Atrial fibrillation in heart failure with preserved ejection fraction: Insights into mechanisms and therapeutics

Global epidemiology of heart failure

Heart failure (HF) is a heterogeneous clinical syndrome marked by substantial morbidity and mortality. The natural history of HF is well established; however, epidemiological data are continually evolving owing to demographic shifts, advances in treatment and variations in access to health care. Although the incidence of HF has stabilized or declined in high-income countries over the past decade, its prevalence continues to increase, driven by an ageing population, an increase in risk factors, the effectiveness of novel therapies and improved survival. This rise in prevalence is increasingly noted among younger adults and is accompanied by a shift towards HF with preserved ejection fraction. However, disparities exist in our epidemiological understanding of HF burden and progression in low-income and middle-income countries owing to the lack of comprehensive data in these regions. Therefore, the current epidemiological landscape of HF highlights the need for periodic surveillance and resource allocation tailored to geographically vulnerable areas. In this Review, we highlight global trends in the burden of HF, focusing on the variations across the spectrum of left ventricular ejection fraction. We also discuss evolving population-based estimates of HF incidence and prevalence, the risk factors for and aetiologies of this disease, and outcomes in different geographical regions and populations.

Coagulation Disorders and Thrombotic Complications in Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is associated with multiple cardiovascular and noncardiovascular comorbidities and risk factors which increase the risk of thrombotic complications, such as atrial fibrillation, chronic kidney disease, arterial hypertension and type 2 diabetes mellitus. Subsequently, thromboembolic risk stratification in this population poses a great challenge. Since date from the large randomized clinical trials mostly include both patients with truly preserved EF, and those with heart failure with mildly reduced ejection fraction, there is an unmet need to characterize the patients with truly preserved EF. Considering the significant evidence gap in this area, we sought to describe the coagulation disorders and thrombotic complications in patients with HFpEF and discuss the specific thromboembolic risk factors in patients with HFpEF, with the goal to tailor risk stratification to an individual patient.

A review of the impact, pathophysiology, and management of atrial fibrillation in patients with heart failure with preserved ejection fraction

Patients with heart failure with preserved ejection fraction (HFpEF) and atrial fibrillation (AF) have increased mortality and increased risk of stroke. Due to the heterogeneous nature of both disease processes, it is difficult to ascertain whether the diagnosis and progression of AF is the cause of deterioration or if it is a symptom of worsening heart failure. This presents physicians with a clinical conundrum of whether optimizing their heart failure will decrease the overall AF burden or if restoration of sinus rhythm is necessary to optimize patients with HFpEF. In this paper, we will review the impact of AF in patients with HFpEF, the pathophysiology and heterogeneity of HFpEF and AF, and the management of these patients. As HFpEF and AF become more prevalent, managing these disease processes needs standardization to improve outcomes. Further research is needed to understand the complex interplay between AF and HFpEF to help determine the best management strategy.

Relative Contribution of Atrial Fibrillation to Outcomes of Patients With Cardiomyopathy Based on Severity of Left Ventricular Dysfunction

In patients with left ventricular (LV) dysfunction, the risk of death or heart failure hospitalizations (HFHs) increases with worsening ejection fraction (EF). Whether the relative contribution of atrial fibrillation (AF) to outcomes is more pronounced in patients with worse EF is not confirmed. The present study aimed to investigate the relative influence of AF on the outcome of cardiomyopathy patients by severity of LV dysfunction. In this observational study, data from 18,003 patients with EF ≤50% seen at a large academic institution between 2011 and 2017 were analyzed. Patients were stratified by EF quartiles (EF<25%, 25%≤EF<35%, 35%≤EF<40%, and EF≥40%, for quartiles 1, 2, 3, and 4, respectively). and followed to the end point of death or HFH. Outcomes of AF versus non-AF patients were compared within each EF quartile. During a median follow-up of 3.35 years, 8,037 patients (45%) died and 7,271 (40%) had at least 1 HFH. Rates of HFH and all-cause mortality increased as EF decreased. The hazard ratios (HRs) of death or HFH for AF versus non-AF patients increased steadily with increasing EF (HR of 1.22, 1.27, 1.45, 1.50 for quartiles 1, 2, 3, and 4, respectively, p = 0.045) driven primarily by the risk of HFH (HR of 1.26, 1.45, 1.59, 1.69 for quartiles 1, 2, 3, and 4, respectively, p = 0.045). In conclusion, in patients with LV dysfunction, the detrimental influence of AF on the risk of HFH is more pronounced in those with more preserved EF. Mitigation strategies for AF with the goal of decreasing HFH may be more impactful in patients with more preserved LV function.

The Association of Glucose Control with Circulating Levels of Red Blood Cell-Derived Vesicles in Type 2 Diabetes Mellitus Patients with Atrial Fibrillation

Hyperglycemia is a trigger for structural alteration of red blood cells (RBCs) and their ability to release extracellular vesicles (EVs). The aim of the study was to elucidate whether glucose control in T2DM patients with concomitant HF and AF affects a circulating number of RBC-derived EVs. We prospectively included 417 T2DM patients with HF, 51 of them had atrial fibrillation and 25 healthy volunteers and 30 T2DM non-HF individuals. Clinical assessment, echocardiography examination and biomarker measures were performed at the baseline of the study. RBC-derived EVs were determined as CD235a+ PS+ particles by flow cytometry. NT-proBNP levels were measured by ELISA. AF patients with glycosylated hemoglobin (HbA1c) < 6.9% had lower levels of CD235a+ PS+ RBC-derived vesicles than those with HbA1c ≥ 7.0%. There were no significant differences in number of CD235a+ PS+ RBC-derived vesicles between patients in entire cohort and in non-AF sub-cohort with HbA1c < 6.9% and HbA1c ≥ 7.0%, respectively. Multivariate linear regression yielded that CD235a+ PS+ RBC-derived vesicles ≥ 545 particles in µL (OR = 1.06; 95% CI = 1.01−1.11, p = 0.044) independently predicted HbA1c ≥ 7.0%. Elevated levels of CD235a+ PS+ RBC-derived EVs independently predicted poor glycaemia control in T2DM patients with HF and AF.

