We performed retrospective analysis of 154 case reports of patients with first episode of non-valvular atrial flutter type I: 133 (86.4 %) men and 21 (13.6 %) women aged 55.4±0.9 years. Over 9 years of follow-up permanent atrial fibrillation or flutter was registered in 66.7 % of patients, rare paroxysms were registered in 25.2 % of patients, frequent paroxysms (at least once every 3 months) – in 5.4 %, no arrhythmias – in 2.7 %. Drug cardioversion was used in 15.6 % patients, drugs combined with electrical cardioversion (in case of drug inefficiency) – in 46.7 % patients, only electrical cardioversion (transesophageal cardiac stimulation or electric impulse therapy) – in 37.8 %. Annual frequency of the permanent form of arrhythmia was in average 6.7 %, which was due to the electrophysiological remodeling of atrial myocardium and not related to the increase of frequency of paroxysms. Frequent paroxysms during 1, 3, 5, 7 and 9 years follow-up occurred from 5.4 to 10.1 % patients.