Real Time Amplitude Spectrum Area to Guide Defibrillation

AMSA trial is a multicenter, randomized, controlled study in out-of-hospital cardiac arrest patients.

The purpose of the study is to test the hypothesis that a real time AMSA analysis during CPR may predict the success of defibrillation and optimize the timing of defibrillation delivery.

The primary end-point is the efficacy of the AMSA-CPR: termination of VF/VT with achievement of ROSC for an AMSA ≥ 15.5 mV-Hz

All patients meeting inclusion/exclusion criteria and receiving cardiopulmonary resuscitation are randomized into two groups: AMSA-guided CPR or standard CPR.

In the AMSA-CPR group, AMSA value suggests when the rescuer should deliver the defibrillation attempt; In the Standard-CPR group, the defibrillation is delivered based on the 2015 European Resuscitation Council (ERC) CPR guidelines.

In the AMSA-CPR intervention, upon arrival of the advanced life support (ALS) rescue team at the cardiac arrest scene and application of the defibrillatory pads to the patient's chest and power on of the defibrillator with the real time AMSA analysis:

* If AMSA is ≥ 15.5 mV-Hz, an immediate defibrillation is attempted, followed by CPR
* If AMSA is \< 15.5 mV-Hz, defibrillation is not attempted and CPR is delivered
* During the 2-min cycle of CPR, AMSA is measured during pauses for ventilations (every 30 CC, approximately every 20/25 sec). If an AMSA value ≥ 15.5 mV-Hz is achieved prior to cycle completion, an immediate defibrillation is delivered (thus the defibrillation attempt is anticipated)

After completion of the first 2-min CPR cycle:

* If AMSA is ≤ 6.5 mV-Hz, the defibrillation is not attempted but CPR is continued
* If AMSA is \> 6.5 mV-Hz, an immediate defibrillation attempt is delivered, followed by CPR
* During the 2-min cycle of CPR, AMSA is measured during pauses for ventilations (every 30 CC, approximately every 20/25 sec). If an AMSA value ≥ 15.5 mV-Hz is achieved prior to cycle completion, an immediate defibrillation is delivered

After completion of the second 2-min CPR cycle and till the end of the resuscitative intervention:

• CPR is continued based on standard 2015 ERC guidelines (a defibrillation attempt every 2-min CPR cycles), except for the possibility to anticipate the defibrillation attempt if AMSA becomes ≥ 15.5 mV-Hz during the CPR cycle.

In the standard CPR intervention, upon arrival of the ALS team at the cardiac arrest scene, and application of the defibrillatory pads to the patient's chest and power on of the defibrillator:

• a defibrillation is immediately attempted and CPR is then started and continued for 2- min. Analysis of rhythm and subsequent defibrillation attempts are performed every 2-min CPR cycles.

In both study groups, the quality of CC and ventilation is monitored in real time thought the feedback integrated into the defibrillator.

Eligibility Criteria:
Inclusion Criteria:

All adult patients (age ≥ 18) suffering of out-of-hospital non traumatic cardiac arrest of presumably cardiac etiology with a presenting shockable rhythm requiring electrical defibrillation: Ventricular Fibrillation and pulseless Ventricular Tachycardia.

Exclusion Criteria:

* age \< 18 years old
* pregnancy
* cardiac arrest with a non-shockable rhythm (pulseless electrical activity and asystole)
* a defibrillation delivered by an AED prior to ALS arrival
* cardiac arrest of traumatic origin
* non-cardiac cause of cardiac arrest
* presumable irreversible death or known terminal illness at the beginning of ALS
* clinical death
* participation in another clinical or device trial within the previous 30 days
* refused informed consent to the use of data.