IntroductionNative T1 mapping values are elevated in acutely injured myocardium. We sought to study whether native T1 values, in the non-infarct related myocardial territories, might differ when supplied by obstructive or nonobstructive coronary arteries.MethodsConsecutive patients (N= 60, mean age 59 years) with the first STEMI following primary percutaneous coronary intervention, underwent cardiac magnetic resonance within 5 ± 2 days. A retrospective review of coronary angiography reports classified coronary arteries as infarct-related coronary artery (IRA) and non-IRA. Obstructive coronary artery disease (CAD) was defined as stenosis ≥50%. Native T1 values were presented using a 16-segment AHA model according to the three main coronary territories: left anterior descending (LAD), left circumflex (LCX), and right coronary artery (RCA).ResultsThe cutoff native T1 value for predicting obstructive non-IRA LAD was 1,309 msec with a sensitivity and specificity of 67% and 82%, respectively (AUC 0.76, 95% CI: 0.57–0.95,p= 0.04).The cutoff native T1 value for predicting obstructive non-IRA RCA was 1,302 msec with a sensitivity and specificity of 83% and 55%, respectively (AUC 0.7, 95% CI: 0.52–0.87,p= 0.05). Logistic regression model adjusted for age and infarct size demonstrated that native T1 was an independent predictor for the obstructive non-IRA LAD (OR 4.65; 1.32–26.96,p= 0.05) and RCA (OR 3.70; 1.44–16.35,p= 0.03).ConclusionElevated native T1 values are independent predictors of obstructive non-IRA in STEMI patients. These results suggest the presence of concomitant remote myocardial impairment in the non-infarct territories with obstructive CAD.