Bruce Goldner

Frequent recurrent polymorphic ventricular tachycardia during sleep due to managed ventricular pacing.

We report a case of a patient with an implantable cardioverter defibrillator and no prior history of heart block with managed ventricular pacing (MVP) programmed who had frequent recurrent episodes of polymorphic ventricular tachycardia. All of the episodes were initiated by transient atrioventricular block which resulted in short‐long‐short sequences permitted by MVP. This case illustrates that MVP should be used with caution not only in patients with complete heart block, but also in patients at risk for brief heart block due to such states as hypervagatonia due to sleep apnea.u2003(PACE 2010; 641–644)

Trends in Fidelis Lead Survival Transition From an Exponential to Linear Pattern of Lead Failure Over Time

Background—The Sprint Fidelis implantable cardioverter-defibrillator lead was recalled in 2007 because of an elevated risk of lead fracture. Several studies have demonstrated an accelerating risk of lead failure over time. We sought to identify predictors and characterize trends of Fidelis lead failure. Methods and Results—We evaluated 604 Fidelis leads with ≥90 days of follow-up implanted at our institution. Fidelis lead survival was analyzed by the Kaplan-Meier method. Analysis of log-log plots of cumulative hazard plots was performed to assess changes in lead failure rate over time. During follow-up of 3.3±1.7 years, 51 (8.4%) Fidelis lead failures were identified. The 3-year and 5-year Fidelis lead survival rates were 93.5% and 85.3%, respectively. Female sex was the only significant predictor of lead failure (heart rate, 2.1; 95% CI, 1.1–3.9; P<0.0001). The rate of lead failure initially increased exponentially with a power of 2.3 (95% CI, 2.22–2.43; P<0.0001). However, log-log analysis of cumulative hazard for leads functioning at 2 and 4 years revealed a stable rate of failure of 4.5%/year. Mathematical modeling of the Fidelis lead failure demonstrated a transition from an exponential to linear pattern of lead failure at 2.9 years. Conclusions—After 3 years, failure rates of Fidelis leads stabilize but at a significantly elevated rate. Female sex is associated with a doubling of the risk of Fidelis lead failure. These findings have implications for Fidelis lead management decisions that are based on the prediction of lead failure risk.Background— The Sprint Fidelis implantable cardioverter-defibrillator lead was recalled in 2007 because of an elevated risk of lead fracture. Several studies have demonstrated an accelerating risk of lead failure over time. We sought to identify predictors and characterize trends of Fidelis lead failure.nnMethods and Results— We evaluated 604 Fidelis leads with ≥90 days of follow-up implanted at our institution. Fidelis lead survival was analyzed by the Kaplan-Meier method. Analysis of log-log plots of cumulative hazard plots was performed to assess changes in lead failure rate over time. During follow-up of 3.3±1.7 years, 51 (8.4%) Fidelis lead failures were identified. The 3-year and 5-year Fidelis lead survival rates were 93.5% and 85.3%, respectively. Female sex was the only significant predictor of lead failure (heart rate, 2.1; 95% CI, 1.1–3.9; P <0.0001). The rate of lead failure initially increased exponentially with a power of 2.3 (95% CI, 2.22–2.43; P <0.0001). However, log-log analysis of cumulative hazard for leads functioning at 2 and 4 years revealed a stable rate of failure of 4.5%/year. Mathematical modeling of the Fidelis lead failure demonstrated a transition from an exponential to linear pattern of lead failure at 2.9 years.nnConclusions— After 3 years, failure rates of Fidelis leads stabilize but at a significantly elevated rate. Female sex is associated with a doubling of the risk of Fidelis lead failure. These findings have implications for Fidelis lead management decisions that are based on the prediction of lead failure risk.

Inappropriate Implantable Cardioverter-Defibrillator Shocks Attributed to Alternating-Current Leak in a Swimming Pool

Implantable cardioverter-defibrillators (ICDs) are the standard of care for preventing sudden cardiac death in patients who are predisposed to malignant ventricular arrhythmias. Causes of inappropriate ICD shock include equipment malfunction, improper arrhythmia evaluation, misinterpretation of myopotentials, and electromagnetic interference. As the number of implanted ICDs has increased, other contributors to inappropriate therapy have become known, such as minimal electrical current leaks that mimic ventricular fibrillation. We present the case of a 63-year-old man with a biventricular ICD who received 2 inappropriate shocks, probably attributable to alternating-current leaks in a swimming pool. In addition, we discuss ICD sensitivity and offer recommendations to avoid similar occurrences.

Charge circuit timeout: a sequence of events leading to failure of an implantable cardioverter-defibrillator to deliver therapy.

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.nnTypically, 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:

Congenital long QT syndrome: a case report of LQT2 and LQT13 in a neonate

Long QT syndrome (LQTS) is a disorder of ventricular myocardial repolarization characterized by a prolonged QT interval on the electrocardiogram (ECG). At least 12 different genes in patients with congenital LQTS have been described, designated LQT 1 through 12. However, more recently …

Trends in Fidelis Lead SurvivalClinical Perspective: Transition From an Exponential to Linear Pattern of Lead Failure Over Time

