Heart rate turbulence (HRT) analysis is a novel, non-invasive method enabling to estimate sudden cardiac death risk. Up till now it was used to determine cardiac death risk in patients suffering from congestive heart failure and especially after myocardial infarction. The aim of the study was to estimate heart rate turbulence parameters in patients with essential hypertension and to find correlations between those parameters and age, left ventricular mass and hypertension stages. Studies were performed in a group of 55 persons: 26 women (54.79 +/- 8.26 years old) and in 29 men (52.34 +/- 5.72 years old) with essential pharmacologically untreated hypertension. Patients were divided into two groups: increased (group I, n = 32) and normal left ventricle mass (group II, n = 23). In each patient 24-hour ECG Holter recording was performed and then turbulence onset (TO) (expressed in %) and turbulence slope (TS) (in ms/RR interval) were estimated. In the group of patients with increased left ventricle mass parameter TO was significantly higher (-0.74 +/- 0.24 vs -1.32 +/- 0.28; p < 0.05) and parameter TS significantly lower (5.26 +/- 1.17 vs 8.46 +/- 2.91; p < 0.01) in comparison to study subjects with normal left ventricle mass. Heart rate turbulence is decreased in people with essential hypertension and increased left ventricle mass in comparison to normal left ventricle mass group. Decreased heart rate turbulence in patients with essential hypertension and increased left ventricle mass may be a predictor of worse prognosis in that group.