Out with the old: Single center experience with transvenous extraction of leads older than 15 years

BACKGROUND

Lead dwell time is the single strongest predictor of failure and complications in transvenous lead extraction.

OBJECTIVES

To report the success rate and complications of transvenous lead extractions with implant dwell time of at least 15 years.

METHODS

Procedural and patient data were prospectively collected into a database. The excimer laser was the primary method for lead extraction with the use of mechanical rotational sheaths and femoral snares at operator discretion.

RESULTS

A total of 442 patients between 2011 and 2020 underwent lead extraction (705 leads) primarily for infection or device failure at our high-volume center. Forty-one patients with 71 leads > 15 years old were included in this cohort. Mean patient age was 53.5 ± 18.5 years, 67.5% were male. Mean lead dwell time was 19.6 ± 4.4 years. Thirty-six of 41 (88%) patients had successful extraction of all leads compared to 96% in the remaining 401 patients, p value.004. Of the five patients without fully successful extractions two of these patients had abandoned leads (three total) that were clinically significant. There were two (4.9%) major complications in the very old lead group and six (1.5%) in the other group. In the very old lead group, one patient experienced right atrial appendage perforation requiring surgical repair and recovered well. One patient experienced new complete heart block requiring 2 min of CPR but did well thereafter. There was no procedure-related mortality.

CONCLUSIONS

Despite challenges posed by older leads, very old leads can be safely and effectively extracted with low complication rates.

Impact of fixation mechanism and helix retraction status on right ventricular lead extraction

Background

The impact of lead fixation mechanism on extractability is poorly characterized.

Objective

We aimed to compare the technical difficulty of transvenous lead extraction (TLE) of active vs passive fixation right ventricular (RV) leads.

Methods

A total of 408 patients who underwent RV TLE by a single expert electrophysiologist at Oregon Health & Science University between October 2011 and June 2022 were identified and retrospectively analyzed; 331 (81%) had active fixation RV leads and 77 (19%) had passive fixation RV leads. The active fixation cohort was further stratified into those with successfully retracted helices (n = 181) and failed helix retraction (n = 109). A numerical system (0-9) devised using 6 procedural criteria quantified a technical extraction score (TES) for each RV TLE. The TES was compared between groups.

Results

Helix retraction was successful in ≥55% of active fixation TLEs. The mean TES for active-helix retracted, active-helix non-retracted, and passive fixation groups was 1.8, 3.5, and 3.7, respectively. The TES of the active-helix retracted group was significantly lower than those of the active-helix non-retracted group (adjusted P < .01) and the passive fixation group (adjusted P < .01). There was no significant difference in TES between the passive fixation and active-helix non-retracted groups in multivariate analysis (P = .18). The TLE success rate of the entire cohort was >97%, with a major complication rate of 0.5%.

Conclusion

TLE of active fixation leads where helical retraction is achieved presents fewer technical challenges than does passive fixation RV lead extraction; however, if the helix cannot be retracted, active and passive TLE procedures present similar technical challenges.

Does Sex Modify an Association of Electrophysiological Substrate with Sudden Cardiac Death? The Atherosclerosis Risk in Communities (ARIC) Study

Background

Sex is a well-recognized risk factor for sudden cardiac death (SCD). We hypothesized that sex modifies the association of electrophysiological (EP) substrate with SCD.

Objective

The purpose of this study was to determine whether there are sex differences in electrocardiographic (ECG) measures and whether sex modifies the association of ECG measures of EP substrate with SCD.

Methods

Participants from the Atherosclerosis Risk in Communities study with analyzable ECGs (n = 14,725; age 54.2 ± 5.8 years; 55% female; 74% white) were included. EP substrate was characterized by heart rate, QRS, QTc, Cornell voltage, spatial ventricular gradient (SVG), and sum absolute QRST integral (SAI QRST) ECG metrics. Two competing outcomes were adjudicated: SCD and non-SCD. Interaction of ECG metrics with sex was studied in Cox proportional hazards and Fine-Gray competing risk models. Model 1 was adjusted for prevalent cardiovascular disease (CVD) and risk factors. Time-updated model 2 was additionally adjusted for incident nonfatal CVD. Relative hazard ratio (RHR) and relative subhazard ratio with 95% confidence interval (CI) for SCD and non-SCD risk for women relative to men were calculated. Model 1 was adjusted for prevalent CVD and risk factors. Time-updated model 2 was additionally adjusted for incident nonfatal CVD.

