Trends and Implications of DF-4 Implantable Cardioverter-Defibrillator Lead Adoption in the United States of America

Long-term performance of single-connector (DF4) implantable defibrillator leads

AIMS

Single-connector (DF4) defibrillator leads have become the predominantly implanted transvenous implantable cardioverter-defibrillator lead. However, data on their long-term performance are derived predominantly from manufacturer product performance reports.

METHODS AND RESULTS

We reviewed medical records in 5289 patients with DF4 leads between 2011 and 2023 to determine the frequency of lead-related abnormalities. We defined malfunction as any single or combination of electrical abnormalities requiring revision including a sudden increase (≥2×) in stimulation threshold, a discrete jump in high-voltage impedance, or sensing of non-physiologic intervals or noise. We documented time to failure, predictors of failure, and management strategies. Mean follow-up after implant was 4.15 ± 3.6 years (median = 3.63), with 37% of leads followed for >5 years. A total of 80 (1.5%) leads demonstrated electrical abnormalities requiring revision with an average time to failure of 4 ± 2.8 years (median = 3.5). Of the leads that malfunctioned, 62/80 (78%) were extracted and replaced with a new lead and in the other 18 cases, malfunctioned DF4 leads were abandoned, and a new lead implanted. In multivariable models, younger age at implant (OR 1.03 per year; P < 0.001) and the presence of Abbott/St. Jude leads increased the risk of malfunction.

CONCLUSION

DF4 defibrillator leads demonstrate excellent longevity with >98.3% of leads followed for at least 5 years still functioning normally. Younger age at implant and lead manufacturer are associated with an increased risk of DF4 lead malfunction. The differences in lead survival between manufacturers require further investigation.

Downgrade of cardiac defibrillator devices to pacemakers in elderly heart failure patients: clinical considerations and the importance of shared decision-making

Implantable cardioverter defibrillators are implanted on a large scale in patients with heart failure (HF) for the prevention of sudden cardiac death. There are different scenarios in which defibrillator therapy is no longer desired or indicated, and this is occurring increasingly in elderly patients. Usually device therapy is continued until the device has reached battery depletion. At that time, the decision needs to be made to either replace it or to downgrade to a pacing-only device. This decision is dependent on many factors, including the vitality of the patient and his/her preferences, but may also be influenced by changes in recommendations in guidelines. In the last few years, there has been an increased awareness that discussions around these decisions are important and useful. Advanced care planning and shared decision-making have become important and are increasingly recognised as such. In this short review we describe six elderly patients with HF, in whose cases we discussed these issues, and we aim to provide some scientific and ethical rationale for clinical decision-making in this context. Current guidelines advocate the discussion of end-of-life options at the time of device implantation, and physicians should realise that their choices influence patients’ options in this critical phase of their illness.

Examining the Need to Standardize Implanted Stimulator Connectors: NANS Survey Results

INTRODUCTION

Connectors between implanted stimulator electrodes and pulse generators allow revisions, including battery changes or generator upgrades, to proceed without disturbing uninvolved components, such as the electrode. As new devices are introduced, however, connector incompatibility, even with updated hardware from the same manufacturer, can lead to additional procedures, expense, and morbidity.

MATERIALS AND METHODS

Following the example of the cardiac pacemaker/defibrillator industry, the Institute of Neuromodulation (IoN) met to explore the possibility of creating connector standards for implanted neurostimulation devices. At a subsequent meeting of the Association for the Advancement of Medical Instrumentation, which coordinates the development of such standards, industry representatives asked for data defining the need for a new standard. Accordingly, IoN prepared an online survey to be sent to the North American Neuromodulation Society mailing list regarding experience with the connectivity of spinal cord stimulation (SCS) generators and electrodes.

RESULTS

The 87 respondents of 9657 surveyed included 77 clinicians, who reported a total of 42,572 SCS implants and revisions. More than a quarter of revisions (2741 of 9935) required the interconnection of devices made by separate manufacturers, in most cases (n = 1528) to take advantage of a new feature (e.g., rechargeability, new waveform) or because an original component could not be replaced (n = 642). Connector adapters provided by manufacturers were used in less than half (n = 1246) of these cases. Nearly all (94%) of the clinicians agreed that standardized connectors should be developed for SCS, and 86% opined that standardized connectors should be developed for other neurostimulation therapies.

CONCLUSION

Those who responded to our survey support the development of standard connectors for implanted stimulators, with voluntary compliance by manufacturers, to mitigate the need for adapters and facilitate interchanging components when appropriate. Other advantages to patients and manufacturers might accrue from the adoption of standards, as technology evolves and diversifies.