amboss makes it very clear that pharmacologic stress tests can be done through either vasodilatory (coronary steal syndrome ) or positive ionotropy (dobutamine) methods. This card is an oversimplification and the previous suggestion was correct https://next.amboss.com/us/article/DS01bf?q=Coronary%20artery%20disease#Z08cfa0ee1282d4d9b040f39d76056791
Amboss lists the exact same sentence as this card in the pathophysiology section "Coronary steal is the underlying mechanism of pharmacological stress testing." - also, ionotropics would rely on same mechanism. Increased O2 demand (from ionotropes) → arteries with no/minimal athersclerosis are able to vasodilate to increase blood flow to meet increased O2 demand → shunts blood flow from athersclerotic arteries which are not able to vasodilate to meet increased O2 demand.