New research presented at the ESC Acute CardioVascular Care Congress 2025 emphasises the significance of prompt cardiopulmonary resuscitation (CPR) in improving survival rates following out-of-hospital cardiac arrest (OHCA). Led by Prof. Aneta Aleksova of the University of Trieste, the study discovered that, while more bystanders are performing CPR, the most important factor determining survival is how quickly CPR is performed, not who performs it.

The study looked at 3315 patients with ST-elevated myocardial infarction (STEMI), a severe kind of heart attack characterised by total arterial blockage. Among these, 172 individuals experienced OHCA, and 44 received CPR from a bystander. The study found that bystander CPR rates increased significantly in the Friuli Venezia Giulia Region of Italy, from 26% in 2003-2007 to 69% in 2020-2024.

However, the study's main finding was that prompt restoration of spontaneous circulation (ROSC) was critical for in-hospital survival, regardless of whether CPR was performed by a bystander or emergency medical personnel.

Basic Life Support (BLS) training has become increasingly popular over the last two decades. The authors emphasise that home settings account for 80% of OHCA occurrences, making public education and CPR training even more important.

The authors found, "Over time, the fraction of layperson rescuers has consistently increased. The rapid recovery of spontaneous circulation was critical for in-hospital survival, regardless of rescuer type.

Long-term survival rates were also comparable when patients received initial layman or emergency medical service CPR. Our findings emphasise the necessity of rapid resuscitation and the need to raise public awareness and provide BLS training to further enhance survival after out-of-hospital cardiac arrest."

A closer look indicated that the median time to return of spontaneous circulation (ROSC) was 10 minutes overall, but there were substantial differences depending on who administered CPR. When spectators performed CPR, ROSC took an average of 20 minutes, but medical operators achieved it in 5 minutes. This delay had a direct influence on survival rates, with statistical analysis indicating that every 5-minute delay in ROSC increased the probability of death by 38%.

Furthermore, a 5-percentage-point decline in left ventricular ejection fraction (LVEF) increased the chance of death, while every 5-year rise in patient age resulted in a 46% higher likelihood of death. These findings underline the vital necessity for rapid intervention, emphasising that life is determined not only by receiving CPR but also by how rapidly it is provided.

Despite these limitations, there was no significant difference in long-term survival rates between patients who received CPR from bystanders and emergency medical teams. The researchers believe that speedier emergency response times and a well-trained public may have contributed to the higher survival rates.

The survival rates for out-of-hospital cardiac arrest (OHCA) patients in this study were higher than average, but the data highlight the importance of ongoing efforts to improve public CPR training and awareness.

Immediate CPR remains the most important element in determining survival, whether performed by a civilian or a medical expert. With home settings accounting for 80% of all OHCA occurrences, extending public Basic Life Support (BLS) training programs is critical to ensuring that more individuals are prepared to respond in an emergency. Additionally, faster emergency response times, along with increased CPR understanding, can considerably reduce OHCA-related deaths, emphasising the importance of both community education and improved emergency medical services.

As public awareness and CPR training improve, researchers and healthcare professionals seek to save more lives by implementing faster and more effective emergency response measures.