Patients with symptomatic, paroxysmal, untreated atrial fibrillation were randomly assigned to antiarrhythmic drug therapy or cryoablation. At 1 year, there was a significantly lower rate of ...recurrence of atrial fibrillation with cryoablation than with drug therapy.
Abstract The Canadian Cardiovascular Society (CCS) published the complete set of 2010 Atrial Fibrillation (AF) Guidelines in the January, 2011 issue of the Canadian Journal of Cardiology . During its ...deliberations, the CCS Guidelines Committee engaged to a timely review of future evidence, with periodic composition of focused updates to address clinically important advances. In 2011, results were published from 3 pivotal AF trials: the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonist for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET-AF), the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) study, and the Permanent Atrial Fibrillation Outcome Study Using Dronedarone on Top of Standard Therapy (PALLAS), comparing dronedarone with placebo in patients with permanent AF and additional cardiovascular disease risk-factor burden. Each of these large randomized trials provided clear results with major implications for AF management. Other important evidence that has emerged since the 2010 Guidelines includes findings about prediction instruments for AF-associated stroke and bleeding risk, stroke risk in paroxysmal-AF patients, risk-benefit considerations related to oral anticoagulation in patients with chronic kidney disease, and risk/benefit considerations in the use of antiplatelet agents, alone and in combination with each other or with oral anticoagulants, in AF patients. The Guidelines Committee judged that this extensive and important new evidence required focused updating of the 2010 Guidelines with respect to stroke prevention and rate/rhythm control. This report presents the details of the new recommendations, along with the background and rationale.
Objective: The efficacy of catheter-based cardiac ablation procedures can be significantly improved if real-time information is available concerning contact forces between the catheter tip and ...cardiac tissue. However, the widely used ablation catheters are not equipped for force sensing. This paper proposes a technique for estimating the contact forces without direct force measurements by studying the changes in the shape of the deflectable distal section of a conventional 7-Fr catheter (henceforth called the "deflectable distal shaft," the "deflectable shaft," or the "shaft" of the catheter) in different loading situations. Method: First, the shaft curvature when the tip is moving in free space is studied and based on that, a kinematic model for the deflectable shaft in free space is proposed. In the next step, the shaft shape is analyzed in the case where the tip is in contact with the environment, and it is shown that the curvature of the deflectable shaft provides useful information about the loading status of the catheter and can be used to define an index for determining the range of contact forces exerted by the ablation tip. Results: Experiments with two different steerable ablation catheters show that the defined index can detect the range of applied contact forces correctly in more than 80% of the cases. Based on the proposed technique, a framework for obtaining contact force information by using the shaft curvature at a limited number of points along the deflectable shaft is constructed. Conclusion: The proposed kinematic model and the force estimation technique can be implemented together to describe the catheter's behavior before contact, detect tip/tissue contact, and determine the range of contact forces. Significance: This study proves that the flexibility of the catheter's distal shaft provides a means of estimating the force exerted on tissue by the ablation tip.
Background Atrial fibrillation (AF) is associated with extracellular matrix (ECM) remodelling and often coexists with myocardial fibrosis (MF); however, the causality of these conditions is not well ...established. Objective We aim to corroborate AF to MF causality by quantifying left atrial (LA) fibrosis in cardiac magnetic resonance (CMR) images after persistent rapid ventricular pacing and subsequent AF using a canine model and histopathological validation. Methods Twelve canines (9 experimental, 3 control) underwent baseline 3D LGE-CMR imaging at 3T followed by insertion of a pacing device and 5 weeks of rapid ventricular pacing to induce AF (experimental) or no pacing (control). Following the 5 weeks, pacing devices were removed to permit CMR imaging followed by excision of the hearts and histopathological imaging. LA myocardial segmentation was performed manually at baseline and post-pacing to permit volumetric %MF quantification using the image intensity ratio (IIR) technique, wherein fibrosis was defined as pixels > mean LA myocardium intensity + 2SD. Results Volumetric %MF increased by an average of 2.11 ± 0.88% post-pacing in 7 of 9 experimental dogs. While there was a significant difference between paired %MF measurements from baseline to post-pacing in experimental dogs (P = 0.019), there was no significant change in control dogs (P = 0.019 and P = 0.5, Wilcoxon signed rank tests). The median %MF for paced animals was significantly greater than that of non-paced dogs at the 5-week post-insertion time point (P = 0.009, Mann Whitney U test). Histopathological imaging yielded an average %MF of 19.42 ± 4.80% (mean ± SD) for paced dogs compared to 1.85% in one control dog. Conclusion Persistent rapid ventricular pacing and subsequent AF leads to an increase in LA fibrosis volumes measured by the IIR technique; however, quantification is limited by inherent image acquisition parameters and observer variability.