Effects of Shen Song Yang Xin on microcirculation and electrophysiological properties in chronic myocardial infarction rabbit model

Objective To investigate the effects of Shen Song Yang Xin (SSYX) on heart function, myocardial microcirculation and electrophysiology characteristics in 8-week infarcted rabbit hearts and compared with amiodarone. Methods Thirty-two Japanese rabbits were randomly assigned to four groups: sham group (SO group), corresponding myocardial infarction (MI) control group (MI group), MI amiodarone group (AD group) and MI SSYX group (SSYX group). All animals underwent low-energy real-time myocardial contrast echocardiography (RT-MCE) at weeks 2 and 4 after coronary artery occlusion to assess the myocardial perfusion. Then, 2-dimensional echocardiography (2DE) was applied eight weeks after operation for the cardiac function tests. Cardiac electrophysiological study was performed in vivo using the monophasic action potential technique. Results Compared with the MI group, both the AD group and the SSYX group displayed improved left ventricular function and gradually increased A×β values at two and four weeks post-procedure; however, the SSYX group presented a larger increase in these parameters. The two treated groups had similar electrophysiological characteristics, except that the AD group had a larger and longer MAPD90 in the normal zone, whereas the SSYX group displayed an inhibited prolongation of MAPD90 compared with the MI group. Conclusion Our studies indicate that SSYX has favorable advantages in improving left ventricular function and ameliorating the impaired myocardial microcirculation. SSYX has the same efficiency as the antiarrhythmic amiodarone after healing or healed MI, which might be closely associated with dredging collaterals and integration effects. Key words: Shen Song Yang Xin capsule; Amiodarone; Myocardial infarction; Microcirculation; Arrhythmia