The rhythm of the arrest: Epidemiological and electrocardiographic analyses in out-of-hospital cardiac arrest

In out-of-hospital cardiac arrest (OHCA), the main predictor of survival is ventricular fibrillation (VF). When a shock with an automatic external defibrillator (AED) or manual defibrillator is given, survival from OHCA can be more than 60%. In the absence of VF survival is poor, less than 5%. Worldwide, it has been observed that the incidence of VF is declining. In the research described in this thesis, we investigated the possible causes of the decrease in incidence of patients with VF. Without bystander CPR, ventricular fibrillation slowly transitions into asystole. A faster transition from ventricular fibrillation to asystole caused by medication use such as beta blockers might explain part of the decline. However, we did not find any indication in our study that ventricular fibrillation deteriorates faster into asystole, nor that medication use affects the VF signal in a clinical significant way. However, we did observe that the VF signal is affected by a myocardial infarction, this might be used as a marker early in the treatment of OHCA. We also observed that OHCA patients nowadays are older, are more often at home at time of the OHCA and have more underlying diseases compared to patients in public places. Outcome in these patients at home is poor, but this is due to unfavorable OHCA characteristics; in patients at home, OHCA is often unwitnessed, without bystander CPR and with little AED use. AED programs targeting residential areas are essential to improve the survival of patients at home