Non Fluoroscopic APpROach iN atriaL Fibrillation Ablation procEdureS
Condition: Atrial Fibrillation
MeSH terms: Atrial Fibrillation
Study type: Observational

Summary: 
      In electrophysiology, interventional procedures are often assisted by fluoroscopic guidance,
      exposing both patients and healthcare professionals to a considerable dose of radiation.
      Catheter ablation of atrial fibrillation has frequently involved the use of fluoroscopy: in
      fact, it incorporates greater complexity due to the need to perform the transseptal puncture.

      A visible introducer in the 3D electro-anatomical mapping system (which does not involve the
      use of X-rays), has become an important tool for performing transseptal puncture: in
      particular, it is positioned at level of the oval fossa of the right atrium (puncture site);
      subsequently, the needle is introduced inside it; the intervention is guided both by
      electroanatomical mapping and by the use of intracardiac echocardiography for the
      identification of important anatomical landmarks.

      The "zero rays" technique represents a valid alternative to fluoroscopic guidance, widely
      used and validated over the years. In fact, X-ray exposure in an atrial fibrillation ablation
      procedure can reach up to 60 mSv: the radiological risk makes it necessary to study safe and
      effective alternative techniques.

      In this retrospective, observational and monocentric study, 50 catheter ablation procedures
      of atrial fibrillation will be examined, divided into two groups:

        1. 25 patients who performed this procedure according to the classic approach, ie under
           fluoroscopic guidance;

        2. 25 patients who performed this procedure using an ablative approach that involved the
           use of the introducer in combination with the 3D EAM system and intracardiac
           echocardiography.

      Clinical efficacy will be assessed through a cardiological checkup and 24-hour
      electrocardiographic recording (ECG Holter) at 6 months.
    

Detailed description: 
      Atrial fibrillation (AF) is the most common sustained adult tachyarrhythmia found in clinical
      practice. The prevalence of this arrhythmia in the general population varies from 2 to 4% and
      increases significantly in elderly patients and in carriers of diseases such as arterial
      hypertension, heart failure, coronary and valvular disease, obesity, diabetes mellitus and
      chronic kidney disease. In addition to being a marker of underlying heart or vascular
      disease, FA in itself is accompanied by an increased incidence of ischemic stroke, heart
      failure and dementia. The mechanisms underlying this arrhythmia are still debated, but seem
      to involve electrical and structural alterations of the atrium that constitute a
      morpho-functional substrate that facilitate its development.

      Traditionally, five types of atrial fibrillation are distinguished, based on presentation,
      duration and term:

        1. Newly diagnosed AF: first finding of AF, regardless of the duration, presence and
           severity of symptoms;

        2. Paroxysmal AF: AF that resolves within seven days (spontaneously or through
           cardioversion);

        3. Persistent AF: AF that lasts more than seven days or is cardioverted after seven days;

        4. Long lasting AF: AF that lasts more than a year continuously, when a rhythm control
           strategy has been adopted.

        5. Permanent AF: AF accepted by the patient (and by the attending physician) for which no
           further attempt to control the rhythm is undertaken.

      Treatment include heart rate and / or rhythm control strategies, prevention of cerebral
      thromboembolism and reduction / elimination of symptoms, as well as control of major
      cardiovascular risk factors. The decision about the implementation of therapeutic strategies
      aimed at restoring and maintaining sinus rhythm must be shared between doctor and patient,
      weighing on the one hand the effect on quality of life and symptoms, and on the other the
      risk of toxic effects of drugs. used. When AF has been on for less than a year, an early
      rhythm control strategy has been shown to reduce the composite outcome of cardiovascular
      death, stroke, hospitalization for heart failure or acute coronary syndrome in the EAST-AFNET
      4 clinical trial.

