Radiofrequency Catheter Ablation of Type 1 Atrial Flutter Using Large-Tip 8 or 10 mm Electrode Catheters and a High-Output Radiofrequency Energy Generator

• Results
• Design
• Patient Population
• Clinical Relevance
• References

Results

Design

• Prospective, multicenter, single-arm study using objective performance criteria and historical control data from the medical literature.


• Eligible patients had sustainedor recurrent Type 1 atrial flutter.


• Procedural success was defined as complete bidirectional isthmus block with noninducible Type 1 atrial flutter with only the use of the Blazer II XP Catheter and EPT-1000XP™ Cardiac Ablation System and accessories.


• Chronic success was demonstration of acute procedural success and continued absence of targeted type 1 atrial flutter for 6 months after the ablation procedure.


• Procedural safety was the absence of serious complications associated with the use of the Blazer II XP Catheter and EPT-1000XP System within 7 days of the ablation procedure.


• Clinical follow-up was performed at 1, 3, and 6 months, and at 1 and 2 years following the procedure.

Patient Population

Eligible study participants included both male and female patients over 18 years of age that had experienced ≥2 documented episodes of atrial flutter (by ECG, Holter, rhythm strip or ICD) within 6 months prior to enrollment or who had ≥1 documented episodes of atrial flutter (ECG, Holter, rhythm strip, or ICD) during the 6 months preceding study enrollment. Some of the exclusion criteria were:

• Patients with a direct remedial cause of atrial flutter (e.g., thyroid disease, pericarditis, pulmonary embolic disease)
• Patients with any prior isthmus cardiac ablation for Type 1 AFL
• Patients in treatment for non-atrial flutter (Type 1) arrhythmias with anti-arrhythmic drugs (class IA, IC, or III) within 3 months preceding study entry
• Patients who received cardiac ablation or cardioversion for other types of non-atrial flutter (Type 1) arrhythmias within 3 months preceding study entry

 23 U.S. centers
 250 patients enrolled

Clinical Relevance

• To evaluate the safety and effectiveness of large-tip catheter ablation in patients with Type 1 atrial flutter
• The primary endpoints were acute procedural success, chronic (6 month) success, and complication rate per Bayesian analysis
• First trial to demonstrate the safety and effectiveness of 8 and 10 mm tip catheters used with a 100 W system for the treatment of Type 1 atrial flutter

References

1. Summary of Safety and Effectiveness Data. Blazer II XP Cardiac Ablation Catheter, Boston Scientific Corporation, 2003. Data can be found at: www.fda.gov/ohrms/dockets. Enter product name into search field.

2. Of the 235 acute success patients, 84 patients were not included in the follow-up: 30 patients had not completed their 6-month follow-up at the time the Summary of Safety and Effectiveness Data was reported to the FDA, and 54 were not considered due to: persistent atrial fibrillation (1), death (5), withdrawal or lost to follow-up (6), implanted pacemakers or defibrillators (11), and treatment with Class IA, IC, or III antiarrhythmic drugs (31).

3. Patients who reached 6-month follow-up and were not on class IA, IC, or III antiarrhythmic drugs.

4. Total procedure time defined as the time of first diagnostic catheter insertion until the last diagnostic catheter withdrawal (Source: BSCI/EP Technologies US Atrial Flutter Study Procedure Logistics Form, Rev G – 7/12/2001 – PROCLOG2).

Additional References

Feld G, Wharton M, Plumb V, Daoud E, Friehling T, Epstein L, for the EPT-1000 XP Cardiac Ablation System Investigators. Radiofrequency catheter ablation of type 1 atrial flutter using large-tip 8- or 10-mm electrode catheters and a high-output radiofrequency energy generator: Results of a multicenter safety and efficacy study. J Am Coll Cardiol 2004; 43:1466-1472.