Incidence, characteristics and outcomes of out-of-hospital cardiac arrest due to ventricular fibrillation in the general population: data from a single-center long-term registry

Funding Acknowledgements: Type of funding sources: None. Out-of-hospital cardiac arrest (OHCA) is a major public health problem and ventricular fibrillation (VF) is the most common initial rhythm when cardiac disease is the cause of arrest. It can be favorably treated with defibrillation but rapidly tends to deteriorate to non-shockable rhythms over time, so that reported survival rates vary from 3% to 10%. Early defibrillation strategy has led to a considerable survival improvement; however, automated external defibrillators are still used in <3% of episodes of OHCA. Here, we analyze data from a single-center emergency-medical-service (EMS) registry, involving all consecutive OHCA occurring from January 2013 to June 2022 in whom resuscitation or defibrillation has been attempted. The "Progetto Vita" initiative has been developed in our province since 1999 with the aim of improving deployment of automated external defibrillators into the public space so that the first line involved in the chain of survival (laic bystander or policemen/health care staff) and the use of automatic external defibrillators (AED) by policemen/citizens before the arrival of the EMS personnel are crucial indicators involved in the registry. Patients presenting with OHCA due to VF were considered eligible for this analysis. During the 10-year period of examination, 3,124 patients received medical care for OHCA; 323 of them presented VF and were considered for subsequent analysis. VF occurred prevalently at home (73%), in men (75%); mean age was 70. Bystander or laic citizen CPR was performed in 35 cases (11%) with a survival rate of 63%. AED used by either laic bystander or police was used in 30 cases (9%) with a success rate of 77%. Cardiac comorbidities were noted in 67 patients (21%), predominantly males, and CAD was the most common disease. Main historical, clinical, ECG, instrumental features and therapeutic management and differences in sex groups are listed in Table 1. As expected, incidence increased with age; male predominance was observed in all age subgroups although we observed a different distribution between sexes in age subgroups (Table 1). There were 237 deaths (mortality rate 73%), 41 (17%) of them occurring after arrival at Emergency Service.Among successfully admitted patients, VF was mostly related to coronary artery disease (70%) and STEMI was the most frequent manifestation of acute ischemic heart disease, both in males and females. Overall, 87 (27%) patients survived and were successfully admitted to intensive care unit (57%) or coronary care unit (43%). Multivariate logistic regression analysis showed that laic-performed CPR (OR 2.52, 95% CI 1.04, 6.1, p=0.04) and use of AED (OR 7.15; 95% CI 2.66, 19.19, p<0.001) were both independent predictors of survival. VF in the general population is still poorly predictable and mortality remains high: implementation of community involvement in early-defibrillation through publicly available AEDs appears effective in improving survival. [Figure: see text] [Figure: see text]