QT dynamicity and sudden death after myocardial infarction: results of a long-term follow-up study.
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.
Chevalier
Philippe
P
Hôpital Louis Pradel, Lyon, France. philippe.chevalier@chu-lyon.fr
Burri
Haran
H
Adeleine
Patrice
P
Kirkorian
Gilbert
G
Lopez
Michel
M
Leizorovicz
Alain
A
André-Fouët
Xavier
X
Chapon
Philippe
P
Rubel
Paul
P
Touboul
Paul
P
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