Eduprobe
Question:
Which one is correct regarding electrocardiograph (ECG)?
QRS complex represents repolarisation of the ventricles
By counting the number of QRS complexes one can determine the pulse rate.
P-wave represents the electrical excitation of the ventricle
T-wave represents repolarisation of the atria
Solution:
The P-wave represents the electrical excitation (or depolarisation) of the atria, which leads to the contraction of both the atria. The QRS complex represents the depolarisation of the ventricles, which initiates the ventricular contraction. The T-wave represents the return of the ventricles from excited to normal state (repolarisation). So, by counting the number of QRS complexes that occur in a given time period, one can determine the heart beat rate of an individual.