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Objectives The purpose of this study was to provide a systematic multicenter survey on the incidence and causes of death occurring in the setting of or as a consequence of catheter ablation (CA) of ...atrial fibrillation (AF). Background CA of AF is considered to be generally safe. However, serious complications, including death, have been reported. Methods Using a retrospective case series, data relevant to the incidence and cause of intra- and post-procedural death occurring in patients undergoing CA of AF between 1995 and 2006 were collected from 162 of 546 identified centers worldwide. Results Thirty-two deaths (0.98 per 1,000 patients) were reported during 45,115 procedures in 32,569 patients. Causes of deaths included tamponade in 8 patients (1 later than 30 days), stroke in 5 patients (2 later than 30 days), atrioesophageal fistula in 5 patients, and massive pneumonia in 2 patients. Myocardial infarction, intractable torsades de pointes, septicemia, sudden respiratory arrest, extrapericardial pulmonary vein (PV) perforation, occlusion of both lateral PVs, hemothorax, and anaphylaxis were reported to be responsible for 1 death each, while asphyxia from tracheal compression secondary to subclavian hematoma, intracranial bleeding, acute respiratory distress syndrome, and esophageal perforation from an intraoperative transesophageal echocardiographic probe were causes of 1 late death each. Conclusions Death is a complication of CA of AF, occurring in 1 of 1,000 patients. Knowledge of possible precipitating causes is key to operators and needs to be considered during decision making with patients.
Abstract The Canadian Cardiovascular Society (CCS) Atrial Fibrillation (AF) Guidelines Committee provides periodic reviews of new data to produce focused updates that address clinically important ...advances in AF management. This 2016 Focused Update deals with: (1) the management of antithrombotic therapy for AF patients in the context of the various clinical presentations of coronary artery disease; (2) real-life data with non-vitamin K antagonist oral anticoagulants; (3) the use of antidotes for the reversal of non-vitamin K antagonist oral anticoagulants; (4) digoxin as a rate control agent; (5) perioperative anticoagulation management; and (6) AF surgical therapy including the prevention and treatment of AF after cardiac surgery. The recommendations were developed with the same methodology used for the initial 2010 guidelines and the 2012 and 2014 Focused Updates. Using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) standards, individual studies and literature were reviewed for quality and bias; the literature review process and evidence tables are included in the Supplementary Material, and on the CCS Web site. The section on concomitant AF and coronary artery disease was developed in collaboration with the CCS Antiplatelet Guidelines Committee. Details of the updated recommendations are presented, along with their background and rationale. This document is linked to an updated summary of all CCS AF Guidelines recommendations, from 2010 to the present 2016 Focused Update.
Abstract Background Real-world data on patients' and physicians' values related to the use of oral anticoagulant (OAC) therapy for stroke prevention in patients with nonvalvular atrial fibrillation ...are currently lacking. We sought to assess the values, preferences, and experience of patients who receive OAC therapy, and of physicians who prescribe OAC therapy. Methods A national survey of randomly selected patients (n = 266) and physicians (n = 178) was conducted between May and September 2014. Each was asked to evaluate the importance of individual OAC attributes and identify which of 2 medication profiles they would prefer (individual attributes were progressively modified to determine which were the most valued and/or influenced treatment choice). Medication adherence and prescription practice was also assessed. Results The preferences of patients and physicians regarding OAC therapy differed but largely focused on characteristics related to safety and, to a lesser extent, efficacy. When based solely on the basis of the attribute profile (blinded to the specific agent), physicians were more likely to select apixaban (61%), whereas patients showed no significant preference among apixaban, rivaroxaban, and warfarin. Despite this, 49% of physicians spontaneously stated rivaroxaban as their preferred agent (vs 25% apixaban). Patients prescribed and taking once daily medications (rivaroxaban or warfarin) showed better compliance with their OAC therapy (approximately 30% of twice daily medications being taken once daily, with significantly more missed doses compared with once daily medications). Conclusions Real-world prescriptions do not reflect reported values, which suggests that other factors influence patient-physician decision-making around OAC therapy. Data on self-reported adherence to OAC therapy and discordance in the use of OACs from prescribed regimens are concerning and warrant further investigation.
PDF
