Why is atrial repolarization not seen in a ecg?

Answer 1

It is on page 374 of your lab book assuming this is the same question that came out Lab 28 in the Ninth Edition of Seeley's Anatomy & Physiology. The atrial repolarization occurs during ventricualr depolarization and is masked by the larger QRS complex. I actually did my homework :)

Answer 2

[non-professional opinion]

Atrial repolarization is a much lower voltage event than atrial depolarization (the P wave) and it usually occurs during ventricular depolarization (the QRS complex).

Therefore, it is too small to be clearly distinguished from noise on most EKGs and even if it were strong relative to the noise, would typically be obscured by the much stronger QRS complex.

Answer 3

You can't see atrial repolarization on surface ECGs because it's too small a current to get out of the body at the voltages present in the heart.

Atrial repolarization is also timed so that the QRS complex would stomp on it, even if you could see it on a surface lead, and that's often the answer given to this question by non-cardiologist physicians and allied health professionals of every stripe; unless the prof of the course you're using answers.com to, uh, "assist" you with is an actual cardiologist, he or she might be looking for that one. (It would be best to look in the assigned source material. . .)

Answer 4

because it happens during myocardial depolarization (QRS-complex)

Answer 5

Because the atria repolarize while he ventricles are contracting, so the signal is completely hidden.

Answer 6

Atrial repolarization is not seen because the atrium repolarizes while the ventricle is depolarizing and is incorporated into the QRS complex.

Answer 7

contraction of smooth muscle in a blood vessel is referred to as an condition of?