Defibrillation is critically important because it is the only effective treatment to restore a normal heart rhythm in cases of life-threatening cardiac arrhythmias such as ventricular fibrillation (VF) and pulseless ventricular tachycardia. These arrhythmias cause the heart to quiver ineffectively instead of pumping blood, leading to cardiac arrest and a rapid loss of oxygen supply to vital organs, especially the brain. Defibrillation delivers an electrical shock that depolarizes the heart muscle cells, stopping the arrhythmia and allowing the heart's natural pacemaker to regain control and restore an effective rhythm. Early defibrillation is vital because with every minute of delay, the chance of survival decreases by about 7-10%. If defibrillation occurs within the first few minutes of a cardiac arrest, survival rates can be as high as 50-70%. Without timely defibrillation, brain damage or death can occur within minutes due to lack of oxygenated blood circulation. Automated external defibrillators (AEDs) enable even non-medical bystanders to provide rapid defibrillation, dramatically improving survival outcomes before emergency responders arrive. In summary, defibrillation is crucial because it can quickly reverse fatal heart rhythms, significantly increasing survival chances from sudden cardiac arrest, where every second counts.