Initial Double Sequential External Defibrillation for Refractory Ventricular Fibrillation in Cardiac Sarcoidosis

Abstract

Background

Double sequential external defibrillation (DSED) has demonstrated improved outcomes for refractory ventricular fibrillation (VF). Whether “initial” DSED improves outcomes is an area of ongoing research. We present a case of successful resuscitation employing early DSED.

Case Summary

A 65-year-old man with cardiac sarcoidosis experienced a witnessed out-of-hospital cardiac arrest. The emergency medical services team confirmed VF and delivered DSED as the initial shock. Resuscitation inclusive of multiple DSED shocks, advanced airway management, amiodarone, and esmolol resulted in a return of spontaneous circulation. Cardiac magnetic resonance imaging confirmed cardiac sarcoidosis, and the patient was discharged with full neurological recovery.

Discussion

This is to our knowledge the first case of DSED used as the initial defibrillation strategy for refractory VF in cardiac sarcoidosis. Initial DSED may offer substantial benefit for high-risk patients, supporting ongoing evaluation of protocols for earlier use of DSED.

Take-Home Message

DSED can be safely and effectively used as initial therapy in patients with refractory VF.

Graphical Abstract

History of Presentation

A 65-year-old man collapsed suddenly at home while sitting on his couch. His spouse, who witnessed the event, immediately began bystander chest compressions and called 911. On arrival of emergency medical services (EMS), the patient was unresponsive, pulseless, and exhibiting agonal respirations. The presenting rhythm is noted in Figure 1.

Take-Home Messages

• •DSED can be delivered safely as initial therapy for refractory VF in high-risk patients, including those with cardiac sarcoidosis.
• •Early DSED may minimize VF duration, improving survival and neurologic outcomes; ongoing trials will clarify the optimal timing for DSED.

Figure 1.

Presenting Rhythm and DSED Shock 1 (Anterior-Lateral and Anterior-Posterior Pad Positions)

DSED = double sequential external defibrillation.

Past Medical History

The patient's medical history included the comorbidities of hypertension, type 2 diabetes, hyperlipidemia, chronic obstructive pulmonary disease, depression, benign prostatic hyperplasia, restless legs syndrome, and cardiac sarcoidosis (on chronic prednisone).

Differential Diagnosis

In an adult with sudden cardiac arrest and initial ventricular fibrillation (VF), the potential etiologies of cardiac arrest are vast, with the leading causes in this particular case being acute coronary syndrome/myocardial infarction, primary ventricular arrhythmia (including sarcoidosis-related VF), structural heart disease, and pulmonary embolism.

Investigations

Initial rhythm analysis by EMS confirmed VF. Apart from resuscitation, no other investigations occurred in the prehospital setting. Bedside echocardiography in the emergency department (postresuscitation) revealed global left ventricular dysfunction. An initial electrocardiogram after return of spontaneous circulation (ROSC) showed no evidence of ST-segment elevation. Coronary angiography demonstrated no evidence of significant coronary artery stenosis. Cardiac magnetic resonance imaging demonstrated patchy delayed gadolinium enhancement, consistent with the presence of cardiac sarcoidosis.

Management

Recognizing the high arrhythmogenic risk in a patient with cardiac sarcoidosis and the potential for persistent VF as well as a recent protocol change in the service focusing on double sequential external defibrillation (DSED) as an initial defibrillation strategy for VF, EMS immediately performed DSED as the initial shock using 2 defibrillators (pads in the anterior-lateral and anterior-posterior positions) with rapid sequential defibrillation (Figure 2). Shock energy for each defibrillator for the initial and subsequent shocks was 360 J. VF persisted despite short periods of VF termination followed by VF recurrence. Paramedics continued high-quality cardiopulmonary resuscitation (CPR) (manual CPR followed by mechanical CPR), repeated DSED 4 additional times, and administered amiodarone (total 450 mg intraosseous) and esmolol (40 mg intraosseous). Airway management included supraglottic airway insertion, endotracheal intubation, and transition to a Hamilton T1 ventilator. After a total of 5 DSED shocks, the patient developed pulseless electrical activity, prompting epinephrine administration, then reverted to VF, requiring a final DSED shock. ROSC was ultimately achieved, and the patient was transported intubated and ventilated to the hospital. Representative monitor tracings from the defibrillator files of the initial rhythm, DSED shocks delivered, recurrent VF, and ROSC are shown in Figures 3, 4, 5, and 6.

