Question

In the normal ECG the negative waves are
a. PQRS
b. PRT
c. QS
d. XYZ

Answer 1

Hint: ECG is called an electrocardiogram. It is mainly used to know the different conditions of the heart, it is the most important diagnostic tool for heart conditions, electrodes are placed on the heart, where they detect the electric signals that usually cause the heartbeat and these signals are picturized in the forms of waves.

Complete answer:
- Generally, the heartbeat begins with the depolarization of the sinoatrial node or pacemaker, from where they go to the left ventricles and there it travels to the atrioventricular node and to the bundle of His and Purkinje fibers.
- All these actions of the heart, and the electric signals and all sounds are given in the electrocardiogram in the form of waves.
- It consists of 3 important things.
- Normally they are represented in the form of three waves.
- They are P waves which indicate atrial depolarization.
- The QRS complex represents the ventricular depolarization.
- T wave represents ventricular repolarization and U wave represents the papillary muscle repolarization.
- Normally in ECG, a wave of depolarization passes towards the electrode is a positive wave.
- The wave of depolarization passing away from the electrode is a negative wave.
- In normal ECG, the QRS complex shows the negative deflection, while the negative wave starts with Q and it again is positive by R and again negative by S.
- So QS complex is negative in normal ECG.

Hence, The correct answer is option (C).

Note: In ECG, deflection is referred as wave only if it passes through the baseline, any negative waves at first represent the Q wave, if not one can consider the Q wave is absent and any positive wave represent the positive wave and any negative wave after the positive wave is S wave.