Vagal Response and Cardiac Autonomic Modulation. Insides From Cryoballoon Ablation

Study Overview
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Brief Summary
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The investigators sought to evaluate the incidence and influence of vagal response observed during cryoballoon-based pulmonary vein isolation on the cardiac autonomic nervous system (CANS) and ablation outcomes in paroxysmal atrial fibrillation cohort. 296 patients were treated with a 28-mm second-generation cryoballoon (Arctic Front Advance, Medtronic). Preprocedural pulmonary veins anatomy and their ostial dimensions were acquired with a computed tomography. 74 patients without structural heart disease and with no concomitant diseases were chosen for a detailed CANS assessment with heart rate variability analysis. All patients were screened over a 2-year post-ablation period.

Detailed Description
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An interplay between left atrial (LA) ganglionated plexi (GP), a part of the intrinsic cardiac autonomic nervous system (CANS), and pulmonary veins (PVs) is considered to be an important mechanism related with the initiation and maintenance of atrial fibrillation (AF). Therefore additional GP ablation has been reported with better ablation outcomes when added to RF-based PV isolation (PVI). A cryoballoon ablation (CBA) is an anatomically based approach which allows PVI that is highly safe and efficacious. The extension of the scar created by the cryoballoon frequently extends beyond the PV orifice in the acute and chronic post-ablation phase creating a set of lesions that are near the LA-GP area and inadvertent damage. A marked vagal response (VR) observed during CBA is considered a marker for the CANS modification. However, changes in the autonomic tone were independently noted from the presence of VR in several studies. Moreover, it is not clear if these changes are transient or long-lasting, and it has been shown that the presence of VR increases ablation success although with conflicting results. In previous studies assessing the influence of CBA on the autonomic balance, CANS modulation was appraised with different surrogates, a small number of individuals were usually recruited and both paroxysmal and persistent AF populations were included. Therefore, the investigators sought to evaluate the incidence of VR observed during CBA-based PVI, its impact on CANS assessed with widely accepted heart rate variability (HRV) analysis, and in relation to ablation outcomes in a large paroxysmal AF (PAF) cohort.

Official Title
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Does Vagal Response Indicate Cardiac Autonomic Modulation and Improve the Therapeutic Effect of Pulmonary Vein Isolation in Patients With Paroxysmal Atrial Fibrillation? Insides From Cryoballoon Ablation

Conditions
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Vagal Nerve Stimulation, Autonomic Nervous System, Catheter Ablation

Intervention / Treatment
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* Procedure: cryoballoon-based pulmonary veins isolation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnosis of paroxysmal atrial fibrillation Exclusion Criteria: Previous atrial fibrillation ablation

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Cryoballoon-based pulmonary veins isolation cohort<br>Patients treated with a 28-mm second-generation cryoballoon (Arctic Front Advance, Medtronic) for paroxysmal atrial fibrillation and screened over a 2-year post-ablation period. | Procedure: cryoballoon-based pulmonary veins isolation<br>* A cryoballoon is introduced to the LA via a steerable sheath following a single transseptal puncture. The balloon is advanced toward the PV ostium and inflated. PV occlusion is documented by the injection of contrast. Optimal vessel occlusion is assumed when the PV showes complete contrast retention without any backflow to the atrium. The freezing time is chosen between 180 and 240s and left at the operator's discretion, along with a decision if to follow with a bonus-freeze cycle. The application is aborted and the cryoballoon is repositioned in the case of ineffective cooling or when the nadir temperature decreases < -60°C, to avoid excessive cooling. In cases where a real-time recording of PV potentials is available a short time-to-isolation<60s resultes in a single 180s freeze cycle. CBA always startes from the left upper PV (LUPV) followed by the left lower PV (LLPV).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The number of patients free from atrial fibrillation following a cryoballoon-based pulmonary veins isolation beyond a 3-month blanking period. | Outpatient visit was scheduled at 3 months following ablation. A detailed medical history was taken with emphasis on registered atrial fibrillation episodes or atrial fibrillation suggestive symptoms. 24 hour Holter monitoring was performed in all patients. | 3 months | 
| The number of patients free from atrial fibrillation following a cryoballoon-based pulmonary veins isolation beyond a 3-month blanking period. | Outpatient visit was scheduled at 6 months following ablation. A detailed medical history was taken with emphasis on registered atrial fibrillation episodes or atrial fibrillation suggestive symptoms. 24 hour Holter monitoring was performed in all patients. | 6 months | 
| The number of patients free from atrial fibrillation following a cryoballoon-based pulmonary veins isolation beyond a 3-month blanking period. | Outpatient visit was scheduled at 12 months following ablation. A detailed medical history was taken with emphasis on registered atrial fibrillation episodes or atrial fibrillation suggestive symptoms. 24 hour Holter monitoring was performed in all patients. | 12 months | 
| The number of patients free from atrial fibrillation following a cryoballoon-based pulmonary veins isolation beyond a 3-month blanking period. | Outpatient visit was scheduled at 18 months following ablation. A detailed medical history was taken with emphasis on registered atrial fibrillation episodes or atrial fibrillation suggestive symptoms. 24 hour Holter monitoring was performed in all patients. | 18 months | 
| The number of patients free from atrial fibrillation following a cryoballoon-based pulmonary veins isolation beyond a 3-month blanking period. | Outpatient visit was scheduled at 24 months following ablation. A detailed medical history was taken with emphasis on registered atrial fibrillation episodes or atrial fibrillation suggestive symptoms. 24 hour Holter monitoring was performed in all patients. | 24 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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vagal response, atrial fibrillation, cardiac autonomic nervous system, cryoballoon ablation, ganglionated plexi, heart rate variability