Assessment of myocardial viability post myocardial infarction: low dose dobutamine echocardiography versus thallium 201 scintigraphy

The aim of this work is to compare low dose dobutamine echocardiography [LDDE] versus Thallium 201 SPECT for assessment of myocardial viability in patients with previous myocardial infarction. The study included 30 patients with old myocardial infarction All patients had resting echocardiographic wall motion abnormalities. Segmental analysis was done on 16 segments for each patient at base line and during infusion of incremental dose of dobutamine [up to 10 Mg/Kg/Min.]. Thallium-201 SPECT stress-rest with delayed reinjection technique was used as the reference method for assessment of myocardial viability. The study showed that with low dose dobutamine infusion [5 Mg/Kg/Min.], the total number of viable segments were 314 segments [65.4%] while with dobutamine 10 Mg/Kg/min., the number of viable segments were 341 [71%]. Thallium SPECT showed 363 segments with perfusion defects and redistribution images showed improvement in 246 segments, reverse redistribution in 19 segments and no improvement in 98 segments. The total segments that could be considered viable by Ti-201 were 230 segments[out of 312 segments with resting wall motion abnormalities] however, total viable segments by LDDE were 171 segments [significantly lower, P<0.05]. The number of segments that were considered viable by the two methods were 163 segments [52.2%] and that considered non viable were 71 segments [22.8%]. So, total agreement between two methods was 75% and total disagreement was 25%. LDDE Is less sensitive than Ti-201 SPECT for detection of myocardial viability as the sensitivity and specificity of LDDE in relation to Ti-201 were 70.8% and 86.6% respectively

Predicative factors of morbidity and mortality in open mitral surgery: comparison of mitral repair and replacement.

Thirty-three patients with rheumatic valve disease were managed by open heart surgical correction. They were divided into two groups: Group I, non- replacement in 17 patients [included commissurotomy in 3, repair in 2, repair and commissurotomy in 11] and group II, mitral valve replacement in 16. Six out of the 16 patients in group II had aortic valve replacement also. One patient died in each group. Number of patients with complications in group I is 5 [29%], in group II is 5 also [31%]. The incidence of postoperative events was 9 in group I and 17 in group II, some patients had more than one event. Comparison of the six patients with double valve replacement [aortic and mitral] and mitral replacement alone revealed more incidence of complications in double valve patients. The following predictive variables were studied and compared between the non-complicated and the complicated groups: NYHA class, pulmonary hypertension, LV ejection fraction, percentage of FS, redo, end- systolic volume, LV diameter, atrial fibrillation and tricuspid regurgitation. Echocardiographic LV function was compared before and after operation in 26 patients. Comparison of mortality and morbidity between mitral repair and replacement revealed no differences in mortality [6% in each group], and no difference in number of patients with complications, but number of events was more in valve replacement group. NYHA class IV was the only predictive factor found to be related to complications. LV systolic function parameters did not improve immediately after operation