Background—The Sprint Fidelis implantable cardioverter-defibrillator lead was recalled in 2007 because of an elevated risk of lead fracture. Several studies have demonstrated an accelerating risk of lead failure over time. We sought to identify predictors and characterize trends of Fidelis lead failure. Methods and Results—We evaluated 604 Fidelis leads with ≥90 days of follow-up implanted at our institution. Fidelis lead survival was analyzed by the Kaplan-Meier method. Analysis of log-log plots of cumulative hazard plots was performed to assess changes in lead failure rate over time. During follow-up of 3.3±1.7 years, 51 (8.4%) Fidelis lead failures were identified. The 3-year and 5-year Fidelis lead survival rates were 93.5% and 85.3%, respectively. Female sex was the only significant predictor of lead failure (heart rate, 2.1; 95% CI, 1.1–3.9; P<0.0001). The rate of lead failure initially increased exponentially with a power of 2.3 (95% CI, 2.22–2.43; P<0.0001). However, log-log analysis of cumulative hazard for leads functioning at 2 and 4 years revealed a stable rate of failure of 4.5%/year. Mathematical modeling of the Fidelis lead failure demonstrated a transition from an exponential to linear pattern of lead failure at 2.9 years. Conclusions—After 3 years, failure rates of Fidelis leads stabilize but at a significantly elevated rate. Female sex is associated with a doubling of the risk of Fidelis lead failure. These findings have implications for Fidelis lead management decisions that are based on the prediction of lead failure risk.Background— The Sprint Fidelis implantable cardioverter-defibrillator lead was recalled in 2007 because of an elevated risk of lead fracture. Several studies have demonstrated an accelerating risk of lead failure over time. We sought to identify predictors and characterize trends of Fidelis lead failure.nnMethods and Results— We evaluated 604 Fidelis leads with ≥90 days of follow-up implanted at our institution. Fidelis lead survival was analyzed by the Kaplan-Meier method. Analysis of log-log plots of cumulative hazard plots was performed to assess changes in lead failure rate over time. During follow-up of 3.3±1.7 years, 51 (8.4%) Fidelis lead failures were identified. The 3-year and 5-year Fidelis lead survival rates were 93.5% and 85.3%, respectively. Female sex was the only significant predictor of lead failure (heart rate, 2.1; 95% CI, 1.1–3.9; P <0.0001). The rate of lead failure initially increased exponentially with a power of 2.3 (95% CI, 2.22–2.43; P <0.0001). However, log-log analysis of cumulative hazard for leads functioning at 2 and 4 years revealed a stable rate of failure of 4.5%/year. Mathematical modeling of the Fidelis lead failure demonstrated a transition from an exponential to linear pattern of lead failure at 2.9 years.nnConclusions— After 3 years, failure rates of Fidelis leads stabilize but at a significantly elevated rate. Female sex is associated with a doubling of the risk of Fidelis lead failure. These findings have implications for Fidelis lead management decisions that are based on the prediction of lead failure risk.

Trends in Fidelis Lead SurvivalClinical Perspective

Background—The Sprint Fidelis implantable cardioverter-defibrillator lead was recalled in 2007 because of an elevated risk of lead fracture. Several studies have demonstrated an accelerating risk of lead failure over time. We sought to identify predictors and characterize trends of Fidelis lead failure. Methods and Results—We evaluated 604 Fidelis leads with ≥90 days of follow-up implanted at our institution. Fidelis lead survival was analyzed by the Kaplan-Meier method. Analysis of log-log plots of cumulative hazard plots was performed to assess changes in lead failure rate over time. During follow-up of 3.3±1.7 years, 51 (8.4%) Fidelis lead failures were identified. The 3-year and 5-year Fidelis lead survival rates were 93.5% and 85.3%, respectively. Female sex was the only significant predictor of lead failure (heart rate, 2.1; 95% CI, 1.1–3.9; P<0.0001). The rate of lead failure initially increased exponentially with a power of 2.3 (95% CI, 2.22–2.43; P<0.0001). However, log-log analysis of cumulative hazard for leads functioning at 2 and 4 years revealed a stable rate of failure of 4.5%/year. Mathematical modeling of the Fidelis lead failure demonstrated a transition from an exponential to linear pattern of lead failure at 2.9 years. Conclusions—After 3 years, failure rates of Fidelis leads stabilize but at a significantly elevated rate. Female sex is associated with a doubling of the risk of Fidelis lead failure. These findings have implications for Fidelis lead management decisions that are based on the prediction of lead failure risk.Background— The Sprint Fidelis implantable cardioverter-defibrillator lead was recalled in 2007 because of an elevated risk of lead fracture. Several studies have demonstrated an accelerating risk of lead failure over time. We sought to identify predictors and characterize trends of Fidelis lead failure.nnMethods and Results— We evaluated 604 Fidelis leads with ≥90 days of follow-up implanted at our institution. Fidelis lead survival was analyzed by the Kaplan-Meier method. Analysis of log-log plots of cumulative hazard plots was performed to assess changes in lead failure rate over time. During follow-up of 3.3±1.7 years, 51 (8.4%) Fidelis lead failures were identified. The 3-year and 5-year Fidelis lead survival rates were 93.5% and 85.3%, respectively. Female sex was the only significant predictor of lead failure (heart rate, 2.1; 95% CI, 1.1–3.9; P <0.0001). The rate of lead failure initially increased exponentially with a power of 2.3 (95% CI, 2.22–2.43; P <0.0001). However, log-log analysis of cumulative hazard for leads functioning at 2 and 4 years revealed a stable rate of failure of 4.5%/year. Mathematical modeling of the Fidelis lead failure demonstrated a transition from an exponential to linear pattern of lead failure at 2.9 years.nnConclusions— After 3 years, failure rates of Fidelis leads stabilize but at a significantly elevated rate. Female sex is associated with a doubling of the risk of Fidelis lead failure. These findings have implications for Fidelis lead management decisions that are based on the prediction of lead failure risk.