Autonomic cardiac regulation in different types (normal, concentric, and eccentric geometries) of the left ventricle (LV) was evaluated in 86 hypertensive patients. LV structure and function were evaluated by echocardiography). To calculate heart rate variability (HRV), 512 RR intervals were measured in supine rest and passive tilt. Power spectral analysis with fast Furrier transform was used to derive low- and high-frequency power spectra and the sympathovagal index (SVI). In the normal LV geometry group, there was a good response to the tilt test, by causing a 3-fold increase in SVI while in the two LV hypertrophy groups, the index was virtually unchanged or even decreased. The normal LV geometry group patients showed a positive correlation between low-frequency power and the relative LV wall thickness (RLVWT) while the two LV hypertrophy groups did increases in RLVWT and LV myocardial mass, which were associated with a reduction in HRV. In conclusion, HRV is significantly reduced in essential hypertension and is also closely connected with cardiac structure and function. Patients with normal LV geometry showed a preserved response to the tilt test. LVH produces significant autonomic regulatory disturbances possibly due to the lower sensitivity of cardiac adrenoceptors independently of the pattern of LV hypertrophy.