Long-Term Follow-up of Transvenous Defibrillation Leads High Incidence of Fracture in Coaxial Polyurethane Lead

Security millimetre wave body scanner safe for patients with leadless pacemakers or subcutaneous implantable cardioverter-defibrillators

PURPOSE

This study was designed to evaluate the electromagnetic interference (EMI) effects and safety of the new security screening millimetre wave body scanners (MWBSs) for patients with rare cardiac implantable electronic devices (CIEDs).

METHODS

We identified 73 patients with either entirely subcutaneous implantable cardioverter-defibrillators (S-ICD) or leadless pacemakers (LPM) attending routine device follow-up. CIED programming was optimised for the detection of EMI occurrence, and high-voltage therapy was disabled. Patients then underwent millimetre wave body scans under continuous ECG monitoring. Scanning was performed at the recommended distance as well as in close proximity to the scanner emulating accidental exposure. CIED function was observed for EMI effects.

RESULTS

There were no episodes of inhibition of pacing in the leadless pacemaker subgroup, no oversensing in the S-ICD subgroup and no spontaneous device reprogramming in any group. There was no change in pacing or sensing thresholds, and S-ICD vector eligibility remained unchanged after scanning with the MWBS. No CIEDs were identified by the MWBS during the study.

CONCLUSION

No EMI events were detected during the use of MWBSs by patients with either S-ICDs or LPMs. This data should be reassuring for patients suggesting that they can undergo security body scans without worries or disclosure of their CIED status.

Neointimal fibrotic lead encapsulation - Clinical challenges and demands for implantable cardiac electronic devices

Every tenth patient with a cardiac pacemaker or implantable cardioverter-defibrillator implanted is expected to have at least one lead problem in his lifetime. However, transvenous leads are often difficult to remove due to thrombotic obstruction or extensive neointimal fibrotic ingrowth. Despite its clinical significance, knowledge on lead-induced vascular fibrosis and neointimal lead encapsulation is sparse. Although leadless pacemakers are already available, their clinical operating range is limited. Therefore, lead/tissue interactions must be further improved in order to improve lead removals in particular. The published data on the coherences and issues related to lead associated vascular fibrosis and neointimal lead encapsulation are reviewed and discussed in this paper.

Advances in sudden death prevention: the emerging role of a fully subcutaneous defibrillator

Randomized clinical trials support the use of implantable defibrillators for mortality reduction in specific populations at high risk for sudden cardiac death. Conventional transvenous defibrillator systems are limited by implantation-associated complications, infection, and lead failure, which may lead to delivery of inappropriate shocks and diminish survival. The development of a fully subcutaneous defibrillator may represent a valuable addition to therapies targeted at sudden death prevention. The PubMed database was searched to identify all clinical reports of the subcutaneous defibrillator from 2000 to the present. We reviewed all case series, cohort analyses, and randomized trials evaluating the safety and efficacy of subcutaneous defibrillators. The subcutaneous defibrillator is a feasible development in sudden cardiac death therapy and may be useful particularly to extend defibrillator therapy to patients with complicated anatomy, limited vascular access, and congenital disease. The subcutaneous defibrillator should not be considered in patients with an indication for cardiac pacing or who have ventricular tachycardia responsive to antitachycardia pacing. Further investigation is needed to compare long-term, head-to-head performance of subcutaneous defibrillators and conventional transvenous defibrillator systems.

Risk of failure of transvenous implantable cardioverter-defibrillator leads

BACKGROUND

Despite the positive effect on mortality in selected patients, implantable cardioverter-defibrillator therapy is also associated with potential malfunction of the implanted system. The present study provides the long-term lead failure rate in a large single-center cohort.

METHODS AND RESULTS

Since 1992, a total of 2068 implantable cardioverter-defibrillator patients with 2161 defibrillation leads were prospectively collected. Data of the implant procedure and all follow-up visits were recorded. All cases of lead removal or capping or placing of an additional pace or sense lead were noted and analyzed. Lead models were grouped by manufacturer and approximate lead diameter in French. During a mean follow-up of 36 months, 82 (3.8%) cases of lead failure were identified. Cumulative incidence of lead failure at 1 year was 0.6%; at 5 years, 6.5%; and at 10 years, 16.4%. The highest risk of lead failure was found in small-diameter leads. Adjusted hazard ratio was 6.4 (95% CI, 3.2 to 12.8) for Medtronic 7F leads, when compared with all other leads.

CONCLUSIONS

In this large single-center experience, the overall incidence of lead failure was 1.3 (95% CI, 1.0 to 1.6) per 100 lead-years. Comparison of different groups of leads shows major differences in event rates. Specific manufacturer's small-diameter defibrillation leads may have a higher risk of early lead failure.

