Central β-Adrenergic Mechanisms May Modulate Ischemic Ventricular Fibrillation in Pigs

A central noradrenergic process may permit expression of the stress-related increase in cardiac vulnerability to ventricular fibrillation (VF). Thus, the effect of central β-adrenergic receptor blockade with l-propranolol (0.01 and 0.05 mg/kg) on ischemia-induced VF vulnerability was evaluated in the psychologically stressed pig model and compared with Ringerʼs solution and D-propranolol (0.05 mg/kg). The ischemia of a maximum 15-minute left anterior descending coronary artery occlusion was used since we previously determined that pigs surviving 15 minutes usually do not fibrillate. Time to the onset of VF was analyzed by time-to-event analysis and ranged from 0.75 to 13.8 minutes in vulnerable pigs. Intracerebroventricular administration of L-propranolol (0.05 mg/kg) prolonged the time to VF compared with Ringerʼs solution and d-propranolol (p