Mitral Annular Plane Systolic Excursion (MAPSE) as a Predictor of Atrial Fibrillation Recurrence in Patients after Pulmonary Vein Isolation

Introduction

Catheter ablation (CA) with pulmonary vein isolation (PVI) has become widely used in the past years for the treatment of atrial fibrillation (AF). Mitral annular plane systolic excursion (MAPSE) is the parameter that measures left ventricular longitudinal function, and it appears to be a good early marker of LV dysfunction. It is practically independent of poor image quality. The aim of our study was to analyse the role of echocardiographic variables, especially MAPSE in predicting the outcome of CA in patients with AF.

Materials and Methods

We prospectively included 40 patients with paroxysmal and persistent AF that were referred for CA. All patients underwent radiofrequency CA with PVI. Standard transthoracic two-dimensional echocardiography was conducted one day after CA. Demographic data and the patients' characteristics were noted. The endpoint of our study was to estimate the AF recurrence rate diagnosed by ECG within 6 months of the follow-up period.

Results

40 patients, mainly male (67.5%) with an average age of 61.43 ± 8.96 years were included in our study. The majority of patients had paroxysmal AF prior to ablation (77.5%). The AF recurrence rate was 20% after 6 months of follow-up. Lateral MAPSE in the AF-free group was greater than those who relapsed (1.57 ± 0.24 vs. 1.31 ± 0.25; p = 0.012). Patients who remained AF-free after a 6-month follow-up period had a significantly smaller left ventricular volume index (LAVI) than those who relapsed (34.29 ± 6.91 ml/m² vs. 42.90 ± 8.43 ml/m²; p = 0.05). We found a significant reverse relationship between LAVI and MAPSE (p = 0.020).

Conclusion

MAPSE and LAVI present risk factors for AF recurrence, specifically reduced MAPSE and larger LAVI, are related to AF recurrence after CA. In the future, MAPSE could play a significant role when predicting the CA outcome in patients with AF.

Current Management of Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) encompasses nearly half of heart failure (HF) worldwide, and still remains a poor prognostic indicator. It commonly coexists in patients with vascular disease and needs to be recognized and managed appropriately to reduce morbidity and mortality. Due to the heterogeneity of HFpEF as a disease process, targeted pharmacotherapy to this date has not shown a survival benefit among this population. This article serves as a comprehensive historical review focusing on the management of HFpEF by reviewing past, present, and future randomized controlled trials that attempt to uncover a therapeutic value. With a paradigm shift in the pathophysiology of HFpEF as an inflammatory, neurohormonal, and interstitial process, a phenotypic approach has increased in popularity focusing on the treatment of HFpEF as a systemic disease. This article also addresses common comorbidities associated with HFpEF as well as current and ongoing clinical trials looking to further elucidate such links.

Diastolic function: modeling left ventricular untwisting as a damped harmonic oscillator

Objective.We developed a method using cardiovascular magnetic resonance imaging to model the untwisting of the left ventricle (LV) as a damped torsional harmonic oscillator to estimate shear modulus (intrinsic myocardial stiffness) and frictional damping, then applied this method to evaluate the torsional stiffness of patients with resistant hypertension (RHTN) compared to a control group.Approach.The angular displacement of the LV during diastole was measured. Myocardial shear modulus and damping constant were determined by solving a system of equations modeling the diastolic untwisting as a damped, unforced harmonic oscillator, in 100 subjects with RHTN and 36 control subjects.Main Results.Though overall torsional stiffness was increased in RHTN (41.7 (27.1-60.7) versus 29.6 (17.3-35.7) kdyn*cm;p = 0.001), myocardial shear modulus was not different between RHTN and control subjects (0.34 (0.23-0.50) versus 0.33 (0.22-0.46) kPa;p= 0.758). RHTN demonstrated an increase in overall diastolic frictional damping (6.13 ± 3.77 versus 3.35 ± 1.70 kdyn*cm*s;p< 0.001), but no difference in damping when corrected for the overlap factor (74.3 ± 25.9 versus 68.0 ± 24.0 dyn*s/cm3;p = 0.201). There was an increase in the polar moment (geometric component of stiffness; 11.47 ± 6.95 versus 7.58 ± 3.28 cm4;p<0.001).Significance.We have developed a phenomenological method, estimating the intrinsic stiffness and relaxation properties of the LV based on restorative diastolic untwisting. This model finds increased overall stiffness in RHTN and points to hypertrophy, rather than tissue- level changes, as the major factor leading to increased stiffness.

ESC working group on cardiac cellular electrophysiology position paper: relevance, opportunities, and limitations of experimental models for cardiac electrophysiology research

Cardiac arrhythmias are a major cause of death and disability. A large number of experimental cell and animal models have been developed to study arrhythmogenic diseases. These models have provided important insights into the underlying arrhythmia mechanisms and translational options for their therapeutic management. This position paper from the ESC Working Group on Cardiac Cellular Electrophysiology provides an overview of (i) currently available in vitro, ex vivo, and in vivo electrophysiological research methodologies, (ii) the most commonly used experimental (cellular and animal) models for cardiac arrhythmias including relevant species differences, (iii) the use of human cardiac tissue, induced pluripotent stem cell (hiPSC)-derived and in silico models to study cardiac arrhythmias, and (iv) the availability, relevance, limitations, and opportunities of these cellular and animal models to recapitulate specific acquired and inherited arrhythmogenic diseases, including atrial fibrillation, heart failure, cardiomyopathy, myocarditis, sinus node, and conduction disorders and channelopathies. By promoting a better understanding of these models and their limitations, this position paper aims to improve the quality of basic research in cardiac electrophysiology, with the ultimate goal to facilitate the clinical translation and application of basic electrophysiological research findings on arrhythmia mechanisms and therapies.

