Paroxysmal AF is defined as AF that comes and goes on its own, lasts for less than a week and typically does not require cardioversion.
Once stroke risk has been quantified and addressed (with anticoagulation where necessary), the goal of treatment is primarily to improve the symptoms which the AF causes. These can include palpitations, shortness of breath, fatigue, lethargy and dizziness. Typically we try medications in the first instance (either regularly or as needed – “pill-in-the-pocket”). However these medications often do not abolish symptoms and then catheter ablation is considered.
In around 95% of people who have paroxysmal AF, this originates as a result of ectopic beats originating from the pulmonary veins, which are extra electrical impulses which trip the heart up to go out of rhythm; this was originally described in the late 1990s. This led to a treatment strategy called pulmonary vein isolation. The intention of this approach is to cause deliberate localised damage to the wall of the heart where these extra electrical impulses come into the heart so as to stop them from being able to trigger AF.
You can read more about this in the catheter ablation of AF section.
The two predominant strategies we use in order to isolate the pulmonary veins are radio-frequency (RF) ablation and cryo-ablation. RF ablation involves causing small localised burns whereas cryo-ablation involves freezing the part of the heart (in this case, the left atrium) allowing AF to occur. These two strategies were compared in a randomised head-to-head trial called FIRE AND ICE which was published recently.
This study demonstrated that the two technologies are equivalent in terms of their safety and effectiveness, so both approaches are reasonable options for catheter ablation in patients with paroxysmal AF.