Pre-hospital evaluation of electrocardiographic grade 3 ischemia predicts infarct progression and final infarct size in ST elevation myocardial infarction patients treated with primary percutaneous coronary intervention

BackgroundIn STEMI, grade-3 ischemia (G3) on admission ECG predicts larger infarct size (IS) than grade-2 (G2). We evaluated whether pre-hospital G3 and its temporal behavior are associated with IS and salvage after pPCI.MethodsIn 401 STEMI patients, pre-hospital and pre-PCI ECGs were classified as G3 or G2. IS was assessed by single-photon emission computed tomography (SPECT) at 30 days. In 245 patients, pre-PCI SPECT was available to determine myocardium at risk (MaR).ResultsG3 criteria were met by 88, and G2 by 313 patients. G3 was independently associated with IS (p = 0.006). With ST resolution (STR) group as a reference, G2- > G2, G2- > G3 and G3- > G3 were associated with larger IS (B = 4.4, p = 0.004; B = 5.4, p = 0.01; B = 10.2, p < 0.001, respectively), whereas G3- > G2 was not. Salvage was similar between G3 and G2 on pre-hospital ECG if treated early, however lower for G3 when treated later (> 2.5 h); 48% (35-78) vs 62% (40-87); p = 0.04.ConclusionDevelopment or persistence of G3 is associated with larger IS and less salvage, but decreasing grade G3- > G2 was not.