Question

$ECG$ depicts the depolarisation and repolarisation processes during the cardiac cycle. In the $ECG$ of a normal healthy individual one of the following waves is not represented.

• A. Repolarization of ventricles
• B. Depolarisation of ventricles
• C. Depolarisation of atria
• D. Repolarization of atria

Answer 1

The correct option is D

Repolarization of atria

Depolarisation of atria

● $ECG$ consists of the $P$ wave, $QRS$ complex, and the $T$ wave.

● The $P$ and the $QRS$ complex are the depolarization waves and $T$ wave is the repolarization wave.

● Depolarization wave indicate the systole (contraction) and Repolarization(relaxation).

● $P$ wave indicates depolarization of atria,when the atria contracts.

Repolarization of atria

● There is no separate wave representing the atrial repolarization as the atrial repolarization occurs during ventricular depolarisation.

● The amplitude of the repolarization wave is very low.

Depolarisation of ventricles

● The $QRS$ wave represents depolarization of the ventricles.

● The $T$ wave represents the repolarization of the ventricles.

Final answer

b.Repolarization of atria