TY  - JOUR
EP  - 565
UR  - https://doi.org/10.1097/00005344-199410000-00006
SN  - 0160-2446
ID  - publicatio31959
AV  - restricted
TI  - Electrophysiologic effects of detajmium on isolated dog cardiac ventricular and Purkinje fibers
N2  - We studied the electrophysiologic effects of the antiarrhythmic
compound detajmium (Tachmalcor) on isolated dog and rabbit cardiac
preparations, applying the conventional intracellular microelectrode
techniques. In dog ventricular muscle fibers (37 degrees C, stimulation
frequency 1 Hz), 1 mu M detajmium did not change resting potential
(RP), action potential amplitude (APA), AP duration measured at 90% of
repolarization (APD(90)), or effective refractory period (ERP)
significantly, but reduced maximum rate of depolarization (V-max)
significantly from 236.7 +/- 28.9 to 177.3 +/- 22.5 V/s (n = 6, p <
0.01). In dog Purkinje fibers (37 degrees C, stimulation frequency 1
Hz), 1 mu M detajmium significantly decreased APA from 111.1 +/- 12.3
to 100.0 +/- 2.5 mV (n = 8, p < 0.003), APD(90) from 359.0 +/- 17.5 to
262.1 +/- 12.3 ms (n = 8, p < 0.001) and V-max, from 687.5 +/- 57.2 to
523.7 +/- 58.2 V/s (n = 8, p < 0.001) without changing maximal
diastolic potential or ERP/ APD ratio significantly. The effect of
detajmium on V-max in both dog ventricular muscle and Purkinje fibers
was frequency dependent. Fractional V-max block was 0.185 +/- 0.008
1/AP. The recovery kinetics of V-max (offset kinetics) was extremely
slow (time constant = 348.16 +/- 57.43 s) considerably slower than most
of those of other antiarrhythmic drugs yet reported. Detajmium in
concentration <32 mu M did not influence the beta-adrenoceptors or slow
response APs in dog ventricular tissue significantly. On the basis of
its electrophysiologic effects, detajmium, like prajmaline, encainide,
or flecainide, can be best classified as a class I/C antiarrhythmic
drug according to the Vaughan Williams' classification scheme.
Y1  - 1994///
JF  - JOURNAL OF CARDIOVASCULAR PHARMACOLOGY
IS  - 4
SP  - 559
A1  -  Hála Ottó
A1  -  Németh Miklós
A1  -  Varró András
A1  -  Papp Gyula
VL  - 24
ER  -