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PubMed1991

Electrocautery does not interfere with the function of the automatic implantable cardioverter defibrillator.

The automatic implantable cardioverter defibrillator (AICD) manufactured by Cardiac Pacemakers, Inc, contains an automatic sensitivity adjustment. We tested whether this feature would prevent sensing of signals generated by electrocautery by implanting three different models of the AICD in 4 mongrel dogs. Unipolar electrocautery was applied at maximum output to a site close to the rate-sensing leads. The devices were monitored with an AICD-check probe and by auditory monitoring of QRS synchronous tones. No sensing of the electrocautery by the device occurred. Three patients with two different AICD models (1550 and 1520) underwent five surgical procedures in which electrocautery was used. No sensing of electrocautery signals, device charging, or other device malfunction occurred.

Animals↗
PubMed2006

Complications and mortality of single versus dual chamber implantable cardioverter defibrillators.

BACKGROUND: The implantable cardioverter defibrillators (ICDs) are increasingly being used as a treatment modality for life threatening tachyarrhythmia. The purpose of this study was to compare the frequency of complications and mortality between single-chamber and dual-chamber ICD implantation in Shahid Rajaie cardiovascular center. METHODS AND RESULTS: Between January 2000 and December 2004, 234 patients received ICD by a percutaneous transvenous approach and were followed for 33 +/- 23 months. The cumulative incidence of complications was 9.4% over the follow-up period. There was no significant difference in overall complication rate between single chamber (VR) and dual chamber (DR) ICD groups in the follow-up period (P= 0.11). The risk of complications did not have any statistically significant difference in secondary versus primary prevention groups (P=0.06). The complications were not associated with the severity of left ventricular systolic dysfunction (P=0.16). The frequency of lead-related complications was higher in dual chamber ICDs in comparison with single chamber ICDs (P=0.02). There was no significant difference in mortality between different sex groups (P=0.37), different indications for ICD implantation (P=0.43) or between VR and DR ICD groups (P= 0.55). Predictors of mortality were NYHA class III or more (P<0.001), age >65 years (P=0.011) and LVEF<30% (P<0.001). The mortality in patients with CAD and DCM were significantly higher than those with other structural heart diseases (P=0.001). CONCLUSION: Close monitoring of patients during the first 2 month after ICD implantation is recommended because the majority of complications occur early after the procedure.

Journal Article↗
PubMedDate not supplied

Avoidance behaviors in patients with implantable cardioverter defibrillators.

BACKGROUND: Although the implantable cardioverter defibrillator (ICD) has become standard therapy for some malignant cardiac arrhythmias, the shocks delivered by the device are often experienced as aversive. Anecdotal accounts of patients avoiding specific objects or places raise the possibility that conditioned avoidance responses can be established in response to ICD shocks. OBJECTIVE: The objective of the study was to better understand the nature of avoidance behavior among ICD recipients and to examine the relevance of classical conditioning and cognitive models to ICD-related avoidance behavior. METHODS: A total of 143 recipients of ICDs completed an anonymous survey reporting on aspects of their experience with the ICD and whether they had begun avoiding specific places, objects, or activities since receiving an ICD. RESULTS: Fifty-five percent of respondents reported at least 1 category of avoidance since receiving an ICD. The frequency of reported avoidances was highest in activities (39%), followed by objects (27%) and places (17%), which were least avoided. There was no relationship between the reported experience of shocks and avoidance behavior, and little evidence for conditioned avoidance. CONCLUSION: Avoidance that is not medically recommended is common among patients with ICDs. This may have adverse effects on quality of life and perhaps the physical health of some patients. Cognitive models, rather than classical conditioning, seem to explain the majority of avoidance behavior reported in this sample. A brief educational intervention or regular participation in ICD support groups could help to dispel misinformation among patients and discourage inappropriate avoidance.

Adult↗
PubMed1999

Is inappropriate therapy a resolved issue with current implantable cardioverter defibrillators?

