CLEVELAND, OHIO. The Cleveland Clinic has finally released data concerning long-term success of pulmonary vein antrum isolation (PVAI) procedures with the aim of curing atrial fibrillation (AF). The study included 831 patients who underwent a PVAI in 2005. The average age of the patients was 59 years, 78% were male, and 86% had no underlying heart disease (lone AF). The majority (69%) had paroxysmal afib, 20% had the persistent variety, and the remaining 11% had permanent (long-standing persistent AF). All patients underwent PVAI, and 79% also had ablation at the superior vena cava. The study participants were followed for an average of 55 months, with the most recent update in October 2009. Follow-up examinations (including 24-hour Holter monitoring) were done 3, 6 and 12 months post-ablation, and yearly thereafter.
Arrhythmia recurrence was recorded when patients reported symptoms of arrhythmia and/or when an atrial tachyarrhythmia (AF, atrial flutter or atrial tachycardia), lasting 30 seconds or longer, was captured on a 12-lead electrocardiogram, event recorder, or Holter monitor recording. Atrial arrhythmias occurring during the two months following the procedure (blanking period) were not counted as recurrences since they do not necessarily imply failure of the procedure. NOTE: 39% of patients had documented arrhythmia during the blanking period, and 80% during the first month following the ablation. However, 40% of ablatees having arrhythmia during the blanking period were free of arrhythmia at the 12-month check-up.
Twelve months post-ablation, 76.2% of study participants were arrhythmia-free without the use of antiarrhythmic drugs (AADs), while 23.8% had experienced one or more arrhythmia episodes, mostly (83%) atrial fibrillation. At the five-year follow-up, 63% of patients having undergone a single procedure were arrhythmia-free without the use of AADs. It is of interest to note that 87% of ablatees who were arrhythmia-free at 12 months were also arrhythmia-free at 44 months. This indicates a highly favourable long-term prognosis for afibbers who are arrhythmia-free at 12 months.
Of the 198 patients experiencing arrhythmia during the first 12 months (early recurrence), 161 (81.3%) underwent repeat ablations which, after an average 14 months of follow-up, were completely successful (no arrhythmia, no AADs) in 78.9% of cases, and partially successful (no arrhythmia, but still taking AADs) in 13.7% of cases. Of the 74 patients experiencing late recurrence (arrhythmia episodes after the 12-month follow-up), 27 underwent a repeat ablation which was completely successful in 74.1% of cases, and partially successful in 25.9% of cases after 17 months of follow-up. At last follow-up (median 55 months from initial ablation), 660 of 785 patients (46 patients were lost to long-term follow-up) were free of arrhythmia without the use of AADs (84%) after a total of 1019 ablations (1.2 per patient). Another 11% was arrhythmia-free with the use of AADs, leaving only 5% failures that were managed with beta- or calcium channel blockers.
The incidence of procedure-related complications was low at 2.4%. and no procedure-related deaths were observed during follow-up. Antiarrhythmic therapy was continued for two months post-ablation, and warfarin was administered for at least one year post-procedure. Among the 587 patients with no arrhythmia recurrence at the 12-month check-up, warfarin was stopped in the 449 patients (76%) with a CHADS2 score of 2 or less, but continued in all patients with a CHADS2 score of 3 or higher. Over a median follow-up of 44 months, only one patient (0.6%) suffered an ischemic stroke, and this had minimal residual deficit. A multivariable Cox proportional hazards analysis showed that early recurrence was associated with older age, higher body mass index, persistent or permanent afib, reduced left ventricular ejection fraction, enlarged left atrium, and high levels of C-reactive protein and BNP (brain natriuretic peptide). Late recurrence, in contrast, was only associated with an enlarged left atrium, and persistent or permanent afib at baseline. The authors conclude that pulmonary vein isolation is safe and efficacious for long-term maintenance of sinus rhythm in patients with drug-resistant atrial fibrillation. Hussein, AA, Wazni, O, et al. Natural history and long term outcomes of ablated atrial fibrillation. Circulation: Arrhythmia and Electrophysiology, April 14, 2011 [Epub ahead of print] Editor's Comment:
The Cleveland data are a most welcome addition to the information available in regard to the likelihood that an initially successful pulmonary vein isolation (PVI) procedure will still keep an afibber arrhythmia-free for at least five years post-procedure. It is most encouraging to note that 87% of ablatees who were arrhythmia-free at 12 months were also arrhythmia-free at 44 months. This indicates a highly favourable long-term prognosis for afibbers who are arrhythmia-free at 12 months.
We now have five studies providing data on the long-term success of catheter ablation (PVI) in the treatment of atrial fibrillation.
- The San Diego study involved 71 paroxysmal afibbers that underwent an initial PVI procedure at the University of California (San Diego) Medical Center between January 1, 2002 and August 31, 2003 and were followed for a minimum of 5 years. Results were reported in American Journal of Cardiology, Vol. 104, 2009, pp. 366-72
- The afibbers.org 2009 ablation/maze survey involved 88 afibbers (78% paroxysmal) that underwent an initial PVI procedure at various hospitals and clinics between 1997 and 2005 and were followed for up to 10 years. Results were reported in the December 2009/January 2010 issue of The AFIB Report.
- The Hamburg study involved 161 afibbers that underwent an initial PVI procedure at the Asklepios Klinik St. Georg in Hamburg, Germany in 2003 and 2004 and were followed for a median of 4.6 years. Results were reported in Circulation, Vol. 122, 2010, pp. 2368-77
- The Bordeaux study involved 100 afibbers (64% paroxysmal) that underwent an initial PVI procedure at Hopital Cardioloque du Haut Leveque in Bordeaux, France between January 2001 and April 2002 and were followed for a minimum of 5 years. Results were reported in the Journal of the American College of Cardiology, Vol. 57, No. 2, January 11, 2011, pp. 160-66
- The Cleveland study involved 831 afibbers (69% paroxysmal) that underwent an initial PVI procedure at the Cleveland Clinic during 2005 and were followed for 55 months. Results were reported in Circulation: Arrhythmia and Electrophysiology, April 14, 2011 [Epub ahead of print]