Abstract
The need continues for better quantitation of left ventricular function. Previous studies have indicated the nature of intracardiac shunting in tetralogy. Simultaneously recorded left ventricular pressure and biplane cines were analyzed to construct continuous left ventricular function curves in ‘normales’ and in tetralogy patients. The original measurements throughout 3–6 consecutive beats were analyzed by a digital computer with numerical and graphic outputs of: LV pressure, LV volume, rate of volume change (flow), LV mid-circumference and its instantaneous velocity, tension at the endocardial surface, work and power. The force-velocity-length and pressure-volume-flow relationships of the left ventricle were depicted in three dimensional plots during the active state (systole) of the LV muscle for normals and tetralogy patients. In normals, maximum flow and peak velocity of shortening occurred at high tension levels in mid-systole; whereas in tetralogy, peak flow and velocity occurred during ‘isovolumic’ contraction at lower tensions. The continuous ‘function curves’ were markedly abnormal in tetralogy with peak rate of flow and of circumference shortening occurring prior to opening of the aortic valve. The results indicate that the left ventricle in tetralogy functions more efficiently than normal and unloads 15 to 40 percent of its stroke volume during isovolumic contraction. This results in lower than normal stroke work values. (SPR)
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Jarmakani, M., Spach, M., Edwards, S. et al. 8 Influence of Intracardiac Shunting on Left Ventricular Muscle Mechanics in Tetralogy of Fallot. Pediatr Res 1, 202 (1967). https://doi.org/10.1203/00006450-196705000-00015
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DOI: https://doi.org/10.1203/00006450-196705000-00015