Triphenyltetrazolium chloride (TTC) staining and echocardiography (ECHO) are methods used to determine experimental myocardial infarction (MI) size, whose practical applicability should be expanded. Our objectives were to analyze the accuracy of ECHO in determining infarction size in rats during the first days following coronary occlusion and to test whether a simplified single measurement by TTC correctly indicates MI size, as determined by the average value for multiple slices. Infarction was induced in female Wistar rats by coronary artery occlusion and MI size analysis was performed after the acute (7th day) and chronic periods (after 4 weeks) by ECHO matched with TTC. ECHO and TTC showed similar values of MI size (% of left ventricle perimeter) in acute (ECHO: 33 ± 11, TTC: 35 ± 14) and chronic (ECHO: 38 ± 14, TTC: 39 ± 13 periods), and also presented an excellent correlation (r = 0.92, P < 0.001). Although measurements from different heart planes showed discrepancies, a single measurement acquired from the mid-ventricular level by TTC was a good estimate of MI size calculated by the average of multiple planes, with minimal disagreement (Bland-Altman test with mean ratio bias of 0.99 ± 0.07) and close to an ideal correlation (r = 0.99, P < 0.001). In the present study, ECHO was confirmed as a useful method for the determination of MI size even in the acute phase. Also, the single measure of a mid-ventricular section proposed as a simplification of the TTC method is a satisfactory prediction of average MI extension. Coronary artery ligation is often used to produce experimental myocardial infarction (MI) (1-3). Since MI size is a determinant of cardiac remodeling and dysfunction (4,5), establishing the correct quantification of infarction is of critical importance. It has been proven that in vivo echocardiogram (ECHO) satisfactorily predicts infarct size in rats when healing has occurred (6,7); however, no data exist regarding ECHO accuracy during earlier periods. In addition, histopathology does not present the desirable sensitivity for necrosis during the initial hours after coronary occlusion, while histochemical triphenyltetrazolium chloride (TTC) staining has proven to be useful and appears to be simpler and less expensive (8,9). Accordingly, the objectives of the present study were: 1) to define the accuracy of ECHO in determining MI size during acute and chronic periods compared to TTC staining, and 2) to determine whether a single measurement of MI size in a mid-ventricular section correctly indicates the infarct extension determined by multiple planes.

Patients with respiratory indications for ECMO experienced better survival than cardiac patients. The need for more inotropic drugs was a predictor of mortality in VA-ECMO. This is the first published record of the overall experience with ECMO in a Portuguese tertiary hospital.

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