This Procedure Is Now First-Line A-Fib Therapy: New ACC Guidelines

By Wayne Kuznar, MDalert.com contributor

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The most recent guideline on the management of atrial fibrillation (Figures 1, 2, and 3) offers important advances over previous editions. Ablation is now a first-line therapy (Figure 4). Cardiologists should now use the more precise risk stratification scoring system. Tight heart rate control is preferred over lenient. Antithrombotic therapy is to be individualized based on shared decision-making between patient and physician.

 

Figure 1. Atrial fibrillation.
(Sources: Wikipedia Commons/Created by Agateller (Anthony Atkielski)/Public Domain.)

Catheter Ablation: A First-Line Option

Before initiating antiarrhythmic drug therapy, the guideline committee urged treatment of precipitating or reversible causes of atrial fibrillation (AF) (class I evidence) Figure 5). Catheter ablation received first-line status for the treatment of both paroxysmal and persistent AF (class IIa).

Catheter ablation received first-line status for the treatment
of both paroxysmal and persistent AF (class IIa).

 
Figure 2. Atrial fibrillation on electrocardiogram.
(Sources: Wikipedia Commons/By J. Heuser-own work/GNU Free/Creative Commons.).

According to the guideline, catheter ablation (Figure 4.) is useful for patients with symptomatic AF who are unresponsive to or intolerant to anti-arrhythmic drug therapy when rhythm control is desired (class I). Catheter ablation is reasonable in selected patients with symptomatic persistent AF prior to a trial of anti-arrhythmic drug therapy, provided that it is performed at an experienced center (class IIa) and individualized to the particular patient.

 

Figure 3. Atrial fibrillation on Holter monitor.
(Sources: Wikipedia/By JHeuser/Creative Commons.) 

The guideline writers cautioned that AF catheter ablation should not be performed in patients who cannot be treated with anticoagulants during and after the ablation. AF ablation should not be performed to restore sinus rhythm with the sole intent of avoiding the need for anticoagulation (class III). 

Surgical maze procedures are an option as a stand-alone procedure for selected patients with highly symptomatic AF (class IIb) and as a concomitant procedure in patients with AF who are undergoing other types of cardiac surgery (class IIa).

 

Figure 4. Catheter inserted into the heart and through septum wall into left atria.
(Source: a-fib.com.)

 Strict Rate Control Is Preferred

Strict rate control (resting heart rate [RHR] <80 bpm) is preferred over lenient rate control (RHR <110 bpm) for patients with persistent or permanent AF (class IIa). Lenient rate control may be reasonable in patients who are asymptomatic with preserved left ventricular function (class IIb). (Figure 5.)

Unless immediate rate control is required or an enteral route of administration is not available, the guideline writers recommend administration of an oral anticoagulant.

Atrioventricular nodal ablation with permanent pacing was deemed reasonable to control heart rate when pharmacologic therapy is inadequate and rhythm control cannot be achieved (class IIa).

 

Figure 5. Factors affecting heart rate and stroke volume.
(Sources: Wikipedia/By OpenStax College - Anatomy & Physiology/Creative Commons.)  

Antithrombotic Therapy Should Be Individualized

Risk-based antithrombotic therapy is introduced in the guideline with the following statement: “In patients with AF, antithrombotic therapy should be individualized based on shared decision-making after discussion of the absolute and [relative risks] RRs of stroke and bleeding and the patient’s values and preferences.”

Institution of antithrombotic therapy should be based on risk irrespective of the AF pattern. Withholding antithrombotic therapy is a reasonable option for patients with a CHA2DS2-VASc score of 0 (class IIa). One of 3 options can be considered for patients with nonvalvular atrial fibrillation (NVAF) and a CHA2DS2-VASc (Figure 6) score of 1: no antithrombotic therapy, aspirin, or oral anticoagulation (class IIb).

An oral anticoagulant was recommended for prevention of stroke in patients with NVAF and CHA2DS2-VASc score ≥2 (class I). The new oral anticoagulants (NOACs) dabigatran, rivaroxaban, and apixiban were added to warfarin as preferred therapy. A NOAC was recommended for patients in whom warfarin was ineffective in maintaining a therapeutic international normalized ratio (INR).


Figure 6. The CHA2DS2-VASc scoring system.


In patients with major bleeding, the guideline writers concluded that apixiban had lower risk compared with warfarin, and that dabigitran and rivaroxaban were equivalent to warfarin. All 3 NOACs were deemed to have a lower risk of intracranial bleeding compared with warfarin.

Warfarin was recommended for patients with AF who have mechanical heart valves (class I), and “the target international normalized ratio [INR] intensity (2.0 to 3.0 or 2.5 to 3.5) should be based on the type and location of the prosthesis.”

Patients Participate in Decision Making

Shared decision-making with respect to antithrombotic therapy for prevention of thromboembolism and preferential use of the CHA2DS2-VASc scheme (rather than CHADs) for risk stratification of stroke were 2 of the prominent changes in the recent American College of Cardiology/American Heart Association/Heart Rhythm Society guideline for management of atrial fibrillation (AF) compared with previous iterations.

The recent guideline also provided recommendations for the use and selection of anticoagulants, including the non-vitamin K–antagonist anticoagulant agents, and targets for heart rate control.

To assess the risk of stroke in patients with nonvalvular atrial fibrillation, defined as the absence of rheumatic mitral stenosis, mechanical or bioprosthetic heart valve, or mitral valve repair, the guideline writers recommended use of CHA2DS2-VASc score over the CHADS2 (class I recommendation). The CHA2DS2-VASc score for has a broader score range (0 to 9) and includes a larger number of risk factors compared with the CHADS2, the guideline committee noted.

“In a nationwide Danish registry from 1997 to 2008, the CHA2DS2-VASc index better discriminated stroke risk among subjects with a baseline CHADS2 score of 0 to 1 with an improved predictive ability,” guideline authors wrote.