['To study whether and how a lipophilic and a hydrophilic beta-adrenoceptor antagonist affects ventricular fibrillation (VF) after coronary artery occlusion in a rabbit model with high sympathetic and low cardiac vagal activation.', 'Rabbits were treated for 3 weeks (series 1) or 2 hours (series 2) with metoprolol, atenolol or control vehicle. Finally the animals in series 1 were exposed to coronary artery occlusion. Heart rate response to cholinergic blockade was studied in series 2.', 'The incidence of postocclusion VF in metoprolol animals was lower (p<0.05) than that in atenolol or control animals. The two beta-blockers caused similar reductions of heart rate, arterial pressure and myocardial ischemia. However, metoprolol animals had more respiratory sinus arrhythmia higher baroreflex sensitivity and more pronounced tachycardic response to cholinergic blockade than atenolol animals.'] Does prevention of ventricular fibrillation require central beta-adrenoceptor blockade in rabbits?