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End-diastolic wall thickness is an important marker of myocardial viability in patients with suspected hibernation, and it can predict recovery of function similar to T1-201 scintigraphy. Importantly, a simple measurement of EDWT < or =0.6 cm virtually excludes the potential for recovery of function and is a valuable adjunct to DSE in the assessment of myocardial viability.

Background: The present study evaluates the lack of Q waves on the electrocardiogram (ECG) in the prediction of myocardial viability compared with dobutamine stress echocardiography (DSE) and rest-redistribution thallium-201 (Tl-201) scintigraphy. Hypothesis: The lack of pathologic Q waves (NoQ) may be a readily available and specific marker for the presence of viability. Methods: Sixty four patients with stable coronary artery disease (CAD) and ventricular dysfunction underwent rest ECG, DSE, and Tl-201 scintigraphy before revascularization, and a repeat rest 2-Dimensional (2-D) echocardiogram more than 3 mo later. Results: Total viability at baseline (% of total segments) was higher in the NoQ group by Tl-201 scintigraphy (87±19% versus 70±20%, p = 0.008) and by DSE (81±20% versus 65±24%, p = 0.013). As expected, the sensitivity of NoQ waves was low in predicting recovery of function (23%), and inferior to Tl-201 (82%) and DSE (84%) (p<0.05). However, specificity of NoQ waves for predicting recovery of global function was high (72%); higher than Tl-201 (50%) and DSE (45%). Positive predictive values were comparable among all modalities. Results were similar if the data were analyzed regionally for viability. Conclusion: Lack of pathologic Q waves is a specific and readily available marker of myocardial viability in patients with chronic CAD, which should alert the clinician for myocardial hibernation.

Recent developments have permitted myocardial contrast echocardiography (MCE) to become a new method of noninvasively assessing myocardial perfusion in humans. Preliminary studies of myocardial perfusion imaging during adenosine, dipyridamole, and dobutamine stress echocardiography have shown excellent agreement with either radionuclide uptake or quantitative angiography. This article reviews the recent advances in microbubble technology, ultrasound imaging, and myocardial physiology that have made contrast echocardiography a potential new gold standard for perfusion imaging in the new millennium.

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