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Updated: Jul 17, 2026

Methods for ECG Evaluation of Indicators of Cardiac Risk, and Susceptibility to Aconitine-induced Arrhythmias in Rats Following Status Epilepticus
Published on: April 5, 2011
Time dependent variability of QT dispersion after acute myocardial infarction and its relation to ventricular
J D Aitchison1, R W Campbell, P D Higham
1Academic Department of Cardiology, Freeman Hospital, Newcastle-upon-Tyne NE7 7DN, UK. j.d.aitchison@ncl.ac.uk
Objective:
To show whether increased QT dispersion on admission predicts ventricular fibrillation after acute myocardial infarction, and to determine the nature of time related changes in QT dispersion.
Design:
Prospective cohort study.
Setting:
Coronary care units of three teaching hospitals in Newcastle-upon-Tyne over an eight month period.
Patients:
All had acute myocardial infarction according to World Health Organization criteria.
Interventions:
For all patients, QT dispersion (QTd) and Bazett rate corrected QTc dispersion (QTcd) were measured from a high quality 12 lead ECG recorded on admission at a paper speed of 50 mm/s. In a subset, serial ECGs were recorded regularly to show time related changes in QTcd following acute myocardial infarction.
Main Outcome Measures:
Occurrence of ventricular fibrillation within the first 24 hours after myocardial infarction.
Results:
Data collected from 201 patients, 12 of whom (6%) developed ventricular fibrillation within 24 hours. Neither QTd nor QTcd differed between those developing ventricular fibrillation and those who did not: QTd mean (SD), 74 (24) ms (95% confidence interval (CI) 59 to 89) v 66 (24) ms (95% CI 62 to 70), respectively; QTcd, 86 (26) ms(0.5) (95% CI 70 to 102) v 77 (29) ms(0.5) (95% CI 72 to 82), respectively. Significant QTcd changes occurred early after myocardial infarction.
Conclusions:
Admission QTd and QTcd do not predict ventricular fibrillation after acute myocardial infarction. There are significant changes in QTcd with time, which may account for this measured lack of correlation.
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