Distribution of radiolabelled microspheres is widely utilized for determination of regional blood flow in experimental @entity583 studies. The purpose of this investigation was evaluation of the microsphere method during 1 h of regional ischaemia. Special attention was focused upon loss of preocclusion microspheres from @entity1562 ; mechanisms for loss and blood flow distribution in non-ischaemic left ventricle. Microspheres (15 micron) were injected into the left atrium in nine pentobarbital anaesthetized @entity468 prior to @entity1563 and again after 1 h of occlusion. Preocclusion blood flow estimates were lower in ischaemic compared with non- @entity1562 (1.36 vs. 1.62 cm3 X min-1 X g-1, P = 0.002), corresponding to 16% apparent loss. In endocardial ischaemic tissue, development of @entity4 could account for the loss. In epicardial ischaemic tissue, @entity4 was not present and loss was therefore due to migration of microspheres. @entity393 increased in proportion to restoration of left ventricular contractility. There was no evidence for significant microsphere loss through lymphatic pathways. In non-ischaemic left ventricular tissue, myocardial blood flow was evenly distributed from apex to base, and also between endocardial and epicardial layers. This study quantitates an important limitation to measurements of local blood flow in @entity1562 by radiolabelled microspheres.

Measurement of local blood flow in acute XXXX : loss of 15-micron microspheres during the first hour.

@entity4 :: ('MESH:D004487', 'Disease') :: ['oedema'] @entity1563 :: ('MESH:D054059', 'Disease') :: ['coronary artery occlusion'] @entity1562 :: ('MESH:D017682', 'Disease') :: ['ischaemic myocardium'] @entity393 :: ('MESH:D034381', 'Disease') :: ['Epicardial loss'] @entity583 :: ('MESH:D009203', 'Disease') :: ['myocardial infarction'] @entity468 :: ('9685', 'Species') :: ['cats']
@entity583 :: (MESH:D009203,Disease) :: ['myocardial infarction']
