differences in the association between AF and ER visits in both male and female older HF patients. The multivariate logistic analysis showed that coexisting AF significantly increased the risk of 90-day hospital readmission in both male and female older patients. In addition, older age in males and longer periods of time after an HF diagnosis in females were associated with an increased risk of hospital readmission. Consequently, prospective cohort studies are needed to identify the impact of coexisting AF on short- and long-term outcomes in older adult HF patients by sex.

Long-term outcomes of index cryoballoon ablation or point-by-point radiofrequency ablation in patients with atrial fibrillation and systolic heart failure

Catheter ablation is an established effective approach for the treatment of atrial fibrillation (AF) in patients with heart failure, however, the role of cryoablation in this setting is unclear. Procedural success and left ventricular systolic dysfunction (LVEF) improvement in patients with LVEF ≤ 45% undergoing index catheter ablation with cryoablation were evaluated. Freedom from AF recurrence was seen in 43% rising to 59% following repeat procedure. There were significant improvements in LVEF and functional status at long-term follow-up. Results were comparable to a contemporaneous cohort of heart failure patients undergoing index ablation with radiofrequency ablation. Cryoablation is an effective first-line AF ablation approach in the setting of heart failure.

Atrial Fibrillation and Heart Failure: Epidemiology, Pathophysiology, Prognosis, and Management

Atrial fibrillation (AF) and heart failure (HF) have similar risk factors, frequently coexist, and potentiate each other in a vicious cycle. Evidence suggests the presence of AF in both HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF) increases the risk of all-cause mortality and stroke, particularly when AF is incident. Catheter ablation may be an effective strategy in controlling symptoms and improving quality of life in AF-HFrEF. Strong data guiding management of AF-HFpEF are lacking largely due to its challenging diagnosis. Improving outcomes associated with these coexistent conditions requires further careful investigation.

Characteristics, treatment, and outcomes of newly diagnosed atrial fibrillation patients with heart failure: GARFIELD-AF

Aims

Heart failure (HF) and atrial fibrillation (AF) may coexist and influence each other. However, characteristics, anticoagulant treatment, and outcomes of contemporary AF patients with concurrent HF are ill‐defined. This study analyses characteristics, treatment, and 2 year outcomes in newly diagnosed Global Anticoagulant Registry in the FIELD‐Atrial Fibrillation (GARFIELD‐AF) patients with vs. without HF.

Methods and results

GARFIELD‐AF is the world's largest observational AF patient study. At enrolment, 11 758 of 52 072 patients (22.6%) had HF; 76.3% were New York Heart Association class II–III. Patients with HF had comparable demographics, blood pressure, and heart rate but more likely had permanent (15.6% vs. 11.9%) or persistent AF (18.9% vs. 13.8%), acute coronary syndromes (16.7% vs. 8.9%), vascular disease (40.8% vs. 20.2%), and moderate‐to‐severe chronic kidney disease (14.6% vs. 9.0%) than those without. Anticoagulant prescription was similar between the two groups. At 2 year follow‐up, patients with HF showed a greater risk of all‐cause mortality [hazard ratio (HR), 2.06; 95% confidence interval (CI), 1.91–2.21; P < 0.0001], cardiovascular mortality (HR, 2.91; 95% CI, 2.58–3.29; P < 0.0001), acute coronary syndromes (HR, 1.25; 95% CI, 1.02–1.52; P = 0.03), and stroke/systemic embolism (HR, 1.24; 95% CI, 1.07–1.43; P = 0.0044). Major bleeding rate was comparable (adjusted HR, 1.00; 95% CI, 0.84–1.18; P = 0.968). Among patients without HF at baseline, incidence of new HF was low [0.69 (95% CI, 0.63–0.75) per 100 person‐years], whereas propensity to develop worsening HF was higher in those with HF [1.62 (95% CI, 1.45–1.80) per 100 person‐years].

Conclusions

Patients with AF and HF have a high risk of all‐cause and cardiovascular mortality and stroke/systemic embolism and may develop worsening HF.

Multicohort Metabolomics Analysis Discloses 9-Decenoylcarnitine to Be Associated With Incident Atrial Fibrillation

