Aspectos estruturais e funcionais do coraçäo de ratos com e sem infarto do miocárdio. Experiência inicial com ecocardiografia doppler / Structural and functional characteristics of rat hearts with and without myocardial infarct. Initial experience with doppler echocardiography

ABSTRACT

OBJECTIVE: To assess by Doppler echocardiography the structural and functional alterations of rat heart with surgical induced extensive myocardial infarction. METHODS: Five weeks after surgical ligature of the left coronary artery, 38 Wistar-EPM rats of both sexes, 10 of them with extensive infarction, undergone anatomical and functional evaluation by Doppler echocardiography and then euthanized for anatomopathological analysis. RESULTS: Echocardiography was 100 percent sensible and specific to anatomopathological confirmed extensive miocardial infarction. Extensive infarction lead to dilatation of left ventricle (diastolic diameter 0.89cm vs.0.64cm; systolic 0.72cm vs. 0.33cm) and left atrium (0.55cm vs. 0.33cm); thinning of left ventricular anterior wall (systolic 0.14cm vs. 0.23cm, diastolic 0.11cm vs. 0.14cm); increased mitral E/ A wave relation (6.45 vs. 1.95). Signals of increased end diastolic ventricle pressure, B point in mitral valve tracing in 62.5 percent and signs of pulmonary hypertension straightening of pulmonary valve (90 percent) and notching of pulmonary systolic flow (60 percent) were observed in animals with extensive infarction. CONCLUSION: Doppler echocardiography has a high sensitivity and specificity for detection of chronic extensive infarction. Extensive infarction caused dilatation of left cardiac chambers and showed in Doppler signals of increased end diastolic left ventricular pressure and pulmonary artery pressure.