Electrocardiography: Electrical Activity of the Heart

Deflection Waves of ECG

• P wave - initial wave, demonstrates the depolarization from SA Node through both ATRIA; the ATRIA contract about 0.1 s after start of P Wave
  
• QRS complex - next series of deflections, demonstrates the depolarization of AV node through both ventricles; the ventricles contract throughout the period of the QRS complex, with a short delay after the end of atrial contraction; repolarization of atria also obscured
  
• T Wave - repolarization of the ventricles (0.16 s)
  
• PR (PQ) Interval - time period from beginning of atrial contraction to beginning of ventricular contraction (0.16 s)
  
• QT Interval - the time of ventricular contraction (about 0.36 s); from beginning of ventricular depolarization to end of repolarization

Category: Medicine Notes