Results: Time-domain HRV parameters (SDNN, rMSSD, pNN50) in patients with NSVT were lower in than in control subjects (58.2 ± 47.1 ms vs 166.9 ± 78.4 ms; 54.7 ± 47.2 ms vs 123.6 ± 61.5 ms and 13.1 ± 16.7% vs 24.9 ± 17.4% respectively; p<0, 05).