Causes of death in atrial fibrillation: Challenges and opportunities

History of stroke as a predictor of high left atrial fibrosis in patients with persistent atrial fibrillation-insight from the DECAAF II randomized trial

BACKGROUND

There is a strong relationship between left atrial (LA) remodeling and ischemic stroke (IS) risk in atrial fibrillation (AF) patients. The Efficacy of Delayed Enhancement MRI-Guided Ablation vs. Conventional Catheter Ablation of Atrial Fibrillation (DECAAF-II) is the biggest MRI-based, randomized, multicenter clinical trial performed on persistent AF patients. The aim of this study is to evaluate the relationship between history of stroke and atrial fibrosis in the DECAAF II population.

METHODS

Persistent AF patients who underwent Late Gadolinium Enhancement Magnetic Resonance Imaging (LGE-MRI) were included in the study and divided into two different groups: those with a history of stroke and those without. Propensity score matching was performed to adjust for covariates. Atrial fibrosis was compared in both groups. Then, patients were divided into different fibrosis groups, using three different cut-offs of baseline atrial fibrosis: ≥ 15%, ≥ 20%, and ≥ 25%. Univariate logistic regression and adjusted multivariate analysis were performed to assess the effect of clinical characteristics and risk factors on baseline fibrosis.

RESULTS

Eight-hundred forty-three patients were recruited in DECAAF II, of whom 70 (8.3%) had a history of stroke. Patients with history of stroke had a higher prevalence of hypertension (p = 0.043), diabetes (p = 0.014), and hyperlipidemia (p = 0.001). Seventy patients with no history of strokes were matched with patients with history of stroke to adjust for covariates using propensity score analysis. Patients in the stroke group had a significantly higher level of fibrosis than those without (20.2% vs. 8.1%, p = 0.017). Increased age was a significant predictor of all three baseline fibrosis classes (≥ 15%, ≥ 20%, and ≥ 25%). Additionally, history of stroke was found to be a predictor of baseline fibrosis ≥ 25% even after adjusting for other clinical characteristics and risk factors (OR = 1.98 [1.14-3.43], p = 0.01).

CONCLUSIONS

Left atrial fibrosis level greater than 25% correlates with the history of previous stroke episodes in patients with persistent atrial fibrillation.

The hospital frailty risk score effectively predicts adverse outcomes in patients with atrial fibrillation in the intensive care unit

Background

Atrial fibrillation (AF) and frailty are significant global public health problems associated with advancing age. However, the relationship between frailty and older patients with AF in the intensive care unit (ICU) has not been thoroughly investigated. This study aimed to investigate whether the hospital frailty risk score (HFRS) is associated with adverse outcomes in older patients with AF in the ICU.

Methods

This was the first retrospective analysis of older patients with AF admitted to the ICU between 2008 and 2019 at a tertiary academic medical center in Boston. The HFRS was used to measure frailty severity. The outcomes of interest were in-hospital and 30-day mortality and the incidence of sepsis and ischemic stroke.

Results

There were 7,792 participants aged approximately 80 years, almost half (44.9%) of whom were female. Among this group, 2,876 individuals were identified as non-frail, while 4,916 were classified as frail. The analysis revealed a significantly greater incidence of in-hospital (18.8% compared to 7.6%) and 30-day mortality (24.5% versus 12.3%) in the frail group. After accounting for potential confounding factors, a multivariate Cox proportional hazards regression analysis revealed that frail participants had a 1.56-fold greater risk of mortality within 30 days (95% CI = 1.38-1.76, p < 0.001).

Conclusions

Frailty is an independent risk factor for adverse outcomes in older patients with AF admitted to the ICU. Therefore, prioritizing frailty assessment and implementing specific intervention strategies to improve prognostic outcomes are recommended.

