Imaging in endomyocardial fibrosis
Indian Heart Journal
The initial 12 h after acute myocardial infarction is the critical time to salvage myocardium and so, revascularization thereafter may not have any prognostic benefit particularly in absence of chest pain. The presence, extent of viability, and a critical threshold mass of viable myocardium by nuclear perfusion scan help to determine in which patient there will be functional recovery, so benefit of revascularization. The purpose of this study is to establish co-relation of myocardial viability
... ocardial viability in nuclear perfusion scan and patency of infarct related artery in patients of ST elevation myocardial infarction with late presentation. Method: This is single center observational study. The confirmed cases of myocardial infarction with late presentation on the basis of case histories, clinical manifestations, electrocardiogram, cardiac markers. and echocardiography underwent myocardial perfusion scan with 99mTc-sestamibi and coronary angiogram. The findings of myocardial viability were compared with coronary angiogram. Results: The reports of twenty patients were analyzed. The time of presentation after onset of symptoms varies from 15 to 48 h with average of 22.5 h. 80% (n = 16 patients) had nonviable myocardium with TIMI 0 and 1 flow, high thrombus burden, and absence of collaterals ( p > 0.001). The 15% (n = 3 patients) had partially viable myocardium despite of delayed presentation ( p < 0.001). These three patients had high thrombus burden, TIMI 0-1 flow but good retrograde collaterals. One patient (5%) had nonviable myocardium with TIMI 2 flow, TIMI TG 1 thrombus in infract related artery and without collaterals. There was a strong positive correlation between myocardial viability and angiographic findings with correlation co-efficient +0.954 ( p < 0.001). Conclusion: Timely restoration of blood flow in infarct related artery is most important parameter for myocardial viability. However presence of good collateral minimizes or delays the cell death. Presence of thrombus burden is another important factor which determines the extent of viability.