[Isochrone map, its implication and clinical usefulness].

Isochrone maps are useful tools to visually detect local abnormal activation (ventricular activation time; VAT) or repolarization (Activation recovery interval; ARI, Recovery time; RT) sequence, displaying the body surface distribution of them in the form of a map. VAT has long been considered as one of the parameters in the electrocardiographic diagnosis for ventricular hypertrophy. But its significance has not been well established, and its clinical usefulness has been limited. We demonstrated the different significance of VAT in concentric and eccentric LVH (LV dilatation) by means of VAT maps. We also revealed the usefulness of VAT maps in evaluating the conduction deficit such as bundle branch block, hemodynamic disorder and severity of arrhythmias complicated by miscellaneous heart diseases.