Pulsed Field Ablation

Pulsed field ablation is a minimally invasive heart procedure used to treat atrial fibrillation. A thin, flexible tube called a catheter is guided into the heart to treat very small areas of heart muscle that are sending out abnormal electrical signals.

Unlike older methods that use heat (radiofrequency ablation) or extreme cold (cryoablation), pulsed field ablation uses carefully controlled electrical pulses. These pulses disrupt the outer layer of the targeted heart cells, preventing them from triggering abnormal rhythms. This process is called electroporation.

Different types of cells in the body respond differently to these electrical pulses. Because of this, pulsed field ablation can focus primarily on heart muscle cells while largely sparing nearby non heart structures such as the oesophagus, the phrenic nerve, and the pulmonary veins.

This ability to treat only the intended heart tissue, while better protecting surrounding organs, is the key clinical advantage of pulsed field ablation compared with older ablation techniques.

Pulsed field ablation is usually considered for people with atrial fibrillation when:

• Medicines have not been able to keep the heart rhythm under good control
• Medicines cause troublesome side effects and cannot be continued
• The patient would rather choose a one time procedure than stay on long term rhythm control drugs
• The patient has paroxysmal (on and off) or persistent AFib, and isolating the pulmonary veins is the main treatment goal

In some centres, pulsed field ablation is also being studied for other abnormal heart rhythms originating in the lower chambers (ventricles). However, its main, well established use at present is for treating AFib.

Not every person with AFib will benefit from or require ablation. A detailed evaluation by a cardiac electrophysiologist is essential to decide suitability. This assessment evaluates how long AFib has been present, the heart's structure, the size of the left atrium, and the patient's overall health and risk profile.

In cardiology, PFA stands for pulsed field ablation. The technique also goes by pulsed electric field ablation and electroporation-based ablation, all three names refer to the same procedure.

What makes PFA notable is a fundamental departure from how ablation has traditionally worked. For decades, destroying abnormal heart tissue meant applying thermal energy, heat in the case of radiofrequency ablation, or extreme cold with cryoablation. PFA uses neither. It treats the target tissue using brief, high voltage electrical pulses instead, which is why it is now standard terminology in electrophysiology to separate this approach from its thermal predecessors.

The pulsed field ablation procedure is carried out in a specialised cardiac catheterisation laboratory, under general anaesthesia so that you remain comfortable throughout.

• Preparation
  The skin in the groin area is cleaned, sometimes shaved, and numbed with local anaesthesia. An intravenous (IV) line is placed in your arm, and a blood thinner (heparin) is given to prevent clots during the procedure.
• Vascular access and catheter insertion
  A small puncture is made in the skin over the groin, and a short, thin tube called a sheath is placed into the femoral vein. Through this sheath, the doctor gently threads the ablation catheter up through the veins into the right side of the heart, using X ray guidance.
• Transseptal puncture
  From the right atrium, the catheter is guided across into the left atrium through a carefully controlled puncture in the thin wall (septum) between the upper chambers. This allows access to the pulmonary veins, which are usually the source of AFib triggers.
• Electroanatomical mapping
  Advanced 3D mapping systems and fluoroscopy (live X ray) are used to build a detailed picture of the left atrium and pulmonary veins. This helps the electrophysiology team position the catheter precisely and identify the areas responsible for the abnormal rhythm.
• Pulsed field ablation delivery
  The PFA catheter is placed at the opening of each pulmonary vein. Very short bursts of electrical pulses are delivered in rapid succession, each lasting less than a second. During a single procedure, all four pulmonary veins are typically treated sequentially.
• Confirmation and closure
  The team then confirms that each pulmonary vein has been successfully electrically isolated from the left atrium. Once this is done, the catheter and sheath are removed, and pressure is applied to the groin site to prevent bleeding. The small skin puncture is covered with a dressing. In most cases, the entire procedure takes less than two hours, and the actual delivery of PFA energy lasts only a few seconds for each vein.

