Atrial fibrillation is the most common arrhythmia but can be treated by a catheter procedure where specialized wires (so-called catheters) are inserted in the left upper heart chamber. This requires crossing the wall between the right and left atrium with a long needle (a so-called transseptal puncture or TSP). This is typically done using x-ray guidance or echo to check if the needle is in the right position. The investigators developed a method to do the TSP without x-rays using a specialized needle that can be also shown as a little icon on the 3D electroanatomical mapping system (CARTO).3D mapping systems are routinely used to track the location of the catheters in cath labs worldwide, but the position of the needle was not tracked yet. The investigators seek to demonstrate that these procedures can be carried out safely, successfully and in a reproducible fashion without any radiation by taking advantage of "faking" the isolated tip of the needle as a catheter on the 3D mapping system. The results will be compared with historic procedures done by the same operator in the years 2012-2017.

The hypothesis is that patients who undergo one or more TSP(s) for atrial fibrillation or left atrial tachycardia can be studied without the use of fluoroscopy which should result in a low or ZERO overall radiation exposure for the entire ablation procedure. The investigators will assess the feasibility, safety and efficacy of this new approach.

The patient will be admitted in hospital as for a standard procedure and discharged the next day. Before admission, the patient undergoes a CMR/CT scan (routine in our centre). To avoid total radiation CMR would be preferred, if possible.

The technique of the TSP and the use of the RF needle is commonly used worldwide. The ability to visualize the needle tip on the 3D electroanatomical mapping system facilitates the procedure. The additional visualization by TOE helps to assure that the fossa ovalis has been correctly identified.

After the TSP, the ablation procedure itself will be carried out as conventionally performed using the catheter visualization on the 3D mapping system.

An ECG and an echocardiogram are performed before discharge (as standard care).

At 3 months the patient comes for the first visit and has an ECG, a Holter and symptom questionnaire.

At 6 months, the patient has second visit which includes an ECG, a symptom questionnaire, a Holter and an echocardiogram.

If recurrences of any arrhythmia occur, the patient can be scheduled for a second ablation procedure without any restrictions.

Inclusion Criteria:

• Any type of atrial fibrillation or left atrial tachycardia

  • Able to give written informed consent
  • Age >18 years old and ≤ 80 years
  • Fulfill established clinical criteria for catheter ablation of atrial fibrillation (1)
  • No evidence of significant structural heart disease or congenital heart disease

Exclusion Criteria:

Intolerance or unwillingness to oral anticoagulation with Warfarin

• Bleeding disorder
• Contraindication to CT scan
• Presence of intracardiac thrombus
• Vascular disorder preventing access to femoral veins
• Cardiac congenital abnormality
• Severe, life threatening non-cardiac disease
• Active malignant disease and recent (<5 years) malignant disease
• Presence of ASD or PFO closure device
• Unable or unwilling to comply with F/U requirements
• Renal impairment
• Pregnancy

Any data of this trial will be shared only in an anonymised fashion and as part of scientific publications