If Ectopic Impulses Are Occurring in the Heart at a Rate

question 19

Multiple Choice

If ectopic impulses are occurring in the heart at a rate that is faster than the SA node,

• A)the rate at which the SA node fires controls the ectopic rate.
• B)the ectopic beat overrides the SA node and causes the atria and ventricles to depolarize.
• C)the ectopic and SA node impulses cancel each other, resulting in atrial fibrillation.
• D)the SA node impulses control the atria, and the ectopic impulses control the ventricles.