      Trans catheter ablation is a well-established treatment for the reduction of AF relapses and
      is proposed in cases of paroxysmal and persistent AF. It is a procedure that consists in the
      antral circumferential disconnection of the pulmonary veins by radiofrequency, laser or
      cryoblation. It is a safe and effective technique for maintaining sinus rhythm and for
      improving symptoms. When antiarrhythmic drugs fail in rhythm control, the current ESC 2020
      Guidelines place trans-catheter ablation in class I for paroxysmal and persistent AF with or
      without major risk factors for recurrence, while as a first therapeutic approach it is in
      class IIa for paroxysmal AF and IIb for persistent AF without major risk factors for relapse.

      Advanced three-dimensional electro-anatomical mapping systems (3D EAM) have revolutionized
      the transcatheter ablative approach, allowing a new approach to the study of complex
      arrhythmias, such as FA. All the mapping systems, even if based on different principles,
      allow a precise localization of the scaler catheter, starting from the vascular access up to
      the heart chambers. While the catheter scans the different cardiac structures, the system
      records information about the catheter's position and uses the spatial and electrical data to
      create an accurate reproduction of the 3D geometry of the cardiac structures. All this has
      led to a reduction in the use of fluoroscopy and, in particular for the ablation of AF, there
      has been a reduction in radiation during these procedures even if a complete elimination has
      not yet been possible.

      Intracardiac echocardiography is an imaging technique capable of visualizing heart structures
      in real time and with very high spatial resolution, as well as monitoring the position of the
      catheter within the heart chambers and quickly identifying any procedural complications, such
      as the formation of thrombus or pericardial effusion. A further advantage is represented by
      the reduction of the scan times. For these reasons, intracardiac echocardiography has largely
      replaced transesophageal echocardiography in many interventional procedures, including those
      of electrophysiology. In fact, intracardiac echocardiography allows the integration of images
      in real time with electro-anatomical mapping systems, allowing to map those structures that
      are not viewable under fluoroscopy, such as the atrial septum.

      A bi-directional, deflectable guide introducer capable of being visualized on the 3D mapping
      system allows the visualization in real time, allowing to increase the efficiency during the
      mapping and positioning of the scaler catheter, reducing, up to zero, the scan times. It also
      has 2-degree bidirectional deflection capability, reaching up to 180 degrees in both
      directions.

      Furthermore, it is extremely performing during the atrial septal puncture procedures: when,
      in fact, a dilator is introduced through introducer to perform the transseptal puncture, the
      presence of a smooth interface between the dilator and the tip of introducer allows access
      more easily to the left atrium, reducing the force required to advance the system through the
      atrial septum by 33%.

      The fluoroscopic approach is widely validated and has represented for years the gold standard
      in electrophysiological study and ablation procedures. However, this approach exposes the
      operator and the patient to a high dose of radiation: in fact, during an AF ablation
      procedure, the radiological exposure can reach up to 60 mSv, thus increasing the absolute
      risk of developing lifetime cancer by 0.08%. It is therefore very necessary to apply the
      principles of ALARA (a slow as reasonably achievable) as established by the consent document
      of the American College of Cardiology of 1998.

      Recently the trans catheter ablation procedures of AF have undergone a major increase.
      Considering, therefore, the wide diffusion of this technique and the high radiological
      exposure linked to the transseptal puncture and the isolation of the pulmonary veins,
      promoting an approach without radiological exposure becomes extremely crucial.

      The rationale of this study is to evaluate the clinical and procedural features of an
      ablative approach using the steerable introducer in combination with the 3D EAM system and
      intracardiac echocardiography: the combination of these elements is potentially able to
      significantly reduce, to zero, the scanning times and to reduce procedural times,
      guaranteeing efficacy and safety. Complications will also be assessed at 30 days and the
      effectiveness of the procedure at six months.
    

Intervention name(s): Atrial fibrillation ablation
Intervention type(s): Procedure
Intervention description(s): Pulmonary vein isolation
Observational model: Case-Control
Time perspective: Retrospective
Sampling method: Probability Sample
Study population: 
        Patients with atrial fibrillation (paroxysmal or persistent) treated with transcatheter
        ablation
      
Keywords: atrial fibrillation; ablation; radiofrequency; intracardiac echocardiography; zero fluoroscopy; arrhythmias