thaler chapter 1

P Waves, QRS Complexes, T Waves, and Some Straight Lines

25

A

B

QRS complex

( A ) Ventricular depolarization generates ( B ) a complicated waveform on the EKG called the QRS complex.

The Parts of the QRS Complex The QRS complex consists of several distinct waves, each of which has a name. Because the precise configuration of the QRS complex can vary so greatly, a standard format for naming each component has been devised. It may seem a bit arbitrary to you right now, but it actually makes good sense. 1. If the first deflection is downward, that part of the QRS complex is called a Q wave . 2. The first upward deflection is called an R wave . 3. If there is a second upward deflection, it is called R ′ (“R-prime”).