Dual HeartMate 3 in total artificial heart configuration for incessant ventricular fibrillation: a case report

Abstract

Background

Ventricular arrhythmias are a major therapeutic challenge in the management of advanced heart failure, which often complicates the use of conventional mechanical circulatory support (MCS).

Case summary

A 46-year-old man with advanced heart failure developed refractory ventricular tachyarrhythmias. He experienced progressive haemodynamic instability, which necessitated a stepwise escalation of temporary MCS. Despite adequate ventricular unloading and acute antiarrhythmic management, his rhythm deteriorated into incessant ventricular fibrillation that lasted for 28 days. Given the low possibility of myocardial recovery and an anticipated waiting time of more than 2 months (even with urgent listing for heart transplantation in our country), the temporary MCS was transitioned to durable biventricular support using two HeartMate 3 devices in a total artificial heart configuration. This configuration eliminated arrhythmogenic and thrombogenic myocardial substrates and provided stable circulatory support. The patient resumed early active rehabilitation and received a heart transplant after 72 days of dual HeartMate 3 support without adverse events such as pump thrombosis, haemolysis, stroke, or bleeding during support.

Discussion

This case demonstrates that using two continuous-flow ventricular assist devices in a total artificial heart configuration may represent a viable strategy of advanced mechanical circulatory support in highly selected patients with refractory ventricular arrhythmia.

Learning points.

• Refractory ventricular arrhythmias compromise the haemodynamic stability of advanced mechanical circulatory support.

• Implantation of two continuous-flow VADs in a total artificial heart configuration may provide durable support by eliminating prothrombotic substrates in selected patients.

Introduction

Ventricular arrhythmias (VAs) are one of the most challenging scenarios in the management of advanced heart failure.^1,2 Reports on tailored mechanical circulatory support (MCS) strategies for patients with long-standing refractory VA remain limited. This report presents a case of a stepwise escalation of MCS to two HeartMate 3 in a patient who developed incessant ventricular fibrillation (VF) for 28 days.

Summary figure

Surgical configuration of dual HeartMate 3 devices

Schematic of dual HeartMate 3 devices in total artificial heart configuration. The native ventricles were excluded. Left- and right-side pumps were secured to the felt-reinforced subvalvular ventricular rims, and outflow grafts were connected to the aorta and pulmonary artery in an end-to-end fashion.

Case presentation

A 46-year-old man presented with progressive dyspnoea for months. Echocardiography revealed severe left ventricular systolic dysfunction (LVEF 26%). Holter monitoring recorded frequent non-sustained polymorphic ventricular tachycardia (VT). Coronary angiography found extensive multivessel disease, with 95% left main stenosis, complete proximal left anterior descending (LAD) occlusion, significant left circumflex disease (90% proximal, 70% distal), and severe right coronary artery (RCA) involvement (80% proximal, 90% mid, and 95% distal and posterior descending artery). The patient underwent urgent coronary artery bypass grafting, with saphenous vein grafting to the LAD, diagonal branch, and RCA.

On postoperative day (POD) 2, he received extracorporeal cardiopulmonary resuscitation (ECPR) for pulseless VT. Return of spontaneous circulation was achieved after 16 defibrillations. Post-ECPR computed tomography showed patent bypass grafts. However, myocardial recovery remained poor, and his course was complicated by recurrent VA. He was then transferred to our institution on POD 6.

Upon arrival, the patient exhibited sustained VT, dense spontaneous echo contrast (SEC) within LV, and marked pulmonary congestion (Supplementary material online, Video S1&S2). Left atrial venoarterial extracorporeal membrane oxygenation (LAVA-ECMO) was performed immediately. Although pulmonary congestion improved with LAVA ECMO support, under retrograde aortic flow generated by peripheral ECMO, the aortic valve remained closed, and SEC within the LV became more intensified (Supplementary material online, Video S3&;S4). To prevent extensive intraventricular thrombus formation and potential catastrophic neurologic injury due to thromboembolism, direct surgical LV unloading using an extracorporeal left ventricular assist device (eLVAD; LV–aorta configuration) was arranged. With eLVAD flow kept around 4–4.5 L/min, his rhythm returned to sinus rhythm. However, VA recurred early, causing episodic drops in eLVAD flow, and became refractory to intensive acute antiarrhythmic managements (including repeated boluses of lidocaine, amiodarone, magnesium, propofol, and maximal doses of defibrillation). An electrophysiologist was consulted, and catheter ablation was deemed too risky due to hemodynamic instability and concerns about intracardiac microthrombus. Hence, we inserted the extracorporeal right ventricular assist device (eRVAD; right atrium–main pulmonary artery configuration). Although VA remained intractable, flows of extracorporeal biventricular assist devices (eBiVAD) were rather stable (Figure 1A). Following several boluses of esmolol, the sinus rhythm was initially restored but showed a diminishing response within hours (Figure 2). Furthermore, his rhythm deteriorated into incessant VF. Considering the difficulty in substrate mapping, limited cardiac reserve, and high rates of post-ablation VA recurrence, the electrophysiologist did not recommend catheter ablation. A multidisciplinary decision to proceed with urgent listing for heart transplant (status 1A) was made.

