Cardiac ArrestDOUBLE-DNCT06447805
Early Double Sequential Defibrillation in Out-of-hospital Cardiac Arrest
A study testing Double Sequential Defibrillation (DSD) and Standard defibrillation in people with Cardiac Arrest and Fibrillation, Ventricular, run by Karolinska Institutet at 3 sites in Sweden.
Trial summary
Some of the patients affected by Out-of-hospital cardiac arrest (OHCA) with ventricular fibrillation (VF)/ventricular tachycardia (VT) do not respond to initial defibrillation. The survival decreases with number of defibrillations required to terminate VF/VT. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Cardiac Arrest, Fibrillation, Ventricular, Sudden Cardiac Death
- What is being tested?
- Double Sequential Defibrillation (DSD) and Standard defibrillation
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- 3 sitesSweden
- Study dates
- 1 Aug 2024to 23 Sep 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Out-of-Hospital patients with Ventricular Fibrillation/ Ventricular Tachycardia at rhythm analysis after ambulance arrival and at least one defibrillation performed in standard (Antero-Lateral) position
Who cannot join
- Age below 18 years
- Obvious pregnancy
- Known preexisting Do Not Attempt Resuscitation order
Trial locations and contacts
3 sites in 1 country.
Sweden3 sites
Sjukhusen i väster, ambulanssjukvården Alingsås/Lerum
Alingsås, Västra Götalandsregionen, 441 39
Sahlgrenska Universitetssjukhuset, Ambulans och Prehospital Akutsjukvård
Gothenburg, Västra Götalandsregionen, 411 04
Emergency medical services Region Halland
Halmstad, Halland County, 30238
About this study
Official title: "A Pilot Study Assessing Feasibility of a Randomized Trial Comparing the Effect of Early Double Sequential Defibrillation as Soon as Possible in OHCA With a Shockable Rhythm (VT/VF) Compared to Standard Defibrillation"
Some of the patients affected by Out-of-hospital cardiac arrest (OHCA) with ventricular fibrillation (VF)/ventricular tachycardia (VT) do not respond to initial defibrillation. The survival decreases with number of defibrillations required to terminate VF/VT. In 2022, one prospective cluster randomized trial showed increased survival among (OHCA) patients in refractory VF using Double Sequential Defibrillation (DSD).
To evaluate feasibility and safety this randomized pilot trial will compare the effect of double defibrillation strategy initiated as soon as possible after the first defibrillation with continued resuscitation using standard defibrillation, in patients with Out of Hospital Cardiac arrest (OHCA). The results from this pilot trial will form the basis for design of a larger multicenter survival study.
Read the detailed description
The Dubbel-D study is an academic, investigator initiated, open-label pilot study with a randomized controlled trial (RCT) design conducted in the prehospital emergency medical services, i.e. ambulance organizations. The trial will be conducted by participating ambulance units attending OHCA´s. These units will perform screening for inclusion, randomization, intervention or control treatment and initial follow-up.
In all cases of OHCA a defibrillator should always be attached with the standard pad placement, anterio-lateral (A-L) position first. This is in accordance with standard of care. If there is VT/VF or an automated external defibrillator (AED) suggests defibrillation, defibrillation should be performed, and immediate chest compressions resumed. Thereafter, the patient can be screened for inclusion. If two study specific defibrillators (Corpulse 3) on site and no exclusion criteria (age below 18 years, obvious pregnancy, known preexisting Do Not Attempt Resuscitation order) the patient can be included and randomized.
Randomization will be performed by drawing a scratch-card with concealed allocation that will be stored with the EMS defibrillators. All scratch-cards will be pre-randomized in a 3:1 ratio in blocks consisting of 4-8-12 and stratified by region and ambulance provider.
If the patient is randomized to the intervention group, the ambulance crew team will apply the second defibrillator with electrodes placed in the anterio-posterior (A-P) position as soon as possible. Defibrillation is performed by one person defibrillating both defibrillators in a sequential manner "Double Sequential Defibrillation" (DSD). All consecutive defibrillations will thereafter be performed with the DSD strategy until ROSC, termination of resuscitation or decision to move the patient to hospital.
If randomized to the control group, the ambulance crew team will continue Advanced Life Support (ACLS) in accordance with standard of care. Defibrillation is performed with standard electrode placement (A-L position) using a single defibrillator. If an AED is the first defibrillator attached to the patient, the ambulance crew should shift from an AED to their own manual defibrillator, but the mode of defibrillation should remain in A-L position and only one defibrillator should be used for each defibrillation and continue until ROSC, termination of resuscitation or decision to move the patient to hospital.
