Schistosomiasis is an endemic disease in Egypt and is associated with a variety of visceral manifestations.The heavy invasion of the portal vein and tributaries by worms and ova leads to hepatosplenomegaly (Fig; A). In advanced cases the schistosome ova may embolize the lungs, lodging in the pulmonary arterioles and producing the picture of cor pulmonale (Zaky, 1952) with characteristic radiological findings (Special Plate, Figs. 1 and 2). This involvement of the portal and pulmonary circulations gives rise to important circulatory changes, and the haemodynamic shunts associated with these are the subject of this paper. Material ad MethodsThree patients with schistosomal cor pulmonale were studied by the following techniques.1. Right heart catheterization was performed in the usual manner, but multiple samples of blood were withdrawn from the pre-pulmonary wedge position, midway to the hilum, right or left pulmonary artery, and the main pulmonary artery.2. Dye-dhlution technique, with injection of Evans (azovan) blue dye into the aorta and sampling from the pulmonary artery, to demonstrate an aorto-pulmonary shunt via the bronchial arteries. One cardiac catheter was advanced to the pre-wedge position in the pulmonary artery, while another was introduced into the brachial artery and advanced to the upper part of the descending aorta (Special Plate, Fig. 3) This position was chosen in order to avoid the mouths of the coronary arteries and short-circuiting of the dye through the coronary sinus. It also ensures that the bronchial arteries receive a good quantity of dye, since they arise a short way below the catheter tip. The capacity of each catheter was 2.8 ml. One operator injected 10 ml.C of Evans blue into the arterial catheter as rapidly as possible, but giving a signal at the 3-ml. level, at which moment the other operator began to withdraw from the venous catheter for five seconds. This was the first sample, and it averaged 4 ml. The syringe was changed and the second sample of 2 ml. withdrawn from the blood in the catheter. The first sample represented blood withdrawn from the pulmonary artery during the first 1i seconds, and the second sample that withdrawn between 1l and 4 seconds. The samples of blood were examined in a Beckman spectrophotometer for the presence of dye.3. Aortic angiography with a balloon catheter to visualize the bronchial arteries and the pulmonary artery (Special Plate, Fig. 6). A No. 10 cardiac catheter had a rubber balloon fitted over the end hole, and two side holes were made proximal to this. The catheter was advanced via the brachial artery so that the tip lay in the descending aorta just below the lung hilum; 50 ml. of 76% " urografin " (sodium diatrizoate) was injected rapidly, causing the balloon to inflate and block aortic blood-flow, while the remainder of the contrast material escaped from the side holes. Radiographs were taken each second. Results Pulmonary CirculationThe presence of shunts between the bronchial arterial system and the pulmonary artery was suspected on t...

Among 980 consecutive selective coronary angiograms performed, nine patients had myocardial bridges of the left anterior descending (LAD) coronary artery. The overall prevalence of myocardial bridges was 0.92%. Among these patients, three patients had coronary artery disease, while six cases were isolated myocardial muscle bridges. With respect to functional abnormality, three had grade III milking effect, three had grade II and three had grade I milking effect. The indications for coronary angiograms were typical chest pain in seven cases and atypical pain in two cases. Myocardial bridges are sections of a coronary artery, almost all the left anterior descending and/or one of its diagonal branches, which run under a strip of left ventricular muscle and dip below the epicardial surface under small areas of the myocardium: During systole, the segment of the artery surrounded by myocardium is narrowed and appears as localized stenosis. This systolic compression is defined as the "milking" effect. The key to recognizing these myocardial bridges is that the apparent localized stenosis returns to normal during diastole.1 In 1976, Noble et al. stated that myocardial bridges with a milking effect on the proximal third of the left anterior descending artery could represent a new type of ischemic heart disease.2 In 1977, Grondin et al. classified the milking effect as grade I when less than 50% of arterial narrowing occurs, grade II when it is between 50% and 75%, and grade III when it is greater than 75%.3 As early as 1951, Geiringer reported the etiology of this anatomical variant to be congenital, explaining that most of the coronary arteries have an intramyocardial course during fetal life. 4As suggested by Binet et al. in 1975, muscle bridges might explain some cases of sudden death occurring during strenuous exercises among athletes in whom no coronary arterial lesions are demonstrated at postmortem examination. 5 In 1993, on an experimental basis, Campbell et al. studied similarities between dynamic elastance responsible for the left ventricular chamber and the papillary muscle of a rabbit heart. They concluded that the dynamic elements responsible for myofiber stiffness were also responsible for left ventricle chamber elastance. Furthermore, it was possible to describe and interpret dynamic chamber elastance and muscle stiffness with a common model based on the muscle-bridge theory. This model did a reasonable job of reproducing all the important features of experimentally observed left ventricular chamber elastance and muscle stiffness. Thus, dynamic homologies between chamber and muscle were established in experimental data and, in fact, this single interpretive model served equally well for both chamber elastance and muscle stiffness. 5,6 The aim of this study is to assess the prevalence of myocardial bridging of the left anterior descending coronary artery in a population of patients referred for diagnostic coronary angiography and to throw some light on the pathophysiology, clinical implications and prognosi...

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