We performed retrospective analysis of 173 cases of first episode of non-valvular atrial flutter (AF) type I: 150 (86.7 %) men and 23 (13.3 %) women aged 55.2±0.9 years. Over seven years of follow-up, 6 % patients did not have arrhythmia, rare paroxysms were registered in 30.4 %, while frequent (over once every three months) – in 10.1 % of patients. Permanent atrial fibrillation or flutter was registered in 52 % of patients. In one year after arrhythmia relapse annual frequency of the permanent forms was over 5 %. Drug cardioversion was successful in 13.2 % of patients, while drug plus electric cardioversion (in case of drugs inefficacy) – in 38.2 %, while only electric cardioversion (transesophageal stimulation or direct current cardioversion) – in 48.5 % of patients.