Patients with an implantable cardioverter defibrillator (ICD) can undergo inappropriate therapies if electrical activity not originating in the ventricle is wrongly recognized as ventricular by the device. Inappropriate therapy can be the result of detection of supraventricular tachycardias or over-sensing of other artifacts by the device. Enhanced detection criteria in third-generation ICD have been implemented to recognize fast supraventricular arrhythmias. Analysis of the use of these criteria in patients with an ICD has shown that arrhythmias detected in the ventricular tachycardia zone are frequently supraventricular (193 supraventricular of 690 tachycardia episodes in 23 of 59 patients). Use of sudden onset was very effective in detecting sinus tachycardia (65 of 67 episodes) and stability was very useful in detecting atrial fibrillation (31 of 32 episodes). However sensitivity in detecting ventricular tachycardia was only 90% (451 of 497 episodes). Application of the sustained, rate duration criteria allowed appropriate treatment of all ventricular tachycardia episodes, increasing sensitivity to 100%; however, specificity in appropriate nontreatment of supraventricular episodes decreased from 96% to 83%. Subsequent analysis of different algorithms showed that sudden onset > 9% and stability < 40 msec was the algorithm with the best specificity and sensitivity. Programming sudden onset and stability detection criteria with a sustained, rate duration safety net for triggering tachycardia therapy results in appropriate device management in most patients with supraventricular and relatively slow ventricular tachycardia.

Adult↗
PubMed2001

Implantable cardioverter defibrillators in heart failure.

Implantable cardioverter defibrillators provide effective and reliable treatment of spontaneous VT and VF. These devices can be expected to decrease the risk for arrhythmic death in patients with heart failure but do not improve overall survival when death from severe pump dysfunction is imminent. Appropriate patient selection is a major aspect of arrhythmia management. Future devices will incorporate features that have the potential to reduce atrial arrhythmias, improve ventricular function, monitor hemodynamics, and prevent sudden arrhythmic death.

Anti-Arrhythmia Agents↗
PubMed2002

Inappropriate shock delivery due to interference between a washing machine and an implantable cardioverter defibrillator.

Electromagnetic interference with implantable cardioverter defibrillators (ICD) can cause inappropriate delivery of therapies or temporary inhibition of ICD functions. The presented case describes electromagnetic interference between a washing machine and an ICD resulting in an inappropriate discharge of the device due to false detection of ventricular fibrillation.

Adult↗
PubMed2007

[Implantable cardioverter defibrillator: an update].

Automatic implantable cardioverter defibrillator is now a well established therapy to prevent sudden cardiac death. In secondary prevention (patients with a previous cardiac arrest) defibrillator can be considered as a class I indication, if there is no transient or reversible cause. The level of proof is A. in primary prevention the defibrillator is indicated in coronary artery disease patients with or without symptoms of mild to moderate heart failure (NYHA II or III), an ejection fraction lower than 30 %, measured at least one month after a myocardial infarction and 3 months after a revascularisation, surgery or angioplasty (level of proof B). It is also indicated in symptomatic spontaneous sustained ventricular tachycardias with underlying heart disease (level of proof B), in patients with spontaneous sustained ventricular tachycardia, poorly tolerated, without underlying heart disease for which pharmacological treatment or ablation can not be performed or failed (level of proof B). Finally it is also indicated in patients with syncope of unknown cause with sustained ventricular tachycardia or inducible ventricular fibrillation, with an underlying heart disease (level of proof B). The guidelines proposed by the different societies have also proposed class IIa recommendations which are the following: coronary artery disease patients with left ventricular dysfunction (ejection fraction between 31 or 35 %) measured at least one month after a myocardial infarction and 3 months after a revascularisation with an inducible ventricular arrhythmia. It can be also indicated in idiopathic dilated cardiomyopathies with an ejection fraction lower than 30% and NYHA class II or III. It can be also indicated in familial or inherited conditions with a high risk of sudden cardiac death by ventricular fibrillation without any other efficient known treatment and finally in heart failure patients remaining symptomatic, in class III or IV NYHA, with an optimal medical therapy, an ejection fraction lower than 35 % and a QRS complex duration higher than 120 ms: in this case it is an indication of cardiac resynchronization therapy device associated to the defibrillator. All these class IIa indications have a level of proof B.

