Atrial stand still is a rare cardiac rhythm disease with a few familial and sporadic cases described to date that is characterized by a transient or permanent absence of electrical and mechanical atrial activity. Electrocardiographic findings include bradycardia, ectopic supraventricular rhythms, lack of atrial excitability and absent P waves. The disease is Orphanet rare-disease nomenclature entry Orphanet_1344 (Atrial stand still). Also known as: Atrial cardiomyopathy with heart block.