Electrocardiography subtraction method of detecting low-amplitude, high-frequency components (L-HFCs) within the QRS complex of patients with ventricular tachycardia.
A new method of extracting the low-amplitude and high-frequency components (L-HFCs) was developed and this study investigated its usefulness in 86 subjects: 28 normal subjects (group 1) and 58 patients with a previous myocardial infarction (MI). The patients were classified into 3 groups: group 2 with 38 patients without ventricular tachycardia (VT), group 3 with 13 patients with non-sustained VT, and group 4 with 7 patients with sustained VT. The new electrocardiography (ECG) subtraction method, using a mathematical filtering procedure, was used instead of conventional complex filtering. The continuous L-HFCs within the QRS complex were analyzed using a Z-lead recording. The duration of the continuous L-HFCs was significantly longer in group 4 than in groups 1 (p<0.0001), 2 (p<0.0001) or 3 (p<0.05) with all 3 filters. The ECG subtraction method is a powerful and useful new technique for identifying patients at risk for either sustained or non-sustained VT after MI, and overcomes several of the problems with the conventional signal-averaging method.
Nanke
Toshihiko
T
Department of Internal Medicine, St Marianna University School of Medicine, Kawasaki, Japan. t2nanke@marianna-u.ac.jp
Nakazawa
Kiyoshi
K
Arai
Mariko
M
Ryu
Shounosuke
S
Sakurai
Tsuneharu
T
Matsumoto
Naoki
N
Sato
Chuichi
C
Miyake
Fumihiko
F
D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D004562:Electrocardiography / Q000379:methods*; D001330:Electronic Data Processing; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000503:physiopathology*