JBL EMT Practice Exam

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Prepare for the JBL EMT Exam and improve your chances of success. Study with our flashcards, multiple-choice questions, hints, and explanations. Get exam-ready!

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Cardiac output may decrease if the heart beats too rapidly because:

a rapid heartbeat causes a decrease in the strength of cardiac contractions
as the heart rate increases, more blood is pumped from the ventricles than the atria
the volume of blood that returns to the heart is not sufficient with fast heart rates
there is not enough time in between contractions for the heart to refill completely

The correct answer is: a rapid heartbeat causes a decrease in the strength of cardiac contractions

A rapid heartbeat causes a decrease in the strength of cardiac contractions because when the heart beats too quickly, there is not enough time for the ventricles to fill adequately with blood. This results in a decrease in the amount of blood ejected with each contraction, ultimately decreasing the overall cardiac output. This reduction in the strength of cardiac contractions can lead to a decrease in the amount of blood pumped out of the heart per minute, resulting in a decrease in cardiac output. The other options are not directly related to the negative impact of a rapid heartbeat on cardiac output.