Atrial and ventricular lead insulation defects with resulting inappropriate shocks and end-of-life of the ICD pulse generator in a young bodybuilder with congenital long-QT-syndrome

We report on a 19-year-old male with a congenital Long-QT syndrome who was admitted to our hospital because of insulation defects of both atrial and ventricular ICD leads resulting in inappropriate delivered shocks and a non-responding pulse generator during telemetrical evaluation. The insulation defects led to multiple arc marks within the ICD pocket and there was a short circuit between denuded leads and the electrically active pulse generator. The high current flow generated sufficient heat to damage several circuits of the generator. A new ICD system was implanted successfully and the postoperative course has been remained uneventful for almost 6 years.

Safety and efficacy of transvenous high-voltage implantable cardioverter-defibrillator leads in high-risk hypertrophic cardiomyopathy patients

BACKGROUND

The implantable cardioverter-defibrillator (ICD) prevents sudden cardiac death in high-risk patients with hypertrophic cardiomyopathy (HCM). However, recently concerns have been raised regarding the performance of transvenous high-voltage ICD leads (HVL) in this population.

OBJECTIVE

The purpose of this retrospective, multicenter study was to assess the safety and efficacy of HVL in high-risk HCM patients.

METHODS

The study population consisted of HCM patients who received HVL ICDs and were subsequently followed at seven centers in the United States. Kaplan-Meier survival rates were calculated for HVL and patients. HVL failure was a malfunction caused by a noniatrogenic defect.

RESULTS

Between 1992 and 2007, 324 HCM patients (mean age 47 +/- 16 years) received 343 HVL from three major manufacturers. The average HVL implant duration was 3.3 +/- 2.8 years. Overall, the HVL failure rate was 1.4%/year. However, two models (Sprint Fidelis and Transvene, Medtronic, Inc.) accounted for 60% of HVL failures. Survival probabilities for HVL and patients at 10 years were 93% and 91%, respectively. No deaths or serious injuries were reported, although inappropriate shocks occurred in 12% of cases.

CONCLUSIONS

This multicenter experience shows that HVLs are safe and effective in high-risk HCM patients. However, differences in failure rates were found between lead models.

Annual rate of transvenous defibrillation lead defects in implantable cardioverter-defibrillators over a period of >10 years

BACKGROUND

The number of patients with longer follow-up after implantation of an implantable cardioverter-defibrillator is increasing continuously. Defibrillation lead failure is a typical long-term complication. Therefore, the long-term reliability of implantable cardioverter-defibrillator leads has become an increasing concern. The aim of the present study was to assess the annual rate of transvenous defibrillation lead defects related to follow-up time after lead implantation.

METHODS AND RESULTS

A total of 990 consecutive patients who underwent first implantation of an implantable cardioverter-defibrillator between 1992 and May 2005 were analyzed. Median follow-up time was 934 days (interquartile range, 368 to 1870). Overall, 148 defibrillation leads (15%) failed during the follow-up. The estimated lead survival rates at 5 and 8 years after implantation were 85% and 60%, respectively. The annual failure rate increased progressively with time after implantation and reached 20% in 10-year-old leads (P<0.001). Lead defects affected newer as well as older models. Patients with lead defects were 3 years younger at implantation and more often female. Multiple lead implantation was associated with a trend to a higher rate of defibrillation lead defects (P=0.06). The major lead complications were insulation defects (56%), lead fractures (12%), loss of ventricular capture (11%), abnormal lead impedance (10%), and sensing failure (10%).

CONCLUSIONS

An increasing annual lead failure rate is noted primarily during long-term follow-up and reached 20% in 10-year-old leads. Patients with lead defects are younger and more often female.

Amiodarone Therapy in Patients Implanted With Cardioverter-Defibrillator for Life-Threatening Ventricular Arrhythmias

BACKGROUND

Whether amiodarone can improve the patient's clinical outcome by reducing implantable cardioverter-defibrillator (ICD) therapy deliveries for ventricular tachycardia or fibrillation (VT/VF) has not been clearly evaluated.

METHODS AND RESULTS

A total of 507 patients with VT/VF due to organic heart disease who had ICDs implanted were enrolled in this study. The patients were divided into 3 groups: Amiodarone (n=247), Class I anti-arrhythmic drug (n=103) and CONTROL (n=157) groups, and the total cause mortality and arrhythmic event free survival rates were evaluated between the groups. The mean follow-up period was 38+/-27 months. The left ventricular ejection fraction was significantly decreased in the Amiodarone group (Amiodarone: 37+/-15%; Class I: 39+/-16%;

CONTROL

44+/-17%). The mortality and arrhythmic events were significantly higher in the Class I group than the Amiodarone group (p<0.05), but there was no significant difference between the Amiodarone and CONTROL groups (arrhythmic event free rate at 5 years: Amiodarone: 53%; Class I: 35%;

CONTROL

48%; 5 year survival: 86%, 74% and 77%, respectively). Side effects from amiodarone were found in 12% of the patients, but no fatal events were observed.

CONCLUSIONS

The present study could not demonstrate the benefit of amiodarone in ICD patients, probably due to a significant clinical bias exerted in selecting this drug.