Reproducibility of microvolt T-wave alternans in patients with coronary artery disease.
BACKGROUND
Microvolt T-wave alternans (MTWA) measures subtle beat-to-beat fluctuations in the T-wave amplitude. It was found to be associated with cardiac electrical instability in patients with ischemic and dilated cardiomyopathy.


OBJECTIVE
To investigate the reproducibility of the MTWA test results in patients with ischemic heart disease.


METHODS
The study group comprised patients with ischemic heart disease who participated in a rehabilitation program at the Assaf Harofeh Medical Center. MTWA was measured during a bicycle exercise test at the first encounter and repeated after one week.


RESULTS
Of the 40 study patients with coronary artery disease, 4 had an indeterminate result and were excluded from the data analysis; 5 had a positive MTWA in the first and second study (14%), 27 had a negative MTWA in the first and second study (75%), and 4 had a negative MTWA in the first study and a positive MTWA in the second study (11%). Overall, there was a correlation between the results of the first and the second study in 89% of the patients (kappa = 0.652, P = 0.0001).


CONCLUSIONS
MTWA measurements are reproducible in the short term in patients with coronary artery disease.
Arrhythmia Service, Assaf Harofeh Medical Center, Zerifin, affiliated with Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Israel. therese@fuchs.org
Therese
T
Fuchs
Marina
M
Leitman
Itzhak
I
Zysman
Tal
T
Amini
Amram
A
Torjman
D003324:Coronary Artery Disease / Q000503:physiopathology*; D005080:Exercise Test; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results