Increased incidence of electrical abnormalities in a pacemaker lead family

Accurate detection of lead malfunction from ECG-derived bipolar pacing stimulus amplitude

BACKGROUND

One common mode of lead failure is insulation breach, which may result in myopotential noise and device malfunction. "Pseudo-unipolarization" of bipolar pacing stimuli, as observed from a routine 12-lead electrocardiogram (ECG) due to stimulus current leak, has been observed with insulation breaches.

OBJECTIVE

We sought to characterize this electrocardiographic finding to detect this type of lead malfunction.

METHODS

A total of 138 transvenous leads were analyzed, including 88 with known malfunction and 50 normal leads. The amplitude of a bipolar pacing stimulus on the ECG was recorded and compared with a control data set of newly implanted leads with bipolar stimuli normalized for output.

RESULTS

The malfunction group consisted of 61% right atrium and 39% right ventricle leads with mean pacing output of 2.74 V at 0.5 ms. There was a significant difference in ECG bipolar stimulus amplitudes at time of identification of failure (7.89 ± 7.56 mm/V; P < .001) compared with those of normal leads (0.86 ± 0.41 mm/V). Receiver operating characteristic curve for the prediction of lead malfunction based on absolute ECG amplitude displayed an area under the curve of 0.93 (95% CI, 0.891-0.969). When normalized for programmed stimulus output, a cutoff of 5 mm/V demonstrated a sensitivity of 91% and a specificity of 92% (area under the curve, 0.967; 95% CI, 0.938-0.996).

CONCLUSION

The maximum amplitude of a bipolar pacing stimulus on the ECG is significantly lower in normal functioning leads compared with those with known malfunction. This simply derived variable demonstrated good accuracy at identifying lead failure due to insulation breach.

Prevalence and management of electrical lead abnormalities in cardiac implantable electronic device leads

Background

Electrical lead abnormalities (ELAs) can result in device malfunction, leading to significant morbidity in patients with cardiac implantable electronic devices (CIEDs).

Objective

We sought to determine the prevalence and management of ELAs in patients with CIEDs.

Methods

This was a retrospective cohort study of patients implanted with a CIED between 2012 and 2019 at a tertiary care center. The primary outcome was ELA defined as increased capture threshold (≥2× implantation value), decreased sensing (≤0.5 implantation value), change in impedance (>50% over 3 months), or nonphysiologic potentials. A secondary outcome of device clinic utilization was also collected.

Results

There were 2996 unique patients (35% female) included with 4600 leads (57% Abbott, 43% Medtronic). ELAs were observed in 135 (3%) leads, including 124 (92%) Abbott and 10 (7%) Medtronic leads (hazard ratio 9.25, P < .001). Mean follow-up was 4.5 ± 2.2 years. ELAs were associated smaller lead French size, atrial location, and Abbott leads. Lead revision was required in 28% of cases. Patients with lead abnormalities had 38% more in-clinic visits per patient year of follow-up compared with those without (P < .001).

Conclusion

ELAs were more frequent in certain models, which increased rates of revision and follow-up. Identification of factors that mitigate these abnormalities to improve lead performance are required to improve care for these devices and provide efficient healthcare.

Optimization and Its Implementation Impact of Two-Modes Controller Fractional Approximation for Buck Converters

Additional degrees of freedom in a fractional-order control strategy for power electronic converters are well received despite the lack of reliable tuning methods. Despite artificial/swarm intelligence techniques have been used to adjust controller parameters to improve more than one characteristic/property at the same time, smart tuning not always leads to realizable structures or reachable parameter values. Thus, adjustment boundaries to ensure controller viability are needed. In this manuscript the fractional-order approach is described in terms of El-Khazali biquadratic module, which produces the lowest order approximation, instead of using a definition. A two-modes controller structure is synthesize depending on uncontrolled plant needs and parameters are adjusted through particle swarm and genetic optimization algorithms for comparison. Two error-based minimization criteria are used to consider output performance into the process. Two restrictions complement the optimization scheme, one seeks to ensure desired robustness while the other prevents from synthesizing a high-gain controller. Optimization results showed similarity between minima obtained and significant difference between parameters of those controller optimized without the proposed constraints was determined. Numerical and experimental results are provide to validate proposed approach effectiveness. Effective regulation, good tracking characteristic and robustness in the presence of load variations are the main results.

