title: Comparison between fragmented QRS and Q waves in myocardial scar detection using myocardial perfusion single photon emission computed tomography.
abstract: BACKGROUND
  Accurate diagnosis of myocardial infarction (MI) is of paramount importance in patient management, which necessitates the development of efficient and accurate diagnostic methods. Q wave is not present in all patients with MI, and its prevalence is declining. Recently, fragmented QRS (fQRS) complex has been introduced as a marker of prior MI.
  
  
  OBJECTIVE
  To investigate diagnostic value of fQRS compared to Q wave.
  
  
  METHODS
  We included 500 consecutive patients with known or suspected coronary artery disease who underwent two days of gated myocardial perfusion imaging using dipyridamole pharmacologic stress. Electrocardiogram (ECG) was evaluated to detect fQRS as well as Q-wave. Finally, subjects were compared in terms of ventricular perfusion and function indices.
  
  
  RESULTS
  A total of 207 men and 269 women with mean age of 57.06 ± 12 years were studied. ECG analysis showed that 14.3% of the patients had both fQRS and Q waves, 30.7% had fQRS, and 3.8% had Q waves. Fixed myocardial perfusion defect was noted in 22.3% of patients according to MPIs. Sensitivity, specificity, and positive and negative predictive values for myocardial scar detection were 78%, 65%, 39%, and 91%, respectively, for fQRS and 61%, 94%, 76%, and 89%, respectively, for Q wave.
  
  
  CONCLUSIONS
  Although fQRS had lower specificity compared to Q wave in the detection of myocardial scar, due to higher sensitivity and negative predictive value can be an invaluable diagnostic index. There is also an incremental value for fQRS in association with Q-wave in myocardial scar assessment.
authors.forename: Vahid Reza
authors.initials: VR
authors.lastname: Dabbagh Kakhki
authors.affiliation: Nuclear Medicine Research Center, Mashhad University of Medical Sciences. ayatin@mums.ac.ir.
authors.forename: Narjess
authors.initials: N
authors.lastname: Ayati
authors.forename: Seyed Rasoul
authors.initials: SR
authors.lastname: Zakavi
authors.forename: Ramin
authors.initials: R
authors.lastname: Sadeghi
authors.forename: Mohammad
authors.initials: M
authors.lastname: Tayyebi
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Shariati
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002921:Cicatrix / Q000150:complications* / Q000175:diagnosis; D003324:Coronary Artery Disease / Q000150:complications*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging; D009206:Myocardium; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon; D055815:Young Adult