Cardioversion of Atrial Fibrillation for Maintenance of Sinus Rhythm: A Road to Nowhere

Transesophageal Echocardiogram Before Cardioversion in Atrial Fibrillation Patients

Transesophageal echocardiography (TEE) offers an invaluable, non-invasive avenue for diagnosing and managing various cardiac conditions, including atrial fibrillation (AF). As the most common cardiac arrhythmia, AF affects millions and can lead to severe complications. Cardioversion, a procedure to restore the heart's normal rhythm, is frequently conducted on AF patients resistant to medication. Due to inconclusive data, TEE's utility prior to cardioversion in AF patients remains ambiguous. Understanding TEE's potential benefits and limitations in this population could significantly influence clinical practice. This review aims to scrutinize the current literature on the use of TEE before cardioversion in AF patients. The principal objective is to understand TEE's potential benefits and limitations comprehensively. The study seeks to offer a clear understanding and practical recommendations for clinical practice, thereby improving the management of AF patients before cardioversion using TEE. A literature search of databases was conducted using the keywords "Atrial Fibrillation," "Cardioversion" and "Transesophageal echocardiography," resulting in 640 articles. These were narrowed to 103 following title and abstract reviews. After applying exclusion and inclusion criteria with a quality assessment, 20 papers were included: seven retrospective studies, 12 prospective observational studies, and one randomized controlled trial (RCT). Stroke risk associated with direct-current cardioversion (DCC) potentially results from post-cardioversion atrial stunning. Thromboembolic events occur post cardioversion, with or without prior atrial thrombus or cardioversion complications. Generally, cardiac thrombus localizes in the left atrial appendage (LAA), a clear contraindication to cardioversion. Atrial sludge without LAA thrombus in TEE is a relative contraindication. TEE before electrical cardioversion (ECV) in anticoagulated AF individuals is uncommon. In AF patients planned for cardioversion, contrast enhancement facilitates thrombus exclusion in TEE images, reducing embolic events. Left atrial thrombus (LAT) frequently occurs in AF patients, necessitating TEE examination. Despite the increased use of pre-cardioversion TEE, thromboembolic events persist. Notably, patients with post-DCC thromboembolic events had no LA thrombus or LAA sludge. The use of TEE-guided DCC has grown due to its ability to detect atrial thrombi pre-cardioversion, aiding risk stratification. Thrombus in the left atrium also signals an elevated risk of future thromboembolic events in AF patients. While atrial stunning post cardioversion detected by TEE is a significant risk factor for future thromboembolic events, further evidence is required. Therapeutic anticoagulation is essential during and post cardioversion, even if no atrial thrombus is detected. Current data recommends cardioversion guided by TEE, particularly in outpatient settings.

Atrial fibrillation: Primary prevention, secondary prevention, and prevention of thromboembolic complications: Part 2

Atrial fibrillation (AF), the most common sustained cardiac arrhythmia, once thought to be benign as long as the ventricular rate was controlled, is associated with significant cardiac morbidity and mortality. Increasing life expectancy driven by improved health care and decreased fertility rates has, in most of the world, resulted in the population aged ≥65 years growing more rapidly than the overall population. As the population ages, projections suggest that the burden of AF may increase more than 60% by 2050. Although considerable progress has been made in the treatment and management of AF, primary prevention, secondary prevention, and prevention of thromboembolic complications remain a work in progress. This narrative review was facilitated by a search of MEDLINE to identify peer-reviewed clinical trials, randomized controlled trials, meta-analyses, and other clinically relevant studies. The search was limited to English-language reports published between 1950 and 2021. Atrial fibrillation was searched using the terms primary prevention, hyperthyroidism, Wolff-Parkinson-White syndrome, catheter ablation, surgical ablation, hybrid ablation, stroke prevention, anticoagulation, left atrial occlusion and atrial excision. Google and Google scholar as well as bibliographies of identified articles were reviewed for additional references. In these two manuscripts, we discuss the current strategies available to prevent AF, then compare non-invasive and invasive treatment strategies to diminish AF recurrence. In addition, we examine the pharmacological, percutaneous device and surgical approaches to prevent stroke as well as other types of thromboembolic events.

