经胸超声与静脉内微泡与心脏机械感受器的相互作用。

Interaction of transthoracic ultrasound and intravenous microbubbles with cardiac mechanoreceptors.

作者信息

Xie Feng, Tsutsui Jeane M, Gao Lie, Zucker Irving H, Porter Thomas R

机构信息

Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, NE 68198, USA.

出版信息

Ultrasound Med Biol. 2007 Jan;33(1):136-44. doi: 10.1016/j.ultrasmedbio.2006.07.019.

DOI:10.1016/j.ultrasmedbio.2006.07.019

PMID:17189056

Abstract

The purpose of this study was to examine the effect of transthoracic ultrasound (TTU) and intravenous microbubbles (MB) on cardiac mechanoreceptors. In 16 rabbits (eight normal and eight chronic heart failure), renal sympathetic nerve activity (RSNA), heart rate and mean arterial pressure were examined before, during and after 1 MHz TTU at different peak negative pressures (0.12 to 0.43 MPa) and duty cycles in the presence and absence of perfluorocarbon MB. TTU applications were for 10 s, and the overall duration of MB infusion was approximately 60 s for each setting. TTU without MB had no effect on any parameter. During the microbubble infusion, however, TTU at higher peak negative pressures (> or =0.27 MPa) and 100% duty cycle resulted in a consistent decrease in RSNA(-41 +/- 41% p < 0.001). This was accompanied by brief reflex reductions in mean arterial pressure and heart rate. The changes in RSNA induced by TTU and MB in all rabbits were abolished by vagotomy. TTU, in the presence of MB, stimulates mechanoreceptors in the heart reflexively to reduce RSNA.

摘要

本研究的目的是探讨经胸超声（TTU）和静脉注射微泡（MB）对心脏机械感受器的影响。在16只兔子（8只正常兔子和8只慢性心力衰竭兔子）中，在有和没有全氟化碳微泡的情况下，于不同的峰值负压（0.12至0.43兆帕）和占空比下，在1兆赫经胸超声检查前、检查期间和检查后，检测肾交感神经活动（RSNA）、心率和平均动脉压。经胸超声检查持续10秒，每种设置下微泡输注的总持续时间约为60秒。无微泡的经胸超声检查对任何参数均无影响。然而，在微泡输注期间，较高峰值负压（≥0.27兆帕）和100%占空比的经胸超声检查导致肾交感神经活动持续下降（-41±41%，p<0.001）。这伴随着平均动脉压和心率的短暂反射性降低。迷走神经切断术消除了经胸超声检查和微泡在所有兔子中引起的肾交感神经活动变化。在有微泡存在的情况下，经胸超声检查通过反射刺激心脏中的机械感受器以降低肾交感神经活动。