Assist effect of stimulated right latissimus dorsi muscle flap on right atrial function and preventive effect of regurgitation from right atrium to SVC,IVC in atrial systole using synchronously stimulated latissimus dorsi muscle flap wrapped around SVC an

本实验旨在探讨右功能背阔肌瓣是否不仅对右心房功能有辅助作用，而且对心房收缩期二头反流有预防作用。背阔肌瓣分为三段，分别位于右心房上方，包裹在SVC和IVC周围。健肌刺激器（Myostim 7220型），电子公司（澳大利亚）被用作脉冲刺激器，产生5个脉冲序列（脉冲宽度0.4毫秒，间隔30纳秒，5V）。采用多普勒血流探头（Dimension system VF-1）测量主动脉流速，采用Statham P23b传感器（Gould Inc.）测量平均主动脉压（AoP）、右心房压（RAP）。心血管产品，奥克斯纳德，加利福尼亚州)。在SVC和IVC周围肌肉包裹和不包裹的情况下获得稳态数据和爆发刺激时的数据。与不刺激相比，肌肉包裹下的破裂刺激显著增加了最大RAP，但降低了平均RAP、平均AoP和平均主动脉流速。与无刺激相比，无缠绕刺激显著提高了最大RAP和平均RAP，但降低了AoP。刺激时平均主动脉血流速度大于未收缩时（无统计学意义）。这些数据表明，刺激的肌肉包裹主要有血流阻塞的作用，而RA上的右功能背阔肌瓣改善右心房功能可能会增加主动脉血流速度。

The purpose of this experiment is to investigate whether the right functioning latissimus dorsi muscle flap has not only the assist effect on right atrial function but also the preventive effect on bicaval regurgitant flow in atrial systole. The latissimus dorsi muscle flap is divided into three segments which are over the rt. atrium (RA) and wrapped round SVC and IVC,respectively. Cariomyostimulator (Myostim Model 7220, Telektronics Inc. Austrlia) is used as a burst stimulator that makes 5 pulse trains (pulse width 0.4 msec, interval 30 ns, 5V). Aortic flow velocity is measured with Doppler flow probe (Dimension system VF-1) and mean aortic pressure (AoP), right atrial pressure (RAP) are measured with Statham P23b transducer (Gould Inc. Cardiovascular Products, Oxnard, Calif.). Steady-state data and data during burst stimulation were obtained under muscle wrapping around SVC and IVC and without wrapping. Burst stimulation under muscle wrapping significantly increased maximal RAP but decreased mean RAP,mean AoP and mean aortic flow velocity in comparison with these parameters under no stimulation. Burst stimulation without wrapping significantly increased maximal RAP and mean RAP but decreased AoP compared with these parameters under no stimulation. Mean aortic flow velocity on stimulation was greater than that without muscle contraction (no significance). These data indicates stimulated muscle wrapping has mainly the effect of inflow obstruction but only right functioning latissmus dorsi muscle flap over RA improves right atrial function may increase aortic flow velocity.