[The effects of antiarrhythmic peptide AAP10 on ventricular arrhythmias in rabbits with healed myocardial infarction].
OBJECTIVE
To evaluate the effects of antiarrhythmic peptide (AAP10) on ventricular arrhythmias in rabbits with healed myocardial infarction (OMI).


METHODS
Thirty rabbits were randomly divided into three groups (n = 10 each): Sham group, left thoracotomy was performed without coronary ligation; OMI group and OMI + AAP10 group, the circumflex coronaries were ligated. Three months post operation, the electrophysiological and antiarrhythmic effects of AAP10 were assessed in the arterially perfused rabbit left ventricular wedge preparation. Sham and OMI group were perfused with Tyrode's solution and OMI + AAP10 group was perfused with Tyrode's solution + AAP10 (80 nmol/L). Transmembrane action potentials were recorded simultaneously from endocardium and epicardium together with a transmural ECG by use of 2 separate intracellular floating microelectrodes. The stimulus-response-interval (SRI) of the epicardium and the incidence of ventricular tachycardia (VT) were observed. Whole heart and left ventricular weights, the left ventricular thickness at infarct border zone were measured.


RESULTS
Whole heart and left ventricular weights as well as the left ventricular thickness at the infarct border zone significantly increased post infarction. VT was induced in 8 out of 10 rabbits in OMI group and in 2 out of 10 rabbits in OMI + AAP10 group (P < 0.05). SRI was also significantly shortened in OMI + AAP10 group compared to OMI group [SRI-1: (20.59 +/- 0.79) ms vs. (28.71 +/- 0.55) ms; SRI-2: (30.42 +/- 0.74) ms vs. (38.67 +/- 0.49) ms, all P < 0.01]. However, the action potential morphology and duration were similar between OMI and OMI + AAP10 groups.


CONCLUSIONS
The antiarrhythmic peptide (AAP10) can increase gap junctional intercellular conductance without affecting the action potential morphology and duration and decrease the incidence of inducible ventricular tachycardia.
Ren
Yong
Y
Department of Cardiology, Tongji Hospital, Affiliated of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Zhang
Cun-tai
CT
Wu
Jie
J
Ruan
Yan-fei
YF
Pu
Jun
J
He
Li
L
Wu
Wei
W
Chen
Bai-di
BD
Wang
Wen-guang
WG
Wang
Lin
L
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000517:prevention & control*; D008297:Male; D009203:Myocardial Infarction / Q000150:complications / Q000503:physiopathology*; D009842:Oligopeptides / Q000494:pharmacology*; D011817:Rabbits; D011897:Random Allocation
C090806:AAP 10; D009842:Oligopeptides