- Being tested
- Double Sequential Defibrillation (DSD), Standard defibrillation
- Keywords
- Cardiopulmonary resuscitation, Defibrillation, Double sequential defibrillation
- Medical subject headings
- Heart Arrest, Ventricular Fibrillation, Death, Sudden, Cardiac
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Double Sequential Defibrillation (DSD)Device
The second defibrillator will be applyed with electrodes placed in the A-P position
Standard defibrillationDevice
Standard defibrillation uning one defibrillator
| Study group | Role | What they receive |
|---|---|---|
| Double Sequential Defibrillation (DSD) | Experimental | If the patient is randomized to the DSD group, the ambulance crew team will apply the second defibrillator with electrodes placed in the A-P position as soon as possible.
Defibrillation is performed by one person defibrillating both defibrillators in a sequential manner "Double Sequential Defibrillation" (DSD). All consecutive defibrillations will thereafter be performed with the DSD strategy until ROSC, termination of resuscitation or decision to move the patient to hospital. Receives: Device: Double Sequential Defibrillation (DSD) |
| Standard defibrillation | Active comparator | If the patient is randomized to the standard defibrillation group, the ambulance crew team will continue Advanced life support in accordance with standard of care and continue to perform standard defibibrillation using one defibrillator. All consecutive defibrillations will thereafter be performed with the standard defibrillation strategy until ROSC, termination of resuscitation or decision to move the patient to hospital. Receives: Device: Standard defibrillation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Feasibility of early double sequential external defibrillation (DSD)
Number of EMS defibrillations prior to randomization (target > 80% before third defibrillation)
Measured: day 1
Adherence to double sequential external defibrillation (DSD)
Among patients randomized to DSD, proportion that received DSD (target > 80%)
Measured: day 1
Cross-over
Among patients randomized to standard, proportion that received DSD (target < 10%)
Measured: day 1
Feasibility of double sequential external defibrillation (DSD)
Proportion of eligible patients included and randomized (target > 80%)
Measured: day 1
Safety of double sequential external defibrillation
Major adverse events (e.g. defibrillator malfunction)
Measured: day 1
Safety of CPR during double sequential external defibrillation
Chest compression fraction (hands off time during CPR, target > 80% in both groups)
Measured: day 1
Secondary outcomes (7)
Return of spontaneous circulation (ROSC)
Proportion of patients with sustained return of spontaneous circulation (ROSC) at hospital arrival
Measured: day 1
Number of defibrillations to sustained ROSC
Total number of defibrillations to sustained ROSC
Measured: day 1
Survival to hospital admission
Pateint is admitted to hospital alive
Measured: day 1
Survival to discharge
Survival to hospital discharge
Measured: day 1-180
30 day survival
Survival at 30 days
Measured: day 30
Neurological function at 30 days
Neurological function (modified Rankin Scale, mRS 1-6, and Cerebral Performance Category, CPC 1-5) at 30 days
Measured: day 30
Neurological function and Health related Quality of life at 90 and 180 days
Neurological function (modifiied Rankin Scale and Cerebral Performance Category) and Health-related Quality of life at 90 and 180 days (CPC 1-5, mRS 1-6)
Measured: day 90 and 180
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 Jun 2024
- Study start1 Aug 2024
- Primary completion31 May 2025
- Study completion23 Sep 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Cardiac ArrestStudies of the same condition, open and under way.
- More trials run by Karolinska InstitutetThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Academic, investigator initiated, open-label pilot study with a randomized controlled trial (RCT) design and 3:1 allocation (3 intervention: 1 standard).
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 40 participants (actual)
Sponsor and investigators
- Lead sponsor
- Karolinska Institutet
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Gabriel Riva, Karolinska Institutet
- Investigators
- Gabriel Riva, MD, PhD, Principal investigator, Karolinska InstitutetAkil Awad, MD, PhD, Principal investigator, Karolinska InstitutetAndreas Claesson, RN, PhD, Study chair, Karolinska InstitutetCarl Magnusson, RN, PhD, Study chair, Sahlgrenska UniversityLeif Svensson, MD, PhD, Study chair, Karolinska InstitutetJohan Israelsson, RN, PhD, Study chair, Linné UniversityEmma Blick-Nordqvist, MD, Study chair, Karolinska InstitutetMartin Jonsson, Msc, PhD, Study chair, Karolinska Institutet
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06447805
- Sponsor's protocol ID
- CIV-ID-24-01-045759
- Acronym
- DOUBLE-D
- Status last verified
- Sep 2025
- First submitted
- 29 May 2024
- Last updated
- 1 Oct 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Cheskes S, Verbeek PR, Drennan IR, McLeod SL, Turner L, Pinto R, Feldman M, Davis M, Vaillancourt C, Morrison LJ, Dorian P, Scales DC. Defibrillation Strategies for Refractory Ventricular Fibrillation. N Engl J Med. 2022 Nov 24;387(21):1947-1956. doi: 10.1056/NEJMoa2207304. Epub 2022 Nov 6.