Circulatory miR-411-5p as a Novel Prognostic Biomarker for Major Adverse Cardiovascular Events in Patients with Atrial Fibrillation

The risk stratification of patients with atrial fibrillation (AF) for subsequent cardiovascular events could help in guiding prevention strategies. In this study, we aimed at investigating circulating microRNAs as prognostic biomarkers for major adverse cardiovascular events (MACE) in AF patients. We conducted a three-stage nested case-control study within the framework of a prospective registry, including 347 AF patients. First, total small RNA-sequencing was performed in 26 patients (13 cases with MACE) and the differential expression of microRNAs was analyzed. Seven candidate microRNAs with promising results in a subgroup analysis on cardiovascular death were selected and measured via using RT-qPCR in 97 patients (42 cases with cardiovascular death). To further validate our findings and investigate broader clinical applicability, we analyzed the same microRNAs in a subsequent nested case-control study of 102 patients (37 cases with early MACE) by using Cox regression. In the microRNA discovery cohort (n = 26), we detected 184 well-expressed microRNAs in circulation without overt differential expression between the cases and controls. A subgroup analysis on cardiovascular death revealed 26 microRNAs that were differentially expressed at a significance level < 0.05 (three of which with an FDR-adjusted p-value <0.05). We, therefore, proceeded with a nested case-control approach (n = 97) focusing on patients with cardiovascular death and selected, in total, seven microRNAs for further RT-qPCR analysis. One microRNA, miR-411-5p, was significantly associated with cardiovascular death (adjusted HR (95% CI): 1.95 (1.04-3.67)). Further validation (n = 102) in patients who developed early MACE showed similar results (adjusted HR (95% CI) 2.35 (1.17-4.73)). In conclusion, circulating miR-411-5p could be a valuable prognostic biomarker for MACE in AF patients.

Computational Fluid Dynamic Model of Left Atrium to Analyze Hemodynamic Manifestation during Atrial Fibrillation

In this paper, we present a computational fluid dynamic (CFD) model of left atrium (LA) to analyze the manifestation and progression of atrial fibrillation (AF) in terms of hemodynamic metrics. We propose a coupled lumped-CFD (0d-3d) pipeline to model and predict the pulsatile flow and pressure fields of three-dimensional cardiac chamber under the influence of sinus rhythm, high frequency AF (HF-AF) and LA remodeled AF, considering the interactions between the heart and the arterial system through a separately modeled 0d lumped hemodynamic cardiac model. A novel rhythm generator is modeled to generate modulated cardiac chamber compliance and decoupled auricular and ventricular contraction rate to synthesize variation in sinus rhythm and subsequent AF generation. CFD simulation were solved using subject specific CT scan. Systemic and pulmonary flow and pressure along with metrics related to wall shear stress in LA were derived. Left ventricular (LV) hemodynamic parameters associated with global cardio vascular evaluation like ejection fraction, stroke volume, cardiac output, etc. were also generated for all the rhythmic disturbance under consideration. The proposed 0d-3d coupled hemodynamic model of the LA can provide useful insights on the dynamics of AF manifestation and predict vulnerable regions in the cardiac chambers as well as arterial vasculature for probable thrombogenic plaque formation that leads to stroke and infraction, leading to heart failure.

Impact of renin-angiotensin-aldosterone-system inhibitor drugs on mortality in patients with atrial fibrillation and hypertension

BACKGROUND

Renin-angiotensin-aldosterone-system inhibitors markedly play an active role in the primary prevention of atrial fibrillation (AF), but the impact of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) on the mortality of patients with AF remains unclear. This study aimed to examine the relationship between treatment with ACEIs or ARBs and mortality in emergency department (ED) patients with AF and hypertension.

METHODS

This multicenter study enrolled 2016 ED patients from September 2008 to April 2011; 1110 patients with AF and hypertension were analyzed. Patients were grouped according to whether they were treated with ACEI/ARB or not and completed a 1-year follow-up to evaluate outcomes including all-cause death, cardiovascular death, stroke, and major adverse events (MAEs).

RESULTS

Among the 1110 patients with AF and hypertension, 574 (51.7%) received ACEI/ARB treatment. During the 1-year follow-up, 169 all-cause deaths (15.2%) and 100 cardiovascular deaths (9.0%) occurred, while 98 strokes (8.8%) and 255 MAEs (23.0%) occurred. According to the multivariate Cox regression analysis, ACEI/ARB therapy was significantly associated with a reduced risk of all-cause death (HR, 0.605; 95% CI 0.431-0.849; P = 0.004). Moreover, ACEI/ARB therapy was independently associated with a reduced risk of cardiovascular death (HR 0.585; 95% CI 0.372-0.921; P = 0.020) and MAEs (HR 0.651, 95% CI 0.496-0.855, P = 0.002) after adjusting for other risk factors.

