Determination of left ventricular mass in systemic hypertension: comparison of standard and signal averaged electrocardiography.

OBJECTIVE To investigate the quantitative relationship, if any, between signal averaged electrocardiographic variables and echocardiographically determined left ventricular mass in hypertensive subjects. DESIGN Cohort analytic prospective study. SETTING University hospital. SUBJECTS 50 hypertensive subjects selected consecutively from inpatients. Patients older than 75 years, with underlying cardiac disease, with inconclusive echocardiograms with bundle branch block, or in atrial fibrillation were excluded. INTERVENTIONS Antihypertensive therapy involving 41 patients was continued. MAIN OUTCOME MEASURES Left ventricular mass calculated in accordance with the standards of the Penn convention. Thirteen criteria derived from combinations of signal averaged electrocardiographic X, Y, and Z Frank orthogonal leads, including voltage criteria, duration, and time-voltage integrals of the QRS complex. Four widely used standard electrocardiographic criteria for detection of left ventricular hypertrophy. RESULTS There was no difference in the values for any of the electrocardiographic variables between patients with (n = 29) and without left ventricular hypertrophy (n = 21). The time-voltage integral of QRS in the horizontal plane was the best signal averaged variable related to left ventricular mass (r = 0.33, P = 0.019); however, the correlation with Rodstein voltage was stronger (r = 0.46, P = 0.0009). A positive correlation was also found between left ventricular indexed mass and Rodstein voltage (r = 0.43, P = 0.0019). Stepwise regression analysis revealed Rodstein voltage as the only predictor of indexed mass (P = 0.0019), and Rodstein voltage (P = 0.0022) and body weight (P = 0.011) as the only independent correlates of left ventricular mass. CONCLUSIONS The relation between electrocardiographic variables and left ventricular mass or indexed mass is of limited value; signal averaged orthogonal leads do not improve this assessment compared with standard electrocardiographic leads.