Simultaneous assessment of T-wave alternans and heart rate turbulence on holter electrocardiograms as predictors for serious cardiac events in patients after myocardial infarction.
BACKGROUND
T-wave alternans based on the modified moving average method (MMA-TWA) and heart rate turbulence (HRT) have been introduced as predictors for cardiac mortality. In this study, we simultaneously recorded MMA-TWA and HRT in patients after myocardial infarction (MI) and designed a prospective observational study.


RESULTS
We prospectively enrolled 313 consecutive post-MI patients (age 70 ± 12 years, 232 men). The MMA-TWA and HRT were simultaneously measured using algorithms based on 24-h Holter ECG monitoring during daily activity. MMA-TWA was determined positive when the maximal voltage was >64 µV, and HRT was determined positive when both turbulence onset and turbulence slope were abnormal. The endpoint was defined as overall cardiac mortality and fatal arrhythmic events. MMA-TWA was positive in 14 patients (4.4%) and HRT was positive in 61 patients (19.5%). During follow-up of 1,190 ± 441 days, 28 patients (9%) reached the endpoint, including 12 patients with fatal arrhythmic events. Both MMA-TWA and HRT were significant predictors for the endpoint. On multivariate analysis, HRT had the most significant value, with a hazard ratio (HR) of 5.7 (P=0.0008). When focused on fatal arrhythmic events including sudden cardiac death, MMA-TWA had the most significant value (HR 5.8, P=0.0072).


CONCLUSIONS
The present study revealed that both MMA-TWA and HRT were significant predictors. MMA-TWA is more associated with arrhythmic events than cardiac mortality in post-MI patients.
Second Department of Internal Medicine, Kyorin University School of Medicine, Tokyo, Japan.
Kyoko
K
Hoshida
Yosuke
Y
Miwa
Mutsumi
M
Miyakoshi
Takehiro
T
Tsukada
Satoru
S
Yusu
Hideaki
H
Yoshino
Takanori
T
Ikeda
D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology; D015897:Comorbidity; D016757:Death, Sudden, Cardiac / Q000453:epidemiology*; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000401:mortality* / Q000503:physiopathology*; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors