BACKGROUND: The association between the interval between collapse and defibrillation and outcome is well described in out of hospital cardiac arrest but not as well in in-hospital cardiac arrest. We report the outcome among patients who suffered an in-hospital cardiac arrest and were found in ventricular fibrillation (VF) with the emphasis on the delay to defibrillation. METHODS AND RESULTS: In patients who suffered an in-hospital cardiac arrest at Sahlgrenska University Hospital in Göteborg between 1994 and 2002 there were 1.570 calls for the rescue team of which 71% had suffered a cardiac arrest. Among cardiac arrests 47% took place on monitored wards. The proportion of patients found in VF was 59% on wards with monitoring facilities and 45% on wards without (p<0.0001). Approximately 90% of these patients were defibrillated <or=3 min after collapse on monitored wards compared with 54% on non-monitored wards (p<0.0001). Among all patients, there was a strong relationship between the interval between collapse to the first defibrillation and survival to discharge from hospital (p<0.0001): 66% were discharged alive if defibrillated <or=3 min compared with 20% if defibrillated >12 min. On monitored wards, the survival was 63% if defibrillated <or=3 min compared with 60% if defibrillated >3 min after collapse (NS). The corresponding values for non-monitored wards were 72% and 35%, respectively (p=0.0003). Cerebral function among survivors at discharge appeared to be good among the majority of patients both in monitored and non monitored wards. CONCLUSION: If patients with in hospital VF were defibrillated early in both monitored and non monitored wards survival to hospital discharge was high. This highlights the importance of being prepared for the rapid defibrillation on wards without monitoring facilities.