Y. Murakawa et al., 3-DIMENSIONAL ACTIVATION SEQUENCE OF CESIUM-INDUCED VENTRICULAR ARRHYTHMIAS, American journal of physiology. Heart and circulatory physiology, 42(3), 1997, pp. 1377-1385
To investigate the electrophysiological and electrocardiographic chara
cteristics of ventricular arrhythmia due to abnormal repolarization, w
e studied the three-dimensional activation sequence of cesium-induced
ventricular tachycardia (VT) in 10 anesthetized dogs using a 384-chann
el recording system. Seventeen monomorphic VT (mVT) and eight polymorp
hic VT (PVT) episodes induced by cesium chloride (2 or 3 mM/kg) were a
nalyzed. Only a single arrhythmogenic focus was detected in most beats
of VT, whereas two competing foci were temporarily observed in two ep
isodes of pVT. The site of arrhythmogenic focus of mVT was the endocar
dium (5 of 17), the midmyocardium (4 of 17), or undetermined (8 of 17)
. Both endocardial and midmyocardial arrhythmogenic foci were also fou
nd in pVT, and most pVT (6 of 8) were associated with the transition o
f the site of arrhythmogenic focus. These results are consistent with
the view that both myocardial muscle fibers and Purkinje cells can cau
se ventricular arrhythmia due to abnormal repolarization and that chan
ging the site of arrhythmogenic focus is the main mechanism of pVT.