OBJECTIVETo explore the relationship between fragmented QRS complexes (fQRS) and imperfect ST-segment resolution in ST elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (p-PCI).

METHODSThis study included 227 consecutive patients with STEMI who underwent p-PCI. They were divided into two groups: ECG with fQRS (n = 142) and without fQRS (n = 85). Baseline clinical characteristics,Gensini score, coronary angiography features and the rate of ST-segment resolution were compared between the two groups.

RESULTS(1) Patients with fQRS of ECG had higher cTnI, CK, CK-MB levels and Gensini score, prolonged QRS interval, lower rate of ST-segment resolution and left ventricular ejection fraction (LVEF) than in patients without fQRS (all P < 0.01 or P < 0.05). (2) Pearson correlation analysis showed that the rate of ST-segment resolution (r = -0.207, P = 0.002),Gensini score (r = 0.191, P = 0.004), LVEF(r = -0.188, P = 0.006), cTnI(r = 0.172, P = 0.010), and the TIMI grade post p-PCI (r = -0.148, P = 0.028) were significantly related with the presence of fQRS. (3) Multivariate logistic regression analysis demonstrated that presence of fQRS at pre-PCI (OR = 2.908, 95%CI:1.095-7.723, P = 0.032) , the number of leads with fQRS before PCI (OR = 1.582, 95%CI:1.250-2.002, P < 0.001), and increased QRS interval (OR = 0.955, 95%CI: 0.924-0.988, P = 0.008) were independent predictors of imperfect ST-segment resolution.

CONCLUSIONSfQRS is related to imperfect ST-segment resolution in STEMI patients undergoing p-PCI.fQRS may be a useful parameter to identify the patients with severe coronary lesion, larger areas of ischemic injury and myocardial infarction as well as severe left ventricular contracted dysfunction.