Background It is known that fQRS may be of value in determining the risk for sudden cardiac death(SCD). And early repolarization(ER) can be identified in approximately 1/3 of idiopathic ventricular tachycardia/ventricular fibrillation(VT/VF) cases. Objective This study aimed to evaluate the changes in fQRS and QRS complex morphologies after aborted SCD. Methods We reviewed data from 13 subjects(mean짹SD age, 63.0짹10.9; 12 males) who were resuscitated after cardiac arrest due to arrhythmic causes at Yeungnam University Hospital from 2003 to 2010. And the following ECG parameters were evaluated before and after aborted sudden cardiac death : i) PR interval, QRS duration and corrected QT(QTc) interval; ii) fQRS included various RSR' pattern; iii) the presence of initial QRS complex abnormalities(slurring or notching within the initial 40ms of the ascending limb of the R wave) in early repolarization variant(ERPV); iv) the presence of terminal QRS complex abnormalities defined slurring or notching of J-point in ERPV; and v) the narrow and high R-wave amplitude in leads V5 and V6. Results There were no significant differences among the ECG parameters including PR interval, QRS complex duration, and QTc interval before and after aborted SCD. fQRS was newly developed or changed in 6 of 13 patients(46.2%). fQRS was most commonly identified in the inferior leads(4,30.8%). ERPV was newly developed in 4 of 13 patients(30.8%). Of these patients, the morphology of ER was terminal QRS notching in 3 patient, and the combination of initial and terminal QRS complex abnormalities in 1 patient. The narrow and high R-wave was found in 2 patients(15.4%). Conclusion The study demonstrated that the changes in fQRS and QRS complex morphologies were observed in patients who experienced aborted SCD. The changes in these ECG parameters may represent a new ECG markers of prior SCD. Keywords : Sudden cardiac death;,Fragmented QRS, Early repolarization