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

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.

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)