A closed chest animal model for the study of reversible ischemia

An experimental methodology consisting of partial coronary occlusions, pacing-induced myocardial ischemia and photokymography-aided fluoroscopic study of segmental left ventricular motion, was verified in 14 closed chest dogs. A partial intracoronary occluder device was found suitable for single or multiple coronary arterial stenosis, and remained patent up to 10 h with 10/cm3 heparin administration. With 38% proximal left circumflex coronary artery stenosis, pacing up to 220 beats/min produced no significant regional or global left ventricular dysfunction. In contrast, a 68.5% stenosis which was not associated with dysfunction in the resting state produced significant derangements of segmental motions at a pacing rate of 150 beats/min. Photokymography probes placed at several segments of the left ventricular epicardial and endocardial interface delineated by fluoroscopy or ventriculography allowed monitoring of regional contractions in both pacing-induced ischemic and remote nonischemic zones. The methodology is considered ready for further applications in experimental studies of ischemic states and treatments, simulating clinically meaningful coronary stenosis in the animal without requiring prior thoracotomy and pericardiotomy for implanting occluders.