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PubMed2005

Fish oil supplementation and risk of ventricular tachycardia and ventricular fibrillation in patients with implantable defibrillators: a randomized controlled trial.

CONTEXT: Clinical studies of omega-3 polyunsaturated fatty acids (PUFAs) have shown a reduction in sudden cardiac death, suggesting that omega-3 PUFAs may have antiarrhythmic effects. OBJECTIVE: To determine whether omega-3 PUFAs have beneficial antiarrhythmic effects in patients with a history of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF). DESIGN AND SETTING: Randomized, double-blind, placebo-controlled trial performed at 6 US medical centers with enrollment from February 1999 until January 2003. PATIENTS: Two hundred patients with an implantable cardioverter defibrillator (ICD) and a recent episode of sustained VT or VF. INTERVENTION: Patients were randomly assigned to receive fish oil, 1.8 g/d, 72% omega-3 PUFAs, or placebo and were followed up for a median of 718 days (range, 20-828 days). MAIN OUTCOME MEASURES: Time to first episode of ICD treatment for VT/VF, changes in red blood cell concentrations of omega-3 PUFAs, frequency of recurrent VT/VF events, and predetermined subgroup analyses. RESULTS: Patients randomized to receive fish oil had an increase in the mean percentage of omega-3 PUFAs in red blood cell membranes from 4.7% to 8.3% (P<.001), with no change observed in patients receiving placebo. At 6, 12, and 24 months, 46% (SE, 5%), 51% (5%), and 65% (5%) of patients randomized to receive fish oil had ICD therapy for VT/VF compared with 36% (5%), 41% (5%), and 59% (5%) for patients randomized to receive placebo (P = .19). In the subset of 133 patients whose qualifying arrhythmia was VT, 61% (SE, 6%), 66% (6%), and 79% (6%) of patients in the fish oil group had VT/VF at 6, 12, and 24 months compared with 37% (6%), 43% (6%), and 65% (6%) of patients in the control group (P = .007). Recurrent VT/VF events were more common in patients randomized to receive fish oil (P<.001). CONCLUSION: Among patients with a recent episode of sustained ventricular arrhythmia and an ICD, fish oil supplementation does not reduce the risk of VT/VF and may be proarrhythmic in some patients.

Aged↗

PubMed1999

Implantable defibrillator event rates in patients with unexplained syncope and inducible sustained ventricular tachyarrhythmias: a comparison with patients known to have sustained ventricular tachycardia.

OBJECTIVES: To assess the clinical significance of inducible ventricular tachyarrhythmias among patients with unexplained syncope. BACKGROUND: Induction of sustained ventricular arrhythmias at electrophysiology study in patients with unexplained syncope and structural heart disease is usually assigned diagnostic significance. However, the true frequency of subsequent spontaneous ventricular tachyarrhythmias in the absence of antiarrhythmic medications is unknown. METHODS: In a retrospective case-control study, the incidence of implantable cardiac defibrillator (ICD) therapies for sustained ventricular arrhythmias among patients with unexplained syncope or near syncope (syncope group, n = 22) was compared with that of a control group of patients (n = 32) with clinically documented sustained ventricular tachycardia (VT). Sustained ventricular arrhythmias were inducible in both groups and neither group received antiarrhythmic medications. All ICDs had stored electrograms or RR intervals. Clinical variables were similar between groups except that congestive cardiac failure was more common in the syncope group. RESULTS: Kaplan-Meier analysis of the time to first appropriate ICD therapy for syncope and control groups produced overlapping curves (p = 0.9), with 57 +/- 11% and 50 +/- 9%, respectively, receiving ICD therapy by one year. In both groups, the induced arrhythmia was significantly faster than spontaneous arrhythmias, but the cycle lengths of induced and spontaneous arrhythmias were positively correlated (R = 0.6, p < 0.0001). During follow-up, three cardiac transplantations and seven deaths occurred in the syncope group, and two transplantations and five deaths occurred in the control group (36-month survival without transplant 52 +/- 11% and 83 +/- 7%, respectively, p = 0.03). CONCLUSIONS: In patients with unexplained syncope, structural heart disease and inducible sustained ventricular arrhythmias, spontaneous sustained ventricular arrhythmias occur commonly and at a similar rate to patients with documented sustained VT. Thus, electrophysiologic testing in unexplained syncope can identify those at risk of potentially life-threatening tachyarrhythmias, and aggressive treatment of these patients is warranted.

Aged↗

PubMed2002

[Recommendations for protection against electromagnetic interference risk caused by pacemakers and implantable defibrillators in hospitals].

