Pulsed field ablation for rhythm control in acute heart failure and extracorporeal membrane oxygenation: a case report

Abstract

Background

Atrial fibrillation (AF) can be associated with acute heart failure (HF) and can complicate cardiogenic shock. The interaction between AF and HF is challenging, both diagnostically and therapeutically. While AF ablation has been shown to be beneficial in patients with HF, the role of interventional treatment of AF in acute HF remains largely unexplored.

Case summary

A 59-year-old male patient was admitted from an outside hospital after a prolonged intensive care stay developing acute respiratory failure with concomitant acute HF. Previously, the patient experienced a cardiogenic shock after a non-synchronized cardioversion that induced ventricular fibrillation at the end of an AF ablation procedure. After initial improvement, he was transferred to a rehabilitation hospital where he showed signs of respiratory failure and HF. Upon transfer to our hospital, a veno-arterial-venous extracorporeal membrane oxygenation (VAV-ECMO) device was implanted in addition to diuretic and inotropic therapy. While the respiratory function steadily improved, allowing de-escalation to a VV-ECMO device, recurrent episodes of AF with rapid ventricular rate were observed. This resulted in a severely reduced biventricular function despite antiarrhythmic therapy with amiodarone. We opted for pulsed field ablation (PFA) of the pulmonary veins, which finally enabled us to explant the ECMO system under sustained sinus rhythm and improved haemodynamics. An echocardiographic assessment 3 weeks post-ablation demonstrated improved cardiac function and maintained sinus rhythm.

Discussion

This case illustrates the complexities of treating patients with acute HF and AF. Our experience highlights the value of the fast, efficient, and safe PFA modality for ablation in critically ill patients.

Learning points.

• When cardiogenic shock due to atrial fibrillation and heart failure is observed in intensive care patients, early rate and rhythm control can be a feasible strategy to improve cardiac function.

• Pulsed field ablation allows for a fast and safe ablation in patients with atrial fibrillation on extracorporeal membrane oxygenation therapy.

Introduction

Atrial fibrillation (AF) is the most common arrhythmia and frequently associated with heart failure (HF). In some cases, AF can lead to worsening of HF which can exacerbate AF—a vicious cycle. The CASTLE-AF study showed that in AF patients with symptomatic HF and left ventricular ejection fraction (LVEF) < 35%, catheter ablation results in a reduced rate of all-cause death or worsening of HF.¹ These results were expanded by the CASTLE-HTx trial that showed AF patients with end-stage HF benefit from catheter ablation.²

However, a commonly encountered scenario is AF in the presence of acute HF and cardiogenic shock, sometimes leading to mechanical circulatory support (MCS) when conventional therapies fail.^3,4 Rhythm control is usually secondary in these situations. However, newer technologies like pulsed field ablation (PFA) enable fast and safe catheter ablation.

To our knowledge, this is the first case report of PFA being used during the extracorporeal membrane oxygenation (ECMO) weaning process.

Summary figure

Chronology	Treatment
−3 months	Presentation at local hospital for atrial fibrillation ablation. Experiencing ventricular fibrillation after non-synchronised cardioversion at the end of the procedure followed by a prolonged intensive care stay.
−1 month	Transferred to rehabilitation facility and development of acute respiratory failure.
Day 0	Transferred to our hospital. extracorporeal membrane oxygenation (ECMO) therapy initiated due to worsening respiratory failure and cardiogenic shock, and atrial fibrillation (AF) with rapid ventricular rate was observed.
Days 0–10	High-dose diuretic and inotropic therapy, first amiodarone therapy (1 g per day for 10 days) with improvement of cardiac function after conversation to sinus rhythm.
Days 13–15	Recurrent AF episodes causing reduced left ventricular ejection fraction and increased oxygen demand, complicating ECMO weaning.
Day 19	AF ablation using pulsed field ablation to maintain sinus rhythm and improved cardiac function allowed ECMO explanation shortly after.
+3 weeks	Stable cardiac function under maintained sinus rhythm.

