Prevention of sudden cardiac deaths (SCD) is one of major challenges of todays cardiology. Factors, that would permit identification of patients with highest risk of SCD, have been sought for many years now. Although ventricle-dependent sinus arrhythmia has been observed for a few decades, quantification of this phenomenon was performed by Schmidt et al., who introduced new concept of heart rate turbulence (HRT). HRT parameters comprise of turbulence onset (TO) and turbulence slope (TS). When no HRT is observed, SCD risk is markedly increased. The mechanism behind HRT is not fully known, but it is though to be caused by baroreflex sensitivity. This factor has been evaluated in many clinical studies aiming at determining methods of analysis and usefulness of HRT also in others pathological entities. This paper is a short review of these studies.