Canadian Cardiovascular Society atrial fibrillation guidelines 2010: catheter ablation for atrial fibrillation/atrial flutter

Catheter ablation of atrial fibrillation (AF) offers a promising treatment for the maintenance of sinus rhythm in patients for whom a rhythm control strategy is desired. While the precise mechanisms of AF are incompletely understood, there is substantial evidence that in many cases (particularly for paroxysmal AF), ectopic activity most commonly located in and around the pulmonary veins of the left atrium plays a central role in triggering and/or maintaining arrhythmic episodes. Catheter ablation involves electrically disconnecting the pulmonary veins from the rest of the left atrium to prevent AF from being triggered. Further substrate modification may be required in patients with more persistent AF. Successful ablation of AF has never been shown to alter mortality or obviate the need for oral anticoagulation; thus, the primary indication for this procedure should be improvement of symptoms caused by AF. The success rate of catheter ablation for AF is superior to the efficacy of antiarrhythmic drugs, but success is still in the range of 75%-90% after 2 procedures. Ablation is also associated with a complication rate of 2%-3%. Thus, ablation should primarily be used as a second-line therapy after failure of antiarrhythmic drugs. In contrast to AF, catheter ablation of atrial flutter has a higher success rate with a smaller incidence of complications. Thus, catheter ablation for atrial flutter may be considered a first-line alternative to antiarrhythmic drugs.     

Canadian Cardiovascular Society atrial fibrillation guidelines 2010: implementing GRADE and achieving consensus

This article describes the process of the Canadian Cardiovascular Society 2010 atrial fibrillation (AF) guidelines update. Guideline development was based on the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system of evaluation. GRADE separates the quality of evidence (very low, low, moderate, or high quality) from the strength of recommendations (strong or conditional, ie, weak). GRADE allows acknowledgement of values and preferences in the provision of clinical care as well as costs of interventions in determining the strength of recommendations. Disclosures of relationships with industry or other potential conflicts of interest were reported at the outset and annually. Each recommendation was approved by at least a two-thirds majority of the voting panel (those with a significant conflict recusing themselves from voting on those specific recommendations).     

Canadian Cardiovascular Society atrial fibrillation guidelines 2010: prevention and treatment of atrial fibrillation following cardiac surgery

Postoperative atrial fibrillation and atrial flutter (POAF) are the most common complications of cardiac surgery that require intervention or prolong intensive care unit and total hospital stay. For some patients, these tachyarrhythmias have important consequences including patient discomfort/anxiety, hemodynamic deterioration, cognitive impairment, thromboembolic events including stroke, exposure to the risks of antiarrhythmic treatments, longer hospital stay, and increased health care costs. We conclude that prevention of POAF is a worthwhile exercise and recommend that the dominant therapy for this purpose be β-blocker therapy, especially the continuation of β-blocker therapy that is already in place. When β-blocker therapy is contraindicated, amiodarone prophylaxis is recommended. If both of these therapies are contraindicated, therapy with either intravenous magnesium or biatrial pacing is suggested. Patients at high risk of POAF may be considered for first-line amiodarone therapy, first-line sotalol therapy, or combination prophylactic therapy. The treatment of POAF may follow either a rate-control approach (with the dominant therapy being β-blocking drugs) or a rhythm-control approach. Anticoagulation should be considered if persistent POAF lasts >72 hours and at the point of hospital discharge. The ongoing need for any POAF treatment (including anticoagulation) should be reconsidered 6-12 weeks after the surgical procedure.