Pulmonary Vein Isolation for Atrial Fibrillation

Pulmonary Vein Isolation for Atrial Fibrillation

Abstract: Pulmonary vein isolation is the process of electrically isolating the pulmonary veins from the left atrium so that tachycardia focus in the pulmonary vein does not get conducted to the left atrium and cause atrial fibrillation.

Pulmonary vein isolation is extensively used for management of paroxysmal atrial fibrillation and selected cases of persistent atrial fibrillation. Tachycardia foci in the pulmonary veins which initiate atrial fibrillation are mapped and ablated. It may be combined with other ablation lines for management of atrial fibrillation. PVI can be either a catheter procedure done in the electrophysiology laboratory or a surgical procedure¹ done concomitantly with surgery for mitral valve disease.

Catheter based pulmonary vein isolation

In the initial era of catheter based PVI, ablation was carried out directly within the pulmonary veins. Some of these procedures were complicated by the development of pulmonary vein stenosis later. Later it was found that ablation of the junction between the pulmonary vein and left atrium was more effective. Overall more than two thirds of patients get relief from recurrence of atrial fibrillation with PVI.

Re-ablation may be useful in case of recurrences. PVI is usually recommended for drug refractory symptomatic paroxysmal atrial fibrillation. It may also be considered in case of intolerance or reluctance to pharmacotherapy. Success rates of PVI are much less in those with long standing or persistent atrial fibrillation than in paroxysmal atrial fibrillation.²

Pulmonary vein ablation has been found to be superior to ablation of atrioventricular node with implantation of biventricular pacemaker in patients with heart failure.² In that study Khan MN and colleagues randomly assigned those with drug refractory symptomatic atrial fibrillation and ejection fraction of 40% or below with NYHA Class II or III heart failure to either PVI or ablation of the atrioventricular node with biventricular pacing.

There were about forty patients in either groups. Those who underwent PVI had a better symptomatic outcome, longer six minute walk time and higher ejection fraction. Complications noted in pulmonary vein isolation group were pulmonary vein stenosis in two, pericardial effusion in one and pulmonary edema in another. One of the patients who underwent biventricular pacing had lead displacement while another had pneumothorax.

Cryoballoon ablation

Cryoballoon ablation uses cryoballoon instead of the conventional radiofrequency catheter for pulmonary vein isolation. Dedicated catheters capable of achieving PVI with a single ablation lesion have been developed. A review in 2020 by Jason G Andrade has discussed the role of cryoballoon ablation in the invasive management of atrial fibrillation [4].

References

1. Accord RE, van Brakel TJ, Maessen JG. The rationale of surgical pulmonary vein isolation for treatment of atrial fibrillation. Neth Heart J. May 2005; 13(5): 181-185.
2. Keane D, Ruskin J. Pulmonary vein isolation for atrial fibrillation. Rev Cardiovasc Med. 2002 Fall;3(4):167-75.
3. Khan MN, Jaïs P, Cummings J, Di Biase L, Sanders P, Martin DO, Kautzner J, Hao S, Themistoclakis S, Fanelli R, Potenza D, Massaro R, Wazni O, Schweikert R, Saliba W, Wang P, Al-Ahmad A, Beheiry S, Santarelli P, Starling RC, Dello Russo A, Pelargonio G, Brachmann J, Schibgilla V, Bonso A, Casella M, Raviele A, Haïssaguerre M, Natale A; PABA-CHF Investigators. Pulmonary-vein isolation for atrial fibrillation in patients with heart failure.N Engl J Med. 2008 Oct 23;359(17):1778-85.
4. Andrade JG. Cryoballoon ablation for pulmonary vein isolation. J Cardiovasc Electrophysiol. 2020 Aug;31(8):2128-2135. doi: 10.1111/jce.14459. Epub 2020 Apr 13. PMID: 32239557.