The CABANA (Catheter Ablation Versus Antiarrhythmic Drug Therapy for Atrial Fibrillation) trial randomized 2,204 patients with atrial fibrillation (AF) to catheter ablation or drug therapy. Analysis ...by intention-to-treat showed a nonsignificant 14% relative reduction in the primary outcome of death, disabling stroke, serious bleeding, or cardiac arrest.
The purpose of this study was to assess recurrence of AF in the CABANA trial.
The authors prospectively studied CABANA patients using a proprietary electrocardiogram recording monitor for symptom-activated and 24-h AF auto detection. The AF recurrence endpoint was any post–90-day blanking atrial tachyarrhythmias lasting 30 s or longer. Biannual 96-h Holter monitoring was used to assess AF burden. Patients who used the CABANA monitors and provided 90-day post-blanking recordings qualified for this analysis (n = 1,240; 56% of CABANA population). Treatment comparisons were performed using a modified intention-to-treat approach.
Median age of the 1,240 patients was 68 years, 34.4% were women, and AF was paroxysmal in 43.0%. Over 60 months of follow-up, first recurrence of any symptomatic or asymptomatic AF (hazard ratio: 0.52; 95% confidence interval: 0.45 to 0.60; p < 0.001) or first symptomatic-only AF (hazard ratio: 0.49; 95% confidence interval: 0.39 to 0.61; p < 0.001) were both significantly reduced in the catheter ablation group. Baseline Holter AF burden in both treatment groups was 48%. At 12 months, AF burden in ablation patients averaged 6.3%, and in drug-therapy patients, 14.4%. AF burden was significantly less in catheter ablation compared with drug-therapy patients across the 5-year follow-up (p < 0.001). These findings were not sensitive to the baseline pattern of AF.
Catheter ablation was effective in reducing recurrence of any AF by 48% and symptomatic AF by 51% compared with drug therapy over 5 years of follow-up. Furthermore, AF burden was also significantly reduced in catheter ablation patients, regardless of their baseline AF type. (Catheter Ablation vs Anti-arrhythmic Drug Therapy for Atrial Fibrillation Trial CABANA; NCT00911508)
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Mortality and morbidity are higher among patients with atrial fibrillation and heart failure than among those with heart failure alone. Catheter ablation for atrial fibrillation has been proposed as ...a means of improving outcomes among patients with heart failure who are otherwise receiving appropriate treatment.
We randomly assigned patients with symptomatic paroxysmal or persistent atrial fibrillation who did not have a response to antiarrhythmic drugs, had unacceptable side effects, or were unwilling to take these drugs to undergo either catheter ablation (179 patients) or medical therapy (rate or rhythm control) (184 patients) for atrial fibrillation in addition to guidelines-based therapy for heart failure. All the patients had New York Heart Association class II, III, or IV heart failure, a left ventricular ejection fraction of 35% or less, and an implanted defibrillator. The primary end point was a composite of death from any cause or hospitalization for worsening heart failure.
After a median follow-up of 37.8 months, the primary composite end point occurred in significantly fewer patients in the ablation group than in the medical-therapy group (51 patients 28.5% vs. 82 patients 44.6%; hazard ratio, 0.62; 95% confidence interval CI, 0.43 to 0.87; P=0.007). Significantly fewer patients in the ablation group died from any cause (24 13.4% vs. 46 25.0%; hazard ratio, 0.53; 95% CI, 0.32 to 0.86; P=0.01), were hospitalized for worsening heart failure (37 20.7% vs. 66 35.9%; hazard ratio, 0.56; 95% CI, 0.37 to 0.83; P=0.004), or died from cardiovascular causes (20 11.2% vs. 41 22.3%; hazard ratio, 0.49; 95% CI, 0.29 to 0.84; P=0.009).
Catheter ablation for atrial fibrillation in patients with heart failure was associated with a significantly lower rate of a composite end point of death from any cause or hospitalization for worsening heart failure than was medical therapy. (Funded by Biotronik; CASTLE-AF ClinicalTrials.gov number, NCT00643188 .).
The past 3 decades have been characterized by an exponential growth in knowledge and advances in the clinical treatment of atrial fibrillation (AF). It is now known that AF genesis requires a ...vulnerable atrial substrate and that the formation and composition of this substrate may vary depending on comorbid conditions, genetics, sex, and other factors. Population-based studies have identified numerous factors that modify the atrial substrate and increase AF susceptibility. To date, genetic studies have reported 17 independent signals for AF at 14 genomic regions. Studies have established that advanced age, male sex, and European ancestry are prominent AF risk factors. Other modifiable risk factors include sedentary lifestyle, smoking, obesity, diabetes mellitus, obstructive sleep apnea, and elevated blood pressure predispose to AF, and each factor has been shown to induce structural and electric remodeling of the atria. Both heart failure and myocardial infarction increase risk of AF and vice versa creating a feed-forward loop that increases mortality. Other cardiovascular outcomes attributed to AF, including stroke and thromboembolism, are well established, and epidemiology studies have championed therapeutics that mitigate these adverse outcomes. However, the role of anticoagulation for preventing dementia attributed to AF is less established. Our review is a comprehensive examination of the epidemiological data associating unmodifiable and modifiable risk factors for AF and of the pathophysiological evidence supporting the mechanistic link between each risk factor and AF genesis. Our review also critically examines the epidemiological data on clinical outcomes attributed to AF and summarizes current evidence linking each outcome with AF.
