Experimental Cutting of the Septomarginal Trabecula in the Bovine Heart

Abstract

In order to study the function of the septomarginal trabecula (MB); four calves were subjected to the experimental cutting of MB and observed electrocardio-graphically and morphologically. Moreover, the beating heart was observed in another calf by echocardiography.
From the results of echocardiography of the beating heart and radiographic and macroscopic observations of the operated hearts, the MB was not found to tend to prevent of right ventricle from overdistention.
In all the calves the main stems of the right limb of the atrioventricular conducting system were sectioned by cutting the MB. The durations and wave forms of QRS in A-B lead remained unchanged after the cutting of the MB. Two of these showed changes in wave form of QRS in the standard limb, augmented unipolar limb, and unipolar chest leads after the cutting.