Background The molecular mechanisms involved in atrial fibrillation are not well known. We used plasma metabolomics to investigate if we could identify novel biomarkers and pathophysiological pathways of incident atrial fibrillation. Methods and Results We identified 200 endogenous metabolites in plasma/serum by nontargeted ultra-performance liquid chromatography coupled to time-of-flight mass spectrometry in 3 independent population-based samples (TwinGene, n=1935, mean age 68, 43% females; PIVUS [Prospective Investigation of the Vasculature in Uppsala Seniors], n=897, mean age 70, 51% females; and ULSAM [Uppsala Longitudinal Study of Adult Men], n=1118, mean age 71, all males), with available data on incident atrial fibrillation during 10 to 12 years of follow-up. A meta-analysis of ULSAM and PIVUS was used as a discovery sample and TwinGene was used for validation. In PIVUS, we also investigated associations between metabolites of interest and echocardiographic indices of myocardial geometry and function. Genome-wide association studies were performed in all 3 cohorts for metabolites of interest. In the meta-analysis of PIVUS and ULSAM with 430 incident cases, 4 metabolites were associated with incident atrial fibrillation at a false discovery rate <5%. Of those, only 9-decenoylcarnitine was associated with incident atrial fibrillation and replicated in the TwinGene sample (288 cases) following adjustment for traditional risk factors (hazard ratio, 1.24 per unit; 95% CI, 1.06-1.45, P=0.0061). A meta-analysis of all 3 cohorts disclosed another 4 significant metabolites. In PIVUS, 9-decenoylcarnitine was related to left atrium size and left ventricular mass. A Mendelian randomization analysis did not suggest a causal role of 9-decenoylcarnitine in atrial fibrillation. Conclusions A nontargeted metabolomics analysis disclosed 1 novel replicated biomarker for atrial fibrillation, 9-Decenoylcarnitine, but this acetylcarnitine is likely not causally related to atrial fibrillation.

Comparison of Outcomes After Ablation of Atrial Fibrillation in Patients With Heart Failure With Preserved Versus Reduced Ejection Fraction

Catheter ablation improves outcomes in atrial fibrillation (AF) patients with heart failure (HF) with reduced ejection fraction (HFrEF). We sought to evaluate the efficacy and safety of catheter ablation of AF in HF patients with a preserved ejection fraction (HFpEF). We performed a retrospective study of all patients who underwent de novo radiofrequency catheter ablation enrolled in the UC San Diego AF Ablation Registry. The primary outcome was recurrence of all atrial arrhythmias on or off antiarrhythmic drugs (AAD). Of 547 total patients, 51 (9.3%) had HFpEF, 40 (7.3%) had HFrEF, and 456 (83.4%) were without HF. There was no difference in recurrence of atrial arrhythmias on or off AAD (Adjusted Hazard Ratio [AHR] 1.92 [95% CI 0.97 to 3.83] for HFpEF vs HFrEF and AHR 0.90 [95% CI 0.59 to 1.39] for HFpEF vs no HF) or off AAD (AHR 1.96 [95% CI 0.99 to 3.90] for HFpEF vs HFrEF and AHR 1.14 [95% CI 0.74 to 1.77] for HFpEF vs no HF). There was also no difference in rates of all-cause hospitalizations (AHR 1.80 [95% CI 0.97 to 3.33] for HFpEF vs HFrEF and AHR 2.05 [95% CI 1.30 to 3.23] for HFpEF vs no HF) or rates of all-cause mortality (AHR 0.53 [95% CI 0.05 to 6.11] for HFpEF vs HFrEF and AHR 2.46 [95% CI 0.34 to 17.92] for HFpEF vs no HF). There were no significant differences in AAD use (p = 0.176) or procedural complications between groups (p = 0.980). In conclusion, there were no significant differences in arrhythmia-free survival between patients with HFpEF and HFrEF that underwent catheter ablation of AF.

Comprehensive evaluation of electrophysiological and 3D structural features of human atrial myocardium with insights on atrial fibrillation maintenance mechanisms

Atrial fibrillation (AF) occurrence and maintenance is associated with progressive remodeling of electrophysiological (repolarization and conduction) and 3D structural (fibrosis, fiber orientations, and wall thickness) features of the human atria. Significant diversity in AF etiology leads to heterogeneous arrhythmogenic electrophysiological and structural substrates within the 3D structure of the human atria. Since current clinical methods have yet to fully resolve the patient-specific arrhythmogenic substrates, mechanism-based AF treatments remain underdeveloped. Here, we review current knowledge from in-vivo, ex-vivo, and in-vitro human heart studies, and discuss how these studies may provide new insights on the synergy of atrial electrophysiological and 3D structural features in AF maintenance. In-vitro studies on surgically acquired human atrial samples provide a great opportunity to study a wide spectrum of AF pathology, including functional changes in single-cell action potentials, ion channels, and gene/protein expression. However, limited size of the samples prevents evaluation of heterogeneous AF substrates and reentrant mechanisms. In contrast, coronary-perfused ex-vivo human hearts can be studied with state-of-the-art functional and structural technologies, such as high-resolution near-infrared optical mapping and contrast-enhanced MRI. These imaging modalities can resolve atrial arrhythmogenic substrates and their role in reentrant mechanisms maintaining AF and validate clinical approaches. Nonetheless, longitudinal studies are not feasible in explanted human hearts. As no approach is perfect, we suggest that combining the strengths of direct human atrial studies with high fidelity approaches available in the laboratory and in realistic patient-specific computer models would elucidate deeper knowledge of AF mechanisms. We propose that a comprehensive translational pipeline from ex-vivo human heart studies to longitudinal clinically relevant AF animal studies and finally to clinical trials is necessary to identify patient-specific arrhythmogenic substrates and develop novel AF treatments.

