<unk>  are<unk>  seen occasionally in the jugular vein of humans with certain cardiac arrhythmias. When the atria and ventricles contract simultaneously, or when the right atrium contracts against a closed tricuspid valve, the blood will be pushed against the AV valve, and a very large retrograde pressure<unk> travels up the jugular vein.
Cannon a waves
Wave sign
Epsilon wave
A wave
Hill sign
Watson's water hammer pulse
Gallop rhythm
The U Wave