Figure 2.

Pad Positions for DSED

The anterior-lateral position is represented by the black (anterior) and gray (lateral) pads. The anterior-posterior position is represented by the solid orange (anterior) and dotted orange (posterior [placed on the patient's back]) pads. DSED = double sequential external defibrillation.

Figure 3.

DSED Shock 2 With Refibrillation (Anterior-Lateral Pad Position)

DSED = double sequential external defibrillation.

Figure 4.

DSED Shock 3 With Refibrillation 83 Seconds Post-Shock (Anterior-Lateral Pad Position)

DSED = double sequential external defibrillation.

Figure 5.

DSED Shock 6 With Persistent ROSC at 4 Minutes 30 Seconds Post-Shock (Anterior-Lateral Pad Position)

DSED = double sequential external defibrillation; ROSC = return of spontaneous circulation.

Figure 6.

DSED Shock 6 With Organized Rhythm (Anterior-Posterior Pad Position)

DSED = double sequential external defibrillation.

Outcome and Follow-Up

The patient was admitted to the intensive care unit, underwent targeted temperature management, and was gradually weaned from the ventilator and vasopressors. He was discharged to rehabilitation with a cerebral performance category score of 1 (denoting full neurological recovery). An implantable cardioverter-defibrillator was recommended at follow-up for secondary prevention.

Discussion

DSED, the technique of providing 2 rapid shocks from 2 defibrillators with pads placed in the anterior-lateral and anterior-posterior positions, has increased in interest since the 2022 publication of the DOSE-VF (Double Sequential External Defibrillation for Refractory Ventricular Fibrillation) randomized controlled trial was published in the New England Journal of Medicine.¹ The trial showed superior outcomes for all primary and secondary endpoints (VF termination, ROSC, survival to hospital discharge, and neurologically intact survival) with DSED versus standard defibrillation for patients presenting with refractory VF (presenting rhythm of VF or pulseless ventricular tachycardia who remain unchanged after 3 successive shocks each separated by 2 minutes of CPR).

For over 3 decades, case reports, case series, and observational research have shown mixed results regarding the efficacy of DSED, mainly because of the significant heterogeneity of the study designs and the provision of DSED as a “last resort” when all else fails.² Lacking was any randomized controlled trial evidence of benefit to clinical outcomes. The pivotal DOSE-VF trial demonstrated that DSED, implemented in a protocolized fashion by paramedics to those in refractory VF, can improve short-term outcomes of ROSC and survival, as well as the critical patient-centered outcome of neurologically intact survival, when compared with standard defibrillation. A recent mechanistic hypothesis from secondary analyses of the DOSE-VF trial suggests that a further potential mechanism of benefit may be the reduction of total VF “burden” by decreasing time in VF, indicating that even earlier DSED (as the initial shock) could yield further gains.³ As such, one could hypothesize that if DSED decreases time in VF, then earlier DSED may lead to further improved outcomes.

We present a case reporting the employment of an initial DSED strategy as part of a comprehensive resuscitation protocol to an individual with underlying cardiac sarcoidosis, which resulted in successful, neurologically intact survival. Refractory VF is associated with extremely poor outcomes, with survival rarely exceeding 10%.⁴ Cardiac sarcoidosis further complicates resuscitation because of patchy fibrosis and increased defibrillation thresholds.⁵ Mechanistically, DSED leverages both vector and threshold theory, altering shock direction and lowering defibrillation threshold, which may be especially important in heterogeneous substrates such as sarcoidosis.⁶ Recent research by the DOSE-VF investigators suggests that the difference in transthoracic impedance between shocks delivered in the anterior-lateral vector and the anterior-posterior vector may lead to an increase in current delivery to the myocardium, a critical element in defibrillatory success.⁷ This concept is aptly illustrated in Figure 1.

