Should you shock a patient with a defibrillator if their ECG reading shows a flat-line also known as asystole?

No. You should not shock a patient with a defibrillator if their ECG shows asystole (a flat line). Defibrillation is indicated for specific types of life-threatening arrhythmias, such as ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT). In the case of asystole, the correct approach is to perform cardiopulmonary resuscitation (CPR) and identify and treat the underlying causes.