Catheter Ablation and Electrophysiology Procedures
Core concepts
Catheter ablation destroys arrhythmogenic tissue with radiofrequency (heat) or cryoenergy (cold) to cure or control arrhythmias. It is first-line or strongly favored for symptomatic AVNRT, AVRT (WPW), typical atrial flutter (cavotricuspid isthmus ablation), and increasingly for atrial fibrillation (pulmonary vein isolation). VT ablation targets scar-related circuits, often in ischemic cardiomyopathy.
Know the EP lab workflow: vascular access (femoral veins/artery), catheter placement, baseline measurements, programmed stimulation to induce and map the arrhythmia, ablation, then re-testing for inducibility. Mapping techniques include activation mapping, entrainment, and electroanatomic mapping. Anesthetic and anticoagulation management matter - AF ablation requires periprocedural anticoagulation because of thromboembolic risk.
Complications to recognize: vascular access complications (hematoma, pseudoaneurysm, AV fistula), cardiac perforation/tamponade, thromboembolism, phrenic nerve injury (especially with cryo for AF), atrioesophageal fistula (rare, late), and radiation exposure. Post-procedure care includes monitoring for bleeding, arrhythmia recurrence (early recurrence does not always mean failure), and follow-up rhythm monitoring.
Question traps
- Assuming early AF recurrence after ablation means the procedure failed - a blanking period is common.
- Forgetting anticoagulation around AF ablation.
- Overlooking phrenic nerve injury with cryoballoon ablation.
Rule of thumb
Typical flutter → cavotricuspid isthmus; AVNRT → slow pathway; AF → pulmonary vein isolation; WPW → accessory pathway. Match the target to the arrhythmia.