Silent or subclinical asymptomatic atrial fibrillation (SAF) has currently gained wide interest in the epidemiologic, neurologic, and cardiovascular communities. It is well known that the ...electrophysiological and mechanical effects of symptomatic and silent atrial fibrillation (AF) are the same. It is probable that because “AF begets AF,” progression from paroxysmal to persistent or permanent AF might be more rapid in patients with long‐term unrecognized and untreated SAF, because no treatment is sought by or provided to such patients. Moreover, SAF is common and has significant clinical implications. The clinical consequences of SAF, which include emboli (silent or symptomatic), heart failure, and early mortality, are of paramount importance. Consequently, SAF should be considered in estimating the prevalence of the disease and its impact on morbidity, mortality, and quality of life. Several diagnostic methods of arrhythmia detection utilizing the surface electrocardiogram (ECG), subcutaneous ECG, or intracardiac devices have been utilized to seek meaningful arrhythmic markers of SAF. Whereas a wide range of clinical risk factors of SAF have been validated in the literature, there is an ongoing search for those arrhythmic risk factors that precisely identify and prognosticate outcome events in diverse populations at risk of SAF. Modern diagnostic modalities for the identification of SAF exist, but should be further explored, validated, and tailored to each patient needs. The scientific community should undertake the clinical challenge of identifying and treating SAF.
Atrial fibrillation (AF) is a highly prevalent arrhythmia, with substantial associated morbidity and mortality. There have been significant management advances over the past 2 decades, but the burden ...of the disease continues to increase and there is certainly plenty of room for improvement in treatment options. A potential key to therapeutic innovation is a better understanding of underlying fundamental mechanisms. This article reviews recent advances in understanding the molecular basis for AF, with a particular emphasis on relating these new insights to opportunities for clinical translation. We first review the evidence relating basic electrophysiological mechanisms to the characteristics of clinical AF. We then discuss the molecular control of factors leading to some of the principal determinants, including abnormalities in impulse conduction (such as tissue fibrosis and other extra-cardiomyocyte alterations, connexin dysregulation and Na
-channel dysfunction), electrical refractoriness, and impulse generation. We then consider the molecular drivers of AF progression, including a range of Ca
-dependent intracellular processes, microRNA changes, and inflammatory signaling. The concept of key interactome-related nodal points is then evaluated, dealing with systems like those associated with CaMKII (Ca
/calmodulin-dependent protein kinase-II), NLRP3 (NACHT, LRR, and PYD domains-containing protein-3), and transcription-factors like TBX5 and PitX2c. We conclude with a critical discussion of therapeutic implications, knowledge gaps and future directions, dealing with such aspects as drug repurposing, biologicals, multispecific drugs, the targeting of cardiomyocyte inflammatory signaling and potential considerations in intervening at the level of interactomes and gene-regulation. The area of molecular intervention for AF management presents exciting new opportunities, along with substantial challenges.
Percutaneous left atrial appendage closure (LAAC) is noninferior to vitamin K antagonists (VKAs) for preventing atrial fibrillation (AF)–related stroke. However, direct oral anticoagulants (DOACs) ...have an improved safety profile over VKAs, and their effect on cardiovascular and neurological outcomes relative to LAAC is unknown.
This study sought to compare DOACs with LAAC in high-risk patients with AF.
Left Atrial Appendage Closure vs. Novel Anticoagulation Agents in Atrial Fibrillation (PRAGUE-17) was a multicenter, randomized, noninferiority trial comparing LAAC with DOACs. Patients were eligible to be enrolled if they had nonvalvular AF; were indicated for oral anticoagulation (OAC); and had a history of bleeding requiring intervention or hospitalization, a history of a cardioembolic event while taking an OAC, and/or a CHA2DS2-VASc of ≥3 and HAS-BLED of >2. Patients were randomized to receive LAAC or DOAC. The primary composite outcome was stroke, transient ischemic attack, systemic embolism, cardiovascular death, major or nonmajor clinically relevant bleeding, or procedure-/device-related complications. The primary analysis was by modified intention to treat.
A high-risk patient cohort (CHA2DS2-VASc: 4.7 ± 1.5) was randomized to receive LAAC (n = 201) or DOAC (n = 201). LAAC was successful in 181 of 201 (90.0%) patients. In the DOAC group, apixaban was most frequently used (192 of 201; 95.5%). At a median 19.9 months of follow-up, the annual rates of the primary outcome were 10.99% with LAAC and 13.42% with DOAC (subdistribution hazard ratio sHR: 0.84; 95% confidence interval CI: 0.53 to 1.31; p = 0.44; p = 0.004 for noninferiority). There were no differences between groups for the components of the composite endpoint: all-stroke/TIA (sHR: 1.00; 95% CI: 0.40 to 2.51), clinically significant bleeding (sHR: 0.81; 95% CI: 0.44 to 1.52), and cardiovascular death (sHR: 0.75; 95% CI: 0.34 to 1.62). Major LAAC-related complications occurred in 9 (4.5%) patients.
