Editor,—We read with interest the article by Al-Mohammad and colleagues on the prevalence of hibernating myocardium in patients with ischaemic left ventricular dysfunction.1Although we agree with the authors that positron emission tomography (PET) can provide very accurate information for the identification of hibernating myocardium, general statements regarding PET as being the “gold standard” for the diagnosis of viability might be misleading in view of recently published data.2 In a particular subset of patients (those with severe postischaemic left ventricular dysfunction) PET is more accurate than other imaging techniques and, because of its technical characteristics, it is able to provide superior information on tissue viability. However, this requires the adoption of steady-state and standardised study conditions such as those achieved during hyperinsulinaemic euglycaemic clamp for an accurate quantification of the uptake of ¹⁸F fluorodeoxyglucose (FDG) by the myocardium. In addition this method does not require the simultaneous measurement of myocardial blood flow for the assessment of viability.

Using this method we have shown that in patients with severe …