| Objective:To investigate the clinical characteristics of patients with the fragmented QRS complexes (fQRS), the changes of fQRS following primary percutaneous coronary intervention (p-PCI) and the predictive value of fQRS on imperfect ST-segment resolution and main adverse cardiac events (MACE) in patients with ST elevation myocardial infarction (STEMI) who undergoing p-PCI were studied.Methods:The study enrolled204consecutive patients with STEMI who underwent p-PCI. They were divided into two groups:ECG with fQRS (n=116) and without fQRS (n=88). Baseline clinical characteristics, laboratory measurements, Electrocardiogram (ECG) and angiography results parameters, Gensini score, the rate of ST-segment resolution were collected and compared between two groups. The presence or absence of fQRS on pre-and post-PCI ECG and their relationships with Gensini score and the rate of ST-segment resolution following PCI were studied. Further more, the predictive value of fQRS on ST-segment resolution determined using the receiver operating characteristic curve (ROC curve). In addition, all patients enrolled in this study were recorded the incidence of MACE during a mean follow-up period of13.7±4.5months. The relationship between the presence of fQRS and the incidence of MACE and whether fQRS was a clinic prognostic factor of MACE were investigated by Kaplan-Meier analyse of survival curves, ROC curve and multivariate Cox proportional hazards regression analysis.Results:1. Patients with fQRS had higher cardiac enzyme levels, CK, UA, Cr, and Gensini score, prolonged QRS interval, lager left ventricular end systolic and diastolic diameter (LVESD, LVEDD), lower left ventricular ejection fraction (LVEF) and the rate of ST-segment resolution in comparison to patients with non-fragmented QRS (P＜0.01or0.05). 2. The presence or absence of fQRS before and after p-PCI were correlated with Cr, LVEF, LVEDD, LVESD, Delta QRS interval, the rate of ST-segment resolution and Gensini score (P<0.01or0.05).3. After p-PCI, the patients with ST-segment resolution<50%has prolonged Delta QRS interval, higher Gensini score and the appearance rate of fQRS (at48th hour, before and after p-PCI), more leads with fQRS (P＜0.01or0.05).4. The presence and the number of leads with fQRS on pre-PCI, Gensini score and Delta QRS interval were significantly related with the rate of ST-segment resolution (r=-0.174,-0.164,-0.153,0.181; all P＜0.05). The area under the ROC curve values for the presence and the number of leads with fQRS to predict rate of ST-segment resolution<50%were0.645and0.731, separately. The sensitivity and specificity of fQRS for prediction of imperfect ST-segment resolution were68.2%and60.9%compared with66.7%and71.0%for the number of leads with fQRS≥3.5. During the period of follow-up, the rate of MACE was significantly higher in fQRS group than in the nfQRS group (25%vs.8%, P=0.002). The cardiac mortality rate had no difference between the two groups (3.4%vs.0%, P=0.079). The rate of MACE and cardiac mortality were higher in the number of leads with fQRS≥3group than those in the number of leads with fQRS<3group (P<0.05).6. A Kaplan-Meier analysis showed a lower MACE events-free rate in patients with fQRS than that in the patients without fQRS (Long-rank:P=0.002). The cardiac mortality events-free rate had no difference between these two groups (Log-rank: P=0.084). The events-free rate of MACE and cardiac mortality were higher in patients with≥3leads with fQRS than in those with<3leads with fQRS (P<0.05).7. A multivariate Cox proportional hazards regression analysis selected diabetes mellitus disease, LVEF, Gensini score, the presence of fQRS and the number of leads with fQRS at the48th hour were independent predictors of MACE. The area under the ROC curve values for the presence and the leads of fQRS at the48th hour to predict MACE were0.644and0.626, separately. The sensitivity and specificity of fQRS for prediction of MACE were80.6%and51.8%. The sensitivity and specificity of the number of leads with fQRS≥3were63.9%and60.1%respectively. Conclusion:1. fQRS at the48th hour may be useful to identify the patients with severe coronary lesion, larger areas of ischemic injury and myocardium infarction, left ventricular contracted dysfunction, lower rate of ST-segment resolution.2. fQRS was significantly related to LVEF, LVEDD, LVESD, Delta QRS interval, the rate of ST-segment resolution and Gensini score before and after p-PCI.3. The rate of ST-segment resolution was significantly related with Gensini score Delta QRS interval, the presence and the leads of fQRS on pre-PCI ECG. The presence and the number of leads with fQRS≥3were the predictors of imperfect ST-segment resolution.4. The incidence of MACE was significantly related with the presence and the number of leads with fQRS at the48th hour. The presence of fQRS and≥3leads with fQRS at the48th hour were independent predictors of MACE in patients with STEMI undergoing p-PCI. |
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