Question

At which point of ECG, the initiation of ventricular contraction is marked by

• A. P
• B. Q
• C. T
• D. S

Answer 1

The correct option is B Q

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.