What does Arrhythmias, atrial mean?

Arrhythmias, atrial meaning in Medical Dictionary

irregular heart rhythm considering electric disturbances inside atria (the upper chambers of this heart) or perhaps the AV node "relay station", causing fast heart beats. Types of atrial arrhythmias includes atrial fibrillation, atrial flutter, and paroxysmal atrial tachycardia (PAT).