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

Hypothesis:

• Adenosine reveals incomplete conduction block due to partial tissue injury/stunning during catheter ablation of atrial fibrillation.
• 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:

• 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.
• Patients will be randomized to further ablation to achieve complete isolation during adenosine infusion vs to no further ablation.
• 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.
• 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

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

Exclusion criteria

• History of asthma
• Patients with severe coronary artery disease, stable/unstable angina, or ongoing myocardial ischemia
• Previous cardiac surgery ( excluding CABG and mitral valve surgery)
• Symptomatic congestive heart failure including but not limited to NYHA III/IV and/or documented ejection fraction <40% measured by acceptable cardiac testing,
• Left atrial diameter >55mm
• Moderate to severe mitral or aortic valve disease
• Myocardial infarction within three months of enrollment
• Congenital heart disease where it increases the risk of an ablative procedure
• Prior ASD/PFO closure with a device using a percutaneous approach
• Hypertrophic cardiomyopathy (LV wall thickness >1.5mm)
• Pulmonary Hypertension (mean or systolic PA pressure> 50mmHg on Doppler echocardiography
• Any prior ablation of atrial fibrillation
• Enrollment in any other arrhythmia protocol
• Any ventricular arrhythmia being treated where the arrhythmia or management may interfere with this study
• Active infection or sepsis
• Any history of cerebrovascular disease including stroke or TIAs
• Pregnancy or lactation
• Left atrial thrombus at the time of ablation
• Untreatable allergy to contrast media
• Any diagnosis of atrial fibrillation secondary to electrolyte disturbance, thyroid disease, or any other reversible or non-cardiovascular causes
• History of blood clotting(bleeding or thrombotic) abnormalities
• Known sensitivities to heparin or warfarin
• Severe COPD (defined as FEV1 <1)
• 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)