AJP - Heart and Circulatory Physiology, Vol 273, Issue 3 1377-H1385, Copyright © 1997 by American Physiological Society
Three-dimensional activation sequence of cesium-induced ventricular arrhythmias
Y. Murakawa, K. Sezaki, T. Yamashita, Y. Kanese and M. Omata
Second Department of Internal Medicine, University of Tokyo, Japan.
To investigate the electrophysiological and electrocardiographic
characteristics of ventricular arrhythmia due to abnormal repolarization,
we studied the three-dimensional activation sequence of cesium-induced
ventricular tachycardia (VT) in 10 anesthetized dogs using a 384-channel
recording system. Seventeen monomorphic VT (mVT) and eight polymorphic VT
(pVT) episodes induced by cesium chloride (2 or 3 mM/kg) were analyzed.
Only a single arrhythmogenic focus was detected in most beats of VT,
whereas two competing foci were temporarily observed in two episodes of
pVT. The site of arrhythmogenic focus of mVT was the endocardium (5 of 17),
the midmyocardium (4 of 17), or undetermined (8 of 17). Both endocardial
and midmyocardial arrhythmogenic foci were also found in pVT, and most pVT
(6 of 8) were associated with the transition of the site of arrhythmogenic
focus. These results are consistent with the view that both myocardial
muscle fibers and Purkinje cells can cause ventricular arrhythmia due to
abnormal repolarization and that changing the site of arrhythmogenic focus
is the main mechanism of pVT.
