Cardiac Arrest Outside of a Hospital: How Can We Improve Results of Resuscitation?

In the western world, one-fifth of all deaths occur suddenly and unexpectedly,1 ventricular fibrillation being a frequent mechanism. It happens approximately 300 000 times per year both in the United States and in Europe.2 This problem continues to haunt us, for we know that restoring normal heart rhythm by a defibrillation shock not only saves the life of the victim, but is often followed by many years of satisfactory living. Much effort has been put into recognizing the person at high risk of dying suddenly and is clearer in the case of a previous life-threatening arrhythmia or successful resuscitation from circulatory arrest. In such patients, death from a new arrhythmic episode can be prevented by implanting a defibrillator. Accurate risk stratification is much more difficult in the large group of patients with known heart disease but without a history of a life-threatening arrhythmia.3 Patients characterized by a previous myocardial infarction and poor left ventricular function, with or without non-sustained ventricular arrhythmias, can profit from a defibrillator implant, as shown by studies such as the Multicenter Automatic Defibrillator Implantation Trial-I (MADIT I), the Multicenter Unstable Tachycardia Trial (MUSTT), and MADIT II.4–6 However, only 10% of sudden cardiac arrest victims have such a high-risk profile.1,7 The challenge is therefore to improve the outcome of resuscitation in the 90% of patients that we cannot recognize as being at high risk before the event. Of course, risk in the known cardiac patient should be minimized by improving myocardial perfusion and pump function by medical and surgical interventions and other secondary prevention measures. In half of the victims, however, cardiac arrest is the first manifestation of heart disease. That 90% has much less cardiac damage than the 10% with a high risk profile, and they should have a much better …