Coronary blood flow measurements in the presence of arterial obstruction.

As an approach to delivery of inert gas to the myocardium in the presence of coronary artery obstruction, Kr in saline was injected into a catheter in the coronary venous system of intact anesthetized dogs. Isotope delivered at the level of the great cardiac vein was selectively localized in the region of myocardium subserved by the vein and the left anterior descending artery. Similarly, injection at the coronary sinus level was attended by localization of isotope to the area perfused by the circumflex branch of the left coronary artery. Precordial counting of isotope delivered in this retrograde manner yielded coronary blood flow values that closely corresponded to those derived from coronary arterial injection. Coronary thrombus formation in either of the major left coronary branches was reflected in substantial flow reductions when isotope was delivered via the artery distal to the thrombus. A similar flow decrement was observed when the gas was delivered via the corresponding venous site, while normal blood flow levels were derived from the nonischemic area. Application of the method to detection of coronary arterial obstruction in man is discussed. ADDITIONAL