Low molecular weight chitosan oligosaccharides (LMW-COSs) prevent obesity-related metabolic abnormalities in association with the modification of gut microbiota in high-fat diet (HFD)-fed mice

In this study, the two enzymatic low molecular weight chitosan oligosaccharides (LMW-COSs), LMW-COS-H and LMW-COS-L, were prepared with average MWs of 879.6 Da and 360.9 Da, respectively. Compared to LMW-COS-L, the LMW-COS-H was more effective in improving high-fat diet (HFD)-induced metabolic abnormalities, such as obesity, hyperlipidemia, low-grade inflammation and insulin resistance. The subsequent analysis of gut microbiota showed that the supplement of LMW-COSs caused overall structural and genus/species-specific changes in the gut microbiota, which were significantly correlated with the metabolic parameters. Specifically, both of the LMW-COSs significantly decreased the relative abundance of inflammatory bacteria such as Erysipelatoclostridium and Alistipes, whereas that of the beneficial intestinal bacteria (such as Akkermansia and Gammaproteobacteria) increased significantly. This study suggested that there were potential prebiotic functions of LMW-COSs in HFD fed mice, which regulated the dysfunctional gut microbiota, alleviated low-grade inflammation and maintained the intestinal epithelial barrier.

Comorbidities Associated with One-Year Mortality in Patients with Atrial Fibrillation and Heart Failure

BACKGROUND

Heart failure (HF) and atrial fibrillation (AF) commonly coexist and patients with both diseases have a worse prognosis than those with HF or AF alone. The objective of our study was to identify the factors associated with one-year mortality in patients with HF and AF, depending on the left ventricular ejection fraction (LVEF).

METHODS

We included 727 patients with HF and AF consecutively admitted in a clinical emergency hospital between January 2018 and December 2019. The inclusion criteria were age of more than 18 years, diagnosis of chronic HF and AF (paroxysmal, persistent, permanent), and signed informed consent. The exclusion criteria were the absence of echocardiographic data, a suboptimal ultrasound view, and other cardiac rhythms than AF. The patients were divided into 3 groups: group 1 (337 patients with AF and HF with reduced ejection fraction (HFrEF)), group 2 (112 patients with AF and HF with mid-range ejection fraction (HFmrEF)), and group 3 (278 patients with AF and HF with preserved ejection fraction (HFpEF)).

RESULTS

The one-year mortality rates were 36.49% in group 1, 27.67% in group 2, and 27.69% in group 3. The factors that increased one-year mortality were chronic kidney disease (OR 2.35, 95% CI 1.45-3.83), coronary artery disease (OR 1.67, 95% CI 1.06-2.62), and diabetes (OR 1.66, 95% CI 1.05-2.67) in patients with HFrEF; and hypertension in patients with HFpEF (OR 2.45, 95% CI 1.36-4.39).

CONCLUSIONS

One-year mortality in patients with HF and AF is influenced by different factors, depending on the LVEF.

Baseline characteristics of patients in the PARALLAX trial: insights into quality of life and exercise capacity in heart failure with preserved ejection fraction

AIMS

We sought to describe the baseline characteristics of PARALLAX [a randomized controlled trial of sacubitril/valsartan vs. individualized medical therapy in heart failure (HF) with mildly reduced and preserved ejection fraction (HFpEF)]; compare PARALLAX to recent HFpEF trials; and examine the clinical characteristics associated with quality of life (QOL) and 6-min walk test distance (6MWD).

METHODS AND RESULTS

A total of 2566 patients with HF and left ventricular ejection fraction (LVEF) >40% were randomized, of whom 96% had an LVEF ≥45%. Multivariable linear regression was used to determine characteristics associated with Kansas City Cardiomyopathy Questionnaire clinical summary score (KCCQ-CSS) and 6MWD. Mean age was 73 ± 8 years, 51% were female, and comorbidities were common. Of the QOL measures tested in PARALLAX, the Short Form Health Survey-36 physical functioning score was most closely correlated with 6MWD (R = 0.41, P < 0.001), and outperformed the KCCQ physical limitation score (R = 0.33) and KCCQ-CSS (R = 0.31) on multivariable analyses. Female sex, higher body mass index, history of coronary artery disease, lower LVEF, and higher N-terminal pro-B-type natriuretic peptide (NT-proBNP) were associated with worse (lower) KCCQ-CSS; older age, female sex, higher body mass index, diabetes, coronary artery disease, chronic obstructive pulmonary disease, prior HF hospitalization, lower LVEF, and higher NT-proBNP were associated with shorter 6MWD (P < 0.05 for all associations).

CONCLUSIONS

PARALLAX is the largest HFpEF study to date to examine 6MWD together with QOL. The KCCQ-CSS and 6MWD were modestly correlated, and several factors were associated with worse values of both. These results provide insight into the association between QOL and exercise capacity in HFpEF.

Atrial Fibrillation and Heart Failure with Preserved Ejection Fraction: Two Chronic Troublemakers

In this article, the definition; mechanisms; diagnostic strategies, including scoring systems; treatments; prognosis; and future perspectives in heart failure with preserved ejection fraction with atrial fibrillation, which are common comorbid conditions, are reviewed thoroughly.

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.

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.

Ablation Versus Drug Therapy for Atrial Fibrillation in Heart Failure: Results From the CABANA Trial

BACKGROUND

In patients with heart failure and atrial fibrillation (AF), several clinical trials have reported improved outcomes, including freedom from AF recurrence, quality of life, and survival, with catheter ablation. This article describes the treatment-related outcomes of the AF patients with heart failure enrolled in the CABANA trial (Catheter Ablation Versus Antiarrhythmic Drug Therapy for Atrial Fibrillation).

