Characterization of the functional border zone around regionally ischemic myocardium using circumferential flow-function maps

• Published in: Journal of the American College of Cardiology Vol. 8; no. 1; pp. 150 - 158
• Main Authors: Buda, Andrew J., Zotz, Rainer J., Gallagher, Kim P.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.07.1986; Elsevier Science
• Subjects: Animals; Biological and medical sciences; Cardiology. Vascular system; Coronary Circulation; Coronary Disease - pathology; Coronary Disease - physiopathology; Coronary heart disease; Dogs; Echocardiography; Female; Heart; Heart - physiopathology; Hemodynamics; Male; Medical sciences; Myocardium - pathology; Regional Blood Flow; Stroke Volume; Radionuclide study; Fissipedia; Carnivora; Echocardiography; Ultrasonic investigation; Cardiovascular disease; Coronary arteriography; Radioisotope; Coronary vessel; Coronary heart disease; Vertebrata; Experimental disease; Mammalia; Ischemia; Perfusion; Myocardium; Hemodynamics; Dog; Two dimensional technique
• ISSN: 0735-1097; 1558-3597
• DOI: 10.1016/S0735-1097(86)80106-1

Previous studies have suggested that there exists a functional border zone in myocardium at the lateral margins of an ischemic area. The functional border zone is normally perfused but is characterized by abnormal contractile function. To define the spatial characteristics of this border zone, circumferential maps of left ventricular function by two-dimensional echocardiography and of coronary flow using radioactive microspheres were generated in 18 dogs at baseline and after circumflex coronary occlusion. Circumferential left ventricular wall thickening was measured in all dogs at 22.5° intervals over 360°. In seven dogs, the pathologic slice corresponding to the two-dimensional echocardiography image was circumferentially dissected into 16 segments corresponding to 22.5° intervals and a subendocardial myocardial blood flow map was derived. In the other 11 dogs, autoradiography was performed of the pathologic slice corresponding to the two-dimensional echocardiographic image, and the hypoperfusion zone was directly measured. There was no difference between the circumferential extent of hypoperfusion zones by either perfusion measurement technique in the five dogs that had both techniques performed (140 ± 12 versus 124 ± 7°, p = NS). The hypofunctional zone by two-dimensional echocardiography was significantly larger than the hypoperfusion zone (174 ± 4 versus 125 ± 26°, p < 0.0005), indicating that a zone of normally perfused but abnormally contracting muscle surrounds the ischemic area. However, this border zone in our model was small, measuring 49 ± 34° (approximately 8 to 9 mm on either lateral border). This suggests that the functional border zone lateral to ischemic myocardium exists, but is relatively discrete.