Résumé : Objectives : Significant progress has been made in the management of cardiorespiratory arrest and implementation of the survival chain. Early defibrillation using automatic external defibrillators (AED) is an essential element. There is however little information concerning the use of AED in pacemaker patients. The purpose of this work was to study the performance of AED in pacemaker patients experiencing cardiorespiratory arrest. Methods : This was a retrospective analysis using a database on Heartstart 2000 and 3000 (Laerdal) monophasic defibrillators. The sensitivity and specificity of AED in pacemaker patients was determined in comparison with a matched group of patients without a pacemaker. Results : The sensitivity of AED was lower in pacemaker patients than in their counterparts without pacemakers (56 % versus 79 %, p = 0.019). Conclusion : This study demonstrated defective management of pacemaker patients experiencing cardiorespiratory arrest by automatic external defibrillators (Heartstart 2000 and 3000). ©Masson, 2006.