Interplay of cardiovascular mediators, oxidative stress and inflammation in liver disease and its complications

The liver is a crucial metabolic organ that has a key role in maintaining immune and endocrine homeostasis. Accumulating evidence suggests that chronic liver disease might promote the development of various cardiac disorders (such as arrhythmias and cardiomyopathy) and circulatory complications (including systemic, splanchnic and pulmonary complications), which can eventually culminate in clinical conditions ranging from portal and pulmonary hypertension to pulmonary, cardiac and renal failure, ascites and encephalopathy. Liver diseases can affect cardiovascular function during the early stages of disease progression. The development of cardiovascular diseases in patients with chronic liver failure is associated with increased morbidity and mortality, and cardiovascular complications can in turn affect liver function and liver disease progression. Furthermore, numerous infectious, inflammatory, metabolic and genetic diseases, as well as alcohol abuse can also influence both hepatic and cardiovascular outcomes. In this Review, we highlight how chronic liver diseases and associated cardiovascular effects can influence different organ pathologies. Furthermore, we explore the potential roles of inflammation, oxidative stress, vasoactive mediator imbalance, dysregulated endocannabinoid and autonomic nervous systems and endothelial dysfunction in mediating the complex interplay between the liver and the systemic vasculature that results in the development of the extrahepatic complications of chronic liver disease. The roles of ageing, sex, the gut microbiome and organ transplantation in this complex interplay are also discussed.

Does Catheter Ablation Lower the Long-Term Risk of Stroke and Mortality in Patients with Atrial Fibrillation? A Concise Review of the Current State of Knowledge

Atrial fibrillation (AF) is the most common cardiac arrhythmia worldwide and carries a significant risk of morbidity and mortality. Multiple trials have highlighted the benefit of catheter ablation over medical therapy in restoring sinus rhythm and improving quality of life. Whether it reduces long-term risk of stroke and mortality is still unclear.

We performed a literature search using the PubMed database to review the current state of knowledge regarding the long-term outcomes of stroke and mortality in ablated patients compared to patients who receive medical therapy. Our review mainly consisted of recent randomized controlled trials and large observational studies. 

Results from large observational studies show that catheter ablation significantly reduces the risk of stroke in high-risk patients and mortality compared to medical therapy. However, randomized controlled trials have only demonstrated a mortality benefit in patients with comorbid systolic heart failure. In patients with paroxysmal AF, ablation therapy significantly limits the progression to persistent AF and has a higher efficacy in restoring sinus rhythm. Maintenance of sinus rhythm is the most important factor associated with lower long term risk of stroke and mortality.

Large randomized controlled trials similar to the Catheter Ablation Versus Anti-arrhythmic Drug Therapy for Atrial Fibrillation (CABANA) trial are still needed to clarify whether catheter ablation is superior over medical therapy in improving the long-term outcomes of stroke and mortality.

Long noncoding RNA in cardiac aging and disease

Cardiovascular diseases (CVDs) are the main cause of morbidity and mortality in Western society and present an important age-related risk. With the constant rise in life expectancy, prevalence of CVD in the population will likely increase further. New therapies, especially in the elderly, are needed to combat CVD. This review is focused on the role of long noncoding RNA (lncRNA) in CVD. RNA sequencing experiments in the past decade showed that most RNA does not code for protein, but many RNAs function as ncRNA. Here, we summarize the recent findings of lncRNA regulation in the diseased heart. The potential use of these RNAs as biomarkers of cardiac disease prediction is also discussed.

Addressing Comorbidities in Heart Failure: Hypertension, Atrial Fibrillation, and Diabetes

Heart failure (HF) is a growing global epidemic and an increasingly cumbersome burden on health care systems worldwide. As such, optimal management of existing comorbidities in the setting of HF is particularly important to prevent disease progression, reduce HF hospitalizations, and improve quality of life. In this review, the authors address 3 key comorbidities commonly associated with HF: hypertension, atrial fibrillation, and diabetes mellitus. They comprehensively describe the epidemiology, management, and emerging therapies in these 3 disease states as they relate to the overall HF syndrome.