Case report

A 59-year-old patient with preserved left ventricular ejection fraction (LVEF) was admitted to an external hospital for radiofrequency ablation of persistent atrial fibrillation (AF). At the end of the procedure, non-synchronized cardioversion led to ventricular fibrillation, necessitating resuscitation for almost 50 min and multiple shocks. An ischaemic event was excluded via coronary angiography, but the patient developed intracerebral haemorrhage of unclear aetiology resulting in right-sided hemiplegia in intensive care. The patient was transferred to a rehabilitation facility where he developed pneumonia-associated sepsis with acute respiratory failure. Additionally, a pulmonary embolism was identified via computed tomography, which was immediately treated with lysis. Due to worsening of respiratory failure, the patient was transferred to our hospital for ECMO therapy. At that time, his neurological status corresponded to a Cerebral Performance Category Score of 2, and he remained able to communicate. This was his first presentation at our institution.

The patient was first diagnosed with paroxysmal AF in 2013. By 2019, he progressed to persistent AF and developed HF, which was medically managed. Attempts at rate control using beta-blockers were unsuccessful in controlling symptoms. During the global pandemic, the patient declined electrical cardioversion and instead received digitalis. However, subsequent multiple electrical cardioversions failed to maintain sinus rhythm, leading to the indication for catheter ablation. At the time of the index procedure, the patient’s LVEF had normalized under medical management.

At admission to our hospital, the patient was intubated and in right-dominant cardiogenic shock (mean pulmonary arterial pressure 29 mmHg). Mechanical ventilation was performed in BIPAP mode with a PEEP of 8 cmH₂O and inspiratory pressure of 12–14 cmH₂O. The Horowitz index was <60 with an FiO₂ of 100%. Multiple prone positioning attempts had previously failed due to persistent haemodynamic instability. Cardiogenic shock and the critical respiratory failure mandated the implantation of veno-arterial-venous extracorporeal membrane oxygenation (VAV-ECMO). We used a 24 F venous cannula for the right femoral vein, a 17 F cannula in the right internal jugular vein, a 15 F cannula for the arterial right femoral access, and a 7 F distal perfusion access to the right femoral artery.

Initial observations included AF with rapid ventricular rate (RVR), significantly reduced LVEF, paradoxical septal movement, and a dilated right ventricle. The patient also exhibited peripheral oedema and high oxygen demand on both ECMO and the ventilator. High-dose diuretic therapy with furosemide and inotropic therapy with levosimendan and norepinephrine were initiated.

Despite these measures, AF with RVR persisted, and intravenous amiodarone therapy was initiated which led to conversion to sinus rhythm and LVEF improving to 40%–45%. This allowed for a reduction in ECMO flow rates and ventilator oxygen supplementation and the decannulation of the arterial cannula. The 24 F and 17 F cannulas in the right femoral and internal jugular vein remained.

Recurrent AF episodes with RVR continued to occur, leading to drops in mean arterial pressure, reduced LVEF, and increased oxygen demand under veno-venous ECMO (VV-ECMO). With limited options for further antiarrhythmic therapy, we initiated reloading with intravenous amiodarone (1 g/day for 3 days) and proceeded with AF ablation under general anaesthesia. Given the critical haemodynamic situation, we selected PFA using the FARAPULSE system for its safety, efficacy, and time efficiency.

Under ultrasound guidance, we accessed the left femoral vein with a 16.8 F FARADRIVE sheath, along with an 8 F sheath for mapping. After transseptal puncture, an electroanatomical map of the left atrium was created using CARTO 3 (Figure 1A and B). All pulmonary veins were reconnected with normal voltage levels. Eight pulsed field applications at 2.0 kV were delivered to each vein (four in basket configuration, four in flower configuration) using the FARAWAVE catheter (Figure 2). No interference between the ECMO circuit and the FARAWAVE catheter was observed, so ECMO flow was not reduced during the procedure. The total procedure time was 73 min, and a figure-of-eight suture was placed for haemostasis. Post-procedure, sinus rhythm and improved LVEF enabled explantation of the VV-ECMO system. Three weeks post-ablation, echocardiography demonstrated preserved cardiac function. The patient maintained sinus rhythm and showed improved neurological status.

