AIIMS 2014
- Exam
- AIIMS
- Year
- 2014
- Subject
- Zoology
- Chapter
- Body Fluids and Circulation
AIIMS 2014 · Zoology · Body Fluids and Circulation
In a standard ECG which one of the following alphabets is the...
In a standard ECG which one of the following alphabets is the correct representation of the respective activity of the human heart?
Options
- AS - start of systole
- BT - end of diastole
- CP - depolarisation of the atria
- DR - repolarisation of ventricles
Correct answer
C. P - depolarisation of the atria
Step-by-step solution
A normal electrogram (ECG) is composed of a P wave, a QRS wave (complex) and a wave. The P-wave represents the electrical excitation or depolarisation of 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 repolarisation of ventricles. The end of the T-wave marks the end of systole.