Presentation Information
[II-TKIS-P-6]Right versus left ventricular myofiber orientation of various cardiac anomalies analyzed with X-ray phase-contrast tomography
○Shunsuke Matsushima1, Gen Shinohara2, Shuichi Shiraishi3, Takuro Tsukube4, Yoshihiro Oshima5, Hironori Matsuhisa1 (1.Department of Cardiovascular Surgery, Kobe Children's Hospital, Kobe, Japan, 2.Department of Cardiovascular Surgery, JCHO Kyushu Hospital, Kitakyushu, Japan, 3.Division of Thoracic and Cardiovascular Surgery, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan, 4.Division of Cardiovascular Surgery, Japanese Red Cross Kobe Hospital & Hyogo Emergency Medical Center, Kobe, Japan, 5.Department of Cardiovascular Surgery, Kakogawa Central City Hospital, Kakogawa, Japan)
Keywords:
myofiber orientation,congenital heart disease,X-ray phase-contrast tomography
OBJECTIVE. This study analyzed myofiber orientation of human heart specimens with various cardiac anomalies using X-ray phase-contrast tomography.
METHODS. Three whole heart specimens of each normal heart, ventricular septal defect, right atrial isomerism, left atrial isomerism, and ventricular inversion were examined. In reconstructed images of both ventricles, the center of the free wall was resliced parallelly to the myocardial surface. A myofiber helical angle was identified in each slice and plotted from epicardium to endocardium. The plotted curves were compared between both ventricles.
RESULTS. In all ventricles, the helical angle was changed from left-handed on epicardial slices to right-handed on endocardial slices. Whereas the right ventricle's plotted curves were plateau with or without a rapid rise on the endocardial side, the left ventricle's curves had sustained increase with or without a plateau in the middle. The median wall-thickness-scaled helical angle's change rates were 53° and 102° in the right and left ventricle, respectively, and their distribution of each specimen was higher in the left ventricle than in the right ventricle.
CONCLUSIONS. Ventricular myofiber rotation is independent of cardiac looping. The plateau and rapid change of helical angle's curves can permit the identification of layers within the ventricular wall. The left ventricle has more helical fibers than the right ventricle in either normal hearts or cardiac anomalies, which may explain the different functional prognoses of the systemic right and left ventricles.
METHODS. Three whole heart specimens of each normal heart, ventricular septal defect, right atrial isomerism, left atrial isomerism, and ventricular inversion were examined. In reconstructed images of both ventricles, the center of the free wall was resliced parallelly to the myocardial surface. A myofiber helical angle was identified in each slice and plotted from epicardium to endocardium. The plotted curves were compared between both ventricles.
RESULTS. In all ventricles, the helical angle was changed from left-handed on epicardial slices to right-handed on endocardial slices. Whereas the right ventricle's plotted curves were plateau with or without a rapid rise on the endocardial side, the left ventricle's curves had sustained increase with or without a plateau in the middle. The median wall-thickness-scaled helical angle's change rates were 53° and 102° in the right and left ventricle, respectively, and their distribution of each specimen was higher in the left ventricle than in the right ventricle.
CONCLUSIONS. Ventricular myofiber rotation is independent of cardiac looping. The plateau and rapid change of helical angle's curves can permit the identification of layers within the ventricular wall. The left ventricle has more helical fibers than the right ventricle in either normal hearts or cardiac anomalies, which may explain the different functional prognoses of the systemic right and left ventricles.
