Body Fluids and Circulation Question 48

48. The QRS complex in a standard ECG represents

(a) Depolarisation of auricles

(b) Depolarisation of ventricles

(c) Repolarisation of ventricles

(d) Repolarisation of auricles

Show Answer

Answer : b

Hints & Solutions

(b) 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 term electrocardiogram used to describe these wave forms was first coined by Einthoven at the Dutch Medical Meeting of 1893. In 1901 , he successfully developed a new string galvanometer with very high sensitivity, which he used in his electrocardiograph.