Electromagnetic interference and compatibility are problems that claim an increasing attention of biomedical industries, all over the world. For electromagnetic interference we intend a phenomenon that can occur when an electronic device undergoes the influence of an electromagnetic field, which may cause temporary or definitive malfunctioning of the device itself. Indeed, electromagnetic compatibility is the capacity of an electric device either to operate normally, without generating electromagnetic disturbances that may interfere with other devices or to operate without being influenced by electromagnetic field generated by other electric devices. Pacemaker (PM) and implantable-cardioverter defibrillator (ICD) functioning can be significantly compromised by electromagnetic fields, even though their circuits, nowadays, are well protected from most of electromagnetic wave sources. The basis for electromagnetic interference on PM and ICD lays on different factors even physical such as the power of external signal, the distance between the signal and the PM and ICD, the frequency range, modulation type and immunity level of the PM and ICD. The electromagnetic interference on PM and ICD may result into a temporary or permanent malfunctioning, like pacing inhibition, asynchronous pacing, or the switching of the pacing mode. The purpose of this work is to give useful indications for a correct in-hospital management of patients with PM or ICD, in order to avoid dangerous electromagnetic interference.

Defibrillators, Implantable↗

PubMed2006

The cost of implantable defibrillators: perceptions and reality.

AIMS: Recent guidelines have recommended more wide-ranging indications for the use of implantable cardioverter defibrillator (ICD) therapy, yet even more restrained previous guidelines have not been implemented for a variety of reasons. METHODS AND RESULTS: This brief review critically examines the reasons most frequently put forward to explain this failure. Contrary to the frequently repeated speculation that the risk stratification for sudden death and hence prophylactic placement of ICDs is reasonably accurate, there is little cost difference between pharmacotherapy and ICD treatment over the long term. ICD therapy does not utilize an undue proportion of the healthcare budget, and the healthcare systems in Europe can afford this therapy. CONCLUSION: Financial reasons are neither accurate nor adequate explanations for the failure of the European medical community to implement European guidelines for the implantation of ICDs for primary and secondary prevention of sudden cardiac death.

Cardiovascular Agents↗

PubMed1995

Nonthoracotomy cardioverter-defibrillator implantation by electrophysiologists.

Explore the source record for details and available documents.

Defibrillators, Implantable↗

PubMed2001

Use of a transurethral microwave thermotherapeutic device with permanent pacemakers and implantable defibrillators.

OBJECTIVE: To determine whether a device (Urologix Targis system) used for transurethral microwave treatment interferes with sensing, pacing, and arrhythmia detection by permanent pacemakers and implantable cardioverter-defibrillators (ICDs). METHODS: We tested 13 pacemakers in both bipolar and unipolar sensing configurations and 8 ICDs in vitro. Pacemakers and ICDs were programmed to their most sensitive settings. Energy outputs of the microwave device were typical of those used clinically. The probe of the microwave device was anchored 1.2 cm from the pacemaker or ICD being tested. RESULTS: No sensing, pacing, or arrhythmic interactions were noted with any ICD or any pacemaker programmed to the bipolar configuration. One pacemaker (Guidant Vigor 1230) showed intermittent tracking when programmed to the unipolar configuration. CONCLUSIONS: Most patients with permanent pacemakers or ICDs can safely undergo transurethral microwave therapy using the device tested. Pacemakers and ICDs should be programmed to the bipolar configuration (if available) during therapy. The pacemaker or ICD should be interrogated before and after therapy to determine whether programming changes occurred as a result of treatment. However, our findings suggest that this is unlikely.

Artifacts↗

PubMed2000

Antiarrhythmic management and implantable defibrillator use in survivors of prehospital cardiac arrest without myocardial infarction in West Yorkshire.

OBJECTIVE: To explore the current use of secondary preventive treatment in survivors of out of hospital cardiac arrest without myocardial infarction (primary ventricular tachycardia/ventricular fibrillation (VT/VF)) in West Yorkshire, and assess the implications of recent studies on the benefits of implantable cardioverter-defibrillators (AICD) in this context. DESIGN: Retrospective analysis of an ambulance service based database of outcome after resuscitation of out of hospital cardiac arrest and the Leeds AICD implantation database. MAIN OUTCOME MEASURES: Mortality, rate of referral for specialist investigation, antiarrhythmic treatment. RESULTS: Twelve month mortality following successful discharge after primary VF arrest was 15%. Of 53 patients with primary VF/VT, 29 apparently did not see a cardiologist during the initial admission. Amiodarone was the most widely used antiarrhythmic agent. Six patients (15%) received an AICD. During the same period 22 patients from the same catchment area received an AICD following an in-hospital cardiac arrest. CONCLUSIONS: Mortality among survivors of non-infarct related prehospital cardiac arrest remains significant, with few patients being referred for specialist investigation. The implementation of recent guidelines on AICD use in cardiac arrest survivors would have resulted in an approximate 60% increase in the total numbers of defibrillators implanted in the West Yorkshire area.

