title: Fragmented QRS complexes are not hallmarks of myocardial injury as detected by cardiac magnetic resonance imaging in patients with acute myocardial infarction.
abstract: BACKGROUND
  Q waves on a 12-lead electrocardiography (ECG) are considered to be classic hallmarks of prior myocardial infarction. However, one study suggested that the fragmented QRS complex (fQRS) on ECG is a highly sensitive and specific marker of myocardial scarring on a nuclear stress test. The study aimed to investigate the diagnostic accuracy of fragmented QRS complexes compared with Q waves for myocardial injury detected by delayed contrast-enhanced cardiovascular magnetic resonance imaging (DE-CMRI) in subjects with acute myocardial infarction.
  
  
  METHODS
  Electrocardiograms of 190 subjects with myocardial infarction who underwent DE-CMR were analyzed. fQRS was defined by the presence of an additional R wave (R″), or notching of the S wave, or more than one R' in two contiguous leads.
  
  
  RESULTS
  Delayed enhancement was observed in 180 (94.7%) patients. Transmural enhancement was noted in 78 (43.3%) and subendocardial enhancement in 102 (56.7%) patients. The sensitivity and specificity of Q waved and fQRS for diagnosing delayed enhancement were 59.4% vs. 66.7% and 90.0% vs. 40.0%. The area under the receiver-operator characteristics curve of delayed enhancement was 0.75 for Q waves and 0.53 for fQRS (p=0.04). The areas under the ROC curves of the transmurality of delayed enhancement were 0.44 for fQRS and 0.58 for Q waves (p=0.73).
  
  
  CONCLUSIONS
  fQRS has poor accuracy for the detection of myocardial injury compared with Q waves. fQRS and Q waves are not valuable tools for the diagnosis transmural irreversible myocardial injury in acute myocardial infarction.
authors: Cardiology Division, Department of Internal Medicine, Yonsei University Wonju College of Medicine, Wonju, South Korea.
authors: Min-Soo
authors: MS
authors: Ahn
authors: Jin-Bae
authors: JB
authors: Kim
authors: Byung-Su
authors: BS
authors: Yoo
authors: Jun-Won
authors: JW
authors: Lee
authors: Ji Hyun
authors: JH
authors: Lee
authors: Young Jin
authors: YJ
authors: Youn
authors: Sung Gyun
authors: SG
authors: Ahn
authors: Jang-Young
authors: JY
authors: Kim
authors: Seung-Hwan
authors: SH
authors: Lee
authors: Junghan
authors: J
authors: Yoon
authors: Kyung-Hoon
authors: KH
authors: Choe
mesh_terms: D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000503:physiopathology*; D009206:Myocardium / Q000473:pathology; D011379:Prognosis; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index
keywords: Electrocardiography; Magnetic resonance imaging; Myocardial infarction