Association With Current Guidelines/Practice

Current 2023 and 2025 International Liaison Committee on Resuscitation (ILCOR) Advanced Life Support (ALS) Consensus on Science with Treatment Recommendations (CoSTR) recommend considering DSED for adults with persistent VF or pulseless ventricular tachycardia after 3 unsuccessful defibrillation attempts.^8,9 However, the guidelines also state that there is currently insufficient direct evidence to recommend DSED as the initial shock strategy for VF, as the available clinical trial data have not directly addressed this scenario. As such, deploying DSED as the initial defibrillation strategy, as in the current case, falls outside the scope of current guideline-recommended practice and represents an innovative, individualized approach informed by both mechanistic reasoning and secondary analyses suggesting benefit with earlier DSED.²

The question of early DSED (after 1 failed EMS shock) is being studied in multiple randomized controlled trials in Europe: Double-D trial (Early Double Sequential Defibrillation in Out-of-hospital Cardiac Arrest; NCT06447805) and STRAT-DEFI trial (Strategies for Defibrillation During Out-of-Hospital Cardiac Arrest; NCT06781892). Our case is the first to demonstrate the feasibility and potential success of DSED as the initial shock in out-of-hospital cardiac arrest (OHCA), and this question will also be explored in the Dual Defib trial (Initial Double Sequential External Defibrillation in Out of Hospital Cardiac Arrest; NCT06672159), which will compare DSED to standard defibrillation, with DSED being the initial shock strategy.

In our case report, initial application of DSED resulted in prehospital ROSC and a cerebral performance category score of 1 (neurologically intact) in a patient with high-risk cardiac sarcoidosis, supporting the exploration of risk-adapted, etiology-driven resuscitation strategies. In cardiac sarcoidosis and other arrhythmogenic cardiomyopathies, the multivector, high-energy approach of DSED may overcome both anatomical and electrical challenges that limit standard defibrillation. Early ROSC, as achieved in our patient, remains a powerful independent predictor of survival and neurological recovery in OHCA.¹⁰ Although DSED is not a substitute for comprehensive postarrest care, including coronary angiography, targeted temperature management, and risk factor modification, it is an essential and evolving part of the toolkit for refractory VF, especially when considered early for high-risk patients.

Conclusions

This case demonstrates that early DSED, delivered as the initial defibrillation strategy for refractory VF in a patient with cardiac sarcoidosis, can be safely and successfully performed, with excellent clinical outcomes. Our experience supports ongoing research and protocol development for early, individualized DSED in high-risk OHCA populations.

Visual Summary.

Timeline of Prehospital Resuscitation Events and Interventions

Time (HH:MM:SS)	Event/Intervention	Details/Notes
20:01:31	Cardiac monitor (LifePak 15) powered on	—
20:02:20	Initial rhythm check	Ventricular fibrillation
20:03:45	Defibrillators charged	360 J (both devices)
20:03:50	First DSED shock delivered	Rapid sequential shocks, AP + AL pad positions; VF persisted
20:05:53	Airway management	Size 5 iGel inserted, ITD placed
20:06:46	IO access attempt	Initial IO in left femur failed
20:07:32	Second DSED delivered	—
20:09:25	Medication administration	Amiodarone 300 mg IO
20:09:35	Third DSED delivered	—
20:11:46	Fourth DSED delivered	—
20:12:05	Medication administration	Amiodarone 150 mg IO
20:12:31	Medication administration	Esmolol 40 mg IO
20:14:09	Advanced airway secured	ETI via bougie + video laryngoscope; transitioned to Hamilton T1 ventilator
20:14:56	Fifth DSED delivered	Rhythm remained refractory VF
20:16:26	Rhythm check	PEA noted; epinephrine 1 mg IO administered
20:18:35	Rhythm check	Recurrence of VF
20:19:05	Sixth DSED delivered	—
20:21:00	ROSC	Palpable pulses, improved BP
20:30:46	Post-ROSC medication	Epinephrine (push-dose pressor) 10 μg IO
20:31:33	Post-ROSC medication	Epinephrine (push-dose pressor) 10 μg IO
20:31:52	Post-ROSC medication	Ketamine 200 mg IO
20:35:25	Post-ROSC fluids	Normal saline bolus 200 mL
20:36:38	Post-ROSC medication	Epinephrine (push-dose pressor) 10 μg IO
20:36:00	EMS arrival at hospital	Intubated, ventilated

AL = anterior-lateral; AP = anterior-posterior; BP = blood pressure; DSED = double sequential external defibrillation; EMS = emergency medical services; ETI = endotracheal intubation; IO = intraosseous; ITD = impedance threshold device; PEA = pulseless electrical activity; ROSC = return of spontaneous circulation; VF = ventricular fibrillation.

Funding Support and Author Disclosures

Dr Cheskes has received educational speaking fees from Zoll Medical. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Training videos of the technique of DSED performed with 2 manual defibrillators, an automated external defibrillator (AED) and a manual defibrillator, and 2 AEDS can be found at https://first60.ca/education/dsed/.