Studies have shown an association between left ventricular(LV) geometry and complex ventricular ectopic activity. Increased transmural dispersion of repolarization(TDR), which correlates to the interval from the peak to the end of the T wave(Tpe) on the surface electrocardiogram, is linked to ventricular tachyarrhythmias. The relation between LV geometry and TDR is unknown. The mean Tpe interval, measured from leads V1 to V3 of the surface electrocardiogram,was assessed in 300 patients(50% men)who had normal LV systolic function and QRS duration and were categorized into 3 equal groups, which were matched by age and gender, according to echocardiographically determined LV geometry(normal structure, concentric remodeling, and LV hypertrophy). The Tpe interval was corrected for the QT interval using Tpe/QTc and was compared among the 3 groups. Compared with those who had normal LV structure, the Tpe interval was significantly prolonged in those who had LV hypertrophy and significantly shortened in those who had concentric remodeling(p=< 0.0001 for the 2 comparisons). Correcting for the QT interval using Tpe/QTc yielded similar results. Thus, TDR was increased in patients who had LV hypertrophy but decreased in concentric remodeling compared with those who had normal cardiac structure. Although LV hypertrophy represents a maladaptive geometric process that results in an unfavorable electrical substrate, concentric remodeling may represent a structural adaptation that has a more favorable electrical milieu. Studies have shown an association between left ventricular (LV) geometry and complex ventricular ectopic activity. Increased transmural dispersion of repolarization (TDR), which correlates to the interval from the peak to the end of the T wave (Tpe) on the surface electrocardiogram, The relation between LV geometry and TDR is unknown. The mean Tpe interval, measured from leads V1 to V3 of the surface electrocardiogram, was assessed in 300 patients (50% men) who had normal LV systolic function and QRS duration and were categorized into 3 equal groups, which were matched by age and gender, according to echocardiographically determined LV geometry (normal structure, concentric remodeling, and LV hypertrophy). The Tpe interval was corrected for the QT interval using Tpe / QTc and was compared among the 3 groups. Compared with those who had normal LV structure, the Tpe interval was significantly prolonged in those who had LV hypertrophy and significantly sh ortened in those who had concentric remodeling (p = <0.0001 for the 2 comparisons). Correcting for the QT interval using Tpe / QTc yielded similar results. Thus, TDR was increased in patients who had LV hypertrophy but decreased in concentric remodeling compared with those Who had normal cardiac structure. However, LV hypertrophy represents a maladaptive geometric process that results in an unfavorable electrical substrate, concentric remodeling may represent a structural adaptation that has a more favorable electrical milieu.