Aged↗
PubMed1998

Combined use of a true-bipolar sensing implantable cardioverter defibrillator in a patient having a prior implantable spinal cord stimulator for intractable pain.

Reported is a case involving a patient with a previously implanted spinal cord stimulator (SCS) who presented for an implantable cardioverter defibrillator (ICD). The SCS device was located in the left lower abdominal quadrant with a stimulation electrode array placed on the dorsal aspect of the spinal cord at the T-11 thoracic level. Interaction testing demonstrated that the biopolar sensing transvenous ICD system (Medtronic 7221 Cx PCD) did not detect the stimulator's output at burst rates ranging from 20-130 pulses/s, even with the ICD set to its maximum sensitivity of 0.15 m V and the stimulator programmed to the highest patient tolerated output combinations of 5 V, 0.45 ms in the bipolar configuration and 3 V, 0.45 ms in the unipolar (i.e., case-electrode) configuration.

Aged↗
PubMed2005

Effect of concomitant antiarrhythmic therapy on survival in patients with implantable cardioverter defibrillators.

BACKGROUND: Application of implantable cardioverter defibrillator (ICD) therapy is expanding to include both primary and secondary prevention of sudden cardiac death and has been proven to be superior to conventional antiarrhythmic therapies. Concomitant antiarrhythmic drug therapy in patients with ICD is common. These drugs are potentially proarrhythmic, alter defibrillation thresholds, and may affect response to device therapy. However, the impact of concomitant antiarrhythmic drug therapy on survival in patients with ICD devices is unknown. METHODS: We investigated the effect of different antiarrhythmic drugs on survival when given concomitantly in 360 consecutive ICD patients from our university medical center. Mortality data were obtained from the national death index. Survival analysis was performed using the Kaplan-Meier method. Corrections for significant covariates and group differences were made using the Cox regression model. RESULTS: Patients were followed up for 4.4 +/- 3.7 years. There were 68 deaths over this period with a 5-year survival of 80%. Patient characteristics were: age 62 +/- 13 years, left ventricular (LV) ejection fraction (EF) 33 +/- 17%, ischemic etiology of LV dysfunction 68%, diabetes mellitus 19%, hypertension 49%, atrial fibrillation 23%, digoxin 43%, beta-blocker 46%, amiodarone 28%, and sotalol 9%. The use of beta-blockers was associated with a better survival (P = 0.0005). This effect persisted after correcting for age, heart rate, EF, and ischemic etiology. The beneficial effect of beta-blocker was unrelated to its effect on heart rate. Digoxin use was associated with a lower survival only on univariate analysis (P = 0.006), but not after adjusting for other variables on a Cox regression model (P = 0.093). Amiodarone and sotalol were found to have a neutral effect on survival. CONCLUSION: In patients with ICDs, beta-blockers had a favorable effect on survival. Sotalol and amiodarone had a neutral effect on survival. There was a trend toward a deleterious effect with digoxin use. These findings suggest a need for further investigation addressing survival effects of antiarrhythmic drugs when given concomitantly in patients with ICDs.

Adrenergic beta-Antagonists↗
PubMed2000

Dual chamber arrhythmia detection in the implantable cardioverter defibrillator.

