HAMBURG, GERMANY. A group of electrophysiologists at St. Georg Hospital in Hamburg report their first long-term outcomes of catheter ablation for symptomatic, paroxysmal atrial fibrillation (AF). The study included 161 patients (75% men) with an average age of 60 years. The majority (80%) had no structural heart disease (lone AF), but 67% did have hypertension and 12% had coronary artery disease. The patients all underwent an anatomically-guided circumferential pulmonary vein isolation procedure (CPVI) with the endpoint being the absence of any electrical connection between the pulmonary veins and the left atrium 30 minutes after completing the procedure (measured with two Lasso catheters placed within the ipsilateral veins).
During a median follow-up period of 4.8 years, 53.4% of the patients experienced one or more atrial arrhythmias (AF, atrial flutter or atrial tachycardia) lasting more than 30 seconds and identified with ECG or Holter monitoring. The time intervals from procedure completion to the first atrial arrhythmia were as follows:
- Within 1st month - 36 patients (41.9%)
- Between 1 and 3 months - 7 patients (8.1%)
- Between 3 and 6 months - 7 patients (8.1%)
- Between 6 and 12 months - 12 patients (14.0%)
- Between 12 and 24 months - 14 patients (16.3%)
- Between 24 and 36 months - 2 patients (2.3%)
- Between 36 and 48 months - 4 patients (4.7%)
- Between 48 and 60 months - 3 patients (3.6%)
- More than 5 years later - 1 patient (1.2%)
Sufficient clinical improvement was observed in an additional 15 patients (9.3%) who did not require a repeat procedure. It would seem, considering the above date, that having a blanking period of a month or even 3 months could conceivably improve the single procedure success rate from 46.6% to closer to 70%.
Sixty-six patients underwent a second procedure a median of four months from the initial procedure with 56% of the repeats being done three months after the first procedure. Recovered pulmonary vein conduction was observed in 94% of patients. The success rate (no AF, no antiarrhythmics) was 74% after the second procedure. Finally, a third procedure was performed on 12 patients (a median of 21 months after the second procedure) bringing the final success rate to 79.5% after a median follow-up of 4.6 years.
The German researchers also introduced the term "clinical improvement" which was defined as having a greater than 90% reduction in atrial arrhythmia recurrence with or without the use of previously ineffective antiarrhythmics. According to this definition, 13% of patients achieved clinical improvement during a median follow-up of 4.6 years. They point out that only one patient progressed to permanent AF during the study and conclude that CPVI results in stable sinus rhythm in the majority of patients with paroxysmal AF and normal left ventricular function. Ouyang, F, et al. Long-term results of catheter ablation in paroxysmal atrial fibrillation: Lessons from a 5-year follow-up. Circulation, Vol. 122, December 7, 2010, pp. 2368-77 Editor's comment:
The results reported by the German group are indeed encouraging with a 79.5% complete success rate after a median follow-up of almost five years. However, it should be kept in mind that it required 1.5 procedures per patient, on average, to achieve this result. The finding that another 13% of the patients experienced a 90% reduction in their episode frequency is also a cause for celebration bringing the percentage of patients who benefited from the procedures at the 5-year mark to 93%.