QT dynamicity: a prognostic factor for sudden cardiac death in chronic heart failure.
BACKGROUND
The aim of this study was to determine whether impaired adaptation of the QT interval to changes in heart rate predicts sudden death in patients with chronic heart failure (CHF).


METHODS
We prospectively included 175 CHF patients in sinus rhythm. QT dynamicity was evaluated by analyzing 24-h Holter recordings. The linear regression slope of QT interval measured to the apex and to the end of T wave plotted against RR intervals was calculated using a dedicated Holter algorithm.


RESULTS
Mean follow-up was 29.9+/-17.9 months. There were 48 deaths, of which 21 were sudden. The actuarial 3-year mortality rates were 38.4% for overall mortality and 14.1% for sudden death. Of all the parameters, an increased QTe/RR slope (>0.28) was the strongest independent predictor of sudden death (relative risk 3.47, 95% confidence interval 1.43-8.40, p=0.006).


CONCLUSIONS
Increased 24-h QTe dynamicity is independently predictive of sudden death among patients with heart failure. This simple parameter may help to stratify risk and select patients who may benefit from antiarrhythmic prophylaxis.
Pathak
Atul
A
Club d'Etude du Système Nerveux Autonome et INSERM U586, Laboratoire de Pharmacologie médicale et clinique, Faculté de Médecine, 37 allés Jules Guesde, 31073 Toulouse Cedex, France. pathak@cict.fr
Curnier
Daniel
D
Fourcade
Joëlle
J
Roncalli
Jérôme
J
Stein
Phyllis K
PK
Hermant
Patricia
P
Bousquet
Marc
M
Massabuau
Pierre
P
Sénard
Jean-Michel
JM
Montastruc
Jean-Louis
JL
Galinier
Michel
M
D000328:Adult; D000368:Aged; D000465:Algorithms; D016757:Death, Sudden, Cardiac / Q000209:etiology*; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000150:complications / Q000401:mortality* / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012720:Severity of Illness Index; D013318:Stroke Volume / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology*