To investigate the possible electrophysiological background of the greater excitability of concentric and eccentric left ventricular hypertrophy types in relation to the asymmetric type. Methods: 187 patients with essential hypertension, without ishaemic heart disease were divided into three groups with regard to left ventricule type: concentric (relative wall thickness >0.42, interventricular septum/left ventricular posterior wall ≤1.3), eccentric (left ventricular diameter in systoles >32, relative wall thickness <0.42), asymmetric left ventricular hypertrophy (interventricular septum/left ventricular posterior wall >1.3), and three subgroups: mild (interventricular septum or left ventricular posterior wall 11-12 mm), moderate (interventricular septum or left ventricular posterior wall 13-14 mm) and severe left ventricular hypertrophy (interventricular septum or left ventricular posterior wall ≥15 mm). In all patients QT intervals, QT dispersion, left ventricular mass index and ventricular arrhythmias were measured. An upper normal limit for QT corrected interval: 450/460 ms for men/women; for QT dispersion: 70 ms. Results: The QT corrected interval and QT dispersion were increased in severe concentric and eccentric left ventricular hypertrophy (443 and 480 ms for QT corrected; 53 and 45 ms for QT dispersion, respectively), not significantly. QT dispersion in men with severe left ventricular hyper - trophy was significantly enlarged (67.5 vs. 30 ms, p=0.047). QT interval was significantly longer in patients with complex ventricular arrhythmias (p=0.037). Conclusion: No significant association of QT intervals or QT dispersion with the degree/type of left ventricular hypertrophy was found. QT cor - rected interval and QT dispersion tend to increase proportionally to the left ventricular mass only in the concentric and eccentric type.