METHODS

The CABANA trial randomized 2204 patients with AF who were ≥65 years old or <65 years old with ≥1 risk factor for stroke at 126 sites to ablation with pulmonary vein isolation or drug therapy including rate or rhythm control drugs. Of these, 778 (35%) had New York Heart Association class >II at baseline and form the subject of this article. The CABANA trial's primary end point was a composite of death, disabling stroke, serious bleeding, or cardiac arrest.

RESULTS

Of the 778 patients with heart failure enrolled in CABANA, 378 were assigned to ablation and 400 to drug therapy. Ejection fraction at baseline was available for 571 patients (73.0%), and 9.3% of these had an ejection fraction <40%, whereas 11.7% had ejection fractions between 40% and 50%. In the intention-to-treat analysis, the ablation arm had a 36% relative reduction in the primary composite end point (hazard ratio, 0.64 [95% CI, 0.41-0.99]) and a 43% relative reduction in all-cause mortality (hazard ratio, 0.57 [95% CI, 0.33-0.96]) compared with drug therapy alone over a median follow-up of 48.5 months. AF recurrence was decreased with ablation (hazard ratio, 0.56 [95% CI, 0.42-0.74]). The adjusted mean difference for the AFEQT (Atrial Fibrillation Effect on Quality of Life) summary score averaged over the entire 60-month follow-up was 5.0 points, favoring the ablation arm (95% CI, 2.5-7.4 points), and the MAFSI (Mayo Atrial Fibrillation-Specific Symptom Inventory) frequency score difference was -2.0 points, favoring ablation (95% CI, -2.9 to -1.2).

CONCLUSIONS

In patients with AF enrolled in the CABANA trial who had clinically diagnosed stable heart failure at trial entry, catheter ablation produced clinically important improvements in survival, freedom from AF recurrence, and quality of life relative to drug therapy. These results, obtained in a cohort most of whom had preserved left ventricular function, require independent trial verification. Registration: URL: https://www.clinicaltrials.gov/ct2/show/NCT00911508; Unique identifier: NCT0091150.

Heart Failure and Atrial Fibrillation, Like Fire and Fury

Heart failure and atrial fibrillation are 2 common cardiovascular disorders that frequently complicate one another and exert a significant detrimental effect on cardiovascular health and well-being. Both heart failure and atrial fibrillation continue to increase in prevalence as the risk factors underlying each condition become more common. This review encompasses what is currently known about the epidemiology and pathophysiology of these comorbidities along with incorporation of landmark trials that have contributed to current guidelines. The focus is on clinically relevant considerations, including the contribution of inflammation in the pathophysiology of atrial fibrillation and heart failure. We explore the emerging role of catheter ablation relative to medical therapy in the management of heart failure with reduced ejection fraction, along with indications for biventricular pacing modalities in cardiac resynchronization therapy. We discuss current guideline-directed therapies and how practice models and national recommendations will likely change based on the most recent randomized controlled trials.

Association of the H2FPEF Risk Score with Recurrence of Atrial Fibrillation Following Pulmonary Vein Isolation

Background

While atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF) commonly coexist, the efficacy of pulmonary vein isolation in the setting of HFpEF is unclear.

Methods

In a cohort of patients who underwent cryoballoon ablation (CBA) from 2011 to 2016, we calculated the H₂FPEF risk score, a novel 6-item score (scale: 0-9 points) that accurately predicts the probability of HFpEF. We compared characteristics of patients by H₂FPEF score and evaluated the association of H₂FPEF score with 12-month recurrence of AF post-procedure.

Results

Of patients with available data to calculate the H₂FPEF score (n=105), the median H₂FPEF score was 5 (interquartile range: 4-6), corresponding to >80% probability of HFpEF. Compared to patients with H₂FPEF scores ≤4 (n=34), patients with H₂FPEF scores of 5 and 6 (n=46) and ≥7 (n=25) carried higher rates of hypertension (≤4: 21% vs. 5 and 6: 63% vs. ≥7: 88%, P<0.001) and diabetes (≤4: 0% vs. 5 and 6: 9% vs. ≥7: 32%, P=0.001). The overall 12-month recurrence rate of AF was 21%. There was no association between H₂FPEF score and recurrence of AF at 12 months (OR per SD increase in log-H₂FPEF score: 0.87, 95% CI: 0.54-1.40, P=0.57).

Conclusions

Among patients undergoing CBA for AF, median H₂FPEF scores are elevated, and screening for occult HFpEF may be warranted in this population. There was no association of the H₂FPEF score and AF recurrence at 12 months, suggesting efficacy of CBA even among patients with high H₂FPEF scores.

Canine atrial fibrillation: Pathophysiology, epidemiology and classification

Atrial fibrillation (AF) is the most common non-physiological arrhythmia in dogs and humans. Its high prevalence in both species and the impact it has on survival time and quality of life of affected patients, makes it a very relevant topic of medical research. Significant developments in understanding the mechanisms underlying this arrhythmia in humans has occurred over the last decades and some of this knowledge is being applied to veterinary medicine, despite the many differences between species. This article reviews the current understanding of the pathophysiology of AF. The epidemiology and classification of AF in dogs will also be discussed.

Restoration of sinus rhythm by pulmonary vein isolation improves heart failure with preserved ejection fraction in atrial fibrillation patients

AIMS

Atrial fibrillation (AF) in patients suffering from heart failure with preserved ejection fraction (HFpEF) is associated with increased symptoms and higher morbidity and mortality. Effective treatment strategies for this patient population have not yet been established.

