Overall survival rates from Ventricular Fibrillation (VF) are currently very poor. A more efficient biphasic defibrillator with novel low-tilt technology could improve the chances of terminating VF early thus increasing the chances of survival. The primary aim of this study is to determine whether the use of a defibrillator with a low-tilt biphasic waveform will improve the success of defibrillation of ventricular fibrillation.
This project has been reviewed and approved by the Office for Research Ethics Committees in Northern Ireland (ORECNI) on the 8th November 2006 (ref: 06/NIR02/108).
Randomised, controlled, safety and feasability study
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Ventricular fibrillation/cardiac arrest
This will be a safety and feasibility study which aims to show equivalence in the removal of ventricular fibrillation during cardiac arrests between a novel low-tilt defibrillating device and the standard-tilted defibrillator currently in use in the trust (Philips Agilent Heartstart XL).
Standard-tilted biphasic defibrillators are currently available on all hospital wards, to the cardiac arrest team and the physician-led cardiac ambulance. Randomisation will occur on a daily basis between the novel low-tilt device and the standard-tilted defibrillator. The randomised device will be made available to the cardiac arrest team, in the coronary care unit and also to the physician-led cardiac ambulance.
It will not be possible to blind those staff delivering the defibrillating shocks to the device in use due to their appearances.
Patients found to be in VF will receive treatment according to the resuscitation guidelines issued by the Resuscitation Council (UK) 2005. The standard-tilted device will deliver shocks at 150 J and the low-tilt device 120 J. Following any three unsuccessful shocks, a rescue shock of 200 J will be used from the standard-tilted defibrillator.
All shocks will be delivered via standard self-adhesive pads which have previously been validated for clinical use. Defibrillating shocks will be delivered by a doctor, nurse or resuscitation officer who is fully trained in advanced life support.
The following non-invasive parameters will also be recorded and analysed:
1. Time from collapse to arrival of emergency services
2. Time to first shock
3. Whether Cardio-Pulmonary Resuscitation (CPR) is performed pre-shock
4. Any delays in shock delivery
5. Duration of arrest
6. Drugs administered
7. Patient demographics
7. Aetiology of VF (where possible)
There will be no follow up of any patients. Patients will only be included in the study at the time of required defibrillation.
Primary outcome measure
The primary endpoint of the study will be termination of ventricular arrhythmia for greater than or equal to five seconds following shock delivery. This will be determined by analysis of the defibrillator Electrocardiogram (ECG) tracing post-cardiac arrest.
Secondary outcome measures
No secondary outcome measures
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
All adult patients in cardiac arrest with ventricular fibrillation as the identified rhythm.
Target number of participants
Participant exclusion criteria
Patients with existing 'Do not resuscitate' orders.
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Regional Medical Cardiology Centre
Royal Hospitals Trust (UK)
Royal Research Office
The Heart Trust Fund (UK)
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Basic results (scientific)
1. Darragh KM, Doyle C, Walsh SJ, Allen JD, Adgey AAJ, Anderson J, Manoharan G. A novel low tilt biphasic waveform is more efficacious than a standard waveform in the defibrillation of VF. (Abstract) Journal of Electrocardiology, 2007. In Press
2. 2012 results in http://www.ncbi.nlm.nih.gov/pubmed/22579679
Darragh KM, Manoharan G, Di Maio R, Stevenson M, Bennett JR, Walsh SJ, Allen JD, Anderson JM, Adgey AA, A low tilt waveform in the transthoracic defibrillation of ventricular arrhythmias during cardiac arrest., Resuscitation, 2012, 83, 12, 1438-1443, doi: 10.1016/j.resuscitation.2012.04.018.