Lack of Pathologic Q Waves : A Specific Marker of Viability in Myocardial Hibernation

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.