Closed-chest myocardial ischaemia in dog.

Myocardial ischaemia in dog was induced with releasable material in the distal segment of the anterior descending branch of the left coronary artery. Three releasable materials were tested: gel foam, wax microspheres (120-200 micron) and latex balloons, using different methods of introduction. The left carotid route was selected for introduction of a preformed catheter. The gel foam and wax microspheres caused transitory ischaemia, which was proximal for the foam and distal for the microspheres. The balloons made it possible to standardize the ischaemia as its localization and duration could be selected. This material therefore provided a model for stable chronic ischaemia. Nine dogs were observed by means of precordial mapping (36 electrodes) during the phase following ischaemia or for a period of 4 weeks. The results of these experiments are analysed and correlated with histological results for the post-mortem phase.