Optimizing care for suspected cardiac implantable electronic device hypersensitivity: algorithms, evidence gaps, and the role of wearable cardioverter-defibrillator

Zhan et al.1 propose an interesting algorithm for identifying and managing patients at risk of hypersensitivity to cardiac implantable electronic devices (CIEDs). We believe that this approach provides practical and valuable guidance on how to avoid the prolonged, complex, and costly process of suspecting and confirming CIED hypersensitivity. Some additional issues deserve particular attention. First, prospective registries are needed to estimate the true prevalence of CIED hypersensitivity, as well as cost-effectiveness analyses to enable the formulation of evidence-based recommendations. Second, physicians should have the opportunity to implant customized devices without unnecessary delay, and manufacturers are expected to make such options readily available. This is of crucial importance, particularly in pacing-dependent patients. Finally, as new methods of sudden cardiac death prevention—such as subcutaneous and extravascular ICDs—are increasingly preferred, especially in young patients, gold-coated versions of these devices are needed. To our knowledge, they are currently not available. The urgency of sudden cardiac death prevention also warrants discussion. Since the introduction of the wearable cardioverter-defibrillator (WCD), the interval between explantation of the old device and implantation of a new permanent one can be safely extended for weeks or even months, if necessary. This approach is supported by safety and effectiveness analyses.2 In our previous case report,3 commented on by Dr Zhan, we presented a patient with severe hypersensitivity to an ICD implanted for primary prevention of SCD in non-ischaemic cardiomyopathy. The benefit of ICD therapy in such patients is generally debatable, as shown in the latest extended follow-up of the DANISH trial.4 Moreover, in recent years, several studies have demonstrated that reverse remodelling—resulting in loss of indication for ICD implantation in idiopathic dilated cardiomyopathy—may occur with contemporary optimal medical therapy well beyond the conventional 3-month period, even after 1 year.5 Considering this, we believe it is reasonable to reassess the indication for reimplantation in this group, particularly when adverse events such as severe hypersensitivity occur, regardless of the time elapsed since the initial diagnosis. Reassessment is, of course, most appropriate when there is room for further optimization of pharmacotherapy. However, this approach proved ineffective in our originally presented case, and the patient ultimately required—and preferred—ICD reimplantation. In summary, hypersensitivity to CIEDs poses a significant challenge for healthcare professionals. Although large-scale data are lacking, management algorithms have emerged based on well-documented case reports and case series, as proposed by Dr Zhan. The reimplantation assessment process often requires time, which makes the WCD a practical solution. This research received no specific funding. No new data were generated or analysed for the purposes of this commentary.