T Ago22a.p65

Mailing address: Pedro Silvio Farsky Rua Caravelas, 423 04012-090 São Paulo, SP Brazil E-mail: [email protected] Sent for publishing on: 06/23/2004 Accepted on: 02/23/2005 The benefit of myocardial revascularization (RM) surgery was first demonstrated in patients with severe left ventricular dysfunction with CASS registration1. A longer survival, in five years, was verified in patients with left ventricular fraction of ejection (LVFE) lower than 0.26 and submitted to MR. However, those patients showed high surgical risk and higher operative complication rate. At that time, akinetic myocardial segments were characterized as fibrotic, and therefore, insusceptible to improvement. However, Rahimtoola2 verified that some myocardial segments recover contractility when properly reperfused. Those were called hibernating myocardia. Identification of viable myocardium held important prognostic implications. Correction of arterial flow may lead to recovery of segmental, and even global, myocardial contractility, which promotes improvement of symptomatology and even survival3,4. Myocardial viability can be detected by four different methods: metabolic function, cell membrane integrity, perfusion and contractile reserve. Metabolic function can be assessed through capitation of 18 F-fluorodeoxyglucose (FDG). Cell membrane integrity can be assessed through tracer capitation, especially 201 thallium. Myocardial perfusion depends on microvascular integrity and can be assessed through contrast echocardiography. Contractile reserve analysis was first assessed by postextrasystolic potentiation, during contrast ventriculography. However, the currently used method is dobutamine stress echocardiography (DSE). Among the methods mentioned, DSE and 201 thallium myocardial scintigraphy are the most commonly used in our milieu. DSE is widely employed due to its low cost in relation to the others and its availability in many cardiology centers. However, it does depend on operator’s experience and provides a lower sensitivity, especially in akinetic segments5. 201 thallium myocardial scintigraphy is a strong scientific-based method, but when compared with positron emission tomography it shows lower sensitivity. The greatest part of fixed defects, from light to moderate level through 201 thallium myocardial scintigraphy, are regarded as viable by positron emission tomography (PET)6. PET was regarded as gold standard for myocardial viability detection for long time. Moreover, its clinical application has been limited by short half-life and low availability of FDG, associated to equipment high cost. FDG capitation, through conventional gamma Objective To compare Dual-Head Coincidence Gamma Camera (DCDAC) with Dobutamine Stress Echocardiography (DSE) in viability assessment, using functional recovery as the gold standard.