ABSTRACT
BACKGROUND: Post-resuscitation myocardial dysfunction has been implicated as a major cause of fatal outcome in patients who survive initially successful cardiopulmonary resuscitation (CPR). In our previous study, we found that impaired myocardial ß-adrenergic receptor (AR) signaling is a key mechanism in post-resuscitation myocardial dysfunction and Shen-Fu injection (SFI) can attenuate post-resuscitation myocardial dysfunction. However, whether SFI can prevent impaired post-resuscitation myocardial ß-AR signaling is not yet known. In this study, we investigated the effect of SFI on impaired myocardial ß-AR signaling occurring post-resuscitation in a porcine model of cardiac arrest. METHODS: Ventricular fibrillation was induced electrically in anesthetized male landrace domestic pigs. After 4 minutes of untreated ventricular fibrillation, cardiopulmonary resuscitation was initiated. Sixteen successfully resuscitated pigs were randomized to receive a continuous infusion of either SFI (0.5 ml/min; n = 8) or saline (placebo; n = 8) for 6 hours, beginning 15 minutes after the return of spontaneous circulation (ROSC). Hemodynamic and echocardiographic data were recorded. ß-AR signaling was assessed at 6 hours after the intervention by measuring myocardial adenylate cyclase activity, ß-AR density and ß-AR kinase expression. RESULTS: Treatment with SFI produced better maximum rate of left ventricular pressure increase (dp/dt(max)) and maximum rate of left ventricular pressure decline (-dp/dt(max)), cardiac output, and ejection fraction after ROSC. SFI treatment was also associated with lower myocardial ß-adrenergic receptor kinase expression, whereas basal and isoproterenol-stimulated adenylate cyclase activity and the total ß-AR density were significantly increased in the SFI group when compared with the placebo group. CONCLUSION: SFI attenuated post-resuscitation myocardial dysfunction by preventing impaired myocardial ß-AR signaling after CPR.
