What it means
It comes after the P wave and before the T wave and marks the moment the ventricles are triggered to contract. A normal QRS lasts less than 0.12 seconds (three small boxes). A wide QRS means the signal is moving through the ventricles slowly or by an unusual path, as in a bundle branch block or a rhythm starting in the ventricles.
At a glance
| Spanish | complejo QRS |
|---|---|
| Also written | QRS complexes, QRS |
Related terms
electrocardiogram
A test that records the heart's electrical activity as waves on paper or a screen.
ventricle
One of the two lower chambers of the heart, or one of the fluid-filled spaces inside the brain.
ventricular tachycardia
A fast heart rhythm that starts in the lower chambers of the heart (the ventricles), usually over 100 beats per minute.
Purkinje fibers
Special fibers in the walls of the heart's ventricles that spread the electrical signal so the ventricles contract.