Highlights from the Heart Rhythm Society’s Pocket Guide “Practical Rate and Rhythm Management of Atrial Fibrillation”

Dear Readers, In May of this year, the Heart Rhythm Society (HRS) published a pocket guide entitled “Practical Rate and Rhythm Management of Atrial Fibrillation.” It was distributed during the Atrial Fibrillation (AF) Summit of the Annual Scientific Sessions in Boston. Adapted from the ACC/AHA/ESC 2006 Guidelines for the Management of Patients with Atrial Fibrillation, it summarizes key points related to the evaluation and management of AF, includes a dosing guide of commonly used drugs to treat AF, and provides a flow diagram of antiarrhythmic drug selection. Because HRS has previously published two pocket guides related to AF, one covering surgical and catheter ablation and another covering anticoagulation, the main focus of this guide was rate and rhythm control. The target audience for the AF guide is cardiologists, internists, and other health care providers who take care of patients with AF. As the editor of the AF pocket guide, I was preparing to give a lecture covering the topic of AF to the local internal medicine housestaff and hand out copies of the pocket guide. Reinforcing the fundamentals can be a worthwhile investment. During my preparation, 15 main points rose to the surface as the most important: 1. An accurate diagnosis is important. AF should be distinguished from atrial flutter, which has regular organized atrial activity with a rate typically between 240 and 320 bpm, multifocal atrial tachycardia, which has a single P wave from multiple atrial foci preceding each QRS, and regular supraventricular tachycardias such as AV nodal reentry.¹ 2. Management of patients with AF involves 3 objectives: rate control, rhythm control, and prevention of thromboembolism.1 Dividing the management into these 3 categories can be useful during the development of a treatment plan and discussion with the patient. 3. A rate control strategy alone, without attempts at restoration or maintenance of sinus rhythm (SR), is reasonable in some patients with AF, especially those who are asymptomatic.¹ 4. In some circumstances, when the cause of AF is reversible, such as when AF occurs after cardiac surgery, no long-term therapy may be necessary.¹ 5. In patients with AF who do not have mechanical valves, it is reasonable to interrupt anticoagulation for up to 1 week without substituting heparin for procedures that carry a risk of bleeding.¹ Unnecessary periprocedural heparin for patients with a history of AF can be associated with significant morbidity. 6. The CHADS2 scoring system can be used to risk stratify patients with nonvalvular AF to determine the need for warfarin.¹ One point is assigned for a history of any of the following risk factors: congestive heart failure, hypertension, age over 75 years, and diabetes. Two points are assigned when there is a history of stroke. Patients with a CHADS2 score > 1 should be treated with warfarin targeting an international normalized ratio (INR) between 2 and 3. Aspirin or warfarin are reasonable options for patients with a CHADS2 score = 1. 7. Patients with paroxysmal AF and patients with atrial flutter should be treated similarly to patients with persistent AF with regard to anticoagulation. 8. Documentation of anticoagulation adequacy is important prior to cardioversion (CV). For all patients with AF for > 48 hours, or when AF duration is unknown, 3 weeks of therapeutic anticoagulation with an INR ≥ 2.0 are required prior to CV unless a transesophageal echocardiogram (TEE) is performed.¹ 9. TEE can be used to assess for an atrial thrombus as an alternative to 3 weeks of anticoagulation. Even when a TEE has excluded a thrombus, patients must still be therapeutically anticoagulated with warfarin or heparin at the time of CV and must be treated with anticoagulation for at least 4 weeks after CV. 10. The risk of thromboembolism or stroke does not differ between pharmacological and electrical CV.¹ 11. Ablation of the AV conduction system and permanent pacing is an option for patients with rapid ventricular rates despite maximum medical therapy, and often yields remarkable symptomatic relief. However, there is growing concern about the negative effects of long-term RV pacing. Biventricular pacing may overcome many of the adverse hemodynamic effects associated with RV pacing.¹ 12. Pharmacological therapy to maintain SR should be considered in patients who have troublesome symptoms related to paroxysmal AF or recurrent AF after CV who can tolerate antiarrhythmic drugs and have a good chance of remaining in sinus rhythm. Drugs should be used to decrease the frequency and duration of episodes, and to improve symptoms. AF recurrence while taking an antiarrhythmic drug is not indicative of treatment failure and does not necessitate a change in antiarrhythmic therapy.¹ 13. Antiarrhythmic drug choice is based on side effect profiles and the presence or absence of structural heart disease, heart failure, and hypertension.¹ Sodium channel blockers (Vaughan Williams class I drugs such as flecainide) should be avoided in patients with structural heart disease. 14. Catheter ablation for AF is currently considered a second-line therapy in highly symptomatic patients in whom one or more antiarrhythmic agents have failed.1 Intolerance to anticoagulation is not an indication for catheter ablation of AF. 15. Patients who continue to be symptomatic or are difficult to manage should be referred to an electrophysiologist.¹ The hope is that the HRS AF pocket guide will offer practical guidance to those on the front lines managing patients with AF. Guides can be ordered by contacting HRS (www.HRSonline.org).