Which statement best describes why atrial depolarization is usually not detected on a normal ECG?
A) It occurs at the same time as the QRS complex.
B) The electrodes cannot be placed high enough on the chest to detect the atria.
C) The voltage change in the atria is minimal and therefore does not register on an ECG.
D) The atria are so small and the depolarization happens so quickly that it cannot be detected.
E) The atria do not contract only the AV valves open.

Question

Quizplus · Accepted Answer

Atrial depolarization is actually detected on a normal ECG and is represented by the P wave. The statement that it occurs at the same time as the QRS complex is incorrect, which makes this choice the best answer by process of elimination. However, the explanation provided in the choices is based on a misunderstanding. Atrial depolarization is represented by the P wave, which occurs before the QRS complex that represents ventricular depolarization. The confusion might stem from the misinterpretation of the question or the choices provided.

Which Statement Best Describes Why Atrial Depolarization Is Usually Not