Electrode Positioning for Atrial Fibrillation Cardioversion

(SHOCK-VECTOR Trial)

Recruiting at 1 trial location

Overseen By William McIntyre, MD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: McMaster University

Disqualifiers: Insufficient anticoagulation, Anatomic contraindication, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 2

Duration: At time of intervention

1500 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores the optimal electrode positioning on the chest to restore normal heart rhythm in individuals with atrial fibrillation, a common heart rhythm disorder. Researchers are testing whether the anteroposterior (front-to-back) or anterolateral (front-to-side) electrode position proves more effective. They are also evaluating if applying manual pressure to the electrodes aids when the first shock fails. Individuals with atrial fibrillation who are scheduled for a non-urgent corrective procedure might be suitable candidates for this study. As an unphased study, this trial offers a unique opportunity to contribute to innovative research that could enhance treatment options for atrial fibrillation.

Will I have to stop taking my current medications?

The trial protocol does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators or your doctor.

What prior data suggests that this electrode positioning technique is safe for atrial fibrillation cardioversion?

Research has shown that both front-to-side and front-to-back electrode placements are generally safe for cardioversion, a procedure that delivers a controlled electric shock to help the heart return to a normal rhythm. Studies have found that patients tolerate both positions well, with no major safety differences between them.

Both methods are widely used in medical practice, underscoring their safety. Some studies suggest that the front-to-side position might be more effective, but both positions remain reliable and do not pose significant safety risks for patients. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about this trial because it explores two electrode positioning methods for cardioversion in atrial fibrillation: anterolateral and anteroposterior. Unlike traditional methods that might not specify electrode placement, this trial aims to determine if these specific placements can improve the success rate of cardioversion. By experimenting with front-to-side and front-to-back electrode arrangements, the study could identify a more effective way to restore normal heart rhythm, potentially leading to better outcomes for patients with atrial fibrillation.

What evidence suggests that this electrode positioning technique is effective for atrial fibrillation cardioversion?

This trial will compare two electrode positioning methods for atrial fibrillation cardioversion: the anterolateral (front-to-side) and the anteroposterior (front-to-back) shock vectors. Research has shown that placing electrodes on the front and side of the chest is usually more effective than on the front and back for treating atrial fibrillation with electrical shocks. Some studies suggest the front-to-side method works better at restoring a normal heart rhythm. However, a review of multiple studies found no major difference in success between the two methods. Both approaches effectively restore a normal heart rhythm, but the front-to-side method might have a slight advantage according to some research. Overall, both positions can help restore a normal heart rhythm in patients with atrial fibrillation. ^{1 3 4 6 7}

Are You a Good Fit for This Trial?

This trial is for consenting adults set to undergo non-emergency electrical cardioversion for Atrial Fibrillation or Flutter. Participants must be adequately anticoagulated as per guidelines, or have had an echocardiogram to rule out heart clots. Those with skin conditions or wounds preventing electrode placement cannot join.

Inclusion Criteria

I am an adult who has agreed to a planned electrical cardioversion for Atrial Fibrillation or Flutter.

Exclusion Criteria

I haven't had the proper blood thinning treatment or a specific heart scan.

I cannot have treatments placed on certain parts of my body due to skin conditions or wounds.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

Treatment

Participants undergo electrical cardioversion with randomized electrode placement and potential manual pressure application

At time of intervention

1 visit (in-person)

Follow-up

Participants are monitored for cardioversion success and any adverse effects

4 weeks

1 visit (in-person), 1 follow-up call

What Are the Treatments Tested in This Trial?

Interventions

• Anterolateral electrode position
• Anteroposterior electrode position
• Manual pressure

Trial Overview The study tests whether placing electrodes on the front-to-back (anteroposterior) or front-to-side (anterolateral) of the chest and applying manual pressure improves the success of restoring normal heart rhythm in patients with atrial fibrillation.

How Is the Trial Designed?

Group I: Anterolateral shock vector Active Control 2 Interventions

Patients 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.

Group II: Anteroposterior shock vector Active Control 2 Interventions

Patients 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.

Who Is Running the Clinical Trial?

McMaster University

Lead Sponsor

Trials

936

Recruited

2,630,000+

Published Research Related to This Trial

External electrical cardioversion is an effective and simple procedure for terminating persistent atrial fibrillation, which can improve cardiac output in patients experiencing hemodynamic compromise.

Recent studies indicate that using an anterior-posterior electrode position for cardioversion is more effective than the traditional anterior-lateral position, with no safety concerns associated with this new approach.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of electrode position on the outcome of cardioversion. Kirchhof, P., Borggrefe, M., Breithardt, G.[2014]

A meta-analysis of 12 randomized controlled trials involving 2,046 patients found no significant difference in the efficacy of anteroposterior (AP) versus anterolateral (AL) electrode positioning for direct current cardioversion (DCCV) of atrial fibrillation, indicating that both methods are similarly effective.

