Catheter Ablation Success Rates
Catheter ablation success rates have improved over time based on a better understanding of atrial fibrillation, new techniques and technology, and greater doctor experience. In early studies, the majority of centers reported single procedure success rates of 60% or more for paroxysmal atrial fibrillation and 30% or less for persistent atrial fibrillation. For multiple procedures, the majority reported success rates of 70% or more for paroxysmal atrial fibrillation and 50% or more for persistent atrial fibrillation.1 Outcomes varied based on differences in technique, experience, skill, and follow-up.
In 2005, the first worldwide, multicenter survey on catheter ablation was published using data from 181 centers from 1995–2002. It indicated that 52% of patients having an atrial fibrillation catheter ablation were successful and symptom-free without antiarrhythmic drugs. An additional 23.9% were successful but were on antiarrhythmic drugs. For many, those drugs did not work prior to the ablation. Achieving this success required a second procedure for 24.3%, and a third procedure for 3.1%. Success rates were highest in high-volume centers.2
The second worldwide multicenter survey, on catheter ablations performed from 2003–2006, has subsequently been published and showed an improvement in treatment success. The success rate was 70% without antiarrhythmic drugs vs. 52% in the first survey. The overall success rate, which included patients who continued to take antiarrhythmic drugs, was 80% in the second survey vs. 75.5% in the first. What that means is that only 10% of patients in the second survey had to remain on antiarrhythmic drugs vs. 23.9% in the first survey. More than one ablation procedure was needed to achieve these success rates, but the second survey did not indicate what percentage of patients had second and third procedures. When broken down by type of afib, the success rate without antiarrhythmic drugs was 75% for paroxysmal afib, 65% for persistent afib, and 63% for longstanding persistent afib.3
The second worldwide survey showed that doctors were starting to treat more patients with persistent and longstanding persistent atrial fibrillation with catheter ablation. In the first survey, only 53% of centers performed catheter ablation on patients with persistent atrial fibrillation whereas in the second, 86% of centers treated persistent afib. Similarly, only 20% of centers in the first survey treated patients with longstanding persistent atrial fibrillation, which increased to 47% of centers in the second worldwide survey.
Since the second worldwide survey used data on procedures only up until 2006, safety and efficacy should be expected to be higher today using current procedures and experience rates, particularly in high-volume centers. Some centers today cite success rates of 80%–85% for first ablations and 95% for second ablations, but there are variances in how different centers measure success.
Measuring Catheter Ablation Success
The HRS Expert Consensus Statement set guidelines for catheter ablation trials. Immediately after the procedure, there is a three-month "blanking period" during which time atrial fibrillation episodes can occur as part of the body's healing response to the procedure. Any afib activity during that blanking period is not counted in a study's results. After the blanking period, the HRS Expert Consensus Statement defines success as "freedom from afib, atrial flutter or tachycardia" and discontinuation of antiarrhythmic medication. Patients participating in clinical studies should be followed at least 12 months and, at minimum, should have a 24-hour Holter monitor at three months, six months, one year, and two years.1
Not all doctors involved in clinical studies follow the HRS Expert Consensus Statement guidelines, so when looking at treatment success rates, it's important to look at these three factors:
How treatment success was defined — Some studies have a strict definition of treatment success—freedom from atrial fibrillation and antiarrhythmic drugs after a single procedure—while others may count as successes patients who remain on antiarrhythmic medication or who have had multiple procedures. How success is defined can be meaningful because if a study shows a 90% success rate, but only 10% of patients were able to stop taking antiarrhythmic drugs, then you might question the effectiveness of the treatment.
What type of monitoring was used after treatment — Most studies officially start tracking a patient's heart rhythm three months after a procedure as the first three months are considered a "blanking period". Monitoring methods include patient questionnaires about symptoms, an electrocardiogram (ECG) performed in the doctor's office, a Holter monitor (24-hour, 48-hour, seven-day, or longer), an event monitor, or an implantable loop recorder. An implantable loop recorder (a small device implanted under the skin in the chest area) is the most rigorous follow-up method, and the patient questionnaire is the least. Most studies use a 24- or 48-hour Holter monitor to determine whether atrial fibrillation episodes occur following treatment.
What was the length of follow up — Most studies report on treatment successes and failures at one year following the procedure. Generally, success rates that are based on follow up of less than 12 months should be considered preliminary and subject to change as a sizeable percentage of people have an afib recurrence within the first year. In fact, about 30% of patients undergo a second procedure within the first year to treat atrial fibrillation recurrence.
Only you can decide what defines treatment success for you. Success may mean freedom from atrial fibrillation and the ability to stop antiarrhythmic medication after one catheter ablation for some people, but for others, alleviation of symptoms, even though they have to remain on antiarrhythmic drugs, may mean success.
If you're considering a procedure, ask about the catheter ablation success rate for the specific electrophysiologist and for the center in which it would be done. Also ask about how they define success, such as with or without antiarrhythmic drugs and the number of procedures, and how success is measured, such as by event monitoring, and at what intervals it is measured. It also wouldn't hurt to ask for their success rates and complication rates for the specific technology and tools to be used on you.
If you're considering a catheter ablation, you need to know about Catheter Ablation Risks.