The Journal of Thoracic and Cardiovascular Surgery, Vol 70, 100-106, Copyright © 1975 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Intraoperative delineation of ischemic and scarred myocardium by localized detection of potassium-42 in dogs
ES Kirk, TP Nener and FH Ellis Jr
The range of emission from 42-K was shown, in a model experiment, to be
suited to scanning with a detector positioned on the surface of the heart
after intravenous injection of the isotope. This finding was verified by
comparing surface counts with the activity of transmural samples of
underlying tissue. Two groups of dogs were studied. In Group A, dogs with
left ventricular scars produced by the agar injection technique were given
42-K 24 hours before study. In Group B, normal dogs were given 42-K
immediately after ligation of a coronary artery branch. In Group A,
localized counting clearly delineated scar from surrounding normal
myocardium, and the values were 39 per cent of normal. When more 42-K was
given, low flow in scar was indicated by markedly reduced uptake. In Group
B, counts over the acutely ischemic area were as low as 20 per cent of
normal. Thus, the possibility of differentiating scarred from normal
myocardium was shown. Moreover, the results suggest that ischemic but still
viable areas that may be suitable for revascularization can be assessed by
application of the method.
