Clinical Study on Cardiac Asthma.

Abstract

Although there has been marked progress in the development of coronary opacifying procedures and techniques within recent years, a more satisfactory method is still desired. During ventricular systole the ejection of blood from the left ventricle tends to wash the contrast medium away from the coronary ostia. During diastole, with the relative lack of flow in the aortic root and with the maximal rate of coronary artery flow, consequently, contrast medium is minimally diluted with blood in the aortic root and reaches the coronary arteries at a higher concentration. Since it requires several cardiac cycles for contrast medium to cover entirely from the coronary ostia to the minute peripheral branches, more excellent opacification might be obtained by the multiple successive diastolic injections method than by a single diastolic injection method. On the basis of this principle, the author has developed a new method for radiographic visualization of the coronary arteries ("Coronary Arteriography Using Successive Diastolic Injections"), and has attempted to evaluate this procedure experimentally and clinically. Thechniques: The in jector used in these studies was a Davol Heart Pump Model 8500, which was capable to inject contrast medium at any phase in the cardiac cycle in synchronization with a maximum electrocardiographic wave (R wave). The pump ventricle and a circuit including a contrast medium reservoir, two one-way valves and a catheter were specially devised and were very convenient for successive injections. The contrast media used were Diatrizoate (76% Urografin^[○!R]) or Iothalamate sodium (Angio-con-ray^[○!R]). Under general anesthesia, a catheter was introduced into the aortic root through either of the surgically exposed brachial or femoral artery. Contrast medium was injected by the above-mentioned injector under the injection pressure of 3.5 to 4.2 kilograms per square 〓e〓〓imeter for 3 to 4 strokes of the pump ven-tricle which worked in synchronization with the early diastolic phase of the heart. In all experimental animals and the patients with over 100 per minute of cardiac rate, ATP preparation was routinely administered via the catheter for decreasing the cardiac rate and dilating the coronary vessels, prior to the injection of contrast medium. At the same time with the beginning of the injections of contrast medium, serial X-ray filming was started at the rate of 3 films per second for 5 to 10 seconds, in 15 experiments and 9 clinical cases. In 11 experiments, a single X-ray film was exposed at the end of diastolic phase after 2 to 3 successive injections. The dosage of contrast medium ranged 0.13 to 0.80 milliliters per kilogram per stroke in the experimental animals and 0.13 to 0.21 in the clinical cases.