Pharmacologic cardioversion with intravenous amiodarone is likely safe in neurocritically Ill patients

Neurological injury is often associated with cardiac abnormalities, including electrophysiological issues. Cardioversion of acute atrial fibrillation (<48h' duration) without anticoagulation carries about a 0.7% risk of thromboembolism. There is limited data on managing acute atrial fibrillation specifically in the neuroscience intensive care unit (NSICU) setting. We sought to determine the safety of using intravenous (IV) amiodarone for restoring sinus rhythm in patients with presumed new onset atrial or ventricular tachycardia after neurological injury. We conducted a retrospective review of consecutive patients admitted to our NSICU between June 2011 and March 2015 with a primary neurological diagnosis and new onset tachyarrhythmias who received IV amiodarone. Baseline demographics and presence of known risk factors for atrial fibrillation were recorded. The primary end point was new onset stroke. 48 patients were included for the final analysis. No patients developed new stroke after receiving IV amiodarone. The average follow up period was 14.0days. The majority of patients did not have the pre identified risk factors for atrial fibrillation. Ischemic stroke and traumatic brain injury were the most common admitting diagnoses. We conclude that in patients with primary neurological injury, use of IV amiodarone for rhythm control of acute onset atrial fibrillation carries a low risk of cardioembolic stroke in the first 2weeks. Further investigation, including prospective studies, with larger samples and longer follow up periods is warranted.

Fluvastatin combined with benazepril may contribute to the favorable prognosis of patients with atrial fibrillation

The aim of this study was to observe the clinical efficacy of fluvastatin combined with benazepril in the treatment of patients with atrial fibrillation (AF). A total of 92 patients with AF were randomly assigned to the case group (n=46), in which the patients were treated with fluvastatin (80mg) plus benazepril (10mg), or to the control group (n=46), in which the patients were treated with fluvastatin (80mg). The conversion rate of sinus rhythm was higher in the case group than in the control group (P<0.05). The case group had more treatment-effective patients than the control group, with fewer treatment-ineffective patients (P<0.05). The LVEDd, LVESd, LAD, and LVEF indexes in the case group were lower than in the control group after 6 months of treatment (all P<0.05). Levels of hs-CRP were also lower in patients in the case group than in patients in the control group after 1 month of treatment (P<0.05). After 12 months, renin and Ang II concentrations were lower in patients in the case group than in the control group (both P<0.05). Significant differences in IL-6 and TNF-α expression were found between the two groups after 1 month, 6 months, and 12 months of treatment (all P<0.05). Compared to patients in the control group, the levels of total cholesterol (TC), triglycerides, and LDL-C in the case group were lower after 6 and 12 months of treatment (all P<0.05), while the HDL level was higher (P<0.05). Treatment with fluvastatin combined with benazepril further increased the conversion rate of sinus rhythm and significantly improved the quality of life and prognosis of AF patients.

Rivaroxaban in atrial fibrillation cardioversion: insights from the X-VeRT trial

ABSTRACT  Vitamin K antagonists (VKAs) have traditionally been the standard of care for the thromboprophylactic anticoagulation of patients with nonvalvular atrial fibrillation (NVAF) undergoing cardioversion. X-VeRT was the first prospective trial to explore the safety and efficacy of one of the non-VKA oral anticoagulants, rivaroxaban, compared with dose-adjusted VKA as thromboprophylaxis in patients with NVAF scheduled to undergo cardioversion. The protocol allowed either early (1-5 days) or delayed (3-8 weeks) cardioversion to be performed. Rivaroxaban use (20 mg once daily or 15 mg if creatinine clearance was 30-49 ml/min) was associated with a similar incidence of adverse cardiovascular events and bleeding as VKA use; however, rivaroxaban significantly reduced the time to cardioversion in those undergoing delayed cardioversion. Thus, rivaroxaban is a safe alternative to VKAs for thromboprophylaxis in patients with NVAF undergoing elective cardioversion.

