Adenosine to Assess Complete Conduction Block During Catheter Ablation of Paroxysmal Atrial Fibrillation

The purpose of this study is to determine if additional ablation during the first procedure as the result of the ability to medically induce quiet atrial arrhythmias will improve clinical outcome in patients with atrial fibrillation thus decreasing the need for additional ablation procedures.

Hypothesis:

1. Adenosine reveals incomplete conduction block due to partial tissue injury/stunning during catheter ablation of atrial fibrillation.
2. Identification of incomplete conduction block by adenosine improves clinical outcomes including an increase in efficacy and a decrease in need for repeat procedures after catheter ablation of atrial fibrillation.

Objectives:

1. In patients with paroxysmal Atrial Fibrillation (AF), the prevalence of Pulmonary Vein (PV) reconnection during adenosine infusion after complete PV isolation using conventional techniques will be determined.
2. Patients will be randomized to further ablation to achieve complete isolation during adenosine infusion vs to no further ablation.
3. Primary endpoint of the study will be freedom from any atrial arrhythmias 6 months after a single ablation procedure in the absence of antiarrhythmic drug therapy.
4. Secondary endpoints will include number of repeat ablation procedures because of documented recurrence of symptomatic AF or atrial flutter/tachycardia, outcome after 2 ablation procedures; Proportion of patients with AF or atrial flutter/tachycardia occuring during the first three months post ablation, prevalence of recovery of conduction into PVs during repeat ablation procedures in both groups, procedure duration, and incidence of peri-procedural complications including stroke, PV stenosis, cardiac perforation, atrio-esophageal fistulae, and death.

Eligibility Criteria:
Inclusion Criteria:

1. Patients \>18 and \<75 who are able to give informed consent undergoing atrial fibrillation ablation procedure.
2. Paroxysmal Atrial fibrillation lasting = 7 days which is self-terminating. It is considered recurrent if two or more episodes occur.
3. Failure or unwilling to take class I or III anti-arrhythmic drugs

Exclusion Criteria:

1. History of asthma
2. Patients with severe coronary artery disease, stable/unstable angina, or ongoing myocardial ischemia
3. Previous cardiac surgery ( excluding CABG and mitral valve surgery)
4. Symptomatic congestive heart failure including but not limited to NYHA III/IV and/or documented ejection fraction \<40% measured by acceptable cardiac testing,
5. Left atrial diameter \>55mm
6. Moderate to severe mitral or aortic valve disease
7. Myocardial infarction within three months of enrollment
8. Congenital heart disease where it increases the risk of an ablative procedure
9. Prior ASD/PFO closure with a device using a percutaneous approach
10. Hypertrophic cardiomyopathy (LV wall thickness \>1.5mm)
11. Pulmonary Hypertension (mean or systolic PA pressure\> 50mmHg on Doppler echocardiography
12. Any prior ablation of atrial fibrillation
13. Enrollment in any other arrhythmia protocol
14. Any ventricular arrhythmia being treated where the arrhythmia or management may interfere with this study
15. Active infection or sepsis
16. Any history of cerebrovascular disease including stroke or TIAs
17. Pregnancy or lactation
18. Left atrial thrombus at the time of ablation
19. Untreatable allergy to contrast media
20. Any diagnosis of atrial fibrillation secondary to electrolyte disturbance, thyroid disease, or any other reversible or non-cardiovascular causes
21. History of blood clotting(bleeding or thrombotic) abnormalities
22. Known sensitivities to heparin or warfarin
23. Severe COPD (defined as FEV1 \<1)
24. Severe comorbidity or poor general physical/mental health that, in opinion of the investigator, will not allow the patient to be a good study candidate (i.e. other disease processes, mental capacity, substance abuse, shortened life expectancy)