In recent years, catheter ablation for atrial fibrillation(AF) has attracted more and more attention. Some people say that catheter ablation can cure AF, and some state that patients received catheter ablation will eventually face the recurrence of atrial fibrillation. So, what is the effectiveness of radiofrequency ablation, and what are the risks after ablation for AF patients? What should I do if AF recur? Detailed explanation see follow.

Atrial fibrillation is one of the most common clinical arrhythmias. In addition to the antiarrhythmic drugs, catheter ablation can also be chosen.

What is catheter ablation on AF?

1.The effectiveness of catheter ablation on AF

Catheter ablation for AF is a technique that has been popularized in the past 20 years. Generally, it is a safe and minimally invasive interventional therapy. However, it is regrettable that the current treatment effect is not particularly satisfactory. It is through the vascular puncture to send the catheter into the heart to destroy the lesions that cause atrial fibrillation and achieve the cure or improvement of AF. The intervention approaches in catheter ablation have evolved several times, and pulmonary vein isolation (PVI) has become the currently the mainstream. However, the drawbacks of PVI are also increasingly found, among which the low success rate has been most concerned, followed by poor long-term results. For paroxysmal AF, in general, the sooner the ablation, the better the effects. Nevertheless, some patients might be present with serious atrial lesions once AF onset. In the long run, the current mainstream PVI is not particularly satisfactory, especially for persistent AF. For persistent AF, previous reported 5-yeart success rate for a single catheter ablation is between 15% and 50%. The two most important reasons for low success rate of catheter ablation are commonly recognized: On the one hand, the current ablation sites of PVI are relatively limited, and as the disease progresses, new lesions might occur. On the other hand, currently used ablation catheters are difficult to achieve both safe and complete damages. In general, the earlier the discovery, the smaller the left atrium and the fewer comorbidities, the better the ablation effect. Generally, the success rate of ablation for paroxysmal AF might reach 80% in experienced centers, nonetheless, this rate is generally about 30-50% for persistent AF. Even so, there are still many centers that cannot reach this level.

Stepwise linear ablation, first reported by Fuwai hospital, has been presented with higher long-term success rate around the world. However, half of the patients with persistent AF reached completely cured after 5 years of single ablation, and for others, only symptomatic relief was achieved. Recently, thanks to the progressive advancements in technology and instruments, the success rate has been significantly improved: For paroxysmal AF, over 90% of the patients reached complete cure, and for persistent AF, the 1-year success rate has also been up to 70%.

2.What are the risks of catheter ablation for AF?

Experienced operational skills were highly required for ablation of AF. Procedure related complications, for example, cardiac rupture, stroke, or even death, might occur if the operators excessively pursue good results. Especially for patients with older age, large left atrium, and poor physical condition. If the operators pay too much attention to the safety of the operation, the ablation effects might be compromised. Therefore, other ablation approaches, for example, ultrasonic ablation, laser ablation, microwave ablation has all been discovered and clinical used, and eventually disappeared because of other drawbacks. Cryoballoon ablation, as the only surviving ablation approach in the new emerging ablation technology, has been used widely in recent years. However, there is no superiority in efficacy and safety when comparing radiofrequency ablation. The procedure related complications, for example, phrenic nerve injury and iatrogenic atrial septal defect were more easily seen in cryoballoon ablation procedures. As the operational skills were not that highly required than radiofrequency ablation, cryoballoon ablation is more popular in primary hospital.

3. Recurrence of atrial fibrillation after ablation, what should we do?

Hybrid ablation (combining thoracoscopic epicardial surgical and endocardial catheter ablation) recently has been emerging as a new ablation approach for AF. It was firstly implemented in Fuwai hospital (China) and one or two hospitals in Europe.

Hybrid ablation, or convergent epicardial-endocardial ablation, is currently adopted to treat long lasting persistent AF. Usually endocardial catheter ablation will be firstly used and patients were all followed at least 3 months. Successful treatment was regarded if there is no more recurrence of AF within the first 3 months, and clinical or medication observation will be enough for these patients. Surgical epicardial ablation delivered by thoracoscopy can be considered if AF recurs. This strategy is better than a second endocardial ablation. For some patients, especially for those combined with other indications for cardiac surgery, surgical epicardial ablation can be considered first, and endocardial ablation can also be used once AF recurs. This therapeutic pattern was firstly internationally promoted for several years by professor Yan Yao and Zheng Zheng (Fuwai hospital, China). Until now, the success rate of hybrid ablation has reached 90%. Of course, if the patient has concerns about surgical ablation, endocardial ablation can still be performed again, since multiple times of ablation is not uncommon. In general, multiple times of ablation are safe and the success rate can also be gradually increased. Cases have been reported for receiving five to seven times of endocardial ablation in recent years, which implicates that AF is a chronic refractory disease and the ablation procedure of AF is safe enough.