Ablation for Treating Abnormal Heart Rhythms

Ablation post-cardiac arrest is one of the most important treatment options available to survivors whose arrest was caused by an abnormal heart rhythm. When medications have failed to control the arrhythmia, or when a survivor cannot tolerate them, ablation offers a targeted, long-term solution by destroying the precise area of heart tissue responsible for the dangerous electrical signals.

What is Ablation and How Does It Treat Arrhythmias?

Catheter ablation is a minimally invasive procedure that interrupts the abnormal electrical circuits in the heart that can trigger life-threatening arrhythmias. In the context of post-cardiac arrest, ablation is most commonly used when the underlying cause is ventricular tachycardia (VT) or ventricular fibrillation (VF) — the two arrhythmias most directly associated with sudden cardiac arrest.

During the procedure, thin flexible wires called catheters are guided through a vein — usually in the groin — into the heart. These catheters record the heart’s electrical activity in real time, mapping the origin of abnormal signals. Once the source is identified, energy is delivered through the catheter tip to destroy the small area of tissue causing the problem. The most common energy source is radiofrequency energy, which generates heat. Alternatively, cryoablation uses extreme cold to achieve the same result.

The British Heart Foundation’s guide to catheter ablation and the NHS overview of catheter ablation both provide useful introductory reading alongside this page.

When is an Ablation Used After Cardiac Arrest?

Ablation for cardiac arrest is not always the first treatment offered. In many cases, an ICD (implantable cardioverter-defibrillator) will be implanted first to protect against future life-threatening arrhythmias. Ablation may then be recommended in addition to the ICD, particularly in the following situations:

The arrhythmia is occurring frequently and triggering multiple ICD shocks
Antiarrhythmic medications have not been effective in controlling the rhythm
Medications are causing unacceptable side effects
The underlying cause of the cardiac arrest has been identified as a specific, mappable electrical circuit
The survivor has a condition such as Wolff-Parkinson-White syndrome or certain forms of ventricular tachycardia that are well-suited to ablation

The decision to proceed with ablation is made by an electrophysiologist — a cardiologist who specialises in heart rhythm disorders. The recommendation depends on the type of arrhythmia, the underlying heart condition, and the individual survivor’s overall clinical picture.

Types of Ablation Used in Arrhythmia Treatment

Several types of ablation are used in the treatment of arrhythmias associated with cardiac arrest. The most relevant are:

Radiofrequency ablation (RFA) — uses high-frequency radio waves to generate heat and create scar tissue at the target site. This is the most widely used form of ablation for ventricular arrhythmias.
Cryoablation — uses extreme cold (typically -70°C) to freeze and destroy the target tissue. Sometimes preferred for specific locations in the heart where heat ablation carries a higher risk.
Pulsed field ablation (PFA) — a newer technique using electrical pulses to destroy tissue. It is more tissue-selective and is increasingly used for atrial arrhythmias, with growing research interest in ventricular applications.

What Happens During an Ablation Procedure?

Ablation for cardiac arrest typically takes between two and four hours, though complex cases may take longer. The procedure is usually performed under general anaesthetic or deep sedation, so you will not be aware of what is happening during it.

Here is what to expect at each stage:

Preparation — you will have an IV line placed, monitoring equipment attached, and the skin in your groin area cleaned and numbed with local anaesthetic.
Catheter insertion — the catheters are introduced through a small puncture in the vein and guided to the heart under X-ray guidance.
Electrical mapping — the catheters record electrical signals from multiple points within the heart, creating a detailed map of the origin of abnormal activity.
Ablation — once the target is identified, energy is delivered through the tip of the ablation catheter to destroy the tissue. You may feel a brief sensation of warmth or pressure, though most patients feel nothing.
Confirmation — after ablation, the team attempts to re-trigger the arrhythmia to confirm it can no longer be induced.
Recovery in hospital — you will rest for several hours after the procedure, with pressure applied to the catheter entry site to prevent bleeding.

Recovery After an Ablation

Most people recover well after ablation and are able to go home the same day or the following morning. However, recovery after ablation for cardiac arrest can take slightly longer than for simpler ablation procedures, because ventricular ablations are generally more complex and the heart requires time to heal.

General recovery guidelines include:

Avoid heavy lifting for at least two weeks
Avoid driving for the first two to seven days, depending on your consultant’s advice and your underlying condition — DVLA rules for cardiac arrest survivors will also apply separately
Most people return to light daily activities within a day or two
Some chest discomfort, palpitations, or fatigue in the first few weeks is normal as the heart heals
A follow-up appointment will typically be scheduled at six to twelve weeks to assess the outcome

It is important to note that ablation does not always permanently eliminate the arrhythmia. In some cases, a repeat procedure may be needed. Furthermore, ablation does not remove the need for an ICD in most cardiac arrest survivors — the ICD remains in place as a safety net even where ablation has been successful.

Risks of Ablation for Cardiac Arrest

Like all cardiac procedures, ablation carries risks. These are generally low, but it’s worth understanding them before consenting to the procedure. Your electrophysiologist will discuss them with you in detail. The main risks include:

Bleeding or bruising at the catheter insertion site
Damage to the surrounding heart tissue or blood vessels
Stroke or blood clot (risk is managed with anticoagulation)
Heart block — damage to the heart’s natural conduction system, occasionally requiring a pacemaker
Pericarditis — inflammation of the sac surrounding the heart
In rare cases, the arrhythmia may worsen, or new arrhythmias may develop

Overall, the risk of serious complications from catheter ablation at experienced centres is low — typically under 1-2% for most procedures. For many survivors with recurrent ventricular arrhythmias, the benefit of ablation significantly outweighs these risks.

Watch: Ablation Explained

The following video from the BBC’s The Cure series shows a catheter ablation procedure being performed and explains the technology involved.