CARDIOVASCULAR REACTIVITY TO STRESS AND LEFT-VENTRICULAR MASS IN YOUTH

We studied the relationships of cardiovascular reactivity during menta l stress with left ventricular mass index in a group of prepubertal ch ildren 8 to 10 years old and in a group of peripubertal or postpuberta l adolescents 15 to 17 years old. One hundred fifteen participants, va rying in age group, sex, and race (black and white), took part in a la boratory stress protocol consisting of a reaction-time task, a mirror tracing task, a cold forehead challenge, and a stress interview. Cardi ovascular measures included blood pressure and heart rate, as well as cardiac output, stroke volume, total peripheral resistance, and preeje ction period obtained noninvasively with impedance cardiography. Measu res of left ventricular mass were made by echocardiography. Results in dicated that across all participants, left ventricular mass index was associated with cardiovascular responses during the mirror tracing and cold forehead tasks, especially with those responses reflecting incre ased vasoconstriction. Subgroup analyses showed that these association s were significant for males and sometimes adolescents but not for fem ales and children. As mirror tracing and cold forehead tasks most cons istently produce alpha-adrenergic activation, the results suggest a mo del in which vasoconstriction due to mental stress is related to incre ased left ventricular mass in susceptible individuals, even at a young age.