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 and IVC.

1996 Fiscal Year Final Research Report Summary

• Project/Area Number: 07671447
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Thoracic surgery
• Research Institution: Tohoku University
• Principal Investigator: SHOJI Yoshimi Tohoku University, Department of Thoracic and Cardiovascular Surgery, School of Medicine Assistant Professor, 医学部・附属病院, 講師 (00196586)
• Co-Investigator(Kenkyū-buntansha): SADAHIRO Mitsuaki Institution & Department -same as above Assistant Professor, 医学部・附属病院, 講師 (80250778) ; TABAYASHI Koichi Institution & Department-same as above Professor, 医学部, 教授 (90142942)
• Project Period (FY): 1995 – 1996
• Keywords: Dynamic Cardiomyoplasty / pedicled latissimus dorsi muscle / right atrial function / Fontan operation

Research Abstract

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.