QT DISPERSION IN ESSENTIAL-HYPERTENSION

Increased QT dispersion is associated with sudden cardiac death in con gestive heart failure, hypertrophic cardiomyopathy, and following acut e myocardial infarction. Patients with hypertension, in particular tho se with left ventricular hypertrophy, are also at greater risk of sudd en cardiac death. We examined whether QT dispersion, which is easily o btained from a routine EGG, correlates with echo LVH. Sixty-nine untre ated patients with essential hypertension had QT dispersion measured f rom a surface 12-lead electrocardiogram, and two-dimensional echocardi ography performed to measure interventricular septal thickness, poster ior wail thickness, and left ventricular internal diameter. Office blo od pressure was recorded, and in 56 patients, 24 h ambulatory blood pr essure monitoring was also done. Multivariate analysis demonstrated si gnificant relationships between QT dispersion and office systolic bloo d pressure, and left ventricular mass index. Similar findings were obt ained when QT dispersion was corrected for heart rate (QTc dispersion) . After patients with electrocardiographic left ventricular hypertroph y (n=5) were excluded from the analysis, the above relationships persi sted, Increased QT dispersion is thus found in those essential hyperte nsives at greatest risk of sudden death. Since this relationship persi sts even in the absence of electrocardiographic left ventricular hyper trophy, measurement of QT dispersion might be a simple, non-invasive s creening procedure to identify those hypertensives at greatest risk of sudden death.