Figure 1.

Flow variability of the ventricular assist device (VAD) during incessant ventricular arrhythmia. Time course of antiarrhythmic management, mechanical circulatory support escalation, and significant variability in VAD flow during arrhythmic episodes. (A) Marked fluctuations in eLVAD flow were observed during periods of extremely unstable heart rhythm without eRVAD support. Immediate rhythm-independent haemodynamic stability was achieved with eBiVAD support. (B) Because patients with dual HeartMate 3 devices in a total artificial heart configuration are entirely dependent on mechanical support, both pump flows were set to maintain full circulatory support. The patient was listed for urgent heart transplantation (status 1A) throughout the waiting period due to his special nature. eBiVAD, extracorporeal biventricular assist device; eLVAD, extracorporeal left ventricular assist device; EP consult, electrophysiology consult; eRVAD, extracorporeal right ventricular assist device; VF, ventricular fibrillation; VT, ventricular tachycardia.

Figure 2.

Electrocardiogram. Sinus rhythm was temporarily restored after eRVAD implantation. Low-voltage ECG suggests reduced myocardial viability. ECG, electrocardiography; eRVAD, extracorporeal right ventricular assist device.

An oxygenator was incorporated into the temporary system during eBiVAD support to prevent systemic embolization from intracardiac thrombi. Pump thrombosis events were managed by prompt circuit exchanges (Figure 3A–C). The patient achieved meaningful functional recovery on eBiVAD support. However, acknowledging that the anticipated waiting time for status 1A candidates in our country typically exceeds 2 months, our heart transplant team reached a consensus on transitioning to a more durable support strategy to improve the waitlist survival (Figure 1B).³

Figure 3.

Pump thrombosis in temporary VADs. Repeated thrombus formation within the oxygenator (A) and pump (B, C).

To minimize the risk of arrhythmia-related device complications, we elected to implant two HeartMate 3 pumps in a total artificial heart configuration (Summary Figure).⁴ He was extubated on POD 5 and resumed intensive rehabilitation under full and stable circulatory support (Supplementary Materials). He received heart transplantation after 72 days of dual HeartMate 3 support without adverse events such as pump thrombosis, haemolysis, stroke, or bleeding (Figure 4).

Figure 4.

Timeline of clinical events. AO, aorta; BMI, body mass index; CABG, coronary artery bypass grafting; CAD, coronary artery disease; ECPR, extracorporeal cardiopulmonary resuscitation; eLVAD, extracorporeal left ventricular assist device; eRVAD, extracorporeal right ventricular assist device; HFrEF, heart failure with reduced ejection fraction; HM6, HeartMate 6; IHCA, in-hospital cardiac arrest; LAVA ECMO, left atrial venoarterial extracorporeal membrane oxygenation; LM, left main; LV, left ventricle; LVEF, left ventricular ejection fraction; MPA, main pulmonary artery; RA, right atrium; 3VD, three-vessel disease; VF, ventricular fibrillation; VT, ventricular tachycardia.

Discussion

Our case highlights a clinical challenge facing durable MCS. For VA with acute heart failure, temporary BiVAD enables early stabilization, device exchange, and assessment of myocardial recovery. However, in the case of refractory VF lasting for weeks, the therapeutic objective of MCS might extend beyond treating biventricular failure to maintaining stable support in an electrically unstable and prothrombotic milieu.

