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  • If heart sound recording and ECG are superimposed the first heart sound would occur  Option: 1 At P wave

If heart sound recording and ECG are superimposed the first heart sound would occur

 

Option: 1

At P wave

 


Option: 2

Just after P wave

 


Option: 3

Just before QRS complex

 


Option: 4

Just after QRS complex

 


Answers (1)

best_answer
 

As we have learnt in ECG:

QRS wave

  • It begins after a fraction of a second of the P wave 
  • It begins as a small downward deflection (Q) and continues as large upright (R)  and triangular wave, ending as downward wave (S) at its base
  •  QRS wave indicates depolarization of ventricles
  • It is caused by the impulses of the contraction from AV node through the Bundle of His and Purkinje fibres and the contraction of ventricular muscles
  • In this wave there is a spread of electrical impulses through ventricles
  • The normal duration of the QRS complex is <0.10 seconds

If heart sound recording and ECG are superimposed the first heart sound would occur just after QRS complex, As the ventricular cells contract, intraventricular pressures increase above those in the atria, and the atrioventricular valves abruptly close. Closure of the atrioventricular valves results in the first heart sound, S1. 

Hence, the correct answer is option d.

Posted by

manish painkra

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