Use of cardiovascular drugs and risk of incident heart failure in patients with atrial fibrillation

Congestive heart failure (CHF) is the most important cause of death in patients with atrial fibrillation (AF). We aimed to study the association between cardiovascular drugs in AF patients and incident CHF. The study population included all adults (n = 120 756) aged ≥45 years diagnosed with AF in Sweden diagnosed for the period 1998-2006. Outcome was incident congestive heart failure (follow-up 2007-2015) in AF patients. Associations between treatment with cardiovascular pharmacotherapies and CHF were evaluated using Cox regression to estimate hazard ratios (HRs) with 95% CIs, after adjustment for age, sociodemographic variables, and comorbidities. During a mean 5.3 years (SD 3.0) of follow-up, there were 28 257 (23.4%) incident cases of CHF. Treatment with beta-1-selective and non-selective beta-blockers and statins was associated with lower risks of incident CHF in men, HR, (95% CI); 0.90, (0.87-0.94); 0.90, (0.84-0.97), and 0.94, (0.90-0.99), respectively. Only beta-1-selective beta-blockers were protective in women 0.94 (0.91-0.98). Treatment with loop diuretics, potassium-saving agents, ACE inhibitors, and angiotensin receptor blockers was associated with a higher risk of CHF. For men, treatment with heart-active calcium channel blockers also led to a higher risk of CHF. In conclusion, we found that beta-blockers, in particular, but also statins were associated with lower risk of incident CHF in patients with AF.

Heart failure-induced atrial remodelling promotes electrical and conduction alternans

Heart failure (HF) is associated with an increased propensity for atrial fibrillation (AF), causing higher mortality than AF or HF alone. It is hypothesized that HF-induced remodelling of atrial cellular and tissue properties promotes the genesis of atrial action potential (AP) alternans and conduction alternans that perpetuate AF. However, the mechanism underlying the increased susceptibility to atrial alternans in HF remains incompletely elucidated. In this study, we investigated the effects of how HF-induced atrial cellular electrophysiological (with prolonged AP duration) and tissue structural (reduced cell-to-cell coupling caused by atrial fibrosis) remodelling can have an effect on the generation of atrial AP alternans and their conduction at the cellular and one-dimensional (1D) tissue levels. Simulation results showed that HF-induced atrial electrical remodelling prolonged AP duration, which was accompanied by an increased sarcoplasmic reticulum (SR) Ca²⁺ content and Ca²⁺ transient amplitude. Further analysis demonstrated that HF-induced atrial electrical remodelling increased susceptibility to atrial alternans mainly due to the increased sarcoplasmic reticulum Ca²⁺-ATPase (SERCA) Ca²⁺ reuptake, modulated by increased phospholamban (PLB) phosphorylation, and the decreased transient outward K⁺ current (I_to). The underlying mechanism has been suggested that the increased SR Ca²⁺ content and prolonged AP did not fully recover to their previous levels at the end of diastole, resulting in a smaller SR Ca²⁺ release and AP in the next beat. These produced Ca²⁺ transient alternans and AP alternans, and further caused AP alternans and Ca²⁺ transient alternans through Ca²⁺→AP coupling and AP→Ca²⁺ coupling, respectively. Simulation of a 1D tissue model showed that the combined action of HF-induced ion channel remodelling and a decrease in cell-to-cell coupling due to fibrosis increased the heart tissue’s susceptibility to the formation of spatially discordant alternans, resulting in an increased functional AP propagation dispersion, which is pro-arrhythmic. These findings provide insights into how HF promotes atrial arrhythmia in association with atrial alternans.

Atrial Fibrillation (AF) is the most common arrhythmia in adults, especially in the elderly, with the increased incidence of stroke being a major complication that increases morbidity and mortality. The occurrence of AF is often accompanied by heart failure (HF). AF and HF are also known to have the bidirectional relationship that AF worsens HF and HF promotes AF. HF can induce atrial remodelling, including electrical remodelling, atrial fibrosis, stretch and dilatation, and oxidative stress, in which many factors are associated with arrhythmogenic atrial alternans. HF-induced atrial remodelling varies during various stages and complications of HF, but possible mechanisms underlying their pro-susceptibility to alternans have not been completely elucidated. In this study, we investigated the effects of HF-induced atrial remodelling with prolonged action potential duration (APD) and decreased cell-to-cell coupling on susceptibility to atrial alternans. Simulation results showed that HF-induced an increase in sarcoplasmic reticulum Ca²⁺-ATPase (SERCA) Ca²⁺ reuptake caused by increased phospholamban phosphorylation and a decrease in transient outward K⁺ current played significant roles in the genesis of Ca²⁺ transient alternans and action potential alternans at the single-cell level. The HF-induced decline of cell-to-cell coupling and APD prolongation promoted the genesis of spatially discordant alternans in atrial tissue. This provides insights into how HF facilitates atrial arrhythmia in relation to atrial alternans.