Which of the Following is the Most Likely Consequence of a Very

Question

Which of the following is the most likely consequence of a very rapid heart rate?
A) Decreased ventricular filling (with blood)
B) Failure of the AV valves to open
C) Failure of the SA node to fire
D) Failure of the cardiac impulse to enter the His-Purkinje system

Accepted Answer

A very rapid heart rate (tachycardia) can cause decreased ventricular filling, as there is not enough time for the ventricles to completely fill with blood before the next contraction. This can lead to decreased cardiac output and potentially even heart failure. Failure of the AV valves to open, failure of the SA node to fire, and failure of the cardiac impulse to enter the His-Purkinje system could all potentially cause arrhythmias or conduction abnormalities, but they are not the most likely consequence of rapid heart rate.