14th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 2000

Jan. 29 - Feb. 5, 2000
Marilleva, Trento, Italy

S-65

Out-of-hospital early defibrillation to prevent sudden cardiac death: Piacenza Progetto Vita

Alessandro Capucci, Daniela Aschieri, Alessandro Rosi.
Divisione di Cardiologia, Ospedale Civile, Piacenza, Italy

Defibrillation

The vast majority of SCA are caused by VF (74%), which can often be reversed with electrical defibrillation. The incidence of ventricular tachycardia/VF is higher in bystander witnessed SCA than nonwitnessed due to the differences in time to the first electrocardiogram. Nonwitnessed cases are found late after cardiac arrest, by which time a higher proportion of cases had progressed into the final asystolia. The initial incidence of VT/VF calculated in the MONICA study was approximately 60% in the whole population and 80-85% in those with probable cardiac disease³. The electrical shock eliminates VT/VF and enables the heart to resume coordinated, rhythmic beating so that effective pumping of blood can resume. The likelihood of successful resuscitation decreases by approximately 10 percent with each minute following SCA. After 10 minutes, very few resuscitation attempts are successful (0-2%).

The poor survival outcomes in out-of-hospital cardiac arrest appears to be due to 1) low percentage of cardiac arrest patients whose arrest were bystander-witnessed and who were found to be in VF 2) the dispatch to arrival-at-the scene time interval (ambulance driving interval) as a proportion of the complete response interval. In fact most victims do not have immediate access to prompt, definite treatment and too much time elapses before the defibrillator arrives, if it arrive at all. In New York city for example, the average emergency system response time is relatively longer (about 12 minutes) due in part to traffic delay and the logistic of getting to victims in high-rise buildings. There, only 5% of witnessed victims (1-2% of all cardiac arrest victims) survive⁴. Some studies suggest that a two tier system involving a “first responder” with an automatic external defibrillator” (AED) – who can arrive within 4-5 minutes – may improve survival compared wit a single tier system that aims to deliver a fully trained paramedic in 8 minutes⁵. Seattle has achieved an average response time of seven minutes and a VF survival rate of 30%6. In Rochester, Minnesota, response time average six minutes and 45% survive⁷.