INTRODUCTION: Dual chamber implantable cardioverter defibrillator (ICD) technology extended ICD therapy to more than termination of hemodynamically unstable ventricular tachyarrhythmias. It created the basis for dual chamber arrhythmia management in which dependable detection is important for treatment and prevention of both ventricular and atrial arrhythmias. METHODS AND RESULTS: Dual chamber detection algorithms were investigated in two Medtronic dual chamber ICDs: the 7250 Jewel AF (33 patients) and the 7271 Gem DR (31 patients). Both ICDs use the same PR Logic algorithm to interpret tachycardia as ventricular tachycardia (VT), supraventricular tachycardia (SVT), or dual (VT+ SVT). The accuracy of dual chamber detection was studied in 310 of 1,367 spontaneously occurring tachycardias in which rate criterion only was not sufficient for arrhythmia diagnosis. In 78 episodes there was a double tachycardia, in 223 episodes SVT was detected in the VT or ventricular fibrillation zone, and in 9 episodes arrhythmia was detected outside the boundaries of the PR Logic functioning. In 100% of double tachycardias the VT was correctly diagnosed and received priority treatment. SVT was seen in 59 (19%) episodes diagnosed as VT. The causes of inappropriate detection were (1) algorithm failure (inability to fulfill the PR<RP condition in atrial tachyarrhythmias with 1:1 AV conduction, and far-field R wave sensing intermittently present during sinus tachycardia); (2) programming settings (atrial fibrillation/atrial flutter with ventricular rate above the SVT limit); and (3) algorithm limitations (atrial tachycardia with ventricular rate around the shortest programmable SVT limit and SVT redetection following VT therapy). Programming measures improved detection ability in 13 of 59 of inappropriately detected arrhythmias. CONCLUSION: Dual chamber detection algorithms evaluated in a subset of diagnostically difficult arrhythmias allow safe detection of double tachycardias but require further extension and programmability to improve VT:SVT discrimination rules.

Adult↗
PubMed2006

Near fatal arrhythmia induction by an implantable cardioverter defibrillator.

Sudden death among implantable cardioverter defibrillator (ICD) recipients is well known. The underlying mechanism remains unclear in most cases. One possible mechanism is an accidentally induced arrhythmia by the ICD itself. This report describes for the first time a case of a life-threatening ventricular arrhythmia induced by a specific algorithm for ventricular arrhythmia reconfirmation before shock delivery in a fourth-generation ICD.

Arrhythmias, Cardiac↗
PubMed2002

An automated, web-enabled and searchable database system for archiving electrogram and related data from implantable cardioverter defibrillators.

The advent of implantable cardioverter defibrillators (ICDs) has resulted in significant reductions in mortality in patients at high risk for sudden cardiac death. Extensive related basic research and clinical investigation continue. ICDs typically record intracardiac electrograms and inter-beat intervals along with device settings during episodes of device delivery of therapy. Researchers wishing to study these data further have until now been limited to viewing paper plots. In support of multi-center clinical studies of patients with ICDs, we have developed a web based searchable ICD data archiving system, which allows users to use a web browser to upload ICD data from diskettes to a server where the data are automatically processed and archived. Users can view and download the archived ICD data directly via the web. The entire system is built from open source software. At present more than 500 patient ICD data sets have been uploaded to and archived in the system. This project will be of value not only to those who wish to conduct research using ICD data, but also to clinicians who need to archive and review ICD data collected from their patients.

Arrhythmias, Cardiac↗
PubMed1993

Infections of implantable cardioverter defibrillators: approach to management.

Implantable cardioverter defibrillators are being used with increasing frequency for the treatment of life-threatening ventricular arrhythmias. Nevertheless, no guidelines exist for the management of infections of these devices. We report our experience with infections of these devices and review the English-language literature. In all cases, patients presented with local signs of generator infection; systemic signs of infection and bacteremia were often absent. Most infections are due to staphylococcus. Risk factors for the development of infection include placement of the device via median sternotomy during another cardiac surgical procedure, reoperation, and intercurrent infection at another site. Infections are most reliably treated with full explantation of the device and antibiotics. In rare cases, patients may respond to a combination of intravenous antibiotics and removal and replacement of only the generator.

Adult↗
PubMed1991

Psychiatric morbidity following implantation of the automatic implantable cardioverter defibrillator.

