Implantable Cardioverter-defibrillator Failure Research Articles

Can we predict and prevent adverse events related to high-voltage implantable cardioverter defibrillator lead failure?

In 2007, great concern arose regarding failure of implantable cardioverter defibrillator (ICD) leads from several manufacturers. Of this analysis was to evaluate the incidence and predictors of Sprint Fidelis lead failure in order to find the best clinical strategy to prevent lead-related adverse events. Four hundred fourteen patients (357 male, 67 ± 12 years) with ICD equipped with right ventricular Sprint Fidelis leads were followed up in our institution. Over a median follow-up of 35 months (25th-75th percentile = 27-47 months) and a total follow-up of 1,231 patient-years, lead failures occurred in 40 of 414 (9.7%) patients. The annual rate was 3.2% per patient-year. Thirty-five (87.5%) failures were caused by pacing-sensing connector fracture. The risk of lead fracture was higher in patients younger than 70 years (odds ratio = 2.31; 95% confidence interval = 1.14-4.68, p = 0.02). Among 30 patients with pacing-sensing conductor failure and available device diagnostics for failure alerting, the diagnostic parameter which first responded to lead failure was the sensing integrity counter in 15 of 30 (50%), pacing impedance in 12 of 30 (40%), and non-sustained ventricular tachycardia in 3 of 30 (10%). The median time (25th-75th percentile) between diagnostics alert and lead failure-related adverse events or failure acknowledgment was 2.2 (0.3-13.0) days. Twenty-two patients suffered inappropriate shocks due to lead failure. In 50% of patients, daily monitoring by device diagnostics would have alerted physicians to impending lead failure at least 1 day in advance. Automatic algorithms based on device diagnostics may detect impending lead failure in nearly 50% of cases. Remote monitoring may prevent failure-related adverse events.

Charge Circuit Timeout

Since the advent of the implantable cardioverter-defibrillator (ICD) for primary prevention of sudden cardiac death, much attention has been given to the possibility of ICD or lead hardware failures resulting in inappropriate ICD function. Less attention has been given to the potential for software programming errors resulting in inappropriate device behavior. We report a case of a software programming error that led to a premature “end of service” alert that triggered a “lock-up” of the device antitachycardia therapies. Typically, the capacitor charge time for the Medtronic Secura ICD in anticipation of a full energy shock is about 7.7 to 9.2 seconds, depending on how close the device is to the elective replacement time and other factors.1 A charge circuit timeout indicates that at least 1 charging period exceeded 30 seconds. When 3 consecutive charging periods each exceed 30 seconds, the ICD charge circuit becomes inactive, and all automatic therapy functions and manual system tests become disabled except for emergency VVI pacing, all for the purpose of conserving battery voltage for pacemaker dependent patients when the generator reaches end of service.1 An alert is displayed to indicate that the time allotted to reach the programmed output energy (30 seconds) has been exceeded. A charge circuit timeout usually occurs when the battery voltage is depleted below the “elective replacement indicator.” In this specific instance, the charge circuit timeout occurred because of a glitch in the software. Three events occurred almost simultaneously, exposing the software programming error.2 These events occurred during an episode of tachycardia in the brief time span between the end of charging the capacitors and redetection/confirmation before delivery of a shock. The 3 events are:

Effect of Amiodarone on Signal Characteristics of Ventricular Fibrillation and ICD Shock Success

Introduction: Defibrillation threshold (DFT) testing is routinely performed during implantable cardioverter defibrillator (ICD) implantation to test the effectiveness to terminate ventricular fibrillation (VF). However, with the currently implanted ICDs failure of defibrillation is uncommon and the value of DFT testing is under discussion. Amiodarone alters VF and increases defibrillation energy requirements. In patients using amiodarone DFT testing could be essential to ensure effective therapy.

Performance and survival of transvenous defibrillation leads: need for a European data registry

Although the use of implantable cardioverter defibrillator (ICD) therapy has increased over the last decades, the reporting of ICD lead performance is inadequate. So far, there is neither a European nor worldwide registry on ICD leads. The published long-term results from national or multicentre registries encompass relatively small patient cohorts. Nevertheless, the failure of ICD leads may have substantial clinical consequences, including failure to sense, failure to pace, failure to defibrillate, inappropriate shocks, and even death of the patient. The reported ICD lead survival varies significantly between studies: 91-99% at 2 years, 85-95% at 5 years, and 60-72% at 8 years. Thus, the true incidence of lead malfunction cannot be defined as outlined in the present review. One current initiative of the European Heart Rhythm Association is to initiate and develop a Europe-wide registry to monitor, over a prolonged follow-up period, the performance of ICDs and ICD leads.

