When it comes to cardiac arrest, every second counts, and it is the speed with which cardiopulmonary resuscitation is started that makes the real difference, not so much who performs it. This is what emerges from an important study presented at the ESC Acute CardioVascular Care 2025 congress.

The research is the result of the work of a team coordinated by Prof. Aneta Aleksova, cardiologist and lecturer at the Department of Medical Sciences of the University of Trieste and the local health authority (ASUGI). The study group is an integral part of the Department of Cardiology, headed by Prof. Gianfranco Sinagra, and included the contribution of Dr Alessandra Lucia Fluca, research assistant at the Department of Medicine of the University of Trieste, and Dr Andrea Perkan, interventional cardiologist at the Department of Cardiology.

The study analysed 21 years of data (from 2003 to 2024) on 3,315 patients who had suffered a ST-elevation myocardial infarction (STEMI), a particularly serious form of heart attack in which a major coronary artery is completely blocked, preventing blood flow to part of the heart. Among these patients, 172 suffered out-of-hospital cardiac arrest (OHCA) and 44 of them received cardiopulmonary resuscitation (CPR) from bystanders.

Urgent response is crucial 

The results are clear: every 5 minutes of delay in the return of spontaneous circulation (ROSC) increases the risk of death in hospital by 38%. Even a slight reduction in left ventricular ejection fraction (an indicator of heart function) or increased age is associated with a significant increase in mortality.

'We observed that, regardless of whether cardiopulmonary resuscitation was performed by a professional rescuer or a bystander, the determining factor was the speed with which resuscitation was started,' explains Prof. Aleksova, emphasising the value of active prevention. ‘It is essential to raise awareness among the population and promote CPR and defibrillator training courses. Even imperfect intervention, if timely, can save a life. It is better to act immediately than to wait for help without doing anything.’

A positive trend, but still insufficient

The study shows a clear improvement over time: the percentage of CPR performed by bystanders rose from 26% in the period 2003-2007 to 69% in the four-year period 2020-2024. However, considering that about 80% of cardiac arrests occur at home, public involvement remains crucial.

Although the average ROSC times are longer for interventions by bystanders (20 minutes compared to 5 minutes in cases handled by healthcare professionals), the chances of long-term survival do not differ. This suggests that even intervention by ordinary people, provided it is timely, can have a life-saving impact comparable to that of professionals.

A call for public training

The survey also reports that those who receive CPR from bystanders are more frequently subjected to endotracheal intubation (91% versus 65%), indicating more intensive clinical management. But the key factor remains time. All other factors being equal, prompt intervention can mean the difference between life and death.

The study relaunches a simple but urgent message: training more people in basic life support (BLS) techniques is a public health priority. Because every minute counts. And anyone, with the right training, can make a difference.