Electrocardiographs (ECGs or EKGs) provide data about the electrical activity of the heart. By placing a series of "leads" on a person's chest, the electrical activity of the heart can be recorded and analyzed in order to detect irregular heartbeats (arrhythmias) and other conditions. The figure below shows a normal EKG tracing for one cardiac cycle.
The P region represents electrical activity spreading through the atria. The QRS region represents electrical activity spreading through the ventricles. The T region represents electrical activity in the ventricles returning to rest.
-Suppose a person's AV node in their heart suddenly stopped sending signals to the rest of the heart. How would this person's EKG differ from normal?
A) The EKG would have a taller P region.
B) The EKG would not have a QRS region.
C) The EKG would have a shorter T region.
D) The EKG would not have a gap between the S and T regions.

Question

Electrocardiographs (ECGs or EKGs) provide data about the electrical activity of the heart. By placing a series of "leads" on a person's chest, the electrical activity of the heart can be recorded and analyzed in order to detect irregular heartbeats (arrhythmias) and other conditions. The figure below shows a normal EKG tracing for one cardiac cycle.
  The P region represents electrical activity spreading through the atria. The QRS region represents electrical activity spreading through the ventricles. The T region represents electrical activity in the ventricles returning to rest.
-Suppose a person's AV node in their heart suddenly stopped sending signals to the rest of the heart. How would this person's EKG differ from normal?
A) The EKG would have a taller P region. 
B) The EKG would not have a QRS region. 
C) The EKG would have a shorter T region. 
D) The EKG would not have a gap between the S and T regions.

Quizplus · Accepted Answer

If the AV node stopped sending signals to the rest of the heart, the ventricles would not contract as they should, which means that there would be no QRS complex in the EKG tracing. The P and T regions may remain unchanged. The correct answer is B, as this choice describes the absence of the QRS complex.

Electrocardiographs (ECGs or EKGs) Provide Data About the Electrical Activity