METHODS AND RESULTS

We analysed clinical outcomes and echocardiographic parameters of patients with AF and HFpEF who underwent pulmonary vein isolation (PVI). Out of 374 PVI patients, we identified 35 patients suffering from concomitant HFpEF. Freedom from atrial tachyarrhythmia (AT) after 1 year was 80%. Heart failure symptoms assessed by New York Heart Association class significantly improved from 2.7 ± 0.7 to 1.7 ± 0.9 (P < 0.001). We observed regression of diastolic dysfunction by echocardiography 12 months after the index procedure. Moreover, 15 patients (42.9%) experienced complete resolution of HFpEF after a single ablation procedure. Multivariate logistic regression revealed absence of AT recurrence as an independent predictor of recovery from HFpEF (hazard ratio 11.37, 95% confidence interval 1.70-75.84, P = 0.009). Furthermore, resolution of HFpEF by achieving freedom from AT recurrence by PVI, including multiple procedures, led to a significant reduction of hospitalizations.

CONCLUSION

Our results suggest that restoration of sinus rhythm by PVI in HFpEF patients with concomitant AF induces reverse remodelling, improvement of symptoms, resolution of HFpEF and subsequently decrease of hospitalizations. Randomized controlled trials are warranted to confirm our results.

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.

Analysis of Outcomes in Ischemic vs Nonischemic Cardiomyopathy in Patients With Atrial Fibrillation: A Report From the GARFIELD-AF Registry

Importance

Congestive heart failure (CHF) is commonly associated with nonvalvular atrial fibrillation (AF), and their combination may affect treatment strategies and outcomes.

Objective

To assess the treatment strategies and 1-year clinical outcomes of antithrombotic and CHF therapies for patients with newly diagnosed AF with concomitant CHF stratified by etiology (ischemic cardiomyopathy [ICM] vs nonischemic cardiomyopathy [NICM]).

Design, Setting, and Participants

The GARFIELD-AF registry is a prospective, noninterventional registry. A total of 52 014 patients with AF were enrolled between March 2010 and August 2016. A total of 11 738 patients 18 years and older with newly diagnosed AF (≤6 weeks' duration) and at least 1 investigator-determined stroke risk factor were included. Data were analyzed from December 2017 to September 2018.

Exposures

One-year follow-up rates of death, stroke/systemic embolism, and major bleeding were assessed.

Main Outcomes and Measures

Event rates per 100 person-years were estimated from the Poisson model and Cox hazard ratios (HRs) and 95% confidence intervals.

Results

The median age of the population was 71.0 years, 22 987 of 52 013 were women (44.2%) and 31 958 of 52 014 were white (61.4%). Of 11 738 patients with CHF, 4717 (40.2%) had ICM and 7021 (59.8%) had NICM. Prescription of oral anticoagulant and antiplatelet drugs was not balanced between groups. Oral anticoagulants with or without antiplatelet drugs were used in 2753 patients with ICM (60.1%) and 5082 patients with NICM (73.7%). Antiplatelets were prescribed alone in 1576 patients with ICM (34.4%) and 1071 patients with NICM (15.5%). Compared with patients with NICM, use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (72.6% [3439] vs 60.3% [4236]) and of β blockers (63.3% [2988] vs 53.2% [3737]) was higher in patients with ICM. Rates of all-cause and cardiovascular death per 100 patient-years were significantly higher in the ICM group (all-cause death: ICM, 10.2; 95% CI, 9.2-11.1; NICM, 7.0; 95% CI, 6.4-7.6; cardiovascular death: ICM, 5.1; 95% CI, 4.5-5.9; NICM, 2.9; 95% CI, 2.5-3.4). Stroke/systemic embolism rates tended to be higher in ICM groups compared with NICM groups (ICM, 2.0; 95% CI, 1.6-2.5; NICM, 1.5; 95% CI, 1.3-1.9). Major bleeding rates were significantly higher in the ICM group (1.1; 95% CI, 0.8-1.4) compared with the NICM group (0.7; 95% CI, 0.5-0.9).

Conclusions and Relevance

Patients with ICM received oral anticoagulants with or without antiplatelet drugs less frequently and antiplatelets alone more frequently than patients with NICM, but they received angiotensin-converting enzyme inhibitors/angiotensin receptor blockers more often than patients with NICM. All-cause and cardiovascular death rates were higher in patients with ICM than patients with NICM.

Trial Registration

ClinicalTrials.gov Identifier: NCT01090362.

Risks of incident heart failure with preserved ejection fraction in Chinese patients hospitalized for cardiovascular diseases

Background

Endogenous aldehyde damages DNA and potentiates an ageing phenotype. The aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism has a prevalence of 30%–50% in Asian populations. In this study, we aimed to analyze risk factors contributing to the development of heart failure with preserved ejection fraction (HFpEF) along with the genetic exposure in Chinese patients hospitalized with cardiovascular diseases (CVD).

Methods

From July 2017 to October 2018, a total of 770 consecutive Chinese patients with normal left ventricular ejection fractions (LVEF) and established CVD (hypertension, coronary heart diseases, or diabetes) were enrolled in this prospective cross-sectional study. HFpEF was defined by the presence of at least one of symptom (dyspnoea and fatigue) or sign (rales and ankle swelling) related to heart failure; N-terminal pro-B-Type natriuretic peptide (NT pro-BNP ≥ 280 pg/mL); LVEF ≥ 50%; and at least one criterion related to elevated ventricular filling pressure or diastolic dysfunction (left atrial diameter > 40 mm, E/E' ≥ 13, E'/A' < 1 or concurrent atrial fibrillation). Logistic regression was performed to yield adjusted odds ratios (ORs) for HFpEF incidence associated with traditional and/or genetic exposures.

