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:

• 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.

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: 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.