In ischemic VT ablation, the target is best described as which of the following?

• A. Scar-Related Isthmus
• B. Purkinje Network Only
• C. Atrioventricular Node
• D. Left Atrial Appendage

Answer: (A)

Ischemic VT ablation focuses on disrupting the main pathway that sustains the reentrant circuit within scar tissue. After a myocardial infarction, a scar forms a nonconductive core with viable fibers lingering in the border zone. These surviving strands create a narrow conduction channel, or isthmus, through which electrical impulses travel and reentry can continue. Ablation aims to eliminate this critical channel, typically by creating a line of block that interrupts the reentrant loop. Map-guided therapy uses voltage mapping to delineate scar and border zones, identifies late or fractionated signals that mark the channels, and uses pacing or entrainment to confirm which isthmus is essential to the circuit. While the Purkinje network can contribute to some VTs, targeting it alone won’t address the scar-based reentry that drives most ischemic VTs. The AV node and left atrial appendage don’t form the substrate for these ventricular circuits, so they aren’t the optimal targets. Hence, the best target is the scar-related isthmus.