VENEZIA, ITALY. Most clinical trials and studies of the efficacy of catheter ablation for atrial fibrillation (AF) have very limited follow-up and evidence concerning long-term maintenance of normal sinus rhythm (NSR) is scarce indeed. A group of Italian electrophysiologists have just published the results of a study involving follow-ups as long as 6 years. Between February 2001 and October 2003, 229 patients with paroxysmal or persistent AF underwent a single radiofrequency (RF) procedure (segmental approach in 83 patients and anatomical [CARTO] approach in 146 patients). At the 12-month follow-up point, 177 (58% paroxysmal and 42% persistent) of these patients had not experienced any afib or flutter. However, 19% used antiarrhythmics to maintain NSR, thus giving a complete success rate (no afib, no antiarrhythmics) of 58% for the original 229 patients.
The 177 patients (57% had no underlying heart disease) who remained free of afib one year after the ablation were followed for up to 6 years. The percentages of study participants who experienced afib recurrence at the end of the specified year are given below:
- Year 1 – 0%
- Year 2 – 13%
- Year 3 – 22%
- Year 4 – 35%
- Year 5 – 47%
- Year 6 – 55%
Afib-free survival was similar in patients with paroxysmal AF and in those with persistent AF, and there was no difference in afib-free survival between those on antiarrhythmics and those not on these drugs. There was a trend for afibbers with a small left atrium to be more likely to maintain NSR. There was no difference in long-term outcome between patients who had been treated with the segmental protocol and those who had undergone an anatomically-guided ablation.
The recurrent arrhythmias in patients who had paroxysmal AF prior to their ablation were mostly (75%) paroxysmal in nature, but in 25% of originally paroxysmal afibbers, the recurrent arrhythmia was permanent. In the case of originally persistent afibbers, 21% of recurrent arrhythmias were paroxysmal, 48% were persistent, and 31% were permanent. After 4 years, 58.2% of patients (45% of the original 229) were free from arrhythmia with (18.6%) or without (39.6%) the use of antiarrhythmics. The authors of the study conclude that, "Data from published studies and from our experience seem to confirm that success over a 12-month follow-up does not necessarily guarantee long-term success, and that the early hope of AF ablation being a 'curative' procedure continues to be shattered by the harsh reality that AF does in fact recur after a several-month blanking period."
NOTE: The authors point out that their experience with the segmental protocol was limited, perhaps explaining why the outcome of the segmental protocol was not superior to that of the anatomically-guided one. Bertaglia, E, et al. Does catheter ablation cure atrial fibrillation? Europace, Vol. 12, 2010, pp. 181-87 Editor's comment
: The conclusion of this study is certainly not encouraging and is in sharp contrast to the conclusion reached in our 2009 ablation/maze survey involving 88 afibbers who had gone at least 4 years since their latest ablation procedure. "Of the 88 respondents undergoing RF ablation, 55 (63%) underwent only a single procedure, while 33 (37%) underwent 2 or more procedures for the purpose of curing AF. The most widely used and most successful procedure for paroxysmal AF was the pulmonary vein antrum isolation procedure developed by Dr. Andrea Natale followed by the segmental pulmonary vein ablation (Haissaguerre technique), which was especially successful among persistent and permanent afibbers. The most important variable determining long-term success was whether or not a respondent had an initially successful procedure, i.e. they remained in sinus rhythm without the use of antiarrhythmics during the last 6 months of the 12-month period following their final procedure (index period). This, in turn, was dependent on the ranking of the institution at which the final procedure was performed, and on the incidence of AF during the first 6 months following the final procedure (blanking period). In conclusion, the long-term prognosis for an afib-free future with no antiarrhythmics after an initially successful catheter ablation is excellent with 87% of paroxysmal afibbers and 82% of persistent and permanent afibbers achieving this enviable state in the period 5 to 6 years following their final procedure. In comparison, in the initially unsuccessful group only 33% of paroxysmal afibbers and 33% of persistent and permanent afibbers achieved this status. There is also encouraging news for those afibbers whose final procedure was not successful. At the end of year 4, 27% of respondents were still experiencing afib episodes. However, their frequency was down by 95% from pre-procedure levels and the total time spent in afib was down from 7% to 0.2% for paroxysmal afibbers. The reduction in afib burden from pre-procedure days to year 4 was 97% and this decline was pretty well universal with only 1 of 16 respondents reporting an increase in burden. The decline in afib frequency and burden continued throughout years 5 and 6, but then suffered a slight reversal in years 7-10."