A study on the mechanism of ventricular
arrhythmias induced by adenosine
Yu G-S,
Tian J, Zhong J-Z, Liu X-Y, Qian Y-R, Chen Y
Children¡¯s Hospital of Chongqing, China
Objectives: The goal of this study is
to show the electrophysiological effect of adenosine troposphere (ATP) on
the normal heart or how it triggers activities of the mechanism of
arrhythmias induced by adenosine.
Method: A Franz 6F catheter was
introduced into the left ventricle to record monophasic action potentials
(MAPs) using the contact electrode technique to observe the influence to
MAP change of normal heart and with CsCl-induced triggered activities when
adenosine is administered as an intravenous bolus.
Result: On one hand adenosine has
little affects on the amplitude and the maximal upstroke velocity (Vmax) of
MAPs in the normal heart. But at first the heart rate doesn't slow down appreciatively
and adenosine induces early after depolarization (EAD) that are associated
with a prolongation the MAP duration (MAPD90), and in the later
period the heart rate clearly slows and EAD disappears. On the other hand
it has biphasic effect on delayed after depolarization (DAD) or EAD induced
by CsCl. In the initial stage it promotes after depolarization (EAD or DAD)
temporarily and then abolish them quickly.
Conclusion: The effect of adenosine is
different in different heart states. It shows the biphasic effects of
exciting and repression and it's related to dosage, this is important to
the clinical use of ATP.