Bidirectional association between atrial fibrillation and congestive heart failure in the elderly

Atrial fibrillation and risk of adverse outcomes in heart failure with reduced, mildly reduced, and preserved ejection fraction: A systematic review and meta-analysis

INTRODUCTION

Heart failure (HF) and atrial fibrillation (AF) frequently co-exist. Contemporary classification of HF categorizes it into HF with reduced ejection fraction (HFrEF), HF with mildly reduced ejection fraction (HFmrEF), and HF with preserved ejection fraction (HFpEF). Aggregate data comparing the risk profile of AF between these three HF categories are lacking.

METHODS

We conducted a systematic review and meta-analysis aimed at determining any significant differences in AF-associated all-cause mortality, HF hospitalizations, cardiovascular mortality (CV), and stroke between HFrEF, HFmrEF, and HFpEF. A systematic search of PubMed, EMBASE, and Cochrane Library databases until February 28, 2023. Data were combined using DerSimonian-Laird random effects model.

RESULTS

A total of 22 studies comprising 248 323 patients were retained: HFrEF 123 331 (49.7%), HFmrEF 40 995 (16.5%), and HFpEF 83 997 (33.8%). Pooled baseline AF prevalence was 36% total population, 30% HFrEF, 36% HFmrEF, and 42% HFpEF. AF was associated with a higher risk of all-cause mortality in the total population with pooled hazard ratio (HR) = 1.13 (95% confidence interval [CI] = 1.07-1.21), HFmrEF (HR = 1.25, 95% CI = 1.05-1.50) and HFpEF (HR = 1.16, 95% CI = 1.09-1.24), but not HFrEF (HR = 1.03, 95% CI = 0.93-1.14). AF was associated with a higher risk of HF hospitalizations in the total population (HR = 1.29, 95% CI = 1.14-1.46), HFmrEF (HR = 1.64, 95% CI = 1.20-2.24), and HFpEF (HR = 1.46, 95% CI = 1.17-1.83), but not HFrEF (HR = 1.01, 95% CI = 0.87-1.18). AF was only associated with CV in the HFpEF subcategory but was associated with stroke in all three HF subtypes.

CONCLUSIONS

AF appears to be associated with a higher risk of all-cause mortality and HF hospitalization in HFmrEF and HFpEF. With these findings, the paucity of data and treatment guidelines on AF in the HFmrEF subgroup becomes even more significant and warrant further investigations.

Residual Stroke Risk in Atrial Fibrillation

AF contributes to increased stroke risk via various mechanisms, including deranged blood constituents, vessel wall abnormalities and abnormal blood flow. This excess risk is frequently managed with anticoagulation therapy, aimed at preventing thromboembolic complications. Yet, a significant proportion of patients with AF remain at high residual stroke risk despite receiving appropriate dose-adjusted anticoagulation. This article explores the residual stroke risk in AF and potential therapeutic options for these patients.

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.

Clinical risk scores for the prediction of incident Atrial Fibrillation: A modernized review

Atrial fibrillation (AF) is considered the most common sustained arrhythmia. Major cardiovascular risk factors that have been identified to initiate and perpetuate AF include age, sex, arterial hypertension, heart failure, valvular heart disease and diabetes mellitus. In the literature, several studies aimed to formulate easily - applied and accurate risk stratification scores, based on antecedent cardiovascular events, comorbidities and biomarkers for the prediction of new-onset AF. The present narrative review addresses the most universally accepted and efficient clinical scores, with an extended applicability in different populations and ages, particularly scores derived from the Framingham Heart Study, the Atherosclerosis Risk in Communities, the Malmo Diet and Cancer Study, as well as the CHARGE-AF, the CHADS2, CHA₂DS₂-VASc, HATCH and CH2EST scores. Identification of incident AF can be challenging, thus dictating for utilization of validated clinical instruments in everyday clinical practice.

