Long or short postpacing interval response to ventricular tachycardia entrainment: What is the mechanism?

A 58-year-old man with nonischemic cardiomyopathy and an ejection fraction of 25% presented with ventricular tachycardia (VT) storm. Epicardial mapping revealed an inferolateral scar, and during tolerated VT with right bundle branch superior axis morphology with V3 transition (tachycardia cycle length [TCL] 325 ms), overdrive pacing was performed. What is the response to entrainment and why (Figure  1A)?
Source: Heart Rhythm - Category: Cardiology Authors: Tags: Unknown of the Month Source Type: research