March 1, 2003
View Full PaperQT Dynamicity and Sudden Death After Myocardial Infarction:
Key Result
An increased diurnal QTe/RR slope (>0.18) independently predicted sudden death after myocardial infarction (RR 6.07; 95% CI 1.48-24.95; P=0.01).
Study Design
Type
Cohort (n=265)
Multicenter
Yes
Structured PICO
Does increased QT dynamicity predict sudden death in patients after acute myocardial infarction?
P
Population
265 patients evaluated 9 to 14 days after myocardial infarction, followed for a mean of 81 months.
E
Exposure
Measurement of QT dynamicity (diurnal QTe/RR slope) via 24-hour Holter monitoring
O
Outcome
Sudden death and total mortalityhard clinical
Increased diurnal QTe dynamicity is a strong independent predictor of sudden death in post-myocardial infarction patients, potentially aiding in risk stratification.
Main Result
Relative Risk: 6.07 (95% CI 1.48–24.95)
p-value: p=0.01
Abstract
INTRODUCTION: 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. METHODS AND 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). CONCLUSION: 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.