PVI Using Cryoablation Alone in Paroxysmal AF Patients Converted From Persistent AF With Dofetilide

Pulmonary vein isolation is now considered a cornerstone of all atrial fibrillation (AF)
ablation procedures. In patients with paroxysmal AF, pulmonary vein isolation alone is
usually sufficient. The cryoballoon is now FDA approved to achieve PVI in patients with
paroxysmal AF.

Although no ablation system is yet approved in patients with persistent AF, these patients
are increasingly undergoing ablation. Many investigators feel that these patients have more
atrial disease and thus PVI alone is insufficient in these patients. As a result, it is
common for these patients to undergo additional ablation, which is often quite extensive and
exposes patients to proarrhythmia. Commonly utilized strategies include linear lesions (left
atrial roof; mitral isthmus line), ablation of complex fractionated atrial electrograms
(CFAEs), left atrial appendage isolation and/or even right atrial ablation. For years, the
investigators have been concerned about the adverse effects of this additional ablation. The
investigators postulated that the "answer" is not more ablation but trying to "reverse
remodel" patients with persistent AF back to a paroxysmal form, whereby PVI alone would
again be justified and sufficient. The efficacy of such a strategy has previously been
demonstrated.

In brief, the investigators start patients with persistent AF on dofetilide 3 months prior
to scheduled ablation. In 96% of patients, AF either suppresses completely or is transformed
into a paroxysmal pattern. The net effect is "reverse remodeling" of the left atria. The
investigators have confirmed this by using a reduction in P wave duration as a surrogate of
remodeling. At the ablation procedure, the investigators perform PVI alone.

Inclusion Criteria:

- Aged 18 to 80 years

- Able and willing to give written informed consent

- Paroxysmal AF, defined as recurrent AF ( ≥ 2 episodes in 1 month) that terminates
within 7 days as assessed by ECG recordings

- Prior persistent AF, defined as sustained beyond seven days and up to one year,
successfully converted to paroxysmal AF by dofetilide

Exclusion Criteria:

- Previous ablation for AF

- Left atrial size larger than 60mm (parasternal view on transthoracic echocardiogram)

- Patients who have AF episodes triggered by another uniform arrhythmia (e.g. atrial
flutter or atrial tachycardia)

- Presence of severe valvular disease with the need for surgical correction

- AF deemed secondary to a transient or correctable abnormality including electrolyte
imbalance, trauma, recent surgery, infection, toxic ingestion, and endocrinopathy

- Pregnant women or women of child bearing potential and not on reliable methods of
birth control

- Second or third degree AV block, sinus pause > 3 seconds, resting heart rate< 30 bpm
without permanent pacemaker

- History of drug-induced Torsades de Pointes or congenital long QT syndrome

- Uninterrupted AF for more than 12 months prior to randomization unless sinus rhythm
maintained for ≥ 24 hours after cardioversion.