Safety and efficacy of hydrogen peroxide plasma sterilization for repeated use of electrophysiology catheters.

OBJECTIVES: The purpose of this study was to evaluate a new technique for sterilizing nonlumen electrophysiology catheters that uses hydrogen peroxide gas plasma. BACKGROUND: The reuse of electrophysiology catheters may potentially result in a significant cost savings. While ethylene oxide sterilization appears to be safe and effective from a clinical standpoint, toxic ethylene oxide residuals, which exceed Food and Drug Administration standards, have been reported. METHODS: Ten nonlumen electrophysiology catheters were extensively evaluated. Each catheter was used five times and resterilized after each use with hydrogen peroxide gas plasma. Tests for sterility, mechanical and electrical integrity, chemical residuals and standard and electron microscopic inspection were performed. RESULTS: Loss of electrical integrity or mechanical integrity was not observed in any catheter. No evidence of microbial contamination was found. Surface integrity was preserved except for one ablation catheter that exhibited fraying of the insulation at the insulation-electrode interface. Surface inspection using standard magnification and electron microscopy revealed no significant change in surface characteristics associated with the sterilization process. Hydrogen peroxide was the only chemical residual noted, with an average concentration of 0.22% by weight, which is within accepted American Association for the Advancement of Medical Instrumentation limits. The cost for a standard electrophysiology catheter ranges from $200 to $800, and one sterilization cycle costs $10. If electrophysiology catheters are used five times, resterilization could potentially result in a savings of $2,000 per catheter, or $9,000 for five ablation procedures. CONCLUSIONS: Hydrogen peroxide gas plasma sterilization may provide a cost-effective means of sterilizing nonlumen electrophysiology catheters without the problem of potentially harmful chemical residuals. However, careful visual inspection of catheters, particularly at the insulation-electrode interface, is required if catheter reuse is performed.

Radiofrequency catheter ablation versus medical therapy for initial treatment of supraventricular tachycardia and its impact on quality of life and healthcare costs.

We prospectively compared the impact on quality of life and cost effectiveness between ablation and medication as an initial strategy for patients with paroxysmal supraventricular tachycardia (SVT). Seventy-nine consecutive patients with newly documented paroxysmal SVT were treated with either ablation or medication. Health surveys (SF-36 and disease-specific questions) were obtained at baseline and after 12 months of follow up. Cost of health care utilization for the 6 months before and after treatment were measured. Both medication and ablation improved quality of life. However, ablation improved quality of life in more general health categories than medication. At follow up, ablation was associated with significantly improved quality of life in the bodily pain (63+/-24 vs 81+/-20, p <0.005), general health (69+/-21 vs 79+/-21, p <0.05), vitality (55+/-21 vs 66+/-22, p <0.05), and role emotion (78+/-36 vs 94+/-17, p <0.05) categories when compared with medication. Although both medication and ablation decreased frequency of disease-specific symptoms, ablation resulted in complete amelioration of symptoms in more patients (33% vs 74%). Potential long-term costs were similar for medication and ablation. In conclusion, ablation improves health-related quality of life to a greater extent, and in more aspects of general and disease-specific health than medication.

Trends and patterns in electrophysiologic and ablation catheter reuse in the United States.

In a survey of 140 electrophysiologic laboratories in the USA, 49% reuse catheters to some extent. Catheter reuse is associated with significant reductions in cost but is not conducted in a standardized fashion.

A left free-wall, decrementally conducting, atrioventricular (Mahaim) fiber: diagnosis at electrophysiological study and radiofrequency catheter ablation guided by direct recording of a Mahaim potential.

A 64-year-old female with Wolff-Parkinson-White syndrome and an ECG demonstrating a right posterolateral accessory pathway was referred for electrophysiological study. During electrophysiological testing two AV pathways were identified: a right posterolateral pathway that displayed conventional electrophysiological properties: and a left free-wall pathway that conducted only anterogradely and demonstrated decremental properties. Two separate wide complex tachycardias were induced that utilized the left free-wall pathway anterogradely and either the AV node or the right posterolateral accessory pathway retrogradely. A discrete electrical potential on the free wall of the mitral annulus was identified during tachycardia and was utilized to facilitate mapping and ablation.

Modulation of terminal deoxynucleotidyltransferase activity by the DNA-dependent protein kinase.

Rare Ig and TCR coding joints can be isolated from mice that have a targeted deletion in the gene encoding the 86-kDa subunit of the Ku heterodimer, the regulatory subunit of the DNA-dependent protein kinase (DNA-PK). However in the coding joints isolated from Ku86-/- animals, there is an extreme paucity of N regions (the random nucleotides added during V(D)J recombination by the enzyme TdT). This finding is consistent with a decreased frequency of coding joints containing N regions isolated from C.B-17 SCID mice that express a truncated form of the catalytic subunit of the DNA-PK (DNA-PKCS). This finding suggests an unexpected role for DNA-PK in addition of N nucleotides to coding ends during V(D)J recombination. In this report, we establish that TdT forms a stable complex with DNA-PK. Furthermore, we show that DNA-PK modulates TdT activity in vitro by limiting both the length and composition of nucleotide additions.