Advanced Cardiovascular Life Support (ACLS) Practice Exam

Which condition is characterized by irregular and rapid heart rhythms originating from the atria?

1. Ventricular fibrillation

2. Supraventricular tachycardia

3. Atrial fibrillation

4. Sinus tachycardia

The correct answer is: Atrial fibrillation

Atrial fibrillation is a condition defined by irregular and often rapid heart rhythms that originate from the atria, the upper chambers of the heart. In this condition, the normal rhythmic contractions of the atria are disrupted, leading to chaotic electrical activity. This irregularity can result in an erratic heart rhythm that is typically identified on an electrocardiogram (ECG) by the absence of distinct P waves, which are normally seen in a healthy sinus rhythm. Instead, there may be indistinct, fibrillatory waves. The relationship between the atria and ventricles is also affected in atrial fibrillation, as the rapid impulses can cause the ventricles to respond with varying rates, further contributing to the irregularity of the heartbeat. This can lead to decreased cardiac efficiency and increased risk for thromboembolic events, such as stroke, due to the potential for blood clots forming in the atria. Other conditions mentioned involve different mechanisms of arrhythmias. While supraventricular tachycardia does involve rapid heart rhythms, it typically arises from areas above the ventricles and can include a regular rhythm. Ventricular fibrillation is a lethal arrhythmia that originates from the ventricles and is characterized by a loss of