A defibrillator is a crucial medical device designed to address life-threatening cardiac arrhythmias, particularly ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT), which can lead to sudden cardiac arrest (SCA). SCA occurs when the heart's electrical system malfunctions, causing it to beat irregularly or stop altogether. Without prompt intervention, SCA can result in death within minutes.

Defibrillators operate on the principle of delivering an electric shock to the heart to restore its normal rhythm. There are two main types of defibrillators: automated external defibrillators (AEDs) and implantable cardioverter-defibrillators (ICDs).

AEDs are portable devices commonly found in public spaces, workplaces, and healthcare facilities. They are user-friendly and designed to be operated by laypeople with minimal training. A typical AED consists of adhesive electrode pads, which are placed on the patient's chest, and a control unit that analyzes the heart rhythm and delivers a shock if necessary. A voice prompt guides the user through the process, providing instructions on when to administer CPR and when to stand clear during shock delivery.

ICDs, on the other hand, are implantable devices surgically placed under the skin, usually in the chest area. They continuously monitor the heart's rhythm and automatically deliver shocks if dangerous arrhythmias are detected. ICDs are recommended for individuals at high risk of recurrent arrhythmias, such as those with a history of cardiac arrest or certain cardiac conditions.

The mechanism of action of defibrillation involves delivering a high-energy electrical pulse to the heart, momentarily depolarizing the cardiac cells and allowing the heart's natural pacemaker to reestablish a normal rhythm. This process, known as cardioversion, interrupts the chaotic electrical activity in the heart and enables it to resume coordinated contractions, restoring blood flow to vital organs.

Prompt defibrillation is crucial for improving the chances of survival in SCA cases. For every minute that passes without defibrillation, the likelihood of successful resuscitation decreases by approximately 7-10%. Therefore, widespread access to defibrillators in public spaces, along with public awareness and training in cardiopulmonary resuscitation (CPR), plays a vital role in saving lives during cardiac