CONCLUSIONS

Our results revealed that ACEI/ARB therapy was independently associated with a reduced risk of all-cause death, cardiovascular death, and MAEs in ED patients with AF and hypertension. These results provide evidence for a tertiary preventive treatment for patients with AF and hypertension.

Comparisons of HATCH, HAVOC and CHA2DS2-VASc scores for all-cause mortality prediction in atrial fibrillation: a real-world evidence study

OBJECTIVE

This study focused on the predictive ability of the 3 scores for all-cause mortality in 6444 patients with atrial fibrillation (AF).

METHODS

To assess the predictive accuracy of risk of death modelled by HATCH, HAVOC and CHA2DS2-VASc scores, the area under the curve of receiver operating characteristics (AUROC) was applied.

RESULTS

Over follow-up time, the cumulative incidence of death was clearly associated with the three scores (log-rank test, p<0.001). The AUROC for the HATCH (0.6618) was significantly higher than HAVOC Score (0.5733) and CHA2DS2-VAScs Score (0.6423).

CONCLUSIONS

HATCH score has better ability in predicting mortality in comparison to other two scores in patients with AF.

Impact of atrial fibrillation on inflammatory bowel disease hospitalizations-a nationwide retrospective study

Systemic inflammation seen in inflammatory bowel disease (IBD) may cause electrophysiological changes in the atria leading to atrial fibrillation (AF). We analyzed data from the National Inpatient Sample for 2018 to identify all adult hospitalizations with a primary diagnosis of IBD, which were further divided based on the presence or absence of AF. The primary outcome was inpatient mortality while the secondary outcomes included inpatient complications, mean length of stay, and mean total hospital charge. We identified 92,055 IBD hospitalizations, of which 3900 (4.2%) had AF and 88,155 (95.8%) served as controls. IBD hospitalizations with AF were older (70.9 vs. 45.0 years, P < 0.001) and had a higher association with comorbidities compared to the non-AF cohort. Furthermore, the AF cohort had significantly higher adjusted odds of inpatient mortality (2.05% vs. 0.24%; adjusted odds ratio 2.07; 95% confidence interval [CI] 1.09-3.90; P = 0.025), longer length of stay (6.5 vs. 4.9 days; incidence rate ratio 1.23; 95% CI 1.14-1.33; P < 0.001), and higher total hospital charge ($14,587 vs. $11,475; incidence rate ratio 1.26; 95% CI 1.15-1.38; P < 0.001). Additionally, complications such as acute respiratory failure, pulmonary embolism, and necessity of blood product transfusion were more common for IBD hospitalizations with AF than those without.

Effects of Ageing on Aortic Circulation During Atrial Fibrillation; a Numerical Study on Different Aortic Morphologies

Atrial fibrillation (AF) can alter intra-cardiac flow and cardiac output that subsequently affects aortic flow circulation. These changes may become more significant where they occur concomitantly with ageing. Aortic ageing is accompanied with morphological changes such as dilation, lengthening, and arch unfolding. While the recognition of AF mechanism has been the subject of numerous studies, less focus has been devoted to the aortic circulation during the AF and there is a lack of such investigation at different ages. The current work aims to address the present gap. First, we analyse aortic flow distribution in three configurations, which attribute to young, middle and old people, using geometries constructed via clinical data. We then introduce two transient inlet flow conditions representative of key AF-associated defects. Results demonstrate that both AF and ageing negatively affect flow circulation. The main consequence of concomitant occurrence is enhancement of endothelial cell activation potential (ECAP) throughout the vascular domain, mainly at aortic arch and descending thoracic aorta, which is consistent with some clinical observations. The outcome of the current study suggests that AF exacerbates the vascular defects occurred due to the ageing, which increases the possibility of cardiovascular diseases per se.