Outcome of advisory implantable cardioverter-defibrillator replacement: One-year follow-up

Implantable cardioverter defibrillator (ICD) generator advisories present management dilemmas for physicians regarding competing risks of ICD failure and replacement-related complications. There is currently a paucity of long-term data concerning the complications associated with advisory ICD replacement. In a large multicenter advisory ICD generator replacement cohort followed for 12 months, we aimed to assess replacement-related complications by performing a case-control determination of complication risk factors to identify characteristics that could assist with advisory ICD replacement decision making. Twelve large ICD implanting centers reviewed the 1-year follow-up outcome of advisory ICDs replaced between October 2004 and October 2005. The complication cohort was characterized and compared in a nested case-control analysis with age- and gender-matched controls without complications from the same replacement population. At the 12 participating institutions, 451 of 2635 advisory ICD devices were replaced (17.1%). Over 355 +/- 204 days of follow-up, there were 41 (9.1%) complications; 27 (5.9%) required reoperation and included two deaths. There were 14 minor complications (3.1%). Multivariate analysis demonstrated that the number of previous pocket procedures was associated with an increase in complications and that combined consultant and fellow operators was associated with a decrease in complications compared with a single operator alone. Complications from advisory ICD generator replacement are frequent and include infection and, rarely, death. The risk of replacement is increased in patients with multiple previous pocket procedures.

Lessons From the Failure and Recall of an Implantable Cardioverter-Defibrillator

Multiple clinical trials have shown that a properly functioning implantable cardioverter-defibrillator (ICD) is capable of interrupting sudden death caused by ventricular tachyarrhythmias. Unfortunately, ICDs are complex medical devices, and they do not always perform as expected. For example, only 5% of ICD batteries last >7 years, and most dual-chamber ICD models must be replaced for battery depletion every 3 to 5 years.1 Normal battery depletion, however, is reliably predicted by routine follow-up methods before an ICD fails. In contrast, electronic malfunctions are unpredictable and may not be detected by standard follow-up techniques before an ICD is unable to deliver effective therapy. Thus, sudden cardiac arrest or death may be the first and only sign that an ICD has failed.2 Recently, we reported the death of a 21-year-old patient who received a Prizm 2 DR model 1861 ICD pulse generator (Guidant, Inc) in 2001 to prevent sudden cardiac death resulting from hypertrophic cardiomyopathy.3 In March 2005, this young man experienced a witnessed arrest and could not be resuscitated. His ICD was returned to Guidant, which found that the device had failed during the delivery of a shock. The cause of failure was massive electronic damage caused by electrical overstress that occurred when a short circuit developed between a high-voltage wire and a tube used to test the housing during manufacturing (see the Figure). At the time of our patient’s death, Guidant had knowledge of 25 similar Prizm 2 DR model 1861 failures in patients, 3 of whom had required rescue defibrillation. Indeed, Guidant had first observed this mode of failure 3 years earlier, in February 2002, when 2 returned Prizm 2 DR pulse generators exhibited the same short circuiting that caused our patient’s device to fail. Guidant was sufficiently concerned about these failures that manufacturing changes were made …

Deaths associated with implantable cardioverter defibrillator failure and deactivation reported in the United States Food and Drug Administration Manufacturer and User Facility Device Experience Database

The aim of this study was to understand the causes of implantable cardioverter defibrillator (ICD) failure and complications so that adverse events, including unnecessary death, can be prevented. Sudden death may occur if an ICD fails to treat life-threatening ventricular arrhythmias. The United States Food and Drug Administration Manufacturer and User Facility Device Experience Database was searched for ICD devices and the search term "death." The search yielded 212 death events involving 100 ICD pulse generator and lead models from five manufacturers. These death events were associated with (A) ICD devices for which pulse generator interrogation data and/or the results of the manufacturers analysis of returned devices were available; (B) ICD devices for which neither interrogation data nor the results of the manufacturer's analysis were reported; and (C) normally functioning ICDs that had been deactivated. (A) A total of 103 (69%) of 150 death events were associated with defective pulse generators or high-voltage leads. Most (34/42 [81%]) apparently sudden or arrhythmic death events were associated with high-voltage lead failure; other deaths were related to pulse generator failure (8/42 [19%]) caused by electronic component defects. (B) A total of 21 of 51 death events were related to a manufacturer's recall; all deaths were arrhythmic but without allegation of device failure. (C) Eleven death events occurred in patients whose pulse generators were found to be off or deactivated; these devices appeared to have been deactivated accidentally or by exposure to magnetic fields, or they were not reactivated after elective surgery. ICD device failure and unintended pulse generator deactivation have resulted in unnecessary deaths. Although these deaths may be infrequent, improved devices and follow-up techniques are needed. The magnet deactivation feature probably is unsafe, and health professionals and patients should be cautioned.