Relation between functional response to nitroglycerin and extent of myocardial necrosis in dogs: mapping of the left ventricle by 2-dimensional echocardiography.
The relation between functional response to brief nitroglycerin infusions and extent of myocardial damage was studied sequentially in closed-chest dogs with acute occlusion of the left anterior descending coronary artery. Two-dimensional echocardiography was used to derive segmental left ventricular (LV) function (systolic fractional area change and systolic wall thickening), and this function was compared with the extent of necrosis measured 5 hours after occlusion in equivalent segments of corresponding pathologic slabs. Two-dimensional echocardiographic study before the dogs were killed indicated that remote nonnecrotic segments always responded to nitroglycerin by significant augmentation of segmental LV function. Segments in which necrosis was less than 40% showed a significant nitroglycerin-induced potentiation in segmental LV function. In contrast, segments in which necrosis was greater than 60% had no potentiation with nitroglycerin. In those segments in which eventual necrosis was 60 to 80%, significant nitroglycerin-induced augmentation in segmental LV function was observed only before and 30 minutes after the coronary occlusion. When the degree of necrosis was greater than 80%, no significant potentiation of segmental LV function was observed even as early as 30 minutes after occlusion. Thus, the degree of nitroglycerin-induced potentiation of segmental cardiac function is closely associated with the extent of myocardial necrosis in the particular ventricular segment. Two-dimensional echocardiography coupled with a nitroglycerin potentiation test might be useful for assessment of the viability of ischemic myocardium.
D000818:Animals; D003327:Coronary Disease / Q000473:pathology / Q000503:physiopathology; D004285:Dogs; D004452:Echocardiography / Q000379:methods*; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology; D006439:Hemodynamics / Q000187:drug effects; D009206:Myocardium / Q000473:pathology*; D009336:Necrosis; D005996:Nitroglycerin / Q000494:pharmacology*
D005996:Nitroglycerin