Atrial fibrillation (AF) is the most common heart rhythm disorder, impairs quality of life
and increases stroke risk and mortality. Despite advances in medical treatment, AF remains
uncontrolled in many patients. In many patients, AF is initiated by abnormal electrical
impulses from the pulmonary veins. A catheter ablation procedure called pulmonary vein
isolation (PVI) has therefore been developed, using heat to isolate the PV foci from the
heart. PVI is very effective, but must be repeated in up to 50% of cases because the foci
isolation is not permanent after initial PVI. The intravenous administration of a drug called
adenosine during the PVI procedure can unmask residual conduction that would otherwise remain
unnoticed, so-called "dormant conduction". In our experience, additional ablation guided by
adenosine reduces AF recurrence and the need for a repeat PVI procedure. However, the
adenosine-guided approach has not yet been proven as standard therapy. The present study, to
be conducted at 15 clinical centres in Canada, Europe and Australia is therefore intended to
evaluate the efficacy of adenosine-guided ablation to prevent AF recurrence. Five hundred
twenty-six patients will be included in the study, which should be completed within 2 years.
In all patients, the presence of dormant conduction will be tested with adenosine during PVI.
If dormant conduction is observed, additional ablation will be performed in half of these
patients selected randomly. If there is no dormant conduction, randomly selected patients
will be followed in a registry. If the adenosine-guided approach is demonstrated to improve
the success rate of PVI procedures, it should become the standard approach for a "permanent
cure" of AF, and therefore benefit patients by reducing arrhythmia recurrence,
hospitalizations and the need for repeat interventions.