Remote monitoring of pacemakers

Exactly two decades have elapsed since pacemakers first provided automatic remote monitoring. This innovation has been well received by patients. However, there is still a widely held perception that remote monitoring of pacemakers is non-essential, despite the very similar gains that are achieved compared with remote monitoring of implantable cardioverter defibrillators. Reducing in-office evaluations and overall staff workload is important when these resources are stretched to their limits. The early detection ability provided by remote monitoring facilitates device management (extending battery longevity) and the ability to exercise vigilance over recalled components. Clinical complications, such as arrhythmic events, are also detected earlier. Remote monitoring has been shown to produce similar reductions in the risk of all-cause hospitalization and death for pacemakers and implantable cardioverter defibrillators in a mega-cohort observational study. This review is an evidence-based plea for the recognition and systematic implementation of remote monitoring for pacemakers.

Electrical abnormalities with St. Jude/Abbott pacing leads: A systematic review and meta-analysis

BACKGROUND

Although there is a paucity of contemporary data on pacemaker lead survival rates, small studies suggest that some leads may have higher malfunction rates than do others.

OBJECTIVE

The purpose of this study was to determine the malfunction rates of current pacemaker leads.

METHODS

A meta-analysis including studies that examined the non-implant-related lead malfunction rates of current commercially available active fixation pacemaker leads was performed. An electronic search of MEDLINE/PubMed, Scopus, and Embase was performed. DerSimonian and Laird random effects models were used.

RESULTS

Eight studies with a total of 14,579 leads were included. Abbott accounted for 10,838 (74%), Medtronic 2510 (17%), Boston Scientific 849 (6%), and MicroPort 382 (3%) leads. The weighted mean follow-up period was 3.6 years. Lead abnormalities occurred in 5.0% of all leads, 6.1% of Abbott leads, 1.1% of Medtronic, 1.4% of Boston Scientific, and 5.5% of MicroPort. The most common lead abnormality was lead noise with normal impedance. Abbott leads were associated with an increased risk of abnormalities (relative risk [RR] 7.81; 95% confidence interval [CI] 3.21-19.04), reprogramming (RR 7.95; 95% CI 3.55-17.82), and lead revision or extraction (RR 8.91; 95% CI 3.36-23.60). Abbott leads connected to an Abbott generator had the highest abnormality rate (8.0%) followed by Abbott leads connected to a non-Abbott generator (4.7%) and non-Abbott leads connected to an Abbott generator (0.4%).

CONCLUSIONS

Abbott leads are associated with an increased risk of abnormalities compared with leads of other manufacturers, primarily manifesting as lead noise with normal impedance, and are associated with an increased risk of lead reprogramming and lead revision or extraction.

RF. Fatigue Testing of Wearable Sensing Technologies: Issues and Opportunities

Standards for the fatigue testing of wearable sensing technologies are lacking. The majority of published fatigue tests for wearable sensors are performed on proof-of-concept stretch sensors fabricated from a variety of materials. Due to their flexibility and stretchability, polymers are often used in the fabrication of wearable sensors. Other materials, including textiles, carbon nanotubes, graphene, and conductive metals or inks, may be used in conjunction with polymers to fabricate wearable sensors. Depending on the combination of the materials used, the fatigue behaviors of wearable sensors can vary. Additionally, fatigue testing methodologies for the sensors also vary, with most tests focusing only on the low-cycle fatigue (LCF) regime, and few sensors are cycled until failure or runout are achieved. Fatigue life predictions of wearable sensors are also lacking. These issues make direct comparisons of wearable sensors difficult. To facilitate direct comparisons of wearable sensors and to move proof-of-concept sensors from "bench to bedside", fatigue testing standards should be established. Further, both high-cycle fatigue (HCF) and failure data are needed to determine the appropriateness in the use, modification, development, and validation of fatigue life prediction models and to further the understanding of how cracks initiate and propagate in wearable sensing technologies.

Fractional-Order Approximation of PID Controller for Buck-Boost Converters

Viability of a fractional-order proportional-integral-derivative (PID) approximation to regulate voltage in buck-boost converters is investigated. The converter applications range not only to high-power ones but also in micro/nano-scale systems from biomedicine for energy management/harvesting. Using a classic closed-loop control diagram the controller effectiveness is determined. Fractional calculus is considered due to its ability at modeling different types of systems accurately. The non-integer approach is integrated into the control strategy through a Laplacian operator biquadratic approximation to generate a flat phase curve in the system closed-loop frequency response. The controller synthesis considers both robustness and closed-loop performance to ensure a fast and stable regulation characteristic. A simple tuning method provides the appropriate gains to meet design requirements. The superiority of proposed approach, determined by comparing the obtained time constants with those from typical PID controllers, confirms it as alternative to controller non-minimum phases systems. Experimental realization of the resulting controller, implemented through resistor-capacitor (RC) circuits and operational amplifiers (OPAMPs) in adder configuration, confirms its effectiveness and viability.