Final answer:
The loss of ventricular filling as a result of acute atrial fibrillation is approximately 20-30%, due to the loss of the atrial kick which normally contributes to ventricular filling.
Step-by-step explanation:
The loss of ventricular filling as a result of acute atrial fibrillation is approximately 20-30%. This is because the atria contribute this amount to ventricular filling during the atrial kick, which is lost during atrial fibrillation. When atrial fibrillation occurs, the ventricles would still be filled with about 70-80% of their capacity due to inflow during diastole. However, the absence of coordinated atrial contractions, which normally contribute the remaining 20-30%, can lead to a reduction in the efficiency of cardiac output. Therefore, even though the ventricles continue to pump blood, their function is compromised, which could lead to serious health consequences if not managed properly.