Role of microRNAs in cardiac remodelling: new insights and future perspectives

Cardiac remodelling is a key process in the progression of cardiovascular disease, implemented in myocardial infarction, valvular heart disease, myocarditis, dilated cardiomyopathy, atrial fibrillation and heart failure. Fibroblasts, extracellular matrix proteins, coronary vasculature, cardiac myocytes and ionic channels are all involved in this remodelling process. MicroRNAs (miRNAs) represent a sizable sub-group of small non-coding RNAs, which degrade or inhibit the translation of their target mRNAs, thus regulating gene expression and play an important role in a wide range of biologic processes. Recent studies have reported that miRNAs are aberrantly expressed in the cardiovascular system under some pathological conditions. Indeed, in vitro and in vivo models have revealed that miRNAs are essential for cardiac development and remodelling. Clinically, there is increasing evidence of the potential diagnostic role of miRNAs as potential diagnostic biomarkers and they may represent a novel therapeutic target in several cardiovascular disorders. This paper provides an overview of the impact of several miRNAs in electrical and structural remodelling of the cardiac tissue, and the diagnostic and therapeutic potential of miRNA in cardiovascular disease.

Novel pharmacological targets for the rhythm control management of atrial fibrillation

Atrial fibrillation (AF) is a growing clinical problem associated with increased morbidity and mortality. Development of safe and effective pharmacological treatments for AF is one of the greatest unmet medical needs facing our society. In spite of significant progress in non-pharmacological AF treatments (largely due to the use of catheter ablation techniques), anti-arrhythmic agents (AADs) remain first line therapy for rhythm control management of AF for most AF patients. When considering efficacy, safety and tolerability, currently available AADs for rhythm control of AF are less than optimal. Ion channel inhibition remains the principal strategy for termination of AF and prevention of its recurrence. Practical clinical experience indicates that multi-ion channel blockers are generally more optimal for rhythm control of AF compared to ion channel-selective blockers. Recent studies suggest that atrial-selective sodium channel block can lead to safe and effective suppression of AF and that concurrent inhibition of potassium ion channels may potentiate this effect. An important limitation of the ion channel block approach for AF treatment is that non-electrical factors (largely structural remodeling) may importantly determine the generation of AF, so that "upstream therapy", aimed at preventing or reversing structural remodeling, may be required for effective rhythm control management. This review focuses on novel pharmacological targets for the rhythm control management of AF.

New approaches to atrial fibrillation management: treat the patient, not the ECG

Atrial fibrillation causes a significant burden on patients and the health care system. The main goals of atrial fibrillation therapy are to improve symptoms and reduce morbidity. There have been significant recent developments in both stoke prophylaxis and rhythm/rate control. The results of the ACTIVE W study emphasize the importance of effective oral anticoagulant therapy in patients with moderate-to-high risk for stroke. The RE-LY study showed superiority of dabigatran, an oral direct thrombin inhibitor, over warfarin in the prevention of stroke, or systemic embolism. Dronedarone, a new antiarrhythmic drug with multiple class effects, has been recently approved by the US Food and Drug Administration for the treatment of atrial fibrillation. Dronedarone has moderate rhythm and rate control efficacy; however, dronedarone significantly reduced cardiovascular hospitalization, cardiovascular death, and stroke in the large ATHENA trial. There is also an important shift in the paradigm of the goals of atrial fibrillation therapy. Instead of focusing solely on the electrocardiographic outcomes of treatment and considering "rhythm versus rate control," one needs to consider "symptom control" as well as patient well-being. This review will suggest that patient based outcomes rather than ECG-based outcomes should be the primary goals of treatment. Original reports and reviews on specific topics were identified through Medline. Randomized controlled trials were selected as the primary source of information. Analysis included critical review of the evidence available to date.