For patients with long-standing VA, isolated LVAD support may be insufficient due to flow variability, thromboembolism, and progressive RV dysfunction.² Currently, the SynCardia Total Artificial Heart (TAH) is the only approved MCS for biventricular support. However, its clinical application is limited by pneumatic drivers and restricted geographic availability.⁵ Conversely, the favourable survival outcome, improved quality of life, and mature long-term data with continuous-flow VADs have facilitated its wider off-label adoption.⁶ Innovative implant techniques allow two commercial VADs to function as durable biventricular support.^4,7

BiVAD configuration

Because continuous-flow VADs are primarily designed for left ventricular support, their application in the right heart—characterized by trabeculated anatomy, crescent-shaped geometry, and low-afterload physiology—predisposes to frequent suction events, impaired washout, and, thus, an increased risk of pump thrombosis. In earlier reports, largely reflecting experience with the HeartWare HVAD system, RVAD pump thrombosis occurred in up to 30% of patients supported with BiVAD configuration.⁸ Compared with the HVAD, the HeartMate 3’s fully magnetically levitated pump with no mechanical bearings, wide-gap rotor, and artificial pulse technology provides better blood washout, significantly minimizing blood trauma and thrombosis risk.⁹ Nevertheless, RVAD pump thrombosis in HeartMate 3 BiVAD configurations has still been reported in small case series.¹⁰

Total artificial heart configuration

Total artificial heart configuration provides stable, unobstructed inflow by removing ventricular trabeculations and subvalvular apparatus, enabling more predictable haemodynamics.⁴ However, ventriculectomy eliminates any potential for myocardial recovery, rendering patients entirely dependent on mechanical support. Following the same rationale of approved SynCardia TAH, this implant technique is reserved for selected patients with irreversible biventricular failure.^5,11,12

At the time of dual HeartMate 3 implantation in our case, his rhythm had remained in incessant VF for 28 days despite adequate mechanical unloading and acute antiarrhythmic management, rendering myocardial recovery highly unlikely. In the context of prolonged incessant VF, the absence of coordinated ventricular contraction and highly turbulent intracavitary flow patterns created a prothrombotic environment that could compromise the outcomes of a conventional MCS strategy.¹³ Notably, this concern is further substantiated by recurrent pump thrombosis during eBiVAD support. Considering a prolonged waiting time, eBiVAD was transitioned to dual HeartMate 3 as a more durable bridging strategy. Given the inherent risk of RVAD pump thrombosis, using the BiVAD configuration in the presence of incessant VA might further exacerbate this issue. Therefore, we elected to implant dual HeartMate 3 devices in a total artificial heart configuration for this case. Meanwhile, given the special nature of irreversible and complete dependence on MCS following ventriculectomy, our transplant team decided to extend the 1A status throughout the whole waiting period, although he remained clinically stable and free from device-related complications with dual HeartMate 3 support.

This report has several limitations. The use of dual continuous-flow VADs in a total artificial heart configuration is off-label. Ventriculectomy irreversibly precludes myocardial recovery. Patient perspective is not included. As a single-centre experience, the generalizability of this technically complex approach is limited. Direct comparative data between this approach and the conventional TAH system are lacking.

This report describes the complex interplay between prolonged refractory VA and an advanced MCS strategy. Implanting dual HeartMate 3 in a total artificial heart configuration may represent a viable long-term strategy to mitigate the risk of pump thrombosis in highly selected patients.

Lead author biography

Hsun Yi Fu, MD, is a cardiovascular surgeon at National Taiwan University Hospital, specializing in the surgical management of advanced heart failure. Her clinical practice focuses on ventricular assist device implantation and perioperative management of patients with end-stage cardiomyopathy. Dr. Fu is actively involved in the care of high-risk patients requiring mechanical circulatory support as a bridge to recovery, transplantation, or destination therapy, and is committed to optimizing surgical strategies and postoperative outcomes in this challenging patient population.

Supplementary material

Supplementary material is available at European Heart Journal – Case Reports online.

Author contributions

Hsun-Yi Fu (Data curation, Writing—original draft [lead]), Wen Zhuang Then (Data curation, Writing—original draft [equal]), Chuan-I Tsao (Data curation [equal]), and Yih-Sharng Chen (Conceptualization, Supervision, Writing—review & editing [lead])

Consent: Written informed consent for the publication of this case report and accompanying images was obtained from the patient in line with Committee on Publication Ethics guidance.

Funding

This report received no specific grant from any funding agency.

Data availability

The data underlying this article are available in the article and its online Supplementary material.