Video answer: The cardiac cycle, animation
Top best answers to the question «Which wave is contraction of the atria»
The P wave represents depolarization of the atria and is followed by atrial contraction (systole). Atrial systole extends until the QRS complex, at which point, the atria relax. The QRS complex represents depolarization of the ventricles and is followed by ventricular contraction.
Video answer: Premature atrial contractions (pacs), animation.