• myocardial viability
• acute myocardial infarction

• CFR, coronary flow reserve
• FDG, 18-fluoro-deoxyglucose
• LV, left ventricular
• PET, positron emission tomography
• SIFP, slope index of the flow–pressure relation

Assessment of myocardial viability has been a challenge for revascularisation therapeutics in determining the effectiveness of an intervention and patient prognosis. In most cases, the current standard for viability is the recovery of function measured by left ventricular (LV) wall motion and the metabolic activity measured by positron emission tomography (PET) with the uptake of the metabolic tracer 18-fluoro-deoxyglucose (FDG). In this issue of Heart, Schimada and colleagues¹ report how they coupled this imaging methodology of the metabolic activity of viable myocardium with other physiologic indices. In 27 patients, coronary flow and pressure were measured after successful angioplasty in patients undergoing acute myocardial infarction intervention within 12 hours of the onset of symptoms. FDG PET scan results and pressure at zero flow slope index, the SIFP, from simultaneously recorded aortic pressure and coronary flow velocity signals at peak hyperaemia, distal to the lesion in the re-canalised artery were compared. The percentage FDG uptake in the infarct myocardium was normalised for FDG uptake in …