Atrial fibrillation in the elderly: a risk factor beyond stroke

Atrial fibrillation (AF) represents the most common arrhythmia worldwide and its prevalence exponentially increases with age. It is related to increased risk of ischemic stroke or systemic embolism, which determines a significant burden of morbidity and mortality, as widely documented in the literature. AF also constitutes a risk factor for other less investigated conditions, such as heart failure, pulmonary embolism, impairment in physical performance, reduced quality of life, development of disability, mood disorders and cognitive impairment up to dementia. In the elderly population, the management of AF and its complications is particularly complex due to the heterogeneity of the ageing process, the lack of specific evidence-based recommendations, as well as the high grade of comorbidity and disability characterizing the over 65 years aged people. In the present review, we aim to summarize the pieces of the most updated evidence on AF complications beyond stoke, mainly focusing on the elderly population.

Numerical Study of Atrial Fibrillation Effects on Flow Distribution in Aortic Circulation

Atrial fibrillation (AF) is the most common type of arrhythmia, which undermines cardiac function. Atrial fibrillation is a multi-facet malady and it may occur as a result of other diseases or it may trigger other problems. One of the main complications of AF is stroke due to the possibility of clot formation inside the atrium. However, the possibility of stroke occurrence due to the AF and the location from which an embolus dispatches are subject of debate. Another hypothesis about the embolus formation during AF is thrombus formation in aorta and carotid arteries, embolus detachment and its movement. To investigate the possibility of the latter postulation, the current work suggests a parametric study to quantify the sensitivity of aortic flow to four common AF traits including lack of atrial kick, atrial remodelling, left ventricle systolic dysfunction, and high frequency fibrillation. The simulation was carried out by coupling several in-house codes and ANSYS-CFX module. The results reveal that AF traits lower flow rate at left ventricular outflow tract, which in general lowers blood perfusion to systemic, cerebral and coronary circulations. Consequently, it leads to endothelial cell activation potential (ECAP) increase and variation of flow structure that both suggest predisposed areas to atherogenesis and thrombus formation in different regions in ascending aorta, aortic arch and descending thoracic aorta.

Management of atrial fibrillation-flutter: uptodate guideline paper on the current evidence

The term 'flutter' and 'fibrillation' were first coined to differentiate the differences between fast, regular contractions in Atrial Flutter (AFLUT) with irregular, vermiform contractions of Atrial Fibrillation (AFIB). Management of these two diseases has been a challenge for physicians. Rate control (along with rhythm control) is the first line of management for symptomatic AFIB/AFLUT with Rapid Ventricular Rate (RVR). In some situations, atrial rhythms may not be well controlled by these anti-arrhythmic drugs, making cardioversion to sinus rhythm necessary. Anti-coagulation therapy in both the disease population is essential. Catheter ablation is an effective treatment option in certain patients that have AFIB/AFLUT refractory to medical management. Newer techniques like left atrial appendage (LAA) has been developed and is a highly attractive concept for the future in the management of AFIB/AFLUT. Newer novel drugs targeting specific ion channels are approaching the stages of clinical investigation. However, while advances in technologies have helped elucidate many aspects of these diseases, many mysteries still remain. This literature review serves as one of the guideline papers for current up-to-date management on both AFIB and AFLUT.

When are the cardiovascular and stroke risks too high? Pharmacotherapy for stroke prophylaxis

INTRODUCTION

Stroke is a significant source of morbidity and mortality in developed countries. Cardioembolic strokes represent approximately 15-30% of all ischemic strokes. They are frequently related to atrial fibrillation (AF) and have a worse prognosis and high recurrence rates when compared to other causes (e.g. atherosclerosis).

AREAS COVERED

This review includes a summary of general and specific scores to assess cardiovascular and stroke risks, with a focus on specific scores available in AF. Recommendations for antithrombotic therapy are also reviewed.

EXPERT OPINION

Several scores are available for the evaluation of stroke risk. They are useful to identify the risk factors that trigger the need for medical interventions. Integrated risk scores with visual interfaces showing the risk of events, with and without the proposed interventions, can aid decision-making. The risk of stroke can definitely be considered too high in those patients with a history of stroke/transient ischemic attack, who need antiplatelet therapy (after a non-cardioembolic stroke) or anticoagulant therapy (after a cardioembolic stroke). For primary prevention of stroke, antiplatelet therapy is not usually recommended, while anticoagulation should be considered if the patient has concomitant AF and at least one additional risk factor unrelated to sex.