Effect of Intensive Blood Pressure Lowering on the Risk of Atrial Fibrillation

It remains uncertain whether intensive control of blood pressure (BP) results in a lower risk of atrial fibrillation (AF) in patients with hypertension. Using data from SPRINT (Systolic Blood Pressure Intervention Trial), which enrolled participants with hypertension at increased risk of cardiovascular disease, we examined whether intensive BP lowering (target systolic BP [SBP] <120 mm Hg), compared with standard BP lowering (target SBP<140 mm Hg), results in a lower risk of AF. This analysis included 8022 participants (4003 randomized to the intensive arm and 4019 to standard BP arm) who were free of AF at the time of enrollment and with available baseline and follow-up electrocardiographic data. AF was ascertained from standard 12-lead electrocardiograms recorded at biannual study examinations and an exit visit. During up to 5.2 years of follow-up and a total of 28 322 person-years, 206 incident AF cases occurred; 88 in the intensive BP-lowering arm and 118 in the standard BP-lowering arm. Intensive BP lowering was associated with a 26% lower risk of developing new AF (hazard ratio, 0.74 [95% CI, 0.56-0.98]; P=0.037). This effect was consistent among prespecified subgroups of SPRINT participants stratified by age, sex, race, SBP tertiles, prior cardiovascular disease, and prior chronic kidney disease when interactions between treatment effect and these subgroups were assessed using Hommel adjusted P values. In conclusion, intensive treatment to a target of SBP <120 mm Hg in patients with hypertension at high risk of cardiovascular disease has the potential to reduce the risk of AF. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT01206062.

Increased plasma microfibrillar-associated protein 4 is associated with atrial fibrillation and more advanced left atrial remodelling

INTRODUCTION

This study aimed to evaluate the relationship of plasma microfibrillar-associated protein 4 (MFAP4) to atrial fibrillation (AF) and atrial structural remodelling.

MATERIAL AND METHODS

Plasma MFAP4 levels were measured in 92 patients with AF (61 paroxysmal AF (PAF) patients and 31 persistent AF (PersAF) patients) and 71 control subjects without AF. Linear and logistic multivariate regression analyses were performed to determine the potential value of MFAP4 for predicting the incidence of AF and left atrial size. Then, plasma and atrial protein levels of MFAP4 and its association with atrial fibrosis ratio were analysed in an atrial-specific fibrosis rat model.

RESULTS

There were significant differences in MFAP4 levels based on clinical group, with a gradient from control (1.71 ±0.53 ng/ml) to PAF (1.98 ±0.53 ng/ml) to PersAF (2.09 ±0.76 ng/ml) (p < 0.01). With multivariate analyses, plasma MFAP4 was found to be an independent determinant of left atrial diameter in AF patients. In atrial fibrosis rats, both plasma MFAP4 and atrial MFAP4 protein levels increased in atrial fibrosis rats and positively correlated with atrial fibrosis severity.

CONCLUSIONS

Plasma MFAP4 was increased in patients with AF and was highest in those with PersAF; both plasma MFAP4 and atrial MFAP4 protein expression were directly associated with the extent of LA structural remodelling.

Mortality in heart failure with atrial fibrillation: Role of digoxin and diuretics

BACKGROUND

The impact of atrial fibrillation (AF) on mortality of patients with heart failure (HF) has been established. Nevertheless, the effect of some factors in mortality, such as digoxin or diuretic use, remains controversial. This study aims at assessing mortality in community-dwelling patients with stable HF related to AF and determines the relation of these drugs with prognosis.

MATERIALS AND METHODS

Community-based cohort study of HF patients diagnosed between January 2010 and December 2014 attended at any one of the 279 primary healthcare centres of the Catalan Institute of Health (Spain). Follow-up ended on December 31, 2015, and the main outcome was mortality for all causes. The effect of clinical and demographic characteristics on survival was assessed by Cox proportional hazards model.

RESULTS

A total of 13 334 HF patients were included. Mean age was 78.7 years (SD 10.1), and 36.8% had AF. Mean follow-up was 26.9 months (SD 14.0). At the end of the study, 25.8% patients had died, and mortality was higher when AF was present (28.8% vs 24.1%, P < 0.001, respectively). Multivariate model confirmed the higher risk of death for AF patients (HR 1.10 95%, CI 1.02-1.19). Digoxin and diuretics were not associated with higher mortality in AF patients (HR 1.04 95% CI 0.92-1.18 and HR 1.04 95% CI 0.85-1.26, respectively).

CONCLUSIONS

An excess of mortality in HF patients with AF was found in a large retrospective community-based cohort. Digoxin and diuretics did not affect mortality in HF patients with AF.

The association of QT interval components with atrial fibrillation

BACKGROUND

Although abnormalities of the QT interval are associated with atrial fibrillation (AF), it is unclear whether ventricular depolarization (QRS duration) or repolarization (JT interval) is a more important marker of AF risk.

