Question

Consider the following statements with respect to ECG [Electrocardiogram] and choose the correct answer.
Statement I : 'P' wave represents the depolarisation of ventricles.
Statement II : 'T' wave represents the repolarisation of ventricles.

• A. Statement I and Statement II are wrong.
• B. Statement I is correct but Statement II is wrong.
• C. Statement I is wrong but Statement II is correct.
• D. Statement I and Statement II are correct.

Hint:

Mnemonics for ECG waves: P = Atrial De-polarisation. QRS = Ventricular De-polarisation. T = Ventricular Re-polarisation.

Answer 1

The Correct Option is C

Step 1: Understanding the Problem:
An Electrocardiogram (ECG) is a graphical representation of the electrical activity of the heart during a standard cardiac cycle, featuring distinct waves: P, QRS, and T.
Step 2: Approach and Formula:
Relate the standard ECG waves to their corresponding cardiac cycle events (depolarisation and repolarisation of the atria and ventricles).
Step 3: Detailed Explanation:
- Statement I: The 'P' wave on an ECG corresponds to the electrical excitation or depolarisation of the atria, which leads to atrial contraction. It does not represent ventricular depolarisation (which is the QRS complex). Therefore, Statement I is wrong.
- Statement II: The 'T' wave represents the return of the ventricles from an excited state to a normal state, a process called repolarisation. The end of the T-wave marks the end of ventricular systole. Therefore, Statement II is correct.
Since Statement I is false and Statement II is true, the matching option is (C).
Step 4: Final Answer:
Statement I is wrong but Statement II is correct.