AJP - Heart and Circulatory Physiology, Vol 246, Issue 4 475-H482, Copyright © 1984 by American Physiological Society
Transmural DC electrograms after coronary artery occlusion and latex embolization in pigs
J. Cinca, J. Figueras, G. Senador, E. Garcia-Moreno, A. Salas and J. Rius
Changes in epicardial and endocardial direct current (DC) electrograms and
ventricular arrhythmias observed during 60 min of left anterior descending
coronary artery (LAD) occlusion in nine anesthetized pigs were compared
with those observed in eight other pigs after embolization of the LAD with
latex, a procedure able to block collateral blood flow to the ischemic
area. After LAD occlusion 1) T-Q segment depression and S-T segment
elevation showed a faster rate of development, and monophasic potentials
occurred earlier in the endocardium than in the epicardium; 2) T-Q segment
depression was greater at the center than at the periphery of the ischemic
area during the first 20-30 min, and later it become greater at the
periphery than at the center; and 3) a period of transient recovery in the
local activation beginning after 8-15 min and lasting for 10-20 min
occurred in all cases, commonly associated with T-wave alternans. LAD
embolization with latex induced greater T-Q and S-T segment changes in the
epicardium than in the endocardium, increased the incidence of ventricular
fibrillation, and failed to impede the appearance of the period of
transient electrical recovery. Thus, within an acutely ischemic area in the
in situ pig heart, there are inhomogeneities in the magnitude and time
course of the electrical changes, which are not prevented by procedures
able to block collateral blood flow to the ischemic area. Ventricular
fibrillation was also not prevented by such a procedure.
