Isolation of Pulmonary Veins With the Aid of Magnetic Resonance Imaging (ALICIA)

The ALICIA-FA study will elucidate whether targeting atrial myocardial fibrosis identified by late gadolinium-enhanced magnetic resonance imaging (LGE-MRI) improves atrial fibrillation (AF) ablation outcomes.

Atrial fibrosis is a hallmark of the AF substrate. An accurate identification and localization of myocardial fibrosis areas prior to an ablation procedure by means of LGE-MRI might help to target atrial areas harboring AF, thereby improving ablation outcomes and reducing AF recurrences. In order to test this hypothesis, we will conduct a randomized study comparing the isolation of pulmonary veins without fibrosis imaging (conventional ablation procedure) vs. isolation of the pulmonary veins and pathological (fibrotic) tissue with the aid of LGE-MRI. Fibrotic tissue patches will be encircled and isolated in all patients in the active arm; furthermore, LGE-MRI will be used to identify, locate and guide ablation catheter to anatomical gaps surrounding pulmonary veins in re-do procedures. Eventually, we will identify an optimized ablation strategy in patients undergoing AF radiofrequency ablation on the basis of left atrium (LA) fibrosis characterization.

Fibrosis information obtained from post-processed LGE-MRI will be used to guide AF ablation procedures.

Conventional AF ablation will be carried out according to the standard procedure. Atrial anatomical MRI information will be integrated into the navigation system. Ablation procedure will be carried out with a Smart Touch® catheter (temperature 45 °C, 40W or 30W for anterior or posterior wall, respectively). Both in first and re-do procedures, procedure endpoint will be electrical isolation of all pulmonary veins.

Post-processed LGE-MRI will be used to identify left atrial fibrotic patches and lesions surrounding pulmonary veins (re-do procedures). Both MRI atrial anatomical and fibrosis information will be integrated into the navigation system. Ablation procedures will be carried out with a SmartTouch® catheter (temperature 45°C, 40W or 30W for anterior or posterior wall, respectively). Procedural end-point for first ablation procedures will be isolation of all pulmonary veins, and encirclement and isolation of all atrial fibrotic areas. In re-do procedures, all left atrial fibrosis patches will be encircled and isolated and, for electrically non-isolated pulmonary veins, all anatomical gaps in lesions surrounding pulmonary veins (as identified in LGE-MRI) will be closed.

Recurrence is defined as any documented episode of AF/atrial tachycardia lasting more than 30 seconds, after a blanking period of 3 months.

Inclusion Criteria: Patients undergoing a first or subsequent ablation procedure. Pre-procedural 3 Tesla LGE-MRI. Referred for radiofrequency ablation of pulmonary veins (paroxysmal, persistent or long-standing AF). Signed informed consent. Exclusion Criteria: Claustrophobia. Refusal to participate in the study. Presence of atrial thrombus. LA anteroposterior diameter >55 mm. Major renal impairment. Contrast allergy. Pregnancy.

Bisbal F, Benito E, Teis A, Alarcon F, Sarrias A, Caixal G, Villuendas R, Garre P, Soto N, Cozzari J, Guasch E, Junca G, Prat-Gonzalez S, Perea RJ, Bazan V, Tolosana JM, Arbelo E, Bayes-Genis A, Mont L. Magnetic Resonance Imaging-Guided Fibrosis Ablation for the Treatment of Atrial Fibrillation: The ALICIA Trial. Circ Arrhythm Electrophysiol. 2020 Nov;13(11):e008707. doi: 10.1161/CIRCEP.120.008707. Epub 2020 Oct 8.