Before a pulsed field ablation (PFA) procedure, every patient undergoes a structured set of tests and assessments to ensure the treatment is safe and appropriate:

• 12 lead ECG: Confirms the heart rhythm and records the heart's baseline electrical activity.
• 24 hour or 7 day Holter monitoring: Measures how often AFib occurs, how long it lasts, and its pattern in daily life.
• 2D echocardiogram with Doppler: Uses ultrasound to look at the heart's structure, pumping function, and the size of the left atrium.
• CT scan or MRI of the left atrium and pulmonary veins: Provides a detailed 3D view of the heart's anatomy, helping the team plan the procedure and catheter positions.
• Transoesophageal echocardiogram (TOE): Performed on the day of the procedure, using an ultrasound probe gently passed into the oesophagus to ensure there is no clot in the left atrial appendage before ablation.
• Blood tests: Check thyroid and kidney function and the blood's clotting profile.

This comprehensive pre-procedural evaluation, which the team at our center for cardiac science conducts as a standard part of the ablation planning pathway, ensures that only appropriate candidates proceed to PFA and that the procedure is planned with full anatomical and functional information.

Pulsed field ablation offers several important advantages over older ablation techniques:

• Targets heart tissue more precisely: It selectively treats the heart muscle cells causing the abnormal rhythm, while helping to protect nearby structures such as the oesophagus and the phrenic nerve.
• Lower risk to the oesophagus: Injury to the oesophagus is a recognised and potentially serious complication of radiofrequency ablation. With PFA, this risk is greatly reduced.
• No risk of pulmonary vein narrowing: Some radiofrequency and cryoballoon techniques can cause the pulmonary veins to narrow (stenosis). PFA avoids this complication.
• Shorter procedure time: The actual delivery of PFA energy takes only seconds for each vein, and the entire procedure typically lasts less than two hours.
• Quicker recovery and discharge: Most patients can go home the next day.
• Favourable safety profile: PFA has one of the lowest complication rates of any currently available ablation method.
• Effective rhythm control: Success rates for isolating the pulmonary veins with PFA are better than those of established ablation techniques.

For patients considering ablation for AFib, a consultation with our Electrophysiologist provides a thorough review of whether pulsed field ablation is the most suitable option with their heart anatomy and overall clinical profile.

Q1. What is pulsed field ablation, and how is it different from regular ablation?

Pulsed field ablation is a type of heart procedure that uses brief electrical pulses to treat small areas of heart tissue that cause abnormal rhythms. Traditional "regular" ablation usually uses heat (radiofrequency) or cold (cryo) to do this. The key difference is that PFA is more tissue selective: it is designed to target heart muscle cells while largely sparing nearby structures such as the oesophagus and the phrenic nerve, which helps make the procedure safer.

Q2. Who is a good candidate for pulsed field ablation?

Pulsed field ablation is generally suitable for people who have symptomatic paroxysmal (on and off) or persistent AFib, especially when rhythm control medicines have not worked well or have caused side effects. Whether PFA is right for a particular patient is determined after a detailed evaluation by the heart rhythm team, which usually includes tests such as an echocardiogram and a CT scan to assess the heart's structure and the pulmonary veins.

Q3. Is pulsed field ablation painful?

No. The procedure is performed under general anaesthesia or deep sedation, so you do not feel pain during the ablation. After the procedure, some people experience mild chest discomfort, fatigue, or groin soreness where the catheter was inserted. These symptoms are usually mild and settle within a day or two, and most patients feel comfortable again within 48 hours.

Q4. Is pulsed field ablation safe? What are the risks?

Pulsed field ablation has one of the most favourable safety profiles among current ablation technologies. As with any heart procedure, there are potential risks, including fluid around the heart (pericardial effusion), stroke, temporary weakness of the phrenic nerve (phrenic nerve "stun"), and a slow heart rate. These are uncommon and are carefully monitored and managed during and after the procedure. Because PFA is tissue selective, it greatly reduces the risk of oesophageal injury, a concern with some older ablation methods.

Q5. How many sessions of PFA are needed?

Most patients need only one PFA procedure to achieve pulmonary vein isolation. If AFib returns after the first ablation, a second procedure may be discussed. This is usually considered only after a "blanking period" of about three months, during which rhythm control medicines are often continued while the full effect of the ablation takes hold.