Among patients at high risk for stroke and increased risk of bleeding, LAAC was noninferior to DOAC in preventing major AF-related cardiovascular, neurological, and bleeding events. (Left Atrial Appendage Closure vs. Novel Anticoagulation Agents in Atrial Fibrillation PRAGUE-17; NCT02426944)
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Atrial fibrillation (AF) is the most common arrhythmia (estimated lifetime risk, 22%-26%). The aim of this article is to review the clinical epidemiological features of AF and to relate them to ...underlying mechanisms. Long-established risk factors for AF include aging, male sex, hypertension, valve disease, left ventricular dysfunction, obesity, and alcohol consumption. Emerging risk factors include prehypertension, increased pulse pressure, obstructive sleep apnea, high-level physical training, diastolic dysfunction, predisposing gene variants, hypertrophic cardiomyopathy, and congenital heart disease. Potential risk factors are coronary artery disease, kidney disease, systemic inflammation, pericardial fat, and tobacco use. AF has substantial population health consequences, including impaired quality of life, increased hospitalization rates, stroke occurrence, and increased medical costs. The pathophysiology of AF centers around 4 general types of disturbances that promote ectopic firing and reentrant mechanisms, and include the following: (1) ion channel dysfunction, (2) Ca(2+)-handling abnormalities, (3) structural remodeling, and (4) autonomic neural dysregulation. Aging, hypertension, valve disease, heart failure, myocardial infarction, obesity, smoking, diabetes mellitus, thyroid dysfunction, and endurance exercise training all cause structural remodeling. Heart failure and prior atrial infarction also cause Ca(2+)-handling abnormalities that lead to focal ectopic firing via delayed afterdepolarizations/triggered activity. Neural dysregulation is central to atrial arrhythmogenesis associated with endurance exercise training and occlusive coronary artery disease. Monogenic causes of AF typically promote the arrhythmia via ion channel dysfunction, but the mechanisms of the more common polygenic risk factors are still poorly understood and under intense investigation. Better recognition of the clinical epidemiology of AF, as well as an improved appreciation of the underlying mechanisms, is needed to develop improved methods for AF prevention and management.
Mechanisms of atrial fibrillation Wijesurendra, Rohan S; Casadei, Barbara
Heart (British Cardiac Society),
12/2019, Letnik:
105, Številka:
24
Journal Article
Recenzirano
Odprti dostop
Atrial fibrillation (AF) is the most common sustained arrhythmia, currently affecting over 33 million individuals worldwide, and its prevalence is expected to more than double over the next 40 years. ...AF is associated with a twofold increase in premature mortality, and important major adverse cardiovascular events such as heart failure, severe stroke and myocardial infarction. Significant effort has been made over a number of years to define the underlying cellular, molecular and electrophysiological changes that predispose to the induction and maintenance of AF in patients. Progress has been limited by the realisation that AF is a complex arrhythmia that can be the end result of various different pathophysiological processes, with significant heterogeneity between individual patients (and between species). In this focused Review article, we aim to succinctly summarise for the non-specialist the current state of knowledge regarding the mechanisms of AF. We address all aspects of pathophysiology, including the basic electrophysiological and structural changes within the left atrium, the genetics of AF and the links to comorbidities and wider systemic and metabolic perturbations that may be upstream contributors to development of AF. Finally, we outline the translational implications for current and future rhythm control strategies in patients with AF.
Atrial Fibrillation in the ICU Bosch, Nicholas A.; Cimini, Jonathan; Walkey, Allan J.
Chest,
12/2018, Letnik:
154, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Atrial fibrillation (AF) is the most common arrhythmia encountered in the ICU. Preexisting AF is highly prevalent among older patients with chronic conditions who are at risk for critical illness, ...whereas new-onset AF can be triggered by accelerated atrial remodeling and arrhythmogenic triggers encountered during critical illness. The acute loss of atrial systole and onset of rapid ventricular rates that characterize new-onset AF often lead to decreased cardiac output and hemodynamic compromise. Thus, new-onset AF is both a marker of disease severity as well as a likely contributor to poor outcomes, similar to other manifestations of organ dysfunction during critical illness. Evaluating immediate hemodynamic effects of new-onset AF during critical illness is an important component of rapid clinical assessment aimed at identifying patients in need of urgent direct current cardioversion, treatment of reversible inciting factors, and identification of patients who may benefit from pharmacologic rate or rhythm control. In addition to acute hemodynamic effects, new-onset AF during critical illness is associated with both short- and long-term increases in the risk of stroke, heart failure, and death, with AF recurrence rates of approximately 50% within 1 year following hospital discharge. In the absence of a strong evidence base, there is substantial practice variation in the choice of strategies for management of new-onset AF during critical illness. We describe acute and long-term evaluation and management strategies based on current evidence and propose future avenues of investigation to fill large knowledge gaps in the management of patients with AF during critical illness.
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