Cardioversion and defibrillation are life-saving interventions used to restore normal heart rhythms in patients with rapid arrhythmias like atrial fibrillation, ventricular tachycardia, and ventricular fibrillation. Cardioversion can be performed electrically or chemically. Electrical cardioversion delivers a synchronized shock at the peak of a QRS complex to effectively reset the heart’s rhythm. Defibrillation delivers shocks at random parts of the electrical system of the heart, also known as unsynchronized shock, and is typically used in emergent settings. Devices like AEDs and ICDs deliver these kinds of life-saving electrical shocks and are important in resuscitating patients during cardiac arrest. Antiarrhythmic drugs can also be used, like in chemical cardioversion, to regulate heart rhythm but are typically preserved for stable patients.