NEETZoologyBody Fluids and Circulation
What is the significance of counting the number of QRS complexes in an ECG?
Options
- AIt indicates the heart rate of an individual
- BIt indicates the shape of the ECG
- CIt indicates the possible abnormality or disease
- DIt indicates the cardiac cycle
Correct answer
A. It indicates the heart rate of an individual
Step-by-step 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 contraction starts shortly after Q and marks the beginning of the systole. The T-wave represents the return of the ventricles from excited to normal state (repolarisation). The end of the T-wave marks the end of systole. Obviously, by counting the number of QRS complexes th