METHODS

This analysis included 4,181 (95% white; 59% women) participants from the Cardiovascular Health Study (CHS) who were free of baseline AF and major intraventricular delay. A linear scale was used to compute heart rate adjusted QT (QTa), QRS (QRS_a ), and JT (JT_a ) intervals. Prolonged QT_a , QRS_a , and JT_a were defined by values greater than the sex-specific 95th percentile for each measurement. AF events were ascertained during the annual study electrocardiograms and from hospitalization discharge data. Cox regression was used to compute hazard ratios (HR) and 95% confidence intervals (CI) for the associations of prolonged QT_a , QRS_a , and JT_a with AF, separately.

RESULTS

Over a mean follow-up of 12.1 years, a total of 1,236 (30%) AF events were detected. An increased risk of AF (HR = 1.50. 95% CI = 1.20, 1.88) was observed with prolonged QT_a . When we examined the association between individual components of the QT_a interval and AF, the risk of AF was limited to prolonged JT_a (HR = 1.31, 95% CI = 1.04, 1.65) and not prolonged QRS_a (HR = 1.00, 95% CI = 0.77, 1.30). Similar results were obtained per 1-SD increase in QT_a (HR = 1.07, 95% CI = 1.01, 1.13), QRS_a (HR = 0.99, 95% CI = 0.94, 1.06), and JT_a (HR = 1.07, 95% CI = 1.01, 1.13).

CONCLUSIONS

The JT interval is a more important marker of AF risk in the QT interval among persons who do not have ventricular conduction delays.

Atrial Fibrillation and Cardiovascular Outcomes in the Elderly

BACKGROUND

Prior studies have not examined which cardiovascular outcomes most frequently develop in participants with atrial fibrillation (AF) from population-based cohorts of the elderly.

METHODS

This analysis included 4,304 (85% white; 61% women) participants from the Cardiovascular Health Study who were free of baseline cardiovascular disease. AF cases were identified at baseline and as time-updated events during follow-up. Kaplan-Meier estimates were used to compute the 1-, 5-, 10-, and 15-year cumulative incidence rates of the following outcomes: coronary heart disease (CHD), myocardial infarction (MI), heart failure, and ischemic stroke. Cox regression was used to compute hazard ratios (HR) and 95% confidence intervals (CI) for the association between AF and each outcome.

RESULTS

For all time periods, the cumulative incidence estimates of CHD, MI, heart failure, and ischemic stroke were higher for those with AF compared with those without AF. Heart failure was the most frequent outcome in those with AF, while CHD events were the most frequently detected outcome in participants without AF. Compared with persons who did not have AF, the risk of heart failure was higher in those with AF (HR = 3.18, 95% CI = 2.78-3.64), and the magnitude of this association was greater than the other outcomes of interest (CHD: HR = 1.76, 95% CI = 1.54-2.03; MI: 1.40, 95% CI = 1.14-1.71; ischemic stroke: HR = 1.98, 95% CI = 1.63-2.39).

CONCLUSIONS

AF is associated with several adverse cardiovascular outcomes and heart failure is the most frequently detected event. Potentially, risk factor modification strategies for the primary prevention of heart failure will reduce the morbidity and mortality associated with AF.

Biomarkers and the prediction of atrial fibrillation: state of the art

Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice, and it places a substantial burden on the health care system. Despite improvements in our understanding of AF pathophysiology, we have yet to develop targeted preventive therapies. Recently, numerous biological markers have been identified to aid in the prediction of future AF events. Subclinical markers of atrial stress, inflammation, endothelial dysfunction, kidney dysfunction, and atherosclerosis have been linked to AF. The connection between these markers and AF is the identification of subclinical states in which AF propagation is likely to occur, as these conditions are associated with abnormal atrial remodeling and fibrosis. Additionally, several risk scores have been developed to aid in the identification of at-risk patients. The practicing clinician should be aware of these subclinical markers, as several of these markers improve the predictive abilities of current AF risk scores. Knowledge of these subclinical markers also provides clinicians with a better understanding of AF risk factors, and the opportunity to reduce the occurrence of AF by incorporating well-known cardiovascular disease risk factor modification strategies. In this review, we highlight several novel biological markers that have improved our understanding of AF pathophysiology and appraise the utility of these markers to improve our ability to predict future AF events.