When is catheter ablation a sound option for your patient with A-fib?

In patients who progress from paroxysmal to persistent AF (see “Subtypes,” below), 2 distinct pathways, facilitated by the presence of abnormal tissue, continuously activate one another, thus maintaining the arrhythmia. Myocardial tissue in the pulmonary veins is responsible for most ectopic electrical impulses in patients with drug-refractory AF (see “Rhythm control”).

Subtypes. For the purpose of planning treatment, AF is classified as:

• Paroxysmal. Terminates spontaneously or with intervention ≤ 7 days after onset.
• Persistent. Continuous and sustained for > 7 days.
• Longstanding persistent. Continuous for > 12 months.
• Permanent. The patient and physician accept that there will be no further attempt to restore or maintain sinus rhythm.

Goals of treatment

Primary management goals in patients with AF are 2-fold: control of symptoms and prevention of thromboembolism. A patient with new-onset AF who presents acutely with inadequate rate control and hemodynamic compromise requires urgent assessment to determine the cause of the arrhythmia and need for cardioversion.³ A symptomatic patient with AF who does not have high-risk features (eg, valvular heart disease, mechanical valves) might be a candidate for rhythm control in addition to rate control.^3,4

Rate control. After evaluation in the hospital, a patient who has a rapid ventricular response but remains hemodynamically stable, without evidence of heart failure, should be initiated on a rate-controlling medication, such as a beta-blocker or nondihydropyridine calcium-channel blocker. A resting heart rate goal of < 80 beats per minute (bpm) is recommended for a symptomatic patient with AF. The heart rate goal can be relaxed, to < 110 bpm, in an asymptomatic patient with preserved left ventricular function.^5,6

Rhythm control, indicated in patients who remain symptomatic on rate-controlling medication, can be achieved either with an antiarrhythmic drug (AAD) or by catheter ablation.^4,5 In stable patients, rhythm control should be considered only after a thorough work-up for a reversible cause of AF, and can be achieved with an oral AAD or, in select patients, through catheter ablation (TABLE 1^3,6). Other indications for chronic rhythm control include treatment of patients with ­tachycardia-induced cardiomyopathy.⁵

Continuing symptoms when taking rate-controlling medication for atrial fibrillation is one indication for rhythm control with an antiarrhythmic drug or by catheter ablation.

A major study that documented the benefit of early rhythm control evaluated long-term outcomes in 2789 patients with AF who were undergoing catheter ablation.⁷ Patients were randomized to early rhythm control (catheter ablation or AAD) or “usual care”—ie, in this study, rhythm control limited to symptomatic patients. Primary outcomes were death from cardiovascular causes, stroke, and hospitalization with worsening heart failure or acute coronary syndrome. A first primary outcome event occurred in 249 patients (3.9/100 person-years) assigned to early rhythm control, compared to 316 (5.0 per 100 person-years) in the group assigned to usual care.

The study was terminated early (after 5.1 years) because of overwhelming evidence of efficacy (number need to treat = 7). Although early rhythm control was obtained through both catheter ablation and AAD (hazard ratio [HR] = 0.79; 96% CI, 0.66-0.94; P = .005), success was attributed to the use of catheter ablation for a rhythm-control strategy and its use among patients whose AF was present for < 1 year. Most patients in both treatment groups continued to receive anticoagulation, rate control, and optimization of cardiovascular risk.⁷

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