Results

Finally, among 770 patients with CVD, 92 (11.9%) patients were classified into the HFpEF group according to the diagnostic criteria. The mean age of the participants was 67 ± 12 years, and 278 (36.1%) patients were females. A total of 303 (39.4%) patients were ALDH2*2 variant carriers. In the univariate analysis, eight exposures were found to be associated with HFpEF: atrial fibrillation, ALDH2*2 variants, hypertension, age, anaemia, smoking, alcohol consumption and sex. Multivariable logistic regression showed that 4 ‘A’ variables (atrial fibrillation, ALDH2*2 variants, age and anaemia) were significantly associated with an increased risk of HFpEF. Atrial fibrillation was associated with a 3.8-fold increased HFpEF risk (95% CI: 2.21–6.61, P < 0.001), and the other three exposures associated with increased HFpEF risk were the ALDH2*2 variant (OR = 2.41, 95% CI: 1.49–3.87, P < 0.001), age (OR = 2.14, 95% CI: 1.27–3.60, P = 0.004), and anaemia (OR = 1.79, 95% CI: 1.05–3.03, P = 0.032). These four variables predicted HFpEF incidence in Chinese CVD patients (C-statistic = 0.745, 95% CI: 0.691–0.800, P < 0.001).

Conclusions

4 A traits (atrial fibrillation, ALDH2*2 variants, age and anaemia) were associated with an increased risk of HFpEF in Chinese CVD patients. Our results provide potential clues to the aetiology, pathophysiology and therapeutic targets of HFpEF.

Atrial Fibrillation in Heart Failure-Diagnostic, Therapeutic, and Prognostic Relevance

PURPOSE OF REVIEW

Atrial fibrillation (AF) and heart failure (HF) commonly coexist and are associated with an increased risk of hospitalization, morbidity, and mortality. Both conditions develop into epidemics due to the ageing of the population and lead to poorer prognosis for the individual patients. Therapeutic strategies include treatment with oral anticoagulation, and rate and rhythm control concepts to prevent stroke and improve the cardiovascular outcome.

RECENT FINDINGS

Especially in HF patients, data suggest that catheter ablation of AF is superior to medical treatment. In patients with both AF and HF undergoing catheter ablation, significant increases in left ventricular ejection fraction and quality of life and decreases in related symptoms and major adverse cardiac events are reported. In addition, catheter ablation has been shown to reduce mortality and HF hospitalization in the medium term. For patients with AF and HF, an effective individualized therapeutic strategy to minimize potential complications and improve clinical outcomes is needed. Catheter ablation of AF seems to provide advantages in HF patients with AF. However, results of further long-term studies are awaited.

Physical Activity, Quality of Life, and Biomarkers in Atrial Fibrillation and Heart Failure With Preserved Ejection Fraction (from the NEAT-HFpEF Trial)

Although atrial fibrillation/atrial flutter (AF/AFL) and heart failure with preserved ejection fraction (HFpEF) frequently coexist, the influence of AF/AFL on physical activity, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and quality of life in HFpEF is unclear and could have relevance to HFpEF trial design. We evaluated the association between AF/AFL and volitional physical activity, functional performance, NT-proBNP, and quality of life in patients with HFpEF in the Nitrate's Effect on Activity Tolerance (NEAT)-HFpEF trial. Of 99 patients with accelerometer data, 35 (35%) had AF/AFL. There were no differences between AF/AFL versus no AF/AFL in baseline average daily accelerometer units (ADAUs; 9.06 ± 0.54 vs 9.06 ± 0.48, p = 0.75), hours active per day (9.7 ± 2.3 vs 9.2 ± 2.2, p = 0.86), or 6-minute walk distance (6MWD; 307 ± 136m vs 321 ± 110m, p = 0.85). AF/AFL status was associated with higher baseline NT-proBNP (586 [25th to 75th percentile: 291 to 1254] pg/ml vs 154 [25th to 75th percentile: 92 to 288] pg/ml, p <0.001) and Kansas City Cardiomyopathy Questionnaire scores (69 [25th to 75th percentile: 46 to 88] vs 48 [25th to 75th percentile: 37 to 70], p = 0.01). Although treatment responses to isosorbide mononitrate measured by change in ADAUs, hours active per day, or 6MWD did not vary by AF/AFL status (interaction p >0.05 for all), AF/AFL patients had greater reductions in NT-proBNP after isosorbide mononitrate than patients without AF/AFL (interaction p <0.001), possibly due to regression to the mean. In conclusion, baseline measures and treatment-related changes in volitional physical activity (ADAUs) and functional performance (6MWD) did not differ by AF/AFL in NEAT-HFpEF, whereas NT-proBNP did. In HFpEF-where AF/AFL prevalence is high-functional measures may be superior to natriuretic peptides as trial endpoints.

Predictors of Unfavorable Outcomes in Patients with Atrial Fibrillation and Concomitant Heart Failure with Different Ejection Fractions: RIF-CHF Register One-Year Follow-Up

Background

Atrial fibrillation (AF) and heart failure (HF) are tightly interrelated. The concurrence of these pathologies can aggravate the pathological process. The geographic and ethnic characteristics of patients may significantly affect the efficacy of different types of therapy and patients' compliance. The objective of this study was to analyze how the features of the course of the diseases and management of HF + AF influence the clinical outcomes.

Methods

The data of 1,003 patients from the first Russian register of patients with chronic heart failure and atrial fibrillation (RIF-CHF) were analyzed. The endpoints included hospitalization due to HF worsening, mortality, thromboembolic events, and hemorrhage. Predictors of unfavorable outcomes were analyzed separately for patients with HF and preserved ejection fraction (AF + HFpEF), midrange ejection fraction (AF + HFmrEF), and reduced ejection fraction (AF + HFrEF). Prevalence of HF + AF and compliance with long-term treatment of this pathology during one year were evaluated for each patient.

