Arrhythmias are common problems in hypertensive patients. The presence and complexity of both supraventricular and ventricular arrhythmias may influence morbidity, mortality, as well as the quality of life of patients. Diastolic dysfunction of the left ventricle, left atrial size and function, and left ventricular hypertrophy have been suggested as the underlying risk factors for supraventricular and ventricular arrhythmias in hypertensives. Recently, several non-invasive electrocardiographic parameters have been defined and widely investigated to identify the hypertensive patient at risk for the development of arrhythmias. These parameters include signal averaged analysis of P wave, QT interval dispersion, heart rate variability, ventricular late potentials and T wave morphology analysis. The aim of this review was to evaluate the relationships between high blood pressure, ventricular and supraventricular arrhythmias, relevant non-invasive cardiac parameters for risk assessment in hypertensive patients and the effects of blood pressure control. (C) 2002 The European Society of Cardiology. Published by Elsevier Science Ltd. All rights reserved.