AF is not only the most common cardiac arrhythmia,it is also an extensively researched entity in cardiology literature. We are trying to rein in, this arrhythmia for the past three decades with multiple strategies. Drugs, pacemakers, ICDs devices, surgical cuts, RF catheters, and the latest technique is trying to frostbite the atrial electrical circuits with ICE. ( Karl-Heinz Kuck,N Engl J Med 2016 )
It is believed that up 60% of AF originate from pulmonary veins. What does it mean? So, when we blindly suggest PV Isolation routinely for all PAF, there is 40% futility straightaway! Apart from the hugely variable anatomy of the pulmonary veins, there are prohibitive levels of recurrence due to PV reconnections. Maybe, will find new technical solutions as we are now moving in 2nd or third generation cryo balloons, 4D imaging, contact force sensing, etc. But let us not forget there are other sources of focal electrical activity too
Importance of non-PV ectopic beats initiating AF(Ref 1,2)
- Superior vena cava (SVC),
- left atrial posterior free wall (LPFW),
- LA appendage
- crista terminalis (CT),
- coronary sinus ostium (CSO),
- Ligament of Marshall
- Interatrial septum (IAS)
Ablation or no ablation, we need to reflect on two things in the management of AF.
1. AF can be triggered by totally different mechanisms like intermittent hypoxia, adverse electrolytic flux, diffuse atrial interstitial pathology or amyloid, etc. Before calling the appointment desk of the EP guy’s office please rule out all the systemic causes. This could be your last (lost) chance to save the atria from pulmonary burns.
2. This one is more important. Read carefully. It is not a divine protocol that demands us to restore sinus rhythm in all patients with AF. There is an excellent knowledge base, backed up by wonderfully done studies. (Need not mention the trial name, I think) that should effectively neutralize our compulsive & misplaced urge to bring back sinus rhythm in all chronic AF.
With respect to the overall outcome, It hardly matters whether you treat the AF by rate control or rhythm control. While there is major technological leap in our fight with AF.It is heartening to know simple measures like regular exercise can control or reverse AF by atrial fatty mass regression.
Final message
We have played with fire for quite some time within the innocent lesser chambers of the heart (RF ablation) and burnt our reputation considerably. Now, silently we have decided to fall for a more friendly weapon ICE. But we must remember our obsession with the pulmonary vein as the only source of initiation of AF is essentially flawed. Further, all these hyper-technology-based combat of AF is indicated only in a fraction of our patients (Maybe 5-10%)
Reference
Postamble
If you think this write-up is too biased, please read the CABANA trial fully before ditching this post into the dustbin.
Dr.S.Venkatesan MD 