A 52-year-old woman with paroxysmal atrial fibrillation undergoes pulmonary vein isolation (PVI) via radiofrequency catheter ablation. The mechanism by which pulmonary vein isolation prevents AF recurrence is:
- A Creating electrical conduction block between trigger foci in pulmonary veins and the left atrium ✓
- B Reducing left atrial pressure by ablating the posterior wall
- C Ablating the posterior mitral annulus where reentrant circuits originate
- D Destroying sympathetic ganglionic plexi that initiate ectopic impulses
Explanation
Pulmonary vein isolation (PVI) is based on the Haissaguerre observation (1998, NEJM) that >90% of paroxysmal AF triggers originate from ectopic foci (often pacemaker-like cells) in the pulmonary vein ostia. Radiofrequency or cryoablation creates circumferential lesions around each pulmonary vein ostium, electrically isolating the triggering foci from the left atrium, thus preventing trigger conduction. In persistent AF, additional ablation of posterior wall, roof lines, or complex fractionated electrograms may be needed. Autonomic ganglionated plexi ablation is adjunctive, not the primary mechanism. The CABANA and FIRE AND ICE trials support ablation over antiarrhythmic drugs for AF rhythm control.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.