The automatic implantable cardioverter defibrillator (AICD) has found a place in the treatment of sustained ventricular tachycardia and in survivors of sudden arrhythmic death. However, little is known about the psychological impact of this device on patients and their families. In a group of 20 AICD recipients, examined between 3 and 21 months post-implantation, the prevalence of psychiatric disorder was 50%. Following implantation, six patients suffered from adjustment disorder; three suffered from major depression; and one developed panic disorder. Psychiatric morbidity in patients was associated with psychopathology in family members, peri-operative AICD shocks, and social support that was perceived to be inadequate.

Adaptation, Psychological↗
PubMed1999

Defibrillation thresholds are increased by right-sided implantation of totally transvenous implantable cardioverter defibrillators.

Whether an ICD is placed via a left- or right-sided approach depends on venous access, the presence of a preexisting pacemaker, and other factors. Since the DFT is affected by lead position, which in turn is determined in part by the side of access, right-sided venous access could adversely affect DFTs. Furthermore, right-sided active can placement directs electric current toward the right hemithorax, which could further increase DFTs. This study sought to determine whether DFTs were increased by right-sided vascular access, and whether active can technology was beneficial or detrimental with right-sided ICD placement. Stepdown to failure DFTs were found in 290 patients receiving transvenous systems at the time of initial ICD implantation. Of these, 271 (93%) received left-sided systems and 19 (7%) received right-sided systems. The mean DFT in systems placed via left-sided vascular access was 11.3 +/- 5.3 J versus 17.0 +/- 4.9 J for right-sided implantation (P < 0.0001); right-sided DFTs were elevated for both active can and cold can systems. Right-sided active can devices had a lower DFT than right-sided cold can systems (15 +/- 4.1 J vs 19 +/- 4.8 J, P = 0.05). The right-sided implantation of implantable defibrillators results in significantly higher DFTs than the left-sided approach. This may be due to the less favorable distribution of the defibrillating field relative to the myocardium with the devices on the right. When right-sided implantation is clinically mandated, active can devices result in lower thresholds and should be used.

Adult↗
PubMed1992

Continuing experience with the automatic implantable cardioverter defibrillator.

The automatic implantable cardioverter defibrillator (AICD) is now used commonly in the management of malignant ventricular arrhythmias. Its use may obviate the need for antiarrhythmic drugs or endocardial resection. We reviewed our continuing experience with the AICD to determine its safety and efficacy. Since June 1987, 102 patients (mean age: 63 years) who survived out-of-hospital ventricular fibrillation or hemodynamically unstable ventricular tachycardia not associated with acute myocardial infarction underwent implantation of an AICD. There were three operative deaths and nine complications. Eighty-nine patients are alive. No patient has experienced sudden cardiac death. Forty-two patients (43%) have had 1 or more AICD discharges associated with symptoms of cardiac arrest. During AICD implantation, it appears preferable to configure lead placement by individual patient characteristics rather than by a rigid protocol. The relative safety and efficacy of the AICD support its use as an alternative to toxic medications or more dangerous endocardial resection in suboptimal candidates.

Adult↗
PubMed1999

[Simultaneous utilization of an implantable automatic defibrillator in a patient with previously implanted bi-ventricular pacemaker for end-stage heart failure].

We report a case of implantable cardioverter defibrillator (ICD) use after previous biventricular pacemaker insertion for end-stage heart failure. A 75-year-old man with inoperable three-vessel coronary artery disease, permanent atrial fibrillation and end-stage heart failure underwent bi-ventricular pacemaker insertion and His bundle ablation for symptomatic control. NYHA class decreased from class III to II after this procedure. Four months after implant the patient developed paroxysmal sustained, symptomatic ventricular tachycardia. ICD implantation was undertaken. No potentially serious ICD-pacemaker interaction was noted during subsequent follow-up. We conclude that ICD implantation is feasible after previous bi-ventricular pacemaker insertion, without the need to explant the bi-ventricular pacing device.

Aged↗