Which of the following rhythms is associated with a significant risk of stroke?

Atrial fibrillation is associated with a significant risk of stroke due to the nature of its rhythm and the potential for thrombus formation. In atrial fibrillation, the atria do not contract effectively, leading to turbulent blood flow. This turbulence can result in the stasis of blood within the atria, particularly in the left atrial appendage, where clots are likely to form. If a thrombus develops and dislodges, it can travel to the brain, causing an ischemic stroke.

The risk factors for stroke in patients with atrial fibrillation are well-documented and include variables such as age, history of hypertension, prior stroke or transient ischemic attack (TIA), diabetes mellitus, and heart failure, among others. Because of this elevated risk, patients with atrial fibrillation are often managed with anticoagulant therapy to reduce the chances of stroke occurrence.

In contrast, other rhythms listed, such as ventricular fibrillation, sinus tachycardia, and normal sinus rhythm, do not carry the same risk of stroke. Ventricular fibrillation leads to ineffective heart contractions and requires immediate intervention to restore a normal rhythm, while sinus tachycardia is an elevated heart rate without the stasis problem. Normal sinus rhythm