Reconstruction of action potential of repolarization in patients with congenital long-QT syndrome.
A method for reconstructing an action potential during the repolarization period was developed. This method uses a current distribution-plotted as a current-arrow map (CAM)--calculated using magnetocardiogram (MCG) signals. The current arrows are summarized during the QRS complex period and subtracted during the ST-T wave period in order to reconstruct the action-potential waveform. To ensure the similarity between a real action potential and the reconstructed action potential using CAM, a monophasic action potential (MAP) and an MCG of the same patient with type-I long-QT syndrome were measured. Although the MAP had one notch that was associated with early afterdepolarization (EAD), the reconstructed action potential had two large and small notches. The small notch timing agreed with the occurrence of the EAD in the MAP. On the other hand, the initiation time of an abnormal current distribution coincides with the appearance timing of the first large notch, and its end time coincides with that of the second small notch. These results suggest that a simple reconstruction method using a CAM based on MCG data can provide a similar action-potential waveform to a MAP waveform without having to introduce a catheter.
Kandori
Akihiko
A
Central Research Laboratory, Hitachi, Ltd, 1-280 Higashi-koigakubo, Kokubunji, Tokyo 185-8601, Japan. kandori@rd.hitachi.co.jp
Shimizu
Wataru
W
Yokokawa
Miki
M
Kamakura
Shiro
S
Miyatake
Kunio
K
Murakami
Masahiro
M
Miyashita
Tsuyoshi
T
Ogata
Kuniomi
K
Tsukada
Keiji
K
D000200:Action Potentials; D000328:Adult; D001145:Arrhythmias, Cardiac; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008133:Long QT Syndrome / Q000473:pathology*; D008280:Magnetics; D013223:Statistics as Topic; D013997:Time Factors