Adult↗

PubMed2004

Transvenous cardioverter-defibrillator implantation with a double coil lead via persistent left superior vena cava.

A dual-coil defibrillation lead was inserted in a 64-year-old male through a persistent left superior vena cava draining into the coronary sinus. The lead, connected to a cardioverter-defibrillator (ICD) implanted in the left pectoral area, was looped in the right atrium positioning the proximal and distal lead coils in the coronary sinus and right ventricular outflow track respectively and resulting in a low and stable defibrillation threshold. Because of its relative ease and effectiveness, this procedure may be recommended in patients with persistent left superior vena cava requiring an ICD implant.

Angiography↗

PubMed1995

Transvenous versus transthoracic cardioverter-defibrillator implantation. A comparative analysis of morbidity, mortality, and survival.

The hypothesis that transvenous implantation of a cardioverter-defibrillator is associated with less morbidity than use of a transthoracic approach was investigated in a retrospective series of 146 patients. None of these patients had concomitant heart procedures, and the preoperative characteristics of the two groups were similar. When analyzed by actual technique used (transvenous, 57 patients; transthoracic, 89 patients) and by the intention-to-treat method (transvenous, 65 patients, 8 of whom actually underwent thoracotomy; thoracotomy, 81 patients), transvenous implantation was associated with a lower incidence of postoperative respiratory complications and atrial fibrillation. Total cardiac mortality and freedom from sudden cardiac death in the transvenous and transthoracic groups were comparable at 2 years.

Aged↗

PubMed2002

Risk of thromboembolic complications in patients with permanent atrial fibrillation undergoing cardioverter-defibrillator implantation.

BACKGROUND: Cardioversion of atrial fibrillation (AF) carries the risk of thromboembolic complications and, therefore, anticoagulation therapy is routinely administered before and after this procedure. In patients with permanent AF who undergo implantation of cardioverter-defibrillator (ICD), anticoagulants are usually withdrawn during the perioperative period. However, in some patients sinus rhythm may be restored during defibrillation threshold (DFT) testing which potentially may increase the risk of thromboembolic complications. AIM: To assess the frequency of sinus rhythm restoration during ICD implantation in patients with permanent AF and the rate of both thromboembolic events and local bleeding complications which may occur due to temporary withdrawal of anticoagulation therapy and its re-initiation early after the procedure. METHODS: Permanent AF was present in 23 (12%) of 193 patients selected for ICD implantation. All patients received prolonged oral anticoagulation according to the generally accepted standards. Anticoagulation therapy was stopped few days before the procedure and replaced by low molecular weight heparin which was administered up to 24 hours before ICD implantation and re-initiated 12-24 hours afterwards. RESULTS: During DFT testing sinus rhythm was restored in 5 (21.7%) patients with AF. Clinical and DFT characteristics were similar in those who were converted to sinus rhythm and those who remained in AF. No thromboembolic events were noted in either group. Local haematoma at the site of ICD implantation occurred in two (8%) patients. CONCLUSIONS: Sinus rhythm was restored in 21.7% of patients with permanent AF who underwent ICD implantation. Temporary withdrawal of anticoagulation therapy did not increase the risk of thromboembolic complications, however, its early re-initiation after implantation resulted in an increase in local bleeding complication rate.

Journal Article↗

PubMed1997

Mortality trials with implantable defibrillators.

The continuing disappointing results from recent major studies with antiarrhythmic drugs combined with the continuing excellent outcomes with implantable cardioverter-defibrillators is making it exceedingly difficult, ethically, to conduct future randomized trials comparing the 2 treatment options. On the other hand, the high quality of stored Holter electrograms and the therapy history retrievable from current implantable cardioverter-defibrillators creates opportunities for needed trials on drug efficacy without this ethical dilemma.

Arrhythmias, Cardiac↗

PubMed2002

Temporal patterns of atrial arrhythmia recurrences in patients with implantable defibrillators: implications for assessing antiarrhythmic therapies.

