QRS distortion in pre-reperfusion electrocardiogram is a bedside predictor of large myocardium at risk and infarct size (a METOCARD-CNIC trial substudy)

About QRS prolongation, distortion and the acuteness score

“…Duration of ischemia was comparable between the groups. In their study the size of the ischemic area at risk and final infarct size were larger, whereas myocardial salvage index was smaller in patients with grade III [22]. These two large scale studies confirm the results of two previous smaller studies that used CMR [23,24].…”

“…Valle-Caballero et al included a group with grade III ischemia in only one lead and found intermediate results between the grade II and grade III in ≥ 2 leads [22]. This in accordance with the study of Billgren et al that also found that grade III ischemia in one lead has intermediate results concerning myocardial salvage after pPCI [28].…”

“…A major limitation of this study is that the infarct size was not adjusted to the size of the ischemic area at risk and ischemic time. The explanation for the difference in findings between the study of Hassel et al for the whole cohort or the anterior STEMI patients (when infarct size was assessed after 4 months) [15], and the studies of Rommel et al [21] and Valle-Caballero et al [22] (when infarct size was assessed within 4 and 7 days, respectively) is unclear. It may be due to chance or to differential remodeling process in patients with grade II and grade III of ischemia.…”

“…Patients with a score ≥ 3 (n = 16) had a significantly greater myocardia salvage index (82.7%) as compared to patients with score b 3 (n = 27; 41.5%; p = 0.014). The investigators are not reporting, but it seems that the study cohort is composed of a unique patient population, as the salvage index after N 12 h of symptoms seems to be greater than that reported for patients treated after much shorter ischemic times as assessed by CMR [21,22] and nuclear imaging [35,36]. The authors suggested that this may be related to the fact that they assessed infarct size at 30 days and it seems that infarct size (at least as measured by CMR) seems to decrease over the first month [27].…”

“…Unfortunately, the authors do not provide separate analyses for anterior and non-anterior infarcts, despite the fact that the incidence of LAD infarction was lower and that of right coronary artery infarction was higher in the grade III group. Valle-Caballero et al studied patients with first anterior STEMI (101 patients with grade II and 43 patients with grade III in ≥ 2 adjacent leads) [22]. Duration of ischemia was comparable between the groups.…”