Hemiazygous Coil Placement for High-Defibrillation Thresholds in a Patient with a Right-Sided Implantable Cardioverter Defibrillator

Patients with a high defibrillation threshold: Approaches to management

Implantable cardioverter-defibrillators (ICDs) have revolutionized the prognosis for patients at elevated risk of ventricular tachyarrhythmias. For safety, defibrillation should be effective with a minimum of 10 J below the device's maximum energy. While modern ICDs rarely deliver ineffective shocks in primary prevention, the surge in managing severe heart failure patients has led to an increased number of patients with high defibrillation thresholds (DFTs). This article elucidates the potential causes of high DFT, including clinical factors, lead and device placement, the presence of a Left Ventricular Assist Device (LVAD), prolonged ventricular arrhythmias, shock vectors, waveform tilt, medications, and manufacturer-specific options. We also detail management strategies, highlighting alternative shock coil placements, practical recommendations, and case studies from our institution. Our management algorithm suggests addressing preventable causes, re-evaluating coil positions, considering non-invasive system modifications, upgrading to a higher-capacity device, and adding extra coil(s).

Non-traditional implantable cardioverter-defibrillator configurations and insertion techniques: a review of contemporary options

Implantable cardioverter-defibrillators (ICDs) have revolutionized the treatment of acquired or inherited cardiac diseases associated with a high risk of sudden cardiac death due to ventricular tachyarrhythmias. Contemporary ICD devices offer reliable arrhythmia detection and discrimination algorithms and deliver highly efficient tachytherapies. Percutaneously inserted transvenous defibrillator coils with pectoral generator placement are the first-line approach in the majority of adults due to their extensively documented clinical benefit and efficiency with comparably low periprocedural implantation risks as well as the option of providing pain-free tachycardia treatment via anti-tachycardia pacing (ATP), concomitant bradycardiaprotection, and incorporation in a cardiac resynchronization therapy if indicated. Yet, expanding ICD indications particularly among younger and more complex patient groups as well as the increasingly evident long-term consequences and complications associated with intravascular lead placements promoted the development of alternative ICD configurations. Most established in daily clinical practice is the subcutaneous ICD but other innovative extravascular approaches like epicardial, pericardial, extra-pleural, and most recently substernal defibrillator coil placements have been introduced as well to overcome shortcomings associated with traditional devices and allow for individualized treatment strategies tailored to the patients characteristics and needs. The review aims to provide practical solutions for common complications encountered with transvenous ICD systems including restricted venous access, high defibrillation/fibrillation thresholds (DFTs), and recurrent device infections. We summarize the contemporary options for non-traditional extravascular ICD configurations outlining indications, advantages, and disadvantages.

Completely epicardial implantable cardioverter/defibrillator (ICD) and CRT-D systems: A case series and systematic literature review

BACKGROUND

Epicardial ICD systems and CRT-Ds using high voltage coils represent an alternative to transvenous systems in patients without central venous access and prior device complications including infection.

OBJECTIVE

We present a case series in the adult population of epicardial ICD/CRTD systems using high voltage epicardial coils. We summarize the existing data regarding techniques, efficacy, and safety.

METHODS

A retrospective board approved medical record review was conducted for all patients undergoing epicardial ICD/CRTD placement at our institution between January 2010 and May 2020. The literature was reviewed for prior published trials, case reports, and case series of epicardial high voltage coil insertions.

RESULTS

Eleven patients (six female, mean age 48 years) underwent epicardial ICD/CRTD implant including 5/11 completely epicardial CRTD systems. The procedure was performed via median sternotomy in eight patients, left anterior thoracotomy in two patients, and sub-xiphoid approach in one patient. After a mean follow up of 35 months, appropriate successful shocks were delivered in two (18%) patients and no patients received an inappropriate shock. Three of five (60%) patients had volumetric remodeling with CRT with significant improvement of LV EF. Device-related complications requiring a surgical/percutaneous revision or another DFT test occurred in six patients (54%). One patient died during follow up due to refractory heart failure. No cases of epicardial device infection, coronary artery compression, constrictive pericarditis, or erosion of defibrillator coils into intrathoracic organs were reported. No randomized studies comparing safety and efficacy of traditional transvenous or subcutaneous ICD systems and epicardial ICD systems using contemporary high voltage coils were found nor any studies directly comparing epicardial defibrillator patches versus epicardial coils. Thirteen case series and 24 single case reports published between 2004 and 2020 were identified describing in total a heterogenous group of 188 patients with ICD systems incorporating one or more epi- or pericardially positioned shock coils.

CONCLUSION

The use of epicardial defibrillation coils for ICD/CRT-D is a feasible treatment option for patients with either failed or contraindicated transvenous ICD systems. Dedicated epicardial high voltage leads with integrated pace-sense electrodes and specialized delivery tools for minimal invasive implantations may improve longer term outcomes.