Defibrillation. Actually, we don't defibrillate when a patient is flat-lined. That is a tv thing. We can only use the defribrillator, when someone is in ventricular fibrillation (vf), thus the term, defibrillation. Vf is an abnormal rhythm, and is not resulting in a pulse, so there is no blood pressure. When a person has asystole, or a flatline, we use chemicals like Atropine to try and get the heart to start.