How do VT ablation strategies differ from AF ablation strategies?

• A. VT ablation uses substrate and activation mapping to target scar-related circuits; AF ablation targets electrical isolation of the pulmonary veins and substrate modification; hemodynamic stability often guides mapping approach.
• B. AF ablation relies exclusively on patch clamp mapping, while VT ablation uses real-time MRI guidance.
• C. VT ablation only uses pharmacologic therapy with no mapping; AF ablation uses mapping exclusively.
• D. Neither VT nor AF ablation requires mapping instrumentation.

Answer: (A)

The central idea is that VT ablation and AF ablation use different targets and mapping approaches based on where the arrhythmia originates and how it is sustained. Ventricular tachycardia ablation focuses on scar-related circuits in the ventricle, using activation mapping to follow the wavefront and substrate (voltage) mapping to delineate scar and critical channels. This lets you identify and disrupt the circuits that maintain VT. In contrast, atrial fibrillation ablation aims to electrically isolate the pulmonary veins—the usual AF triggers—and often modifies the atrial substrate by targeting low-voltage areas or fractionated signals. The mapping strategy for AF is typically in the atria and can be performed while the patient is hemodynamically stable, whereas VT mapping often depends on the patient’s stability and may rely more on substrate-guided approaches when detailed activation mapping isn’t feasible.

Other statements don’t reflect standard practice: patch clamp mapping isn’t used clinically for AF ablation, real-time MRI guidance isn’t the norm for VT ablation, pharmacologic therapy alone does not replace the need for mapping in VT or AF ablation, and mapping instrumentation is generally required for both procedures.