Results

Over median follow-up of 24.4 years, there were 530 SCDs (incidence 1.72; 95% CI 1.58–1.88 per 1000 person-years). Women compared to men experienced a greater risk of SCD associated with Cornell voltage (RHR 1.18; 95% CI 1.06–1.32; P = .003), SAI QRST (RHR 1.16; 95% CI 1.04–1.30; P = .007), and SVG magnitude (RHR 1.24; 95% CI 1.05–1.45; P = .009), independently from incident CVD.

Conclusion

In women, the global EP substrate is associated with up to 24% greater risk of SCD than in men, suggesting differences in underlying mechanisms and the need for sex-specific SCD risk stratification.

Mechanisms of Arrhythmogenicity in Hypertrophic Cardiomyopathy: Insight From Non-invasive Electrocardiographic Imaging

Background

Mechanisms of arrhythmogenicity in hypertrophic cardiomyopathy (HCM) are not well understood.

Objective

To characterize an electrophysiological substrate of HCM in comparison to ischemic cardiomyopathy (ICM), or healthy individuals.

Methods

We conducted a prospective case-control study. The study enrolled HCM patients at high risk for ventricular tachyarrhythmia (VT) [n = 10; age 61 ± 9 years; left ventricular ejection fraction (LVEF) 60 ± 9%], and three comparison groups: healthy individuals (n = 10; age 28 ± 6 years; LVEF > 70%), ICM patients with LV hypertrophy (LVH) and known VT (n = 10; age 64 ± 9 years; LVEF 31 ± 15%), and ICM patients with LVH and no known VT (n = 10; age 70 ± 7 years; LVEF 46 ± 16%). All participants underwent 12-lead ECG, cardiac CT or MRI, and 128-electrode body surface mapping (BioSemi ActiveTwo, Netherlands). Non-invasive voltage and activation maps were reconstructed using the open-source SCIRun (University of Utah) inverse problem-solving environment.

Results

In the epicardial basal anterior segment, HCM patients had the greatest ventricular activation dispersion [16.4 ± 5.5 vs. 13.1 ± 2.7 (ICM with VT) vs. 13.8 ± 4.3 (ICM no VT) vs. 8.1 ± 2.4 ms (Healthy); P = 0.0007], the largest unipolar voltage [1094 ± 211 vs. 934 ± 189 (ICM with VT) vs. 898 ± 358 (ICM no VT) vs. 842 ± 90 μV (Healthy); P = 0.023], and the greatest voltage dispersion [median (interquartile range) 215 (161–281) vs. 189 (143–208) (ICM with VT) vs. 158 (109–236) (ICM no VT) vs. 110 (106–168) μV (Healthy); P = 0.041]. Differences were also observed in other endo-and epicardial basal and apical segments.

Conclusion

HCM is characterized by a greater activation dispersion in basal segments, a larger voltage, and a larger voltage dispersion through LV.

Clinical Trial Registration

www.clinicaltrials.gov Unique identifier: NCT02806479.

Bringing Critical Race Praxis Into the Study of Electrophysiological Substrate of Sudden Cardiac Death: The ARIC Study

Background Race is an established risk factor for sudden cardiac death (SCD). We sought to determine whether the association of electrophysiological substrate with SCD varies between black and white individuals. Methods and Results Participants from the ARIC (Atherosclerosis Risk in Communities) study with analyzable ECGs (n=14 408; age, 54±6 years; 74% white) were included. Electrophysiological substrate was characterized by ECG metrics. Two competing outcomes were adjudicated: SCD and non-SCD. Interaction of ECG metrics with race was studied in Cox proportional hazards and Fine-Gray competing risk models, adjusted for prevalent cardiovascular disease, risk factors, and incident nonfatal cardiovascular disease. At the baseline visit, adjusted for age, sex, and study center, blacks had larger spatial ventricular gradient magnitude (0.30 mV; 95% CI, 0.25-0.34 mV), sum absolute QRST integral (18.4 mV*ms; 95% CI, 13.7-23.0 mV*ms), and Cornell voltage (0.30 mV; 95% CI, 0.25-0.35 mV) than whites. Over a median follow-up of 24.4 years, SCD incidence was higher in blacks (2.86 per 1000 person-years; 95% CI, 2.50-3.28 per 1000 person-years) than whites (1.37 per 1000 person-years; 95% CI, 1.22-1.53 per 1000 person-years). Blacks with hypertension had the highest rate of SCD: 4.26 (95% CI, 3.66-4.96) per 1000 person-years. Race did not modify an association of ECG variables with SCD, except QRS-T angle. Spatial QRS-T angle was associated with SCD in whites (hazard ratio, 1.38; 95% CI, 1.25-1.53) and hypertension-free blacks (hazard ratio, 1.52; 95% CI, 1.09-2.12), but not in blacks with hypertension (hazard ratio, 1.15; 95% CI, 0.99-1.32) (P-interaction=0.004). Conclusions Race did not modify associations of electrophysiological substrate with SCD and non-SCD. Electrophysiological substrate does not explain racial disparities in SCD rate.

