Percutaneous radiofrequency ablation for atrial fibrillation

# Guidance
Current evidence on the safety and efficacy of percutaneous radiofrequency ablation for atrial fibrillation appears adequate to support the use of this procedure in appropriately selected patients (see section 2.1.4) provided that normal arrangements are in place for audit and clinical governance.
Clinicians should ensure that patients fully understand the potential complications, the likelihood of success and the risk of recurrent atrial fibrillation associated with this procedure. In addition, use of NICE's information for the public is recommended.
This procedure should only be performed in specialist units and with arrangements for cardiac surgical support in the event of complications.
This procedure should only be performed by cardiologists with extensive experience of other types of ablation procedures.
The National Institute for Cardiovascular Outcomes Research runs the National Congenital Heart Disease Audit database and clinicians are encouraged to enter all patients undergoing percutaneous radiofrequency ablation for atrial fibrillation onto this database.# The procedure

# Indications
Atrial fibrillation is the irregular and rapid beating of the upper two chambers of the heart (the atria). It may be classified as paroxysmal, persistent or permanent. Patients with atrial fibrillation may be asymptomatic or they may have symptoms including palpitations, dizziness, breathlessness and fatigue. They have an increased risk of stroke as a result of blood clots forming in the left atrium and then embolising to the brain.
Atrial fibrillation usually occurs in the absence of structural heart disease.
Conservative treatments include medication to control the heart rhythm and rate, electrical cardioversion and anticoagulation to prevent blood clots forming. Surgery for atrial fibrillation is usually performed at the same time as open heart surgery for another indication, such as for the correction of mitral valve disease. The conventional surgical approach, known as the Cox maze procedure, involves making multiple, strategically placed incisions in both atria to isolate and stop the abnormal electrical impulses. Alternative methods of creating lesions in the atria by ablation have been developed using energy sources such as radiofrequency, microwave, cryotherapy and ultrasound.
Percutaneous radiofrequency ablation is a treatment option for symptomatic patients with atrial fibrillation refractory to anti-arrhythmic drug therapy or where medical therapy is contraindicated because of co-morbidity or intolerance.

# Outline of the procedure
Percutaneous radiofrequency ablation is a minimally invasive procedure that is usually carried out under sedation. A catheter is inserted into the femoral vein and advanced into the heart, using X-ray fluoroscopic guidance to ensure correct positioning. An attachment at the tip of the catheter sends out radiofrequency energy, producing heat that damages the targeted area of the conduction pathway. Electrophysiological testing is undertaken before the procedure to identify and map the source of the abnormal electrical signals. Advanced imaging and mapping techniques that do not require fluoroscopy have also been developed for use in this procedure.
Several different strategies may be used, including linear ablation in the left or right atrium and focal pulmonary vein to isolate triggers of atrial fibrillation that arise from within the pulmonary vein. This guidance does not refer to the procedure of atrioventricular node ablation and pacing.

# Efficacy
In a randomised controlled trial of 70 patients, recurrence of atrial fibrillation at 1 year follow-up was 13% (4/32) after radiofrequency ablation compared with 63% (22/35) after anti-arrhythmic medication (p < 0.001). There were also significantly fewer episodes of hospitalisation in the radiofrequency ablation group: 9% (3/32) and 54% (19/35) of patients, respectively (p < 0.001). Quality-of-life measurements at 6 months favoured the radiofrequency ablation treatment. In a smaller randomised controlled trial, frequency of symptoms decreased from a mean of 42.8 attacks per month at baseline to 0.9 attacks per month at 1 year in 14 patients after percutaneous radiofrequency ablation (p < 0.001).
In a non-randomised comparative study of 1171 patients, 78% of patients treated with radiofrequency ablation were estimated to be free of atrial fibrillation at 3 years, compared with 37% of patients treated with medication (p < 0.001). Patients receiving percutaneous radiofrequency ablation had a 54% reduction in risk of death compared with those receiving medication (p < 0.001).
A large survey reported that 76% (6644/8745) of treated patients had resolution of symptoms of atrial fibrillation after a median follow-up of 12 months (this proportion ranged from 22% to 91% among different centres). For more details, refer to the Sources of evidence.
The Specialist Advisors noted the lack of long-term data.

# Safety
A complication rate of 6% (524/8745) was reported in the survey of 8745 patients who had undergone percutaneous radiofrequency ablation for atrial fibrillation. The most significant complications reported in this study were four early deaths (< 1%), 20 strokes (< 1%), 47 transient ischaemic attacks (1%), 117 cases of pulmonary vein stenosis (1%), 107 episodes of cardiac tamponade (1%) and 37 cases of arteriovenous fistula (< 1%).
In two comparative studies of 1171 and 30 patients, complications specific to percutaneous radiofrequency ablation included cardiac tamponade in less than 1% (4/589) of patients, stroke in 7% (1/14) and groin haematoma in 7% (1/14).
Two of the studies also reported that 2% and 4% of patients (12/589 and 340/8745, respectively) developed atypical atrial flutter of new onset after undergoing percutaneous radiofrequency ablation. In a case series of 632 procedures a cardiac perforation rate of 2% (15 procedures) was reported, each case requiring pericardiocentesis: all the patients affected survived. For more details, refer to the Sources of evidence.
The Specialist Advisors listed the potential adverse events as stroke, cardiac tamponade, atrio-oesophageal fistula and pulmonary vein stenosis.# Further information
NICE has issued guidance on radiofrequency ablation, microwave ablation and cryoablation for atrial fibrillation in association with other cardiac surgery.
NICE has also developed interventional procedures guidance on high-intensity focused ultrasound ablation for atrial fibrillation as an associated procedure with other cardiac surgery and a guideline on the management of atrial fibrillation.

# Sources of evidence
The evidence considered by the Interventional Procedures Advisory Committee is described in the interventional procedure overview of percutaneous radiofrequency catheter ablation for atrial fibrillation.

# Information for patients
NICE has produced information for patients and carers on this procedure. It explains the nature of the procedure and the guidance issued by NICE, and has been written with patient consent in mind.