Q 1: Do you know the naming convention for Q, R, S, QS

Q 2: What is the normal duration of  QRS complex? 

Q 3: What does alteration in duration of  QRS duration mean?

Answer

Answers

Q 1: Do you know the naming convention for Q, R, S, QS

Naming convention:

• Q wave: first downstroke of the QRS complex. Usually very small or absent.
• R wave: first upward deflection of the QRS complex. Upward deflections occurring after an S wave are noted by a "prime mark" such as R'
• S wave: the first downward deflection occurring after the R wave.
• A monophasic negative QRS complex is called QS.

Q 2: What is the normal duration of  QRS complex? 

Duration: 0.08-0.12 seconds (2-3 horizontal boxes)

contour is same between beats

Q 3: What does alteration in duration of  QRS duration mean?

Duration:

• Prolonged: Bundle branch blocks, drug toxicity, electrolyte imbalance
• Shortened:  WPW

Contour

Change of contour between beats suggests ectopic foci

Abnormal  but constant contour suggests

• Bundle branch blocks
• Drug toxicity
• Electrolyte imbalance