The expansion of LVADs continues in the field of end-stage heart failure (HF), with improvements positioning them as a viable alternative to heart transplantation when transplantation is not feasible. On the other hand, the benefits of ICDs in HF are well-established and included in clinical guidelines, often resulting in the coexistence of both device types.

While guidelines recommend reactivation of ICD therapies post-LVAD implantation (class I, level of evidence A) and consider new ICD implantation following LVAD insertion (class IIa, level of evidence B), questions remain about the net benefit of these recommendations for patients. This study aims to assess the incidence and predictors of ICD therapies, as well as the complications associated with these devices, in LVAD patients.

A retrospective analysis included 234 patients (median age 59 years, range 52-66 years, 89.7% male) consecutively recruited from five Italian centers between 2006 and 2020. The primary outcome was the evaluation of appropriate ICD therapies, defined as shocks or anti-tachycardia pacing (ATP) for correctly identified ventricular arrhythmias. Secondary outcomes included inappropriate therapies (shocks or ATP due to supraventricular tachycardias), the combined incidence of appropriate and inappropriate therapies, ICD-related complications (pocket hematoma and infection), and LVAD-related complications (infection and bleeding). The most frequently implanted LVAD was the HVAD® (131 patients, 56%), followed by the Hearmate II® (57 patients, 24.4%) and the Hearmate III® (27 patients, 11.5%). As for ICDs, 86.8% of patients received them for primary prevention; the majority (95.3%) already had an ICD at the time of LVAD implantation, and 23.9% had a history of appropriate therapy before the LVAD was implanted.

During a median follow-up of 21 months, 66 patients (28.2%) received appropriate therapy, and 22 patients (9.4%) inappropriate therapy, with 77 patients (32.9%) experiencing some form of therapy. Predictors identified in multivariate analysis included left ventricular end-diastolic diameter and the presence of a ventricular tachycardia (VT) zone in the ICD programming. Regarding complications, 11 patients (4.7%) developed a pocket hematoma, all post-generator replacement, and 15 patients (6.4%) had ICD-related infections (generator, leads, or both). Of the 15 patients with ICD infection, 14 also had LVAD infections, although the specific type of LVAD infection was not reported. In total, 41 patients (17.5%) experienced some form of adverse effect from the ICD (inappropriate therapy, pocket hematoma, and/or infection), with three predictive factors identified in multivariate analysis: active infection associated with the LVAD, prior generator replacement, and VT zone programming.

The authors conclude that ICD therapies, appropriate or not, are relatively common in LVAD patients. Given the significant morbidity associated with generator replacements, they recommend a “conservative” programming approach to extend device lifespan and minimize replacement needs.

COMMENTARY:

Malignant ventricular arrhythmias are common in patients with advanced HF. Beyond secondary prevention, clinical guidelines recommend ICDs for primary prevention in HF patients with severely depressed function (LVEF <35%), with a class I recommendation for ischemic etiology and IIa for non-ischemic, both with a level of evidence A. Consequently, it is common for patients receiving LVADs to also carry an ICD, either as a standalone device or as an ICD-resynchronizer.

While the benefits of treating ventricular arrhythmias with an ICD are well established in the general population, the case is more complex in LVAD patients. On the one hand, these arrhythmias are better tolerated in LVAD patients, often self-limiting and rarely causing hemodynamic instability, syncope, or sudden death, thus having a lesser prognostic impact than in the general population. Conversely, generator replacement procedures are associated with significant morbidity, posing direct and indirect complication risks for LVAD patients. These factors make the final risk-benefit balance of ICD therapy less clear-cut.

The current study examines this association. First, the authors found that ICD therapies are relatively common after LVAD implantation, a finding supported by previous studies. Although the study lacks mortality and hospitalization data (one of its main limitations), the authors suggest that not only inappropriate therapies but also a significant proportion of appropriate therapies might be unnecessary. Furthermore, ICD-related complications are not insignificant, with generator replacement as an independent risk factor. This leads the authors to suggest individualized assessments of whether to replace the generator in patients with device depletion. Additionally, to “save” battery life and prevent this situation, they propose a more “conservative” programming approach, involving only a ventricular fibrillation zone with the longest possible detection times and avoiding VT detection zones.

The study has some limitations that should be considered in interpreting the results. Its observational, retrospective nature inherently introduces biases, and the lack of mortality and hospitalization data further limits conclusions. Furthermore, the HVAD®, the most commonly used LVAD in the study, is now off the market, while the Heartmate III® was only used in 11.5% of patients, potentially limiting the applicability of the results to current clinical practice. Finally, the study does not differentiate between shocks or ATP in the analysis of therapies, which is significant given their differing implications for battery consumption and patient quality of life.

Despite these limitations, the takeaway is that ICD therapies in LVAD-supported patients will be relatively frequent without necessarily offering clear clinical benefit, even when treating genuine ventricular arrhythmias. Given the potential complication risks associated with generator replacements, further studies are needed to evaluate the prognostic benefit of a “conservative” programming strategy, as proposed by the authors.

REFERENCE:

Rordorf R, Pignalosa L, Casula M, Perna E, Baroni M, Garascia A, et al. Real-world data of patients affected by advanced heart failure treated with implantable cardioverter defibrillator and left ventricular assist device: Results of a multicenter observational study. Artif Organs. 2024 Jan 12. doi: 10.1111/aor.14708.