Question

Normal wave pattern of ECG wave form is shown in the figure below. Identify the missing wave from the wave form. 

• A. R wave
• B. S wave
• C. Q wave
• D. P wave

Hint:

Remember: ECG sequence = P → QRS → T. P represents atrial depolarization and is the first wave.

Answer 1

The Correct Option is D

Step 1: Identify ECG Wave Components.
An electrocardiogram (ECG) typically comprises the P wave, QRS complex, and T wave.
- P wave: Signifies atrial depolarization.
- QRS complex: Represents ventricular depolarization (Q = initial negative deflection, R = prominent positive deflection, S = negative deflection following R).
- T wave: Indicates ventricular repolarization.

Step 2: Examine the Provided ECG Image.
The image displays a significant upward peak (R wave), a subsequent downward deflection (S wave), and a rounded wave thereafter (T wave).
The initial small wave preceding the QRS complex (P wave) is absent.

Step 3: Eliminate Incorrect Choices.
- (A) R wave: Present in the figure.
- (B) S wave: Observed following the R wave.
- (C) Q wave: Typically a small downward deflection before the R wave, but the P wave is entirely absent here.
- (D) P wave: The missing wave; this is the correct identification.

Step 4: Final Determination.
Consequently, the absent wave in the ECG tracing is the P wave.