What is a likely consequence of a rapid ventricular rate in atrial fibrillation?

A rapid ventricular rate in atrial fibrillation can lead to decreased cardiac output, which is a significant concern in patients experiencing this condition. In atrial fibrillation, the heart's upper chambers (the atria) do not contract effectively, leading to the potential for a disorganized and rapid heartbeat. When the ventricular rate increases significantly, the ventricles may not have sufficient time to fill with blood during diastole, resulting in inadequate blood being pumped out with each contraction. This reduced stroke volume contributes to a decline in overall cardiac output, which can impact tissue perfusion and lead to symptoms such as dizziness, fatigue, or even heart failure in more severe cases.

Options indicating improved preload, excessive oxygen delivery, or increased blood pressure are typically not associated with the rapid ventricular rate in atrial fibrillation. In fact, these conditions often arise from effective cardiac function rather than the disordered rhythm seen in atrial fibrillation accompanied by a rapid ventricular rate. Therefore, decreased cardiac output is the most appropriate consequence associated with this scenario.