Abstract. The purpose of the study was to investigate the heart rate variability in the patients with atrial flutter in lying position, during an active orthostasis test and after successful catheter ablation. Atrial flutter was diagnosed in 18 patients (age 55.44±4.47 years). 500 RR intervals were recording at rest, during orthostatic test, standing position, clinostatic test and again in lying position. The next day after successed catheter ablation all procedures were repeated. General heart rate variability and power spectral analysis (very low frequency, low frequency and high frequency) was performed. Analysis of data showed that average heart rate frequency before and after catheter ablation in the patients with atrial flutter was similar (RR1=0.85±0.11 s; RR2=0.83±0.08 s). General heart rate variability before treatment in lying and standing position was ó1=0.074, ó2=0.068, and after catheter ablation ó1=0.051, ó2=0.041. Also was noted improvement maximal heart rate reaction during the active orthostatic test in the patients after catheter ablation (DRRB%1=17.53±7.72; DRRB%2=19.3±8.62). Sinus rhythm recovery time after clinostatic test was better in the patients after catheter ablation (SNRT=23.56 s, SNRT=26.2 s). Our data showed improvement of cardiovascular state and autonomic regulation in the patients with atrial flutter after successful catheter ablation in early period.