Gillebert T C, De Hert S G, Andries L J, Jageneau A H, Brutsaert D L
Department of Physiology and Medicine, University of Antwerp, Belgium.
Am J Physiol. 1992 Dec;263(6):H857-65. doi: 10.1152/ajpheart.1992.263.3.H857.
Irradiation of isolated cardiac muscle by high-power, high-frequency, continuous wave ultrasound selectively damages endocardial endothelium (EE). We evaluated this ultrasound effect in vivo on the performance of the intact ejecting canine left ventricle (LV). A cylindrical ultrasound probe (0.9 MHz, 25 W), mounted on a catheter, was inserted in the LV cavity through an apical stab wound and was activated for 60, 120, and 240 s, followed each time by a recovery period of 10-15 min. Ultrasound transiently and repeatedly abbreviated the time interval from end diastole to peak (-)dP/dt (from 241 +/- 30 to 229 +/- 32 ms after 240 s; P < 0.001), accelerated LV pressure fall, did not alter peak (+)-dP/dt or peak systolic pressure, increased diastolic and systolic segment lengths, and decreased fractional shortening. Microscopic analysis revealed dispersed granulocytes attached to the EE. EE cells were visibly damaged only in a limited area surrounding the probe. Accordingly, high-power, high-frequency, continuous wave ultrasound reversibly modulated LV performance, presumably by transient alteration of EE function.
用高功率、高频连续波超声照射离体心肌可选择性地损伤心内膜内皮（EE）。我们评估了这种超声效应在活体状态下对完整的射血犬左心室（LV）功能的影响。将一个圆柱形超声探头（0.9兆赫，25瓦）安装在导管上，通过心尖刺伤插入左心室腔，并分别激活60、120和240秒，每次激活后有10 - 15分钟的恢复期。超声可使舒张末期至峰值（-）dP/dt的时间间隔短暂且反复缩短（240秒后从241±30毫秒缩短至229±32毫秒；P < 0.001），加快左心室压力下降，不改变峰值（+）dP/dt或收缩压峰值，增加舒张期和收缩期节段长度，并降低缩短分数。显微镜分析显示有分散的粒细胞附着于心内膜内皮。心内膜内皮细胞仅在探头周围的有限区域明显受损。因此，高功率、高频连续波超声可可逆地调节左心室功能，推测是通过短暂改变心内膜内皮功能实现的。
