Effects of angiotensin converting enzyme inhibition on cardiac innervation and ventricular arrhythmias after myocardial infarction.
OBJECTIVE
To investigate the influence of angiotensin-converting enzyme inhibitor (ACEI) on cardiac innervation and inducible ventricular arrhythmias (VAs) in healed myocardial infarction (MI).


METHODS
Left anterior descending coronary artery was ligated to induce MI in 30 rabbits. After oral captopril (10mg/kg/d) for 8 weeks, electrophysiological study was performed to evaluate the incidence of inducible VAs. RT-PCR and immunohistochemistry were used to measure the cardiac innervation.


RESULTS
Eight weeks after the operation, the incidence of inducible VAs in the MI-placebo group was higher (58.3%, 7/12) than in the sham operation group (16.7%, 2/12, P < 0.05). However, the incidence of inducible VAs in the MI-captopril group was lower (27.2%, 3/11) than in the MI-placebo group (P < 0.05). Proliferation and growth of nerve fibres in the MI-placebo group were mainly distributed at the periphery of the infarcted and perivascular regions of the myocardium. The density of nerve fibres increased in the MI-placebo group (3889+/-521 microm2/mm2) compared with the sham group (1727+/-304 microm2/mm2, P < 0.01) at the infarct border. In the MI-captopril group, the density of nerve fibres (3507+/-433 microm2/mm2) at the infarct border did not differ from that in the MI-placebo group (P=0.07). MI-induced abnormal nerve fibre distribution was partly restored by captopril treatment.


CONCLUSIONS
In this study, prolonged captopril treatment was effective in preventing VAs in healed MI, partly by attenuating the spatial heterogeneity of cardiac innervation.
Yan
Su-hua
SH
Department of Cardiology, Qianfoshan Hospital of Shandong Province, Jinan, 250014, China. yansuhua5537@163.com
Hu
He-sheng
HS
Wang
Le-xin
LX
Xing
Qi-chong
QC
Cheng
Wen-juan
WJ
Xue
Mei
M
D000284:Administration, Oral; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage* / Q000494:pharmacology; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000188:drug therapy* / Q000473:pathology; D002216:Captopril / Q000008:administration & dosage* / Q000494:pharmacology; D004594:Electrophysiology; D006352:Heart Ventricles / Q000187:drug effects* / Q000294:innervation / Q000473:pathology; D007150:Immunohistochemistry; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000473:pathology; D009412:Nerve Fibers / Q000187:drug effects* / Q000473:pathology; D010919:Placebos; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D000806:Angiotensin-Converting Enzyme Inhibitors; D010919:Placebos; D002216:Captopril