This happens as a result of the narrowed coronary arteries being always maximally dilated to compensate for the decreased upstream blood supply.
In worse cases, symptoms can include dizziness, flushing, headaches, nausea, and shortness of breath.
Dipyridamole is thus a pharmacological success diagnostically, but a therapeutic failure because of the coronary steal phenomenon.
The test result is positive if the patient's symptoms reappear or if ECG alterations are seen.
[citation needed] Hydralazine can potentially cause this condition as well, as it is a direct arteriolar vasodilator.