Hemodynamic function at rest, during acute stress, and in the field - Predictors of cardiac structure and function 2 years later in youth

Left ventricular hypertrophy is an independent predictor of cardiovascular morbidity and mortality. However, predictors of cardiac structure and funct ion in youth are not completely understood. On 2 occasions (2.3 years apart ), we examined 146 youth aged initially 10 to 19 years (mean age, 14.2+/-1. 8 years). On the initial visit, hemodynamic function was assessed at rest, during laboratory stress (ie, orthostasis, car-driving simulation, video ga me, and forehead cold), and in the field (ie, ambulatory blood pressure). Q uantitative M-mode echocardiograms were obtained on both visits. On both vi sits, black compared with white youth had higher resting laboratory systoli c blood pressure (P<0.02), greater relative wall thickness (P<0.003), great er left ventricular mass indexed by either body surface area or height(2.7) (P<0.01 for both), and lower midwall fractional shortening ratio (P<0.05). Hierarchical stepwise regression analysis indicated that significant indep endent predictors of follow-up left ventricular mass/height(2.7) were the i nitial evaluation of left ventricular mass/height(2.7), body mass index, ge nder (males more than females), and supine resting total peripheral resista nce (final model R-2=0.53). Left ventricular mass/body surface area was pre dicted by initial left ventricular mass/body surface area, weight, gender, mean supine resting total peripheral resistance, and systolic pressure resp onse to car-driving simulation (final model R-2=0.48). Midwall fractional s hortening was predicted by initial midwall fractional shortening, race (whi te more than black), and lower mean supine total peripheral resistance (fin al model. R-2=0.13). The clinical significance of these findings and their implications for improved prevention of cardiovascular diseases are yet to be determined.