Results

The study involved 39% AF + HFpEF patients, 15% AF + HFmrEF patients, and 46% AF + HFrEF patients. AF + HFpEF patients were significantly older than patients in two other groups (40.6% of patients were older than ≥75 years vs. 24.8%, respectively, p < 0.001) and had the lowest rate of prior myocardial infarctions (25.3% vs. 46.1%, p < 0.001) and the lowest adherence to rational therapy of HF (27.4% vs. 47.1%, p < 0.001). AF + HFmrEF patients had the highest percentage of cases of HF onset after AF (61.3% vs. 49.2% in other patient groups, p=0.021). Among patients with AF + HFrEF, there was the highest percentage of males (74.2% vs. 41% in other patient groups, p < 0.001) and the highest percentage of ever-smokers (51.9% vs. 29.4% in other patient groups, p < 0.001). A total of 57.2% of patients were rehospitalized for decompensation of chronic heart failure within one year; the risk was the highest for AF + HFmrEF patients (66%, p=0.017). Reduced ejection fraction was associated with the increased risk of cardiovascular mortality (15.5% vs. 5.4% in other patient groups, p < 0.001) rather than ischemic stroke (2.4% vs. 3%, p=0.776). Patients with AF + HFpEF had lower risk to achieve the combination point (stroke + IM + CV death) as compared to patients with AF + HFmrEF and AF + HFrEF (12.7% vs. 22% and 25.5%, p < 0.001). Regression logistic analysis revealed that factors such as demographic characteristics, disease severity, and administered treatment had different effects on the risk of unfavorable outcomes depending on ejection fraction group. The clinical features and symptoms were found to be significant risk factors of cardiovascular mortality in AF + HFmrEF, while therapy characteristics were not associated with it.

Conclusions

Each group of patients with different ejection fractions is characterized by its own pattern of factors associated with the development of unfavorable outcomes. The demographic and clinical characteristics of patients with midrange ejection fraction demonstrate that these patients need to be studied as a separate cohort.

Anticoagulation in atrial fibrillation with heart failure

Heart failure (HF) and atrial fibrillation (AF) frequently coexist, and they can beget one another due to similar factors and shared pathophysiology. These pathophysiologic changes promote the episodes of AF, while they in turn predispose to the exacerbation of HF. In this review, we will discuss pathophysiological mechanisms shared by AF and HF. Patients with concomitant HF and AF are at a particularly high risk of thromboembolism, which contribute to even worse symptoms and poorer prognosis. Vitamin K antagonists (VKA) (warfarin) were the traditional medication in AF patients for the prevention of stroke, whereas the advance of novel non-VKA oral anticoagulants (NOACs) (dabigatran, apixaban, rivaroxaban, and edoxaban) is challenging these standard prescriptions. NOACs' potential advantages over warfarin, including fixed dosing regimens, wide therapeutic window, and more sustained anticoagulant response, promote clinicians to consider these novel agents in the first place. However, some data suggested patients with AF and HF may receive different therapeutic response than those with AF alone in anticoagulant treatment. Accordingly, we aim to assess the potential role of oral anticoagulants, especially NOACs, in the management of patients with concomitant AF and HF.

Drug Targets for Heart Failure with Preserved Ejection Fraction: A Mechanistic Approach and Review of Contemporary Clinical Trials

Heart failure with preserved ejection fraction (HFpEF) accounts for over half of prevalent heart failure (HF) worldwide, and prognosis after hospitalization for HFpEF remains poor. Due, at least in part, to the heterogeneous nature of HFpEF, drug development has proved immensely challenging. Currently, there are no universally accepted therapies that alter the clinical course of HFpEF. Despite these challenges, important mechanistic understandings of the disease have revealed that the pathophysiology of HFpEF is distinct from that of HF with reduced ejection fraction and have also highlighted potential new therapeutic targets for HFpEF. Of note, HFpEF is a systemic syndrome affecting multiple organ systems. Depending on the organ systems involved, certain novel therapies offer promise in reducing the morbidity of the HFpEF syndrome. In this review, we aim to discuss novel pharmacotherapies for HFpEF based on its unique pathophysiology and identify key research strategies to further elucidate mechanistic pathways to develop novel therapeutics in the future.

History of Atrial Fibrillation and Trajectory of Decongestion in Acute Heart Failure

OBJECTIVES

This study sought to characterize the course of decongestion among patients hospitalized for acute heart failure (AHF) by history of atrial fibrillation (AF) and/or atrial flutter (AFL).

BACKGROUND

AF/AFL and chronic heart failure (HF) commonly coexist. Little is known regarding the impact of AF/AFL on relief of congestion among patients who develop AHF.

METHODS

We pooled patients from 3 randomized trials of AHF conducted within the Heart Failure Network, the DOSE (Diuretic Optimization Strategies) trial, the ROSE (Renal Optimization Strategies) trial, and the CARRESS-HF (Cardiorenal Rescue Study in Acute Decompensated Heart Failure) trial. The association between history of AF/AFL and in-hospital changes in various metrics of congestion was assessed using covariate-adjusted linear and ordinal logistic regression models.

RESULTS

Of 750 unique patients, 418 (56%) had a history of AF/AFL. Left ventricular ejection fraction was higher (35% vs. 27%, respectively; p < 0.001), and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were nonsignificantly lower at baseline (4,210 pg/ml vs. 5,037 pg/ml, respectively; p = 0.27) in patients with AF/AFL. After adjustment of covariates, history of AF/AFL was associated with less substantial loss of weight (-5.7% vs. -6.5%, respectively; p = 0.02) and decrease in NT-proBNP levels (-18.7% vs. -31.3%, respectively; p = 0.003) by 72 or 96 h. History of AF/AFL was also associated with a blunted increase in global sense of well being at 72 or 96 h (p = 0.04). There was no association between history of AF/AFL and change in orthodema congestion score (p = 0.67) or 60-day composite clinical endpoint (all-cause mortality or any rehospitalization; hazard ratio: 1.21; 95% confidence interval: 0.92 to 1.59; p = 0.17).

CONCLUSIONS

More than half of the patients admitted with AHF had a history of AF/AFL. History of AF/AFL was independently associated with a blunted course of in-hospital decongestion. Further research is required to understand the utility of specific therapies targeting AF/AFL during hospitalization for AHF.

