R-wave amplitude change during aerobic exercise in hypertensive adolescents after treatment

This study attempts to determine whether the blunted reduction in R-wave amplitude during progressive aerobic exercise observed in adolescents with systemic hypertension could be altered by pharmacologic therapy to reduce blood pressure. Twenty-nine hypertensive adolescents were randomly assigned to treatment with either a diuretic, hydrochlorothiazide, or a centrally acting agent, clonidine. After 16 weeks of therapy, casual blood pressure was significantly reduced in both groups. Repeat exercise stress testing on therapy demonstrated a significant change in R-wave response. In both treatment groups the change in R-wave amplitude during exercise corresponded with the R-wave response pattern observed in normotensive control subjects. These observations indicate that the altered R-wave amplitude response to exercise observed in young hypertensive subjects is reversible and suggest that the altered R-wave response before treatment is related to a higher vascular resistance.