Catheter Ablation — How It Works, Benefits & Recovery — Procedure Guide, Recovery & Risks | MyMedicPlus

Catheter ablation is a minimally invasive cardiac procedure that uses energy delivered through thin flexible catheters threaded into the heart via blood vessels to destroy (ablate) the abnormal electrical tissue responsible for cardiac arrhythmias. The most widely used energy source is radiofrequency current, which generates heat at the catheter tip to create precise scar lesions that block aberrant electrical circuits. Cryoablation uses extreme cold (cryotherapy) as an alternative energy, particularly favoured for pulmonary vein isolation in atrial fibrillation because of its gentler freeze-thaw cycle and the ability to test the lesion before making it permanent. High-power short-duration (HPSD) ablation and pulsed-field ablation (PFA) are newer techniques that improve procedural efficiency and reduce collateral tissue injury. Electroanatomical mapping systems (CARTO, EnSite Navx) create three-dimensional virtual maps of the heart's electrical activation, allowing highly targeted ablation without excessive fluoroscopy. Catheter ablation is now the preferred rhythm control strategy for symptomatic atrial fibrillation resistant to antiarrhythmic drugs, based on evidence from the CABANA and EAST-AF-NET trials showing superiority over medical management for quality of life and — in selected patients — clinical outcomes.

Catheter ablation is indicated for a range of cardiac arrhythmias where it offers curative or highly effective treatment. Primary indications include: symptomatic paroxysmal or persistent atrial fibrillation (AF) where antiarrhythmic drug therapy has failed or is not tolerated, or as first-line rhythm control in younger patients or those with heart failure and reduced ejection fraction (LVEF <35%); typical atrial flutter, where cavotricuspid isthmus (CTI) ablation achieves cure rates above 95%; atrioventricular nodal reentrant tachycardia (AVNRT) — the most common paroxysmal SVT, with catheter ablation offering a 95% cure rate; Wolff-Parkinson-White (WPW) syndrome with an accessory pathway causing tachycardia or pre-excitation at risk of sudden death; and symptomatic ventricular tachycardia (VT) refractory to drug therapy, either idiopathic (outflow tract VT) or structural (post-MI scar VT). Selection criteria include symptom burden, drug intolerance or failure, patient preference, and in AF, the presence of left atrial dilation, duration of persistent AF, and degree of atrial fibrosis assessed by late gadolinium enhancement MRI.

The procedure is performed in a dedicated electrophysiology (EP) laboratory under fluoroscopic guidance. Catheters are introduced via the femoral vein (for left-sided procedures, requiring a transeptal puncture through the atrial septum) and subclavian or femoral vein for right-sided access. Continuous haemodynamic and ECG monitoring is maintained throughout. For AF ablation (pulmonary vein isolation, PVI): the electroanatomical mapping system creates a virtual 3D map of the left atrium. Radiofrequency or cryotherapy is applied circumferentially around the pulmonary vein ostia to electrically isolate them from the atrial body, targeting the trigger source of AF in over 90% of patients. Ablation points are confirmed by demonstration of pulmonary vein isolation (entrance block). For typical flutter: a linear lesion across the cavotricuspid isthmus produces bidirectional block confirmed by differential pacing. For WPW and AVNRT: the electrophysiology study maps the accessory pathway or slow pathway; ablation at the specific anatomical location terminates tachycardia and prevents recurrence. A post-procedure chest X-ray is obtained to exclude pneumothorax or pericardial effusion. The procedure is performed in a dedicated electrophysiology (EP) laboratory. Catheters are introduced via the femoral vein (for left-sided procedures, requiring a transseptal puncture through the atrial septum using a Brockenbrough needle under fluoroscopic and echocardiographic guidance) and subclavian or femoral vein for right-sided access. Continuous 3D electroanatomical mapping (CARTO or EnSite) integrates real-time electrogram signals with catheter position to construct colour-coded voltage and activation maps of the cardiac chamber. The ablation catheter is navigated to the target site using mapping data. For AF ablation, radiofrequency energy creates encircling lesions around the pulmonary vein ostia — pulmonary vein isolation (PVI) — confirmed by entrance and exit block. For VT ablation, the re-entry circuit or focal trigger is mapped and ablated at the critical isthmus. Cryo-ablation (cryoballoon) is an alternative to radiofrequency specifically for pulmonary vein isolation, using freezing energy to achieve electrical isolation. Procedure duration is 2–4 hours for AF ablation.

Catheter ablation offers significant advantages over long-term antiarrhythmic drug therapy for many arrhythmias. For typical atrial flutter, a single ablation session achieves permanent cure in over 95% of patients, eliminating the need for lifelong rate or rhythm control medication. For AVNRT (the most common SVT), ablation cures 95–98% of patients in a single procedure. For WPW syndrome, ablation eliminates the accessory pathway in 95% of cases, permanently removing the risk of tachycardia and — critically — the rare risk of sudden cardiac death from rapid pre-excited AF. For paroxysmal AF, single-procedure freedom from AF without antiarrhythmic drugs is achieved in 60–80% of patients; cumulative success after multiple procedures reaches 85–90% in appropriate candidates. The CABANA trial demonstrated that AF ablation reduced the composite of death, disabling stroke, serious bleeding, and cardiac arrest compared to drug therapy in AF patients with cardiovascular risk factors. Ablation also improves left ventricular function in patients with tachycardia-induced cardiomyopathy, frequently reversing heart failure symptoms when the arrhythmia is eliminated.

Catheter ablation is a relatively safe procedure in experienced electrophysiology centres with an overall serious complication rate of 2–4%. Cardiac tamponade from perforation of the atrial wall or left ventricle occurs in approximately 1% of AF ablation procedures and requires urgent pericardiocentesis; rarely, emergency surgery. Thromboembolic stroke is a risk of 0.3–1% in left-sided procedures due to clot formation on catheters in the left atrium; continuous anticoagulation during the procedure with heparin (activated clotting time 300–400 seconds) and continuation of oral anticoagulation perioperatively significantly reduces this risk. Pulmonary vein stenosis (narrowing of the vein at the ablation site) occurs in up to 1% with radiofrequency energy but is rare with cryoablation. Phrenic nerve injury (causing diaphragmatic paralysis and breathlessness) occurs in approximately 1–2% of cryoablation cases due to the proximity of the right phrenic nerve to the right pulmonary vein — close monitoring of phrenic nerve function during cryoablation is standard practice. Atrioesophageal fistula is an extremely rare but life-threatening complication of posterior wall AF ablation. Access site complications (haematoma, arteriovenous fistula) and groin pain are common but usually self-limiting.

Following the procedure, patients are transferred to a cardiac ward for monitoring for 1–2 days. Bed rest is advised for 4–6 hours after removal of the femoral venous sheaths to allow the access sites to seal and minimise haematoma formation. Anticoagulation with warfarin or a DOAC continues for a minimum of 3 months after AF ablation regardless of CHA₂DS₂-VASc score, and long-term if the patient has a high stroke risk score. A blanking period of 3 months after AF ablation is recognised during which early recurrences do not necessarily predict procedural failure, as inflammatory changes resolve and pulmonary vein isolation consolidates. Antiarrhythmic drugs are often continued for 2–3 months after the procedure during this period. Driving is restricted for 1 week after elective ablation in most national guidelines. Strenuous exercise is avoided for 2 weeks. A repeat ECG and echocardiogram are performed at 3 months. Palpitations during the blanking period are common and usually benign; a wearable ECG monitor helps assess their significance.