Subgroup analyses suggest that while overall results are comparable, certain patients—specifically older individuals with higher body mass index and longer durations of atrial fibrillation—may benefit more from AL electrode positioning, particularly when using biphasic defibrillators.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Anteroposterior Versus Anterolateral Electrode Position for Direct Current Cardioversion of Atrial Fibrillation: A Meta-Analysis of Randomised Controlled Trials. Virk, SA., Rubenis, I., Brieger, D., et al.[2022]

In a study of 90 patients undergoing elective cardioversion for atrial fibrillation, the position of electrode pads (anteroanterior vs. anteroposterior) did not significantly affect the success rate of cardioversion, which was 81% overall.

Both electrode positions required similar energy levels for successful cardioversion, indicating that factors like the duration of atrial fibrillation are more critical for predicting success than the pad placement.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Randomised comparison of electrode positions for cardioversion of atrial fibrillation. Mathew, TP., Moore, A., McIntyre, M., et al.[2019]

In a multicenter trial involving 468 patients, anterior-lateral electrode positioning was found to be significantly more effective than anterior-posterior positioning for cardioverting atrial fibrillation, with 54% of patients achieving sinus rhythm after the first shock compared to 33% in the anterior-posterior group.

The overall success rate after up to 4 shocks was also higher in the anterior-lateral group (93%) compared to the anterior-posterior group (85%), while safety outcomes showed no significant differences between the two electrode positions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Anterior-Lateral Versus Anterior-Posterior Electrode Position for Cardioverting Atrial Fibrillation. Schmidt, AS., Lauridsen, KG., Møller, DS., et al.[2022]

In a study of 123 patients undergoing biphasic external cardioversion for persistent atrial fibrillation, both anteroposterior (AP) and anterolateral (AL) electrode positions showed similar success rates and first-shock efficacy, indicating that either position can be effectively used.

The incidence of early recurrent atrial fibrillation was comparable between the two groups, with 8.1% experiencing relapse shortly after successful cardioversion, suggesting that electrode positioning does not significantly impact the likelihood of immediate AF recurrence.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Randomized comparison of anterolateral versus anteroposterior electrode position for biphasic external cardioversion of atrial fibrillation. Siaplaouras, S., Buob, A., Rötter, C., et al.[2006]

A meta-analysis of 11 clinical trials involving 1845 patients found that using anteriolateral electrode positions significantly increases the success rate of electrical cardioversion for atrial fibrillation, with an odds ratio of 1.40.

The anteriolateral electrode position is particularly effective in patients receiving fewer than five shocks, those aged 60 years or older, and patients with a left atrial diameter greater than 45 mm, indicating specific populations that may benefit more from this approach.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Anteriolateral versus anterior-posterior electrodes in external cardioversion of atrial fibrillation: A systematic review and meta-analysis of clinical trials. Motawea, KR., Mostafa, MR., Aboelenein, M., et al.[2023]

In a randomized clinical trial involving 91 patients with atrial fibrillation, the apex-anterior (A-A) electrode position was found to be more effective for electrical cardioversion, requiring fewer shocks and less energy compared to the left anteroposterior (A-P) position.

Sinus rhythm was restored in 92% of cases, with the A-A group needing an average of 1 shock at 150 J, while the A-P group required 2 shocks at 350 J, highlighting the A-A position as the preferred method for this procedure.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Electrode position in elective electrical cardioversion of atrial fibrillation. A randomized study]. Muñoz-Martínez, T., Castañeda-Saiz, A., Vinuesa-Lozano, C., et al.[2016]

Citations

1. ahajournals.org ahajournals.org/doi/10.1161/CIRCULATIONAHA.121.056301

Anterior–Lateral Versus Anterior–Posterior Electrode ... Anterior–lateral electrode positioning was more effective than anterior–posterior electrode positioning for biphasic cardioversion of atrial fibrillation.

2. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/36163316/

Anteroposterior Versus Anterolateral Electrode Position for ... This meta-analysis was conducted to systematically compare the efficacy of anteroposterior (AP) versus anterolateral (AL) electrode placement for DCCV of AF.

3. sciencedirect.com sciencedirect.com/science/article/pii/S2352906722001786

A meta-analysis of randomized controlled trials Meta-analysis of randomized data showed no difference between AP and AL electrode positions in the success rate of DC cardioversion of AF.

4. clinicaltrials.gov clinicaltrials.gov/study/NCT05511389

Anteroposterior Versus Anterolateral Electrode Position for ... This study will demonstrate whether front-to-back, or front-to-side placement of the electrodes is more effective for electrical cardioversion of atrial ...

5. onlinelibrary.wiley.com onlinelibrary.wiley.com/doi/10.1002/clc.23987

Anteriolateral versus anterior–posterior electrodes in ... Our meta-analysis revealed that anterior–lateral electrodeposition is more effective and better than anterior–posterior electrodeposition in ...

6. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/34814700/

Anterior-Lateral Versus Anterior-Posterior Electrode ... Anterior-lateral electrode positioning was more effective than anterior-posterior electrode positioning for biphasic cardioversion of atrial fibrillation.

7. rebelem.com rebelem.com/epic-trial/

EPIC Trial: Electrode Positioning in Cardioverting Atrial ... Anterior–lateral electrode positioning was more effective than anterior–posterior electrode positioning for biphasic cardioversion of atrial fibrillation.