INTRODUCTION: The statistical measures commonly used to assess therapies for recurrent atrial arrhythmias (such as time to first recurrence) often assume a uniformly random pattern of arrhythmic events over time. However, the true temporal pattern of atrial arrhythmia recurrences is unknown. The aim of this study was to use linear and nonlinear analyses to characterize the temporal pattern of atrial arrhythmia recurrences in patients with implantable cardioverter defibrillators. METHODS AND RESULTS: The time and date of atrial tachyarrhythmias recorded in 65 patients with combined atrial and ventricular defibrillators were used to construct a probability density function (PDF) and a model of a Poisson distribution of arrhythmic events for each patient. Average patient age was 66 +/- 10 years and follow-up was 7.8 +/- 4.8 months. A total of 10,759 episodes of atrial tachyarrhythmias were analyzed (range 43 to 618 episodes per patient). The PDF fit a power law distribution for all 65 patients, with an average r2 = 0.89 +/- 0.08. The PDF distribution differed significantly from the model Poisson distribution in 47 of 65 patients (P = 0.0002). Differences from the Poisson distribution were noted for patients both taking (30/43 patients; P < or = 0.015) and not taking (17/22 patients; P < or = 0.017) antiarrhythmic drugs. Median time between atrial arrhythmia detections for all 65 patients was 10.8 minutes. CONCLUSION: In implantable cardioverter defibrillator patients, the temporal pattern of frequent recurrences of atrial tachyarrhythmias usually is characterized by a power law distribution. The unique statistical properties of this type of distribution should be considered in designing outcome measures for treatment of atrial tachyarrhythmias.

Adult↗

PubMed1993

Influence of left ventricular function on survival and mode of death after implantable defibrillator therapy (Cleveland Clinic Foundation and Montefiore Medical Center experience).

To determine the influence of left ventricular (LV) function on survival and mode of death in patients with an implantable cardioverter-defibrillator (ICD), sudden death, surgical mortality, total arrhythmia-related death, total cardiac death and total death were retrospectively evaluated in 377 consecutive patients. The outcomes were also compared between patients with an LV ejection fraction > or = 30% (214 patients, group 1) and < 30% (148 patients, group 2). Surgical mortality was 3.9% (1.8% in group 1, 7% in group 2). During the follow-up of 25 +/- 20 months, actuarial survival rates of all patients at 3 years were 96% for sudden deaths, 81% for total cardiac deaths and 74% for total mortality. When the 2 groups were compared, survival rates of groups 1 and 2 at 3 years, respectively, were 99 and 90% for sudden death (p < 0.05), 97 and 84% for sudden death and surgical mortality (p < 0.01), 94 and 80% for the total arrhythmia-related death (p < 0.001), 88 and 68% for total cardiac death (p < 0.0001), and 81 and 62% for total mortality (p < 0.002). In group 2, 73% of total cardiac deaths within 1 year were causally related to the arrhythmia. Thus, in patients with an ICD, sudden death rates were very low. However, total cardiac death and total death rates were relatively higher. The outcomes of patients with an ICD were strongly influenced by the degree of LV dysfunction.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗

PubMed1998

Comparison of results in two implantable defibrillators. Jewel 7219D Investigators.

The Jewel 7219D was the first non-thoracotomy implantable cardioverter-defibrillator (ICD) with biphasic shock capability small enough to be placed in the prepectoral subcutaneous position. Size reduction of ICDs is desirable, but safety and efficacy of smaller devices must be demonstrated. Outcomes of patients treated with the Jewel 7219D defibrillator (n = 1,781) and with its precursor model PCD 7217B (n = 2,637) were compared. To use PCD patients (n = 2,637) as historical (n = 2,574) and concurrent controls (n = 63), statistical adjustments using the Cox proportional-hazards regression model were made. Jewel recipients (n = 1,781) treated in 106 US and 32 non-US centers exhibited similar characteristics including a mean age of 59 years, 78% men, ejection fraction of 34%, history of aborted sudden cardiac death in 41%, and coronary artery disease in 70%. Implantation was completed in 1,777 of 1,781 (99.9%) attempts and success with the first electrode configuration and polarity was 89.5%. Kaplan-Meier cumulative first-year survivals for cardiac and all-cause mortality were 98.5% and 93.3%. Complication-free first-year survival for Jewel implants in prepectoral subcutaneous (n = 582), subpectoral submuscular (n = 366), and abdominal (n = 449) positions did not differ (p > 0.05). First-year survival free of pocket-related complications exceeded 98% in all locations. Adjusted cardiac and all-cause first-year mortality, and efficacy in terminating spontaneous tachyarrhythmias did not differ between the 2 device groups. In conclusion, the safety and efficacy of Jewel model 7219D in the prepectoral subcutaneous position are at least equal to either those of Jewel models implanted in different positions or to those of the previously extensively characterized PCD 7217B.