Collagen microsphere serving as a cell carrier supports oligodendrocyte progenitor cell growth and differentiation for neurite myelination in vitro

Introduction

Microspheres fabricated from natural materials serve as a promising biodegradable and biocompatible carrier in a small volume for efficient cell delivery to the lesion of the injured neural tissue to generate biological functions. As the major component of extracellular matrix and due to its natural abundance within the body, collagen may be fabricated into microspheres and improve the ability of pre-seeded cells on the microspheres to encounter the hostile micro-environment in the lesion.

Methods

In this study, collagen microspheres were fabricated using the water-in-oil emulsion technique and cross-linked with 1-ethyl-3-(3-dimethylaminopropryl) carbodiimide. Oligodendrocyte progenitor cells isolated from postnatal day P1 to 2 rats were cultured and differentiated on the microspheres. The microspheres carrying the oligodendrocyte progenitor cells were co-cultured with dorsal root ganglions from 15-day-old rat embryos. The myelination formation was studied for the co-culture of oligodendrocyte progenitor cells and dorsal root ganglions.

Results

We showed that the viability of oligodendrocyte progenitor cells, B104 cells and PC12 cells grown on microspheres was not significantly different with those in cell culture plates. Oligodendrocyte progenitor cells differentiated into oligodendrocytes on collagen microspheres. The oligodendrocytes grown on microspheres extended processes that wrapped the axons of dorsal root ganglion neurons and the formation of myelin sheath was observed in the co-culture.

Conclusions

This study demonstrates the feasibility of collagen microspheres in further applications for the delivery of neural progenitor cells for neural regeneration.

CD40 ligand expression deficiency in a female carrier of the X-linked hyper-IgM syndrome as a result of X chromosome lyonization

We report on the case of a girl with an immune deficiency characterized by recurrent infections of the upper and lower respiratory tract, low IgG and IgA serum levels as well as deficiency of the in vivo antibody response. Since this patient is the sister of a boy affected with a hyper-IgM syndrome due to a defect in CD40 ligand (CD40L) expression, the involvement of CD40L in this phenotypic expression was investigated. A very low fraction of activated T cells (5%) in this female patient expressed CD40L. This resulted from the presence of a heterozygous CD40L nonsense mutation associated with a skewed pattern of X chromosome inactivation as determined by methylation pattern analysis. Although carriers of X-linked hyper-IgM are considered to be asymptomatic, this study indicates that extreme lyonization of the normal X can lead to a mild expression of the hyper-IgM syndrome which is similar to common variable immune deficiency (CVID). Therefore, it is possible that some cases of CVID in females represent partial deficiency of CD40L expression in carriers of the CD40L mutation.

[Value and limits of selective bronchial obstruction in neonatal unilateral interstitial emphysema]

BACKGROUND

Two methods of selective ventilation have been used for treating severe localized pulmonary emphysema in the neonates: controlateral selective intubation and selective bronchial obstruction.

CASE REPORTS

Three neonates with acute respiratory distress required respiratory support that was complicated by development of severe localized pulmonary interstitial emphysema of the right lobe (two cases) and the middle lobe (one case). Selective bronchial obstruction with a Swann Ganz catheter SF was tentatively made: in one case, improvement was moderate and transitory, requiring middle lobectomy. The localized emphysema disappeared within 3 days in the two other cases but a localized emphysema appeared in the controlateral lung in one of them, requiring left inferior lobectomy because the ineffectiveness of selective intubation or selective obstruction.

CONCLUSION

Selective bronchial obstruction may fail but this easy and well tolerated method should be tried in severe localized emphysema, specially in those patients who cannot be ventilated with high-frequency oscillation.