title: QT dynamicity and sudden death after myocardial infarction: results of a long-term follow-up study.
abstract: BACKGROUND
  The aim of this study was to determine whether impaired adaptation of the QT interval to changes in heart rate predicts sudden death after an acute myocardial infarction.
  
  
  RESULTS
  The Groupe d'Etude du Pronostic de l'Infarctus du Myocarde (GREPI) trial was a prospective multicenter study designed to evaluate the long-term outcome of myocardial infarction. QT dynamicity was evaluated in 265 patients by analyzing 24-hour Holter recordings obtained 9 to 14 days after myocardial infarction. The linear regression slope of QT intervals measured to the apex and to the end of the T wave (QTe) plotted against RR intervals was calculated using a dedicated Holter algorithm. The value of QT/RR in predicting sudden death and total mortality was compared with those of ejection fraction, heart rate variability, and late potentials. Mean follow-up was 81 +/- 27 months. There were 73 deaths, of which 23 were sudden. Of all the parameters, an increased diurnal QTe/RR slope (>0.18) was the strongest independent predictor of sudden death (relative risk 6.07, confidence interval 1.48-24.95, P = 0.01).
  
  
  CONCLUSIONS
  Increased diurnal QTe dynamicity is independently predictive of sudden death among patients with myocardial infarction. This simple parameter may help to stratify risk and select patients who may benefit from antiarrhythmic prophylaxis.
authors.affiliation: Hôpital Louis Pradel, Lyon, France. philippe.chevalier@chu-lyon.fr
authors.forename: Philippe
authors.initials: P
authors.lastname: Chevalier
authors.forename: Haran
authors.initials: H
authors.lastname: Burri
authors.forename: Patrice
authors.initials: P
authors.lastname: Adeleine
authors.forename: Gilbert
authors.initials: G
authors.lastname: Kirkorian
authors.forename: Michel
authors.initials: M
authors.lastname: Lopez
authors.forename: Alain
authors.initials: A
authors.lastname: Leizorovicz
authors.forename: Xavier
authors.initials: X
authors.lastname: André-Fouët
authors.forename: Philippe
authors.initials: P
authors.lastname: Chapon
authors.forename: Paul
authors.initials: P
authors.lastname: Rubel
authors.forename: Paul
authors.initials: P
authors.lastname: Touboul
mesh_terms: D000368:Aged; D016757:Death, Sudden, Cardiac / Q000209:etiology*; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000175:diagnosis / Q000401:mortality* / Q000503:physiopathology; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment; D013318:Stroke Volume / Q000502:physiology; D016019:Survival Analysis