title: Course and prognostic implications of QT interval and QT interval variability after primary coronary angioplasty in acute myocardial infarction.
abstract: OBJECTIVE
  The aim of this study was to determine the influence of early reperfusion on the course of QT interval and QT interval variability in patients undergoing primary percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction (AMI) and its prognostic implications on major arrhythmic events during one-year follow-up.
  
  
  BACKGROUND
  Although early coronary artery recanalization by primary angioplasty is an established therapy in AMI, a substantial number of patients is still threatened by malignant arrhythmias even after early successful reperfusion, which may be caused by an inhomogeneity of ventricular repolarization despite reperfusion.
  
  
  METHODS
  Temporal fluctuations of ventricular repolarization were studied prospectively in 97 consecutive patients with a first AMI by measurements of QT interval and QT interval variability during and after successful PTCA (Thrombolysis in Myocardial Infarction flow grades 2 and 3). Continuous beat-to-beat QT interval measurement was performed from 24-h Holter monitoring, which was initiated at admission before PTCA.
  
  
  RESULTS
  Reperfusion caused a significant continuous increase of mean RR interval (738 +/- 98 to 808.5 +/- 121 ms; p < 0.001) and a significant decrease of parameters of QT interval (QTc: 440 +/- 32 to 416.5 +/- 37ms; p < 0.001) and QT interval variability (QTcSD: 27.5 +/- 3 to 24.9 +/- 6 ms; p < 0.001) in the majority of patients. However, in patients with major arrhythmic events at the one-year follow-up (sudden cardiac death, ventricular fibrillation or sustained ventricular tachycardia, n = 15), parameters of QT interval remained unaltered after successful reperfusion (QTc: 447.3 +/- 41 to 432.9 +/- 45 ms, p = NS; QTcSD: 35.1 +/- 13.4 to 29.0 +/- 9.1 ms, p = NS).
  
  
  CONCLUSIONS
  Reduction of QT interval and QT interval variability after timely reperfusion of the infarct-related artery may be a previously unreported beneficial mechanism of primary PTCA in AMI, indicating successful reperfusion.
authors.affiliation: Medizinische Klinik II, Medizinische Universität zu Lübeck, Germany. Bonnemei@medinf.mu-luebeck.de
authors.forename: H
authors.initials: H
authors.lastname: Bonnemeier
authors.forename: F
authors.initials: F
authors.lastname: Hartmann
authors.forename: U K
authors.initials: UK
authors.lastname: Wiegand
authors.forename: F
authors.initials: F
authors.lastname: Bode
authors.forename: H A
authors.initials: HA
authors.lastname: Katus
authors.forename: G
authors.initials: G
authors.lastname: Richardt
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008133:Long QT Syndrome / Q000175:diagnosis* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D015428:Myocardial Reperfusion Injury / Q000175:diagnosis* / Q000628:therapy; D015996:Survival Rate; D016896:Treatment Outcome