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Atrial fibrillation (AF) is an increasingly prevalent arrhythmia; its pathophysiology and progression are well studied. Stroke and bleeding risk models have been created and validated. Decision tools for stroke prophylaxis are evolving, with better options at hand. Utilization of various diagnostic tools offer insight into AF burden and thromboembolic risk. Rate control, rhythm control, and stroke prophylaxis are the cornerstones of AF therapy. Although antiarrhythmic drugs are useful, AF ablation has become a primary therapeutic strategy. Pulmonary vein isolation is the cornerstone of AF ablation, and methods to improve ablation safety and efficacy continue to progress. Ablation of nonpulmonary vein sites is increasingly being recognized as an important strategy for treating nonparoxysmal AF. Several new ablation techniques and technologies and stroke prophylaxis are being explored. This is a contemporary review on the prevalence, pathophysiology, risk prediction, prophylaxis, treatment options, new insights for optimizing treatment outcomes, and emerging concepts of AF., (Copyright © 2020. Published by Elsevier Inc.)

Introduction: Phrenic nerve (PN) injury is one of the major complications of pulmonary vein isolation (PVI). Pace mapping for PN capture is routinely used to identify areas with high risk for injury along the anterior border of the right pulmonary veins (PVs). Our aim was to evaluate the feasibility of using preprocedural imaging to identify areas where no PN capture is possible along the anterior border of the right PVs, thus avoiding the need for pace mapping during PVI., Methods and Results: It was hypothesized that PN capture along the anterior border of the right PVs does not occur in the area where the right and left atria overlap. Three-dimensional segmentation of both atria was performed on preprocedural magnetic resonance and computed tomography angiograms in 40 patients before undergoing PVI. The area of overlap between the right and left atria was delineated. Image registration was performed during the procedure. Using pacing, regions with and without PN capture were marked along the anterior border of the right PVs. A total of 361 points were tested for PN stimulation (9 ± 4 points/patient). PN capture occurred in 97 out of the 189 points (51%) in the area with no overlap between the right and left atria. No PN capture occurred in the area of overlap (172 points, P< 0.001)., Conclusion: Delineation of the area of overlap between the right and left atria derived from preprocedural imaging reliably identifies regions where PN pace capture does not occur. Testing for PN stimulation before ablation may not be necessary in these regions., (© 2015 Wiley Periodicals, Inc.)

Obstructive sleep apnea (OSA) is increasingly recognized as an important risk factor for arrhythmogenesis. Epidemiological and clinical studies have suggested a strong association between OSA and atrial fibrillation (AF). With the increasing global epidemic of obesity, the incidence of OSA is also expected to rise. Various mechanisms mediated through adverse electrical and structural changes have been proposed to explain the increased risk of AF in patients with OSA. Multiple studies have also observed a greater risk of AF recurrence after cardioversion and catheter ablation (CA) in the patients with untreated OSA. The epidemiological and pathophysiological associations between OSA and AF have significant implications on the treatment outcomes of rhythm-control strategies for AF. Adequate screening and optimal management of OSA are of key importance to help improve the clinical outcomes following cardioversion and CA. In this review, we sought to describe the role of various mechanisms by which OSA mediates the pathogenesis of AF and contributes to adverse outcomes following CA.

Background: Pulmonary vein isolation (PVI) has become one of the primary treatments for symptomatic drug-refractory atrial fibrillation (AF). During this procedure, delivery of ablation lesions to certain regions of the left atrium can be technically challenging. Among the most challenging regions are the ridges separating the left pulmonary veins (LPV) from the left atrial appendage (LAA), and the right middle pulmonary vein (RMPV) from the right superior (RSPV) and right inferior (RIPV) pulmonary veins. A detailed anatomical characterization of these regions has not been previously reported., Methods: Magnetic resonance angiography (MRA) was performed in patients prior to undergoing PVI. Fifty consecutive patients with a RMPV identified by MRA were included in this study. Ridges associated with the left pulmonary veins were examined in an additional 30 patients who did not have a RMPV. Endoluminal views were reconstructed from the gadolinium-enhanced, breath-hold three-dimensional MRA data sets. Measurements were performed using electronic calipers., Results: The width of the ridge separating the LPV from the LAA was found to be 3.7 +/- 1.1 mm at its narrowest point. The segment of this ridge with a width of 5 mm or less was 16.6 +/- 6.4 mm long. The width of the ridges separating the RMPV from the RSPV and the RIPV was found to be 3.0 +/-1.5 mm and 3.1 +/-1.8 mm, respectively. There were no significant differences between LPV ridges for patients with versus without a RMPV., Conclusion: The width of the ridges of atrial tissue separating LPV from the LAA and the RMPV from its neighboring veins may explain the technical challenge in obtaining stable catheter positions in these areas. A detailed assessment of the anatomy of these regions may improve the safety and efficacy of catheter ablation at these sites.

The article discusses whether there is a need for a novel algorithm for accessory pathways localization. Topics include the usefulness of electrocardiogram in the localization of accessory pathways, premature ventricular contractions site of origin, and pacing sites; algorithms that are being used by clinicians; and description of most of the accessory pathways' localization algorithms.

The article offers information on Idiopathic ventricular arrhythmias (VAs) which are defined as premature ventricular complexes or ventricular tachycardias that occur in the absence of structural heart disease. It mentions arrhythmias typically originate from the right ventricular outflow tract (RVOT), specifically from the superior septal aspect, but can also originate from the left ventricular outflow tract (LVOT) and the coronary cusps.

Background Atrioventricular reciprocating tachycardia (AVRT) utilizing a concealed accessory pathway is common. It is well appreciated that some patients may have multiple accessory pathways with separate atrial and ventricular insertion sites. Methods We present three cases of AVRT utilizing concealed pathways with evidence that each utilizing a single ventricular insertion and two discrete atrial insertion sites. Results In case one, two discrete atrial insertion sites were mapped in two separate procedures, and only during the second ablation was the Kent potential identified. Ablation of the Kent potential at this site remote from the two atrial insertion sites resulted in the termination of the retrograde conduction in both pathways. Case two presented with supraventricular tachycardia (SVT) with alternating eccentric atrial activation patterns without alteration in the tachycardia cycle length. The two distinct atrial insertion sites during orthodromic AVRT and ventricular pacing were targeted and each of the two atrial insertion sites were successfully mapped and ablated. In case three, retrograde decremental conduction utilizing both atrial insertion sites was identified prior to ablation. After mapping and ablation of the first discrete atrial insertion site, tachycardia persisted utilizing the second atrial insertion site. Only after ablation of the second atrial insertion site was SVT noninducible, and VA conduction was no longer present. Conclusions Concealed retrograde accessory pathways with discrete atrial insertion sites may have a common ventricular insertion site. Identification and ablation of the ventricular insertion site or the separate discrete atrial insertion sites result in successful treatment. [ABSTRACT FROM AUTHOR]

The article discusses that intraprocedural reproducibility of clinical premature ventricular contractions (PVCs) during catheter ablation has been well recognized to be a major determinant of the success rate of the procedure, with an improvement in the long-term clinical outcome of affected patients; and mentions that all enrolled patients had no evidence of structural heart disease, as evaluated by echocardiography and coronary angiography.

Background: Recent interest has focused on the left atrial appendage (LAA) in the setting of atrial fibrillation as a potential source of thromboembolism and stroke, which may be amenable to permanent occlusion by a variety of investigational catheter-delivered devices. Precise anatomic characterization of the LAA is necessary to determine the suitability of a patient for device placement and for device selection and sizing.Objectives: The purpose of this study was to perform detailed three-dimensional characterization of LAA size and geometry by magnetic resonance angiography.Methods: Fifty patients with chronic atrial fibrillation undergoing cardiac magnetic resonance angiography in preparation for catheter ablation of atrial fibrillation were analyzed for LAA volume, neck size, depth, and overall geometry.Results: The average LAA volume was 17.3 +/- 6.7 mL, with a depth of 26.6 +/- 4.9 mm and a "neck" diameter of 20.0 +/- 5.3 mm x 14.1 +/- 4.7 mm. The average number of LAA lobes was 1.4 +/- 0.7 (range 1-4). Substantial interpatient variability was present in the relative dimensions and morphology of the LAA. There was a significant correlation between left atrial size and LAA neck dimensions.Conclusion: There is significant heterogeneity in LAA size and dimensions among patients with atrial fibrillation. Device occlusion of the LAA may require devices that are available in multiple sizes/shapes or that can adapt to this heterogeneity. [ABSTRACT FROM AUTHOR]