title: Evaluation of depolarization changes during acute myocardial ischemia by analysis of QRS slopes.
abstract: OBJECTIVE
  This study evaluates depolarization changes in acute myocardial ischemia by analysis of QRS slopes.
  
  
  METHODS
  In 38 patients undergoing elective percutaneous coronary intervention, changes in upward slope between Q and R waves and downward slope between R and S waves (DS) were analyzed. In leads V1 to V3, upward slope of the S wave was additionally analyzed. Ischemia was quantified by myocardial scintigraphy. Also, conventional QRS and ST measures were determined.
  
  
  RESULTS
  QRS slope changes correlated significantly with ischemia (for DS: r = 0.71, P < .0001 for extent, and r = 0.73, P < .0001 for severity). Best corresponding correlation for conventional electrocardiogram parameters was the sum of R-wave amplitude change (r = 0.63, P < .0001; r = 0.60, P < .0001) and the sum of ST-segment elevation (r = 0.67, P < .0001; r = 0.73, P < .0001). Prediction of extent and severity of ischemia increased by 12.2% and 7.1% by adding DS to ST.
  
  
  CONCLUSIONS
  The downward slope between R and S waves correlates with ischemia and could have potential value in risk stratification in acute ischemia in addition to ST-T analysis.
authors.affiliation: Department of Cardiology, Lund University, Lund, Sweden. michaelringborn@yahoo.com
authors.forename: Michael
authors.initials: M
authors.lastname: Ringborn
authors.forename: Daniel
authors.initials: D
authors.lastname: Romero
authors.forename: Esther
authors.initials: E
authors.lastname: Pueyo
authors.forename: Olle
authors.initials: O
authors.lastname: Pahlm
authors.forename: Galen S
authors.initials: GS
authors.lastname: Wagner
authors.forename: Pablo
authors.initials: P
authors.lastname: Laguna
authors.forename: Pyotr G
authors.initials: PG
authors.lastname: Platonov
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015906:Angioplasty, Balloon, Coronary; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D017256:Technetium Tc 99m Sestamibi / Q000008:administration & dosage
chemical_list: D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi