Donner R, Carabello B A, Black I, Spann J F
Am J Cardiol. 1983 Mar 15;51(6):946-51. doi: 10.1016/s0002-9149(83)80171-4.
It is known that children with aortic stenosis (AS) frequently have supernormal indexes of left ventricular (LV) pump function and remain compensated for many years. Factors causing this increase in pump performance have not been elucidated. A study was done on LV mechanics in 11 children with AS (aortic valve area 0.5 +/- 0.3 cm2/m2) and 10 normal subjects. The ejection fraction in the AS group (0.88 +/- 0.08) was significantly higher than in normal subjects (0.64 +/- 0.08, p less than 0.001). The mean velocity of fiber shortening was also higher in AS patients (1.80 +/- 0.35 circ/s) than in normal subjects (1.22 +/- 0.21 circ/s, p less than 0.001). The end-systolic volume index in patients with AS (9 +/- 8 ml/m2) was much lower than in normal subjects (27 +/- 8 ml/m2). LV mass in patients with AS was 180 +/- 58 g/m2 compared with 96 +/- 9 in normal subjects. LV wall stress was reduced throughout the cardiac cycle in patients with AS. Peak stress in patients with AS was 238 +/- 51 dynes/cm2 X 10(3) versus 439 +/- 85 in normal subjects. The end-systolic stress-end-systolic volume index ratio, an indicator of contractile state, was not elevated in patients with AS. It is suggested that diminished wall stress in concert with normal contractile function permits the supernormal pump function seen at rest in children with AS.
已知患有主动脉瓣狭窄（AS）的儿童左心室（LV）泵功能指标常常超常，并能多年保持代偿状态。导致这种泵功能增强的因素尚未阐明。对11名患有AS（主动脉瓣面积为0.5±0.3 cm2/m2）的儿童和10名正常受试者进行了左心室力学研究。AS组的射血分数（0.88±0.08）显著高于正常受试者（0.64±0.08，p<0.001）。AS患者的纤维缩短平均速度（1.80±0.35周/秒）也高于正常受试者（1.22±0.21周/秒，p<0.001）。AS患者的收缩末期容积指数（9±8 ml/m2）远低于正常受试者（27±8 ml/m2）。AS患者的左心室质量为180±58 g/m2，而正常受试者为96±9 g/m2。AS患者在整个心动周期中左心室壁应力均降低。AS患者的峰值应力为238±51达因/cm2×10(3)，而正常受试者为439±85达因/cm2×10(3)。收缩末期应力-收缩末期容积指数比值作为收缩状态的指标，在AS患者中并未升高。提示壁应力降低与正常收缩功能共同作用，使得患有AS的儿童在静息状态下呈现超常的泵功能。