Figure 1.

(A) Fluoroscopic view with contrast medium of the right superior pulmonary vein. The 17 F ECMO cannula in the right internal jugular vein is visible on the left. (B) Bipolar voltage map using CARTO 3 System (Biosense Webster, Irvine, CA, USA) of the left atrium in posterior–anterior view.

Figure 2.

Detection of reconnected right-sided pulmonary vein (PV) signals with a 7 F steerable decapolar catheter (Inquiry^™, Abbott) during atrial fibrillation in 100 m/s (A) and the first on the right inferior pulmonary vein (RIPV) using the pentaspline FARAWAVE catheter in sinus rhythm in 40 mm/s (B).

Discussion

Acute HF in the presence of AF is characterized by complexity in diagnosis and appropriate treatment strategy. Catheter ablation is increasingly recognized as a viable treatment option.

In this case, the patient’s cardiogenic shock was compounded by respiratory failure. The precise duration of AF prior to ECMO implantation and its contribution to multi-organ failure remains unclear, but AF was initially treated as secondary. The significance of AF in this case of acute HF only became apparent in our ICU when episodes of AF recurred under therapy, leading to a directly observable deterioration in cardiac function during the weaning process from ECMO.

Traditionally, rate control is performed to improve symptoms as initial therapy, and it is recommended with a Class I indication in the most recent AF guidelines.³ Conversely, rhythm control via electrical cardioversion is the preferred approach in unstable patients. The superiority of pharmacological rhythm control over rate control in HF patients is debated.^5–7 In this case, distinguishing between the effect of rate and rhythm control was challenging due to the variable heart rate and ECMO therapy. However, significant haemodynamic improvement with sinus rhythm under amiodarone and beta-blockers was evident through ECMO parameters and clinical monitoring.

Faced with recurrent AF episodes and exhausted conservative measures, we opted for catheter ablation. The CAMERA-MRI study and CASTLE-AF demonstrated an improvement in cardiac function and symptoms with catheter ablation compared to rate control.⁸ Additionally, CASTLE-HTX highlighted the significant benefit of AF ablation in improving symptoms in patients with end-stage HF, specifically in reducing hard endpoints such as death, implantation of MCS, or transplantation.² Maintaining sinus rhythm was also identified as a potential driver of reducing cardiovascular outcomes in the sub-analysis of the EAST-AFNET 4 trial. Given the patient’s age and medical history, as well as the risk for device-associated infection, we opted against a pace and ablate strategy.

To allow a short procedure duration under ECMO, a PFA system was used, which was safe and effective in the ADVENT trial and the MANIFEST-17K study.^9,10 It was not necessary to stop VV-ECMO during the procedure due to interference problems, but it cannot be ruled out that VA-ECMO might behave differently.

In this case report, we demonstrated that PFA in a patient with AF and acute HF on ECMO constitutes an effective rhythm control strategy.

Lead author biography

Lauritz Schoof is a cardiologist in training at the University Medical Center Hamburg, Germany. His main areas of interest are electrophysiology, heart failure therapy, and sports cardiology.

Author contributions

Lauritz Johannes Schoof (Data curation, Formal analysis, Writing—original draft), Marc D. Lemoine (MD) (Data curation, Methodology, Writing—review & editing), Gerold Söffker (MD) (Data curation, Methodology, Writing—review & editing), Andreas Rillig (MD) (Data curation, Methodology, Writing—review & editing), and Shinwan Kany (MD) (Conceptualization, Methodology, Supervision, Writing—review & editing)

Data availability

The data underlying this article will be shared on reasonable request to the corresponding author. The medical history of the patient outside of this case report cannot be shared without patient consent.