PubMed 36342151Riva G, Nordkvist EB, Magnusson C, Claesson A, Jonsson M, Israelsson J, Nordius C, Barret K, Sidebottom DB, Martner P, Cavefors O, Tenning A, Wibring K, Waldemar A, Edholm G, Awad A. Feasibility of early double sequential defibrillation in out-of-hospital cardiac arrest: the double-D randomised pilot trial. Heart. 2026 Jun 30:heartjnl-2026-327905. doi: 10.1136/heartjnl-2026-327905. Online ahead of print.
PubMed 42379878
Study at a glance
From the registry record, last updated by the sponsor on 1 Oct 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- "A Pilot Study Assessing Feasibility of a Randomized Trial Comparing the Effect of Early Double Sequential Defibrillation as Soon as Possible in OHCA With a Shockable Rhythm (VT/VF) Compared to Standard Defibrillation"
- ClinicalTrials.gov ID
- NCT06447805
- Acronym / sponsor ID
- DOUBLE-D / CIV-ID-24-01-045759
- Keywords
- Cardiopulmonary resuscitation, Defibrillation, Double sequential defibrillation
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 40 participants (actual)
- Lead sponsor
- Karolinska InstitutetUniversity, hospital or other
- Study start
- 1 Aug 2024 (actual)
- Primary completion
- 31 May 2025 (actual)
- Study completion
- 23 Sep 2025 (actual)
- First posted
- 7 Jun 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Some of the patients affected by Out-of-hospital cardiac arrest (OHCA) with ventricular fibrillation (VF)/ventricular tachycardia (VT) do not respond to initial defibrillation. The survival decreases with number of defibrillations required to terminate VF/VT. In 2022, one prospective cluster randomized trial showed increased survival among (OHCA) patients in refractory VF using Double Sequential Defibrillation (DSD).
To evaluate feasibility and safety this randomized pilot trial will compare the effect of double defibrillation strategy initiated as soon as possible after the first defibrillation with continued resuscitation using standard defibrillation, in patients with Out of Hospital Cardiac arrest (OHCA). The results from this pilot trial will form the basis for design of a larger multicenter survival study.
Detailed description
The Dubbel-D study is an academic, investigator initiated, open-label pilot study with a randomized controlled trial (RCT) design conducted in the prehospital emergency medical services, i.e. ambulance organizations. The trial will be conducted by participating ambulance units attending OHCA´s. These units will perform screening for inclusion, randomization, intervention or control treatment and initial follow-up.
In all cases of OHCA a defibrillator should always be attached with the standard pad placement, anterio-lateral (A-L) position first. This is in accordance with standard of care. If there is VT/VF or an automated external defibrillator (AED) suggests defibrillation, defibrillation should be performed, and immediate chest compressions resumed. Thereafter, the patient can be screened for inclusion. If two study specific defibrillators (Corpulse 3) on site and no exclusion criteria (age below 18 years, obvious pregnancy, known preexisting Do Not Attempt Resuscitation order) the patient can be included and randomized.
Randomization will be performed by drawing a scratch-card with concealed allocation that will be stored with the EMS defibrillators. All scratch-cards will be pre-randomized in a 3:1 ratio in blocks consisting of 4-8-12 and stratified by region and ambulance provider.
If the patient is randomized to the intervention group, the ambulance crew team will apply the second defibrillator with electrodes placed in the anterio-posterior (A-P) position as soon as possible. Defibrillation is performed by one person defibrillating both defibrillators in a sequential manner "Double Sequential Defibrillation" (DSD). All consecutive defibrillations will thereafter be performed with the DSD strategy until ROSC, termination of resuscitation or decision to move the patient to hospital.
