Which type of cardiac arrhythmia is a significant contributor to ischemic stroke?

Atrial fibrillation is the correct answer because it is the most significant contributor to ischemic stroke among the listed arrhythmias. This condition is characterized by an irregular and often rapid heart rate that can lead to poor blood flow. In atrial fibrillation, the atria do not contract effectively, leading to stasis of blood in the left atrium, particularly in the left atrial appendage. This stasis can result in the formation of thrombi (blood clots). If these clots dislodge, they can travel through the bloodstream and occlude cerebral arteries, leading to an ischemic stroke.

In contrast, other arrhythmias listed, such as atrial flutter, can also increase the risk for stroke but are generally less common and their associated risks are not as pronounced as those seen in atrial fibrillation. Bradycardia typically results in slower heart rates that are less likely to contribute directly to stroke. Ventricular tachycardia is often associated with decreased cardiac output and can lead to instability and other complications, but it is not primarily linked with the thromboembolic events that are associated with atrial fibrillation. Thus, atrial fibrillation remains a key focus in the prevention of ischemic strokes due