Left ventricular hypertrophy (LVH) has been associated with an increased incidence of ventricular arrhythmias and sudden cardiac death in hypertensive patients. However, it is not known whether this relationship exists in early asymptomatic hypertensives with mild LVH. We prospectively examined 100 consecutive patients with essential hypertension, 35 without and 65 with mild LVH on echocardiography. All underwent a detailed noninvasive arrhythmia work-up and were subsequently followed-up for 3 +/- 1 years in an ambulatory hypertension clinic. None of the 12-lead electrocardiographic parameters examined differed between the two hypertensive groups. A similarly low incidence of simple forms of ventricular ectopy was present in both groups, whereas complex forms of ventricular ectopy were extremely rare in either group. The signal-averaged electrocardiographic parameters examined were also not significantly affected by the presence of mild LVH. Arrhythmia-related symptoms or malignant ventricular arrhythmia events were not observed in either group of patients during follow-up with antihypertensive treatment. The latter resulted in LVH regression in the 65 patients with mild LVH at baseline. It appears that mild LVH among ambulatory hypertensive patients does not carry an additive arrhythmogenic risk and can be successfully reversed with the appropriate antihypertensive therapy, with no need of additional antiarrhythmic management.