NEW YORK, NY. Most successfully ablated afibbers, myself included, do wonder sometimes if their cure is permanent or whether "the beast" will eventually rear its ugly head again. Researchers at the St. Luke's-Roosevelt Hospital Center now report on the long-term "durability" of initially successful pulmonary vein isolation (PVI) procedures.
Their study involved 350 consecutive patients (65% male) with paroxysmal (86%) or persistent (14%) atrial fibrillation. The authors do not state the proportion of lone afibbers in the group; however, 41% had hypertension, 29% had hyperlipidemia, and 15% had coronary artery disease. All patients underwent a standard PVI with no additional lesions. At the end of the first year following the procedure, 264 patients (75%) were still in normal sinus rhythm without the use of antiarrhythmics. These patients were followed for an additional 34 months (on average) during which time 20 paroxysmal (8.7%) and 3 persistent (8.8%) afibbers experienced recurrent bouts of symptomatic afib. The risk of recurrence was substantially higher among those with hypertension (70% vs. 39%) and hyperlipidemia (61% vs. 30%). None of the 264 patients were taking antiarrhythmics; however, 57% were on beta-blockers, 48% on statins, 14% on ACE inhibitors, and 10% on angiotensin II receptor blockers.
An actuarial calculation concluded that the recurrence rate was 5.8% at 2 years, 8.8% at 3 years, 13% at 4 years, and 25% at 5 years. However, the authors point out that the number of observations made at the 4- and 5-year marks were not sufficient to achieve statistical significance.
Eighteen of the 23 patients with late recurrence underwent a repeat PVI with additional linear lesions as necessary. In each case, mapping showed that electrical conduction had been re-established between the left atrium and at least one pulmonary vein. The researchers conclude that recurrence of afib after a seemingly successful PVI is related to one or more of the following factors:
Shah, AN, et al. Long-term outcome following successful pulmonary vein isolation: pattern and prediction of very late recurrence. Journal of Cardiovascular Electrophysiology, Vol. 19, July 2008, pp. 661-67 Editor's comment:
- Presence of hypertension and/or hyperlipidemia (elevated levels of LDL cholesterol and/or triglycerides).
- Resumption of electrical connection at previously ablated sites.
- Failure to target all pulmonary veins during the initial ablation.
- Emergence of triggers outside the areas encircled by the PVI procedure.
- Progression of heart disease and modification of atrial substrate that would promote AF.
When considering the above conclusion that about 9% of afibbers undergoing an initially successful PVI can expect to be back in afib within 3 years, it should be kept in mind that this conclusion is unlikely to apply to a healthy lone afibbers without hypertension or hyperlipidemia who had their ablation performed by a highly skilled EP, especially if this EP took the time to look for triggers outside the pulmonary veins and eliminate them. I am not aware of any published data on this, but from my own survey (and gut feel), I would be very surprised if the percentage of lone afibbers who go back into afib after 3-5 years would exceed 3% - assuming that their PVI was performed by a highly skilled EP. Incidentally, the 9% figure for long-term relapse is very similar to the published figure of 8% for the Cox maze procedure.