If randomized to the control group, the ambulance crew team will continue Advanced Life Support (ACLS) in accordance with standard of care. Defibrillation is performed with standard electrode placement (A-L position) using a single defibrillator. If an AED is the first defibrillator attached to the patient, the ambulance crew should shift from an AED to their own manual defibrillator, but the mode of defibrillation should remain in A-L position and only one defibrillator should be used for each defibrillation and continue until ROSC, termination of resuscitation or decision to move the patient to hospital.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
- Model description
- Academic, investigator initiated, open-label pilot study with a randomized controlled trial (RCT) design and 3:1 allocation (3 intervention: 1 standard).
| Arm | Type | Receives |
|---|---|---|
| Double Sequential Defibrillation (DSD) | Experimental | Device: Double Sequential Defibrillation (DSD)If the patient is randomized to the DSD group, the ambulance crew team will apply the second defibrillator with electrodes placed in the A-P position as soon as possible. Defibrillation is performed by one person defibrillating both defibrillators in a sequential manner "Double Sequential Defibrillation" (DSD). All consecutive defibrillations will thereafter be performed with the DSD strategy until ROSC, termination of resuscitation or decision to move the patient to hospital. |
| Standard defibrillation | Active comparator | Device: Standard defibrillationIf the patient is randomized to the standard defibrillation group, the ambulance crew team will continue Advanced life support in accordance with standard of care and continue to perform standard defibibrillation using one defibrillator. All consecutive defibrillations will thereafter be performed with the standard defibrillation strategy until ROSC, termination of resuscitation or decision to move the patient to hospital. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Out-of-Hospital patients with Ventricular Fibrillation/ Ventricular Tachycardia at rhythm analysis after ambulance arrival and at least one defibrillation performed in standard (Antero-Lateral) position
Key exclusion criteria (3 listed)
- Age below 18 years
- Obvious pregnancy
- Known preexisting Do Not Attempt Resuscitation order
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Double Sequential Defibrillation (DSD)The second defibrillator will be applyed with electrodes placed in the A-P position | Device | Double Sequential Defibrillation (DSD) |
| Standard defibrillationStandard defibrillation uning one defibrillator | Device | Standard defibrillation |
Primary outcome
Feasibility of early double sequential external defibrillation (DSD)
Time frame: day 1
Number of EMS defibrillations prior to randomization (target > 80% before third defibrillation)
Adherence to double sequential external defibrillation (DSD)
Time frame: day 1
Among patients randomized to DSD, proportion that received DSD (target > 80%)
Cross-over
Time frame: day 1
Among patients randomized to standard, proportion that received DSD (target < 10%)
Feasibility of double sequential external defibrillation (DSD)
Time frame: day 1
Proportion of eligible patients included and randomized (target > 80%)
Safety of double sequential external defibrillation
Time frame: day 1
Major adverse events (e.g. defibrillator malfunction)
Safety of CPR during double sequential external defibrillation
Time frame: day 1
Chest compression fraction (hands off time during CPR, target > 80% in both groups)
7 secondary outcomes
Return of spontaneous circulation (ROSC)
Time frame: day 1
Number of defibrillations to sustained ROSC
Time frame: day 1
Survival to hospital admission
Time frame: day 1
Survival to discharge
Time frame: day 1-180
30 day survival
Time frame: day 30
Neurological function at 30 days
Time frame: day 30
Neurological function and Health related Quality of life at 90 and 180 days
Time frame: day 90 and 180
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 Oct 2025.
- Results publication: PubMed 36342151Cheskes S, Verbeek PR, Drennan IR, McLeod SL, Turner L, Pinto R, Feldman M, Davis M, Vaillancourt C, Morrison LJ, Dorian P, Scales DC. Defibrillation Strategies for Refractory Ventricular Fibrillation. N Engl J Med. 2022 Nov 24;387(21):1947-1956. doi: 10.1056/NEJMoa2207304. Epub 2022 Nov 6.
- Derived from this study: PubMed 42379878Riva G, Nordkvist EB, Magnusson C, Claesson A, Jonsson M, Israelsson J, Nordius C, Barret K, Sidebottom DB, Martner P, Cavefors O, Tenning A, Wibring K, Waldemar A, Edholm G, Awad A. Feasibility of early double sequential defibrillation in out-of-hospital cardiac arrest: the double-D randomised pilot trial. Heart. 2026 Jun 30:heartjnl-2026-327905. doi: 10.1136/heartjnl-2026-327905. Online ahead of print.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Gabriel Riva, MD, PhD principal investigator
Karolinska Institutet
Akil Awad, MD, PhD principal investigator
Karolinska Institutet
Andreas Claesson, RN, PhD study chair
Karolinska Institutet
3 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Double Sequential Defibrillation (DSD) and Standard defibrillation in people with Cardiac Arrest and Fibrillation, Ventricular, run by Karolinska Institutet at 3 sites in Sweden.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 1 Oct 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 3 sites in Sweden. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Feasibility of early double sequential external defibrillation (DSD) (time frame: day 1). The study lists 6 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06447805, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 1 Oct 2025.