QRS Complex

Video 31 of 45
2 min 9 sec
English
English
Want to watch this video? Sign up for the course or enter your email below to watch one free video.

Unlock This Video Now for FREE

This video is normally available to paying customers.
You may unlock this video for FREE. Enter your email address for instant access AND to receive ongoing updates and special discounts related to this topic.

Understanding the QRS Complex in ECG: Significance and Interpretation

The QRS Complex: Introduction

Largest Complex: The QRS complex is the largest in terms of height on a normal ECG and represents ventricular depolarization.

Components of the QRS Complex

Q Wave: The first downward deflection on the ECG.

R Wave: The first positive deflection on the ECG.

S Wave: The next downward deflection following the R wave.

Role of the AV Node

Electrical Impulse Transmission: The AV node receives an electrical impulse from the SA node (sinus node) and slows it down to regulate the heart rate.

Bundle Branches and Purkinje Fibers: The impulse travels through the left and right bundle branches, which then spread out into the Purkinje fibers.

QRS Complex Duration

Normal Range: The duration of the QRS complex should be between 0.08 seconds and 0.12 seconds, equivalent to two to three small squares on the ECG paper.

Abnormal Duration: Prolonged QRS complex duration indicates a potential blockage or delay in the electrical impulse's pathway through the heart.

Ventricular Contraction and Blood Circulation

Stimulation and Contraction: The ventricles are stimulated by the electrical impulse, leading to their contraction.

Blood Ejection: The contraction forces blood out of the ventricles and into the aortic or pulmonary arteries.

Summary

The QRS complex represents ventricular depolarization and consists of the Q, R, and S waves. The AV node plays a crucial role in regulating the heart rate. Abnormal QRS complex duration may indicate a blockage in the bundle branches. Understanding the QRS complex helps interpret the electrical activity and contraction of the ventricles.