Anteroposterior Versus Anterolateral Electrode Position for Electrical Cardioversion of Atrial Fibrillation
SHOCK-VECTOR
A Randomized Controlled Trial of Anterior-posterior Versus Anterior-lateral Shock Vectors for Electrical Cardioversion of Atrial Fibrillation
1 other identifier
interventional
1,500
1 country
2
Brief Summary
Atrial fibrillation is the most common heart rhythm disorder (arrhythmia) worldwide. Nearly 40 million people are affected by atrial fibrillation worldwide, and this number is expected to increase by over 50% by 2050. Atrial fibrillation can cause strokes, heart attacks, heart failure, poor quality of life and even death. Almost half a million deaths worldwide are expected to be related to atrial fibrillation by 2050, and many billions of dollars are spent on atrial fibrillation related healthcare in North America every year. We believe health outcomes for patients with atrial fibrillation, and healthcare costs associated with treating atrial fibrillation could be improved by optimizing existing treatments for atrial fibrillation and maximizing the likelihood of restoring normal heart rhythm. This allows them to benefit from lower stroke risk, better heart function, fewer symptoms and increased quality of life. Restoring normal sinus rhythm earlier prevents atrial fibrillation from causing permanent structural damage to the heart that in turn, makes atrial fibrillation intractable. Furthermore, patients in whom initial attempts to control atrial fibrillation are unsuccessful frequently require more medications or invasive catheter ablation procedures which are costly and carry substantial risk. Electrical cardioversion is the main way physicians restore normal heart rhythm. In this procedure, the heart is "shocked" back into normal rhythm using two electrodes on the chest. Done correctly, this procedure is safe and effective. Many things are known about electrical cardioversion, for example, the best type and amount of electricity to use. What we don't know is the best position of the electrodes on the chest and whether applying direct, physical pressure to the electrodes makes cardioversion more successful. Our prior research suggests that improving positioning and applying pressure may improve cardioversion, but this finding needs to be verified with a rigorous, dedicated trial. This study will demonstrate whether front-to-back, or front-to-side placement of the electrodes is more effective for electrical cardioversion of atrial fibrillation. We will also demonstrate whether manually applying pressure to the electrodes makes cardioversion more effective. Should our trial demonstrate a benefit for these techniques, we expect them to be universally applied around the world. Because hundreds of thousands of cardioversions are done each year, even small increases in cardioversion success means thousands fewer patients progress to needing more medications or invasive procedures to manage their atrial fibrillation. We will study consenting adults presenting for non-urgent cardioversion of their atrial fibrillation. After explaining the study to participants and gaining their consent, we will randomly assign them to front-to-side or front-to-back electrode placement. Patients who remain in atrial fibrillation after the first shock will randomly receive either manual pressure or not. We will compare the success of cardioversion for front-side versus front-back electrode placement, and for manual pressure versus none. We will evaluate success by using electrocardiograms to assess for restoration of the heart rhythm back to normal. We hypothesize that anterolateral electrode positioning is superior to anteroposterior electrode positioning. We also hypothesize that manual pressure is effective relative to none, when applied in patients who have had one unsuccessful shock already.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P75+ for not_applicable atrial-fibrillation
Started Feb 2023
Typical duration for not_applicable atrial-fibrillation
2 active sites
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
August 19, 2022
CompletedFirst Posted
Study publicly available on registry
August 23, 2022
CompletedStudy Start
First participant enrolled
February 22, 2023
CompletedPrimary Completion
Last participant's last visit for primary outcome
June 1, 2027
ExpectedStudy Completion
Last participant's last visit for all outcomes
July 1, 2027
May 14, 2025
May 1, 2025
4.3 years
August 19, 2022
May 8, 2025
Conditions
Outcome Measures
Primary Outcomes (1)
First-shock cardioversion success
Reversion to sinus rhythm (5 consecutive P waves within 5 seconds of shock)
At time of intervention
Secondary Outcomes (2)
Cumulative cardioversion success for anterolateral versus anteroposterior placement afte
At time of intervention
Second shock success for manual pressure versus none
At time of intervention
Other Outcomes (4)
Descriptive analysis of techniques and results for third, unrandomized, clinician directed shock
At time of intervention
First shock cardioversion success (subgroup analysis) by electrode position
At time of intervention
Second shock cardioversion success by manual pressure versus none
At time of intervention
- +1 more other outcomes
Study Arms (2)
Anterolateral shock vector
ACTIVE COMPARATORPatients with electrodes placed on the chest to obtain an anterolateral (front-to-side placement; also known as anteroapical) shock vector. If first shock is unsuccessful, participants who proceed to a second shock will be randomized to manual pressure versus none but electrode placement will remain the same.
Anteroposterior shock vector
ACTIVE COMPARATORPatients with electrodes placed on the chest to obtain an anteroposterior (front-to-back placement) shock vector. If first shock is unsuccessful, participants who proceed to a second shock will be randomized to manual pressure versus none but electrode placement will remain the same.
Interventions
Manual pressure applied to the anterior electrode
Eligibility Criteria
You may qualify if:
- Consenting adult patients scheduled for non-emergent electrical cardioversion of Atrial Fibrillation or Flutter
You may not qualify if:
- Insufficiently anticoagulation for cardioversion as per Canadian Cardiovascular Society guidelines or have not undergone trans-esophageal echocardiography to rule out left atrial thrombus
- Anatomic contraindication to anterolateral or anteroposterior placement (e.g. skin conditions or wounds)
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (2)
Hamilton Health Sciences
Hamilton, Ontario, L8L2X2, Canada
St Joseph's Healthcare Hamilton
Hamilton, Ontario, L8N4A6, Canada
MeSH Terms
Conditions
Condition Hierarchy (Ancestors)
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- not applicable
- Allocation
- RANDOMIZED
- Masking
- NONE
- Purpose
- TREATMENT
- Intervention Model
- PARALLEL
- Sponsor Type
- OTHER
- Responsible Party
- PRINCIPAL INVESTIGATOR
- PI Title
- Adult Cardiology Fellow
Study Record Dates
First Submitted
August 19, 2022
First Posted
August 23, 2022
Study Start
February 22, 2023
Primary Completion (Estimated)
June 1, 2027
Study Completion (Estimated)
July 1, 2027
Last Updated
May 14, 2025
Record last verified: 2025-05