Atrial Fibrillation and Heart Failure: Untangling a Modern Gordian Knot

Heart failure (HF) and atrial fibrillation (AF) share common risk factors and frequently coexist. Both are highly prevalent in our aging population, and mortality associated with the combination is significantly higher than for each alone. An intricate link exists between AF and HF, including interrelated mechanisms and pathophysiology. Asymptomatic left ventricular systolic or diastolic dysfunction can exacerbate or be exacerbated by AF, resulting in HF with reduced ejection fraction or preserved ejection fraction. A number of treatment strategies have improved symptoms, exercise tolerance, and quality of life for patients with HF, but few have resulted in alteration in prognosis. Sinus rhythm, achieved pharmacologically, has not altered important outcomes, including cardiovascular or total mortality in patients with HF. In recent studies, catheter ablation to achieve sinus rhythm seems to have a significant impact on symptoms, heart function, and possibly mortality. Until future studies can confirm or clarify the impact of catheter ablation on outcomes, the field remains cautious but optimistic that better treatment strategies for patients with HF with reduced ejection fraction or preserved ejection fraction are within reach.

Atrial Fibrillation in Heart Failure With Preserved Ejection Fraction: The TOPCAT Trial

OBJECTIVES

This study assessed the relationship between atrial fibrillation (AF) and outcomes in the TOPCAT (Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist) trial, to evaluate whether AF modified the treatment response to spironolactone and whether spironolactone influenced post-randomization AF.

BACKGROUND

AF is common in heart failure with preserved ejection fraction (HFpEF) and likely contributes to increased risk of adverse outcomes.

METHODS

A total 1,765 patients enrolled in TOPCAT trial in North and South America were divided into 3 groups: no known AF, history of AF without AF at enrollment, and AF found on the electrocardiogram (ECG) at enrollment. We assessed outcomes and treatment response to spironolactone in all groups, and the association between post-randomization AF and outcomes in patients free of AF at baseline. The primary outcome of the TOPCAT trial was a composite of cardiovascular mortality, aborted cardiac arrest, or heart failure hospitalization.

RESULTS

A total of 760 patients (43%) had a history of AF (18%) or AF on ECG at enrollment (25%). The highest adjusted risk was associated with AF at enrollment (primary outcome, hazard ratio: 1.34; 95% confidence interval: 1.09 to 1.65; p = 0.006; and an increased early risk of secondary outcomes). Neither history of AF nor AF at enrollment modified the beneficial treatment effect of spironolactone. Post-randomization AF, which occurred in 6.3% of patients, was not influenced by spironolactone treatment, but was associated with an increased early risk of the primary outcome (hazard ratio: 2.32; 95% confidence interval: 1.59 to 3.40; p < 0.0001) and secondary outcomes.

CONCLUSIONS

AF at enrollment was associated with increased cardiovascular risk in HFpEF patients in the TOPCAT study. Post-randomization AF, which was associated with an increased risk of morbidity and mortality, was not influenced by spironolactone. (Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist [TOPCAT]; NCT00094302).

Current Management and Future Directions of Heart Failure With Preserved Ejection Fraction: a Contemporary Review

Heart failure with preserved ejection fraction (HFpEF), a complex and debilitating syndrome, is commonly seen in elderly populations. Exacerbation of HFpEF is among the most common reasons for hospital admission in the USA. The high rate of morbidity and mortality from this condition underscores the fact that HFpEF is heterogeneous, complex, and poorly characterized. Randomized, controlled trials have been very successful at identifying treatments for HF with reduced ejection fraction (HFrEF), but effective treatment options for HFpEF are lacking. Here, we discuss (1) the pathophysiology of HFpEF, (2) a standardized diagnostic and therapeutic approach, (3) a comparison of the management of recent guidelines, and (4) challenges and future directions for HFpEF management. The authors believe that it is important to identify new subtypes of HFpEF to better classify genotypes and phenotypes of HFpEF and to develop novel targeted therapies. It is our hypothesis that big data analytics will shine new light on unique HFpEF phenotypes that better respond to treatment modalities.

Pneumonia as a trigger for atrial fibrillation

In a rural mountainous region on a Friday, a 78-year-old man was seen in his physician’s office for leg edema and diagnosed with new onset atrial fibrillation. He was discharged home to start medications for atrial fibrillation and heart failure. He was hospitalized the next day with septic shock due to pneumococcal pneumonia. The new onset of atrial fibrillation requires a trigger acting on a vulnerable substrate. These triggers include acute conditions such as alcohol intoxication, myocardial infarction and pulmonary embolism. Pneumonia may act as a trigger causing the new onset of atrial fibrillation.

Atrial Fibrillation in Heart Failure: a Therapeutic Challenge of Our Times

Atrial fibrillation (AF) and heart failure (HF) are growing cardiovascular disease epidemics worldwide. There has been an exponential increase in the prevalence of AF and HF correlating with an increased burden of cardiac risk factors and improved survival rates in patients with structural heart disease. AF is associated with adverse prognostic outcomes in HF and is most evident in mild-to-moderate left ventricular (LV) dysfunction where the loss of "atrial kick" translates into poorer quality of life and increased mortality. In the absence of underlying structural heart disease, arrhythmia can independently contribute to the development of cardiomyopathy. Together, these 2 conditions carry a high risk of thromboembolism due to stasis, inflammation and cellular dysfunction. Stroke prevention with oral anticoagulation (OAC) remains a mainstay of treatment. Pharmacologic rate and rhythm control remain limited by variable efficacy, intolerance and adverse reactions. Catheter ablation for AF has resulted in a paradigm shift with evidence indicating superiority over medical therapy. While its therapeutic success is high for paroxysmal AF, it remains suboptimal in persistent AF. A better mechanistic understanding of AF as well as innovations in ablation technology may improve patient outcomes in the future. Refractory cases may benefit from atrioventricular junction ablation and biventricular pacing. The value of risk factor modification, especially with regard to obesity, sleep apnea, hypertension and diabetes, cannot be emphasized enough. Close interdisciplinary collaboration between HF specialists and electrophysiologists is an essential component of good long-term outcomes in this challenging population.