Atrial fibrillation is irregular and rapid beating of the atria. It can be classified as paroxysmal, persistent or permanent, depending on the duration of episodes and patients' response to treatment. Atrial fibrillation can cause fatigue, palpitations, chest pain, shortness of breath and fainting. There is an increased risk of death and stroke.
Medication for atrial fibrillation (AF) may aim either to maintain a normal cardiac rhythm or control the rate of the ventricular response, and to reduce the risk of thromboembolism (which may cause stroke). Ablation procedures are used when drug therapy is either not tolerated or is ineffective.
Thoracoscopic epicardial radiofrequency ablation is carried out with the patient under general anaesthesia. Two or more small incisions are made in the chest wall. The right lung is deflated and the right pulmonary veins are accessed via blunt dissection. A bipolar radiofrequency device is inserted through a catheter and positioned around the atrium adjacent to the pulmonary veins. Radiofrequency energy is applied to create full thickness ablation in the myocardium, with the aim of electrically isolating the pulmonary veins. Intraoperative electrophysiological testing may be used to check whether isolation has been achieved. The procedure is repeated on the left pulmonary veins.
The left atrial appendage may be excised during the procedure, to minimise the risk of subsequent thromboembolic events.
Sections 2.3 and 2.4 describe efficacy and safety outcomes which were available in the published literature and which the committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the overview for this guidance.
In four case series of 70, 26, 22 and 20 patients with paroxysmal or persistent AF, 93% (65 out of 70), 81% (21 out of 26), 91% (20 out of 22) and 90% (18 out of 20) were in sinus rhythm at follow-up ranging from 6 to 18 months.
In the case series of 70 patients, 43%, 23% and 14% of patients with paroxysmal AF (n=42) were using anti-arrhythmic medication at 3, 6 and 12 months, respectively (absolute numbers not reported). In the same study, 61%, 26% and 38% of patients with persistent AF (n=28) were using anti-arrhythmic medication at 3, 6 and 12 months, respectively (absolute numbers not reported). In two case series of 27 and 26 patients, 65% (15 of the 23 patients with follow-up of at least 3 months) and 57% (12 of the 21 patients in sinus rhythm at 6-month follow-up), respectively, were no longer using anti-arrhythmic medication. In the case series of 22 and 20 patients, 91% (20 out of 22) and 85% (17 out of 20) were not using anti-arrhythmic medication at their last follow-up (mean follow-up 18 and 17 months, respectively).
The specialist advisers considered key efficacy outcomes to include reduced use of anti-arrhythmic medication and decreased burden of AF for patients with paroxysmal AF. One specialist adviser stated that the procedure's long-term efficacy was uncertain.
The case series of 70 patients reported two major complications: 1 patient required revision surgery 10 days postoperatively because of fistula formation between the left atrium and the oesophagus, and another required angioplasty and stent insertion for stenosis of the circumflex coronary artery 6 weeks after the procedure. The case series of 27 patients reported one case each of right pneumothorax and suspected pericarditis. In the case series of 26 patients, 1 patient required aspiration of pleural effusion.
The specialist advisers stated that theoretical and anecdotal adverse events included injury to the heart or adjacent structures, bleeding from the atrial appendage, coronary artery occlusion, pulmonary vein stenosis and increased risk of arrhythmias postoperatively.
The fact that that some patients had concomitant excision of the left atrial appendage, and others did not, complicated interpretation of the evidence.