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Question: Answered & Verified by Expert
In a standard ECG which one of the following alphabets is the correct representation of the respective activity of the human heart?
BiologyBody Fluids and CirculationAIIMSAIIMS 2014
Options:
  • A S - start of systole
  • B T - end of diastole
  • C P - depolarisation of the atria
  • D R - repolarisation of ventricles
Solution:
2385 Upvotes Verified Answer
The correct answer is: P - depolarisation of the atria
A normal electrogram (ECG) is composed of a P wave, a QRS wave (complex) and a $\mathrm{T}$ wave. The P-wave represents the electrical excitation or depolarisation of 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 repolarisation of ventricles. The end of the T-wave marks the end of systole.

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