Significance and usefulness of narrow fragmented QRS complex on 12-lead electrocardiogram in acute ST-segment elevation myocardial infarction for prediction of early mortality and morbidity.

Background: The presence of notched R or S waves without accompanying typical bundle branch blocks, or the existence of an additional wave like RSR' pattern in the original QRS complex (with a duration of <120 ms) has been defined as narrow QRS fragmentation. Persistence of the fQRS found on the admission electrocardiogram (ECG) in patients with acute ST segment elevation myocardial infarction (STEMI) will have prognostic significance in the short term. Methods: The study was carried out using retrospectively collected data of 296 consecutive patients diagnosed as acute STEMI. fQRS group had fQRS both in admission and latest ECGs (n = 80, 27%), and non-fQRS group had no fQRS in last ECG (n = 216, 73%). Primary end points were in-hospital cardiovascular mortality, hemodynamic instability, and electrical instability. Results: MI localization, symptom duration, reperfusion therapy (RPT) rate, RPT modality, rate of successful reperfusion did not differ. Mean ejection fraction was lower and all end points were more frequent in the fQRS group. Irrespective of the RPT modality and success of RPT, mortality rate was higher in patients with persistent fQRS. GRACE score >120 points (OR = 4.765), age >70 years (OR = 4.041), anterior MI localization (OR = 3.148), and presence of fQRS (OR = 2.484) were significant predictors of primary end points. fQRS increased the predictive ability of GRACE score >120 about two folds (OR = 7.305, P < 0.001). Conclusion: Persistent fQRS on ECG is associated with poor prognosis and there is a lack of expected mortality benefit of RPT, particularly that of fibrinolytic therapy, in STEMI patients with fQRS.