What cardiac rhythm is often associated with an increased risk of sudden cardiac arrest?

Ventricular fibrillation is a chaotic and disorganized electrical activity in the ventricles of the heart, leading to ineffective contraction and a cessation of blood flow. This rhythm is known for its acute onset and association with sudden cardiac arrest.

In ventricular fibrillation, the heart is unable to pump blood effectively, which can result in loss of consciousness and death within minutes if not corrected promptly. This makes it critical to recognize and treat this rhythm immediately, often with defibrillation, to restore a normal rhythm and maintain circulatory function.

Other rhythms listed, while they may be concerning in various contexts, are not directly linked to the same high level of immediate risk for sudden cardiac arrest as ventricular fibrillation. Atrial fibrillation, for example, can lead to stroke and other complications but does not typically result in the immediate cessation of blood flow like ventricular fibrillation. Bradycardia may also pose risks depending on the degree and cause, but it does not inherently create the same acute emergency situation as ventricular fibrillation. Normal sinus rhythm indicates a stable and effective heart rhythm, which is the opposite of what occurs in ventricular fibrillation.