What is the most common rhythm observed in cases of cardiac arrest?

Ventricular fibrillation is recognized as the most common rhythm seen in cases of cardiac arrest. It is characterized by rapid, erratic electrical impulses in the heart, preventing it from pumping blood effectively and leading to a cessation of circulation. This chaotic rhythm means that the heart is unable to contract normally, resulting in the absence of effective blood flow, which is critical for sustaining life.

Understanding the context of other rhythms is important. For instance, while ventricular tachycardia can lead to cardiac arrest, it often presents with some degree of cardiac output, unlike ventricular fibrillation, which has none. Atrial fibrillation is a common arrhythmia but is less likely to result in immediate cardiac arrest compared to ventricular fibrillation. Asystole, which is the absence of any electrical activity in the heart, does indeed occur during cardiac arrest but is not as prevalent as ventricular fibrillation prior to or during the onset of cardiac arrest events. Hence, ventricular fibrillation is a critical focus area in advanced cardiac life support protocols, emphasizing its significance in emergency response scenarios.