Time-domain T-wave alternans measured from Holter electrocardiograms predicts cardiac mortality in patients with left ventricular dysfunction: a prospective study.
BACKGROUND
Time-domain T-wave alternans (TWA) is useful for identifying patients at risk for serious events after myocardial infarction.


OBJECTIVE
The purpose of this study was to prospectively evaluate the utility of time-domain TWA measured from Holter ECGs in predicting cardiac mortality in patients with left ventricular (LV) dysfunction.


METHODS
Two hundred ninety-five consecutive patients with LV dysfunction were enrolled in the study. Patients were divided into two groups: the ischemic group (n = 195) and the nonischemic group (n = 100). Time-domain TWA was assessed using the modified moving average method from routine 24-hour Holter ECGs recorded during daily activity. The maximal time-domain TWA voltage at heart rate <or=120 bpm in either lead V(5) or V(1) was derived and its value defined as positive when the voltage was >or=65 microV. The primary end-point was defined as cardiac mortality.


RESULTS
Mean maximal time-domain TWA voltage was 54 +/- 16 microV. During follow-up of 390 +/- 212 days, 27 patients (17 in the ischemic group and 10 in the nonischemic group) died of cardiac causes. Fifty-three patients (18%) were time-domain TWA positive and 242 (82%) were time-domain TWA negative. Univariate Cox proportional hazards analyses revealed that older age, New York Heart Association functional class III or IV, diabetes, renal dysfunction, nonsustained ventricular tachycardia, and time-domain TWA were associated with cardiac mortality. In multivariate analysis, time-domain TWA had the most significant value (hazard ratio = 17.1, P <.0001). This index also was significant in both subgroups (ischemic group: hazard ratio = 19.0, P <.0001; nonischemic group: hazard ratio = 12.3, P = .002).


CONCLUSIONS
Time-domain TWA measured from 24-hour Holter ECGs predicts cardiac mortality in patients with ischemic and nonischemic LV dysfunction.
Sakaki
Katsura
K
Second Department of Internal Medicine, Kyorin University School of Medicine, Tokyo, Japan.
Ikeda
Takanori
T
Miwa
Yosuke
Y
Miyakoshi
Mutsumi
M
Abe
Atsuko
A
Tsukada
Takehiro
T
Ishiguro
Haruhisa
H
Mera
Hisaaki
H
Yusu
Satoru
S
Yoshino
Hideaki
H
D000368:Aged; D018572:Disease-Free Survival; D015716:Electrocardiography, Ambulatory; D005260:Female; D006331:Heart Diseases / Q000401:mortality*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted; D018487:Ventricular Dysfunction, Left / Q000209:etiology / Q000401:mortality / Q000503:physiopathology*