title: Dynamicity of early and late phases of repolarization in patients with remote anterior myocardial infarction: the interlead differences.
abstract: BACKGROUND
  Repolarization dynamicity (QT/RR) is supposed to be a prognostic marker in post-MI patients. However, data on the relationships between early and late phases of QT and RR intervals (QT peak/RR and T peak-T end/RR) are insufficient, and which ECG lead should be used for the analysis is unclear. We analyzed repolarization dynamicity in patients after anterior MI with and without VT/VF history using two leads of Holter recordings- modified V(5) and V(3) . The daytime and nighttime periods were also analyzed.
  
  
  METHODS
  Cohort of 88 patients after anterior MI (>6 months) consisted of 43 patients without VT/VF (33 males; 59 ± 12 years; LVEF: 41 ± 7%; NoVT/VF), and 45 patients with VT/VF history- ICD implanted as secondary prevention (40 males; 64 ± 10 years; LVEF: 32 ± 8%; VT/VF). QT/RR, QT peak/RR and T peak-T end/RR were calculated from 24-hour ECG for the entire recording, daytime and nighttime periods, from V(5) and V(3) leads, respectively.
  
  
  RESULTS
  VT/VF patients had lower LVEF (P = 0.001). There were no differences in age and gender. VT/VF group had steeper QT/RR, QT peak/RR, and T peak-T end/RR in V(5) : 0.233 ± 0.04 versus 0.150 ± 0.05, P = 0.0001, 0.181 ± 0.04 versus 0.120 ± 0.04, P = 0.0001, 0.052 ± 0.02 versus 0.030 ± 0.02, P = 0.0001, and in V(3) : 0.201 ± 0.04 versus 0.149 ± 0.05, P = 0.0001, 0.159 ± 0.03 versus 0.118 ± 0.04, P = 0.0001, and 0.042 ± 0.02 versus 0.031 ± 0.02, P = 0.004; respectively. VT/VF patients had higher indices in V(5) than in V(3) lead (P = 0.001). QT/RR and QT peak/RR were steeper at daytime period in both leads. It was not found for T peak-T end/RR.
  
  
  CONCLUSIONS
  Patients with VT/VF history are characterized by steeper relationships between repolarization duration and RR intervals. These findings are more evident in modified V(5) lead.
authors.affiliation: Department of Cardiology, Medical University of Silesia, Katowice, Poland. krzysztofszydlo@onet.eu
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Szydlo
authors.forename: Krystian
authors.initials: K
authors.lastname: Wita
authors.forename: Maria
authors.initials: M
authors.lastname: Trusz-Gluza
authors.forename: Artur
authors.initials: A
authors.lastname: Filipecki
authors.forename: Witold
authors.initials: W
authors.lastname: Orszulak
authors.forename: Dagmara
authors.initials: D
authors.lastname: Urbanczyk
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Tabor
mesh_terms: D000704:Analysis of Variance; D004452:Echocardiography; D015716:Electrocardiography, Ambulatory; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric