Electrocardiogram (ECG)

• What is an Electrocardiogram?

  Electrical activity in the heart can be detected on the surface of the skin by placing electrodes on the chest or limbs as the body tissues and fluids conduct electricity well. Such a recording is called an ECG
• What does the ECG indicate?

  The spread of the electrical signal generated by the SA node as it travels throughout the heart
• What are the five waves the normal ECG tracing of a healthy individual?

  P, Q, R, S and T
• What does the P wave represent?

  It represents the impulse from SA node as it sweeps over the atria ( atrial depolarization )
• What does the QRS complex represent?


  Rapid spread of impulse from the AV node throughout the ventricles and electrical activity of the ventricular muscles ( ventricular depolarization )
• What does the T wave represent?

  ventricular repolarization and relaxation of the ventricular muscles
• Why does the atrial repolarization which occurs during ventricular contraction is not seen?

  Due to the larger QRS complex
• How is the information about the heart function of a person (state of the myocardium and the cardiac conduction system ) can be obtained?

  by examining the pattern of waves and the time interval between cycles and parts of cycles