Question

Match the following:

$\begin{array}{cc}\text{A. P wave}& \text{i) depolarisation of atria}\\ \text{B. T wave}& \text{ii) repolarisation of ventricles}\\ \text{C. QRS wave}& \text{iii) depolarisation of ventricles}\end{array}$

• A. a-i, b-ii, c- iii
• B. a-ii, b-iii, c-i
• C. a-iii, b-i, c-ii
• D. a-iii, b-ii, c-i

Answer 1

The correct option is A a-i, b-ii, c- iii

Electrocardiograph is a machine that produces electrocardiogram. ECG is a graphical representation of the electrical activity of the heart during a cardiac cycle. The ECG produces peaks and each peak is marked with a letter from P to T that corresponds to a specific electrical activity of the heart.

The P wave in the ECG represents the electrical excitation of the atria (depolarisation) which causes contraction of both the atria.

The QRS wave represents the depolarisation of the ventricles, which causes the ventricular contraction.

The T wave represents the return of ventricles from excited to normal state (repolarisation).