Cardiac Surgical Procedures↗

PubMed2006

Prevention of implantable defibrillator shocks by cognitive behavioral therapy: a pilot trial.

BACKGROUND: Although psychological stress is known to favor ventricular arrhythmic events, there is no evidence that stress management intervention decreases ventricular electrical instability in implantable cardioverter-defibrillator (ICD) patients. The aim of the study was to determine whether cognitive behavioral therapy (CBT) results in a decrease of arrhythmic events requiring ICD intervention through an improvement in sympathovagal balance. METHODS: Of 253 consecutive ICD patients (age 59 +/- 10 years, 64 men), 70 were randomly assigned to CBT (n = 35) or conventional medical care (n = 35). Measures of heart rate variability, psychological well-being, and quality of life were assessed at baseline, 3 months, and 1 year. The primary outcome was appropriate ICD shock. RESULTS: Although, it was not statistically different, the number of patients requiring shocks was less in the CBT group than in the conventional treatment group. At 3 months, among patients without antiarrhythmic drugs, none of the subjects in the CBT group had experienced arrhythmic events requiring ICD intervention, as compared with 4 in the control group (P < .05). At 12 months, there was no difference in the number of arrhythmic events requiring therapy between the CBT group versus the control group. Among heart rate variability indexes, daytime pNN 50 and nocturnal SDNN improved significantly in the CBT group, as compared with the control group. CONCLUSIONS: By decreasing anxiety and possibly improving sympathovagal balance, cognitive behavior therapy may decrease the propensity for ventricular arrhythmias in ICD patients. However, these effects appear to be limited over time.

Arrhythmias, Cardiac↗

PubMed1999

Comparison of the long-term efficacy of implantable defibrillators and sotalol for documented spontaneous sustained ventricular tachyarrhythmias secondary to coronary artery disease.

BACKGROUND: The relative efficacy of antitachycardia pacing implantable cardioverter defibrillators (ATPICD) and sotalol in the treatment of ventricular tachyarrhythmias is controversial. AIM: To compare the mortality in patients treated with ATPICD and sotalol for documented spontaneous sustained ventricular tachyarrhythmias occurring late after previous myocardial infarction. METHODS: In this non-randomised retrospective study of 139 consecutive patients all patients had inducible ventricular tachycardia at baseline electrophysiological studies. Before the availability of ATPICD, 22 patients were treated with sotalol as part of a randomised study comparing the efficacy of sotalol to amiodarone. After ATPICD became available sotalol was used in 49 patients in whom intravenous testing predicted sotalol to be effective and ATPICD were implanted in 68 patients in whom sotalol was predicted to be ineffective at electrophysiological testing. Thus, 68 patients were treated with an ATPICD and 71 with sotalol. RESULTS: The two groups were well-matched for age, type of presenting arrhythmia, severity of coronary artery disease and ventricular function. At 36 months Kaplan-Meier estimates of mortality from ventricular tachyarrhythmia were 0% with ATPICD and 15% with sotalol (p=0.03). Kaplan-Meier estimates of total mortality at 36 months were 12% with ATPICD and 25% with sotalol (p=0.09). Multivariate analysis showed hazard ratio of 7.9 (p=0.06) for death from ventricular tachyarrhythmia in patients treated with sotalol compared to ATPICD. CONCLUSIONS: While no difference in total mortality was demonstrated, treatment with ATPICD is probably superior to sotalol for preventing deaths due to ventricular tachyarrhythmia.

Aged↗

PubMed2006

Implantable cardioverter defibrillator implant-explant-implant case study: addressing the psychological adjustment to multiple shocks.

This case study details the multidisciplinary approach to a patient who underwent implantable cardioverter defibrillator (ICD) explantation for psychological reasons. The patient was unable to manage the stress associated with multiple shocks. He had a class I indication for an ICD but initially refused to undergo reimplantation. Treatment included the provision of comprehensive medical, nursing, and psychological care, with emphasis on patient autonomy and respect for the patient's experience.

Adaptation, Psychological↗

PubMed1994

[Hypertrophic cardiomyopathy with two episodes of recuperated sudden death. Report of the first implantable defibrillator cardioverter inserted in Chile].

We report a 29 years old male with a non obstructive hypertrophic cardiomyopathy that survived two episodes of cardiac arrest and with a familiar history of the disease and sudden death. He had an implant of an automatic implantable cardioverter defibrillator by a left anterior thoracotomy with intraoperative electrophysiology. The postoperative outcome was uneventful. After one year of follow up, the patient is in good functional capacity and the implanted device has not performed defibrillations.

Adult↗