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Cardioverter Defibrillator (cardioverter + defibrillator)
Kinds of Cardioverter Defibrillator Terms modified by Cardioverter Defibrillator Selected AbstractsAn Unusual Cause of Syncope in a Patient with an Internal Cardioverter DefibrillatorJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2009SLIM KACEM M.D. No abstract is available for this article. [source] Clustering of Ventricular Tachyarrhythmias in Heart Failure Patients Implanted with a Biventricular Cardioverter DefibrillatorJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2006MAURIZIO LUNATI M.D. Background: Temporal patterns of ventricular tachyarrhythmia (VT/VF) have been studied only in patients who have received implantable cardioverter defibrillators (ICD) for secondary prevention of sudden death, and mainly in ischemic patients. The aim of this study was to evaluate VT/VF recurrence patterns in heart failure (HF) patients with biventricular ICD and to stratify results according to HF etiology and ICD indication. Methods and Results: We studied 421 patients (91% male, 66 ± 9 years). HF etiology was ischemic in 292 patients and nonischemic in 129. ICD indication was for primary prevention in 227 patients and secondary prevention in 194. Baseline left ventricular ejection fraction (LVEF) was 26 ± 7%, QRS duration 168 ± 32 msec, and NYHA class 2.9 ± 0.6. In a follow-up of 19 ± 11 months, 1,838 VT/VF in 110 patients were appropriately detected. In 59 patients who had ,4 episodes, we tried to determine whether VT/VF occurred randomly or rather tended to cluster by fitting the frequency distribution of tachycardia interdetection intervals with exponential functions: VT/VF clusters were observed in 46 patients (78% of the subgroup of patients with ,4 episodes and 11% of the overall population). On multivariate logistic analysis, VT/VF clusters were significantly (P < 0.01) associated with ICD indication for secondary prevention (odds ratio [OR]= 3.12; confidence interval [CI]= 1.56,6.92), nonischemic HF etiology (OR = 4.34; CI = 2.02,9.32), monomorphic VT (OR = 4.96; CI = 2.28,10.8), and LVEF < 25% (OR = 3.34; CI = 1.54,7.23). Cardiovascular hospitalizations and deaths occurred more frequently in cluster (21/46 [46%]) than in noncluster patients (63/375 (17%), P < 0.0001). Conclusions: In HF patients with biventricular ICDs, VT/VF clusters may be regarded as the epiphenomenon of HF deterioration or as a marker of suboptimal response to cardiac resynchronization therapy. [source] Endocardial Implantation of a Cardioverter Defibrillator in Early ChildhoodJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2005MAURIZIO GASPARINI M.D. Introduction: Experience in endovascular/endocardial techniques for implanting implantable cardioverter defibrillators in early childhood is limited. Potentially, this type of approach could limit the surgical risk, while increasing ICD therapy efficacy. The safety and feasibility of adopting a complete endovascular/endocardial approach for implanting ICDs is assessed by considering the cases of two young children. Methods and Results: Two boys, aged 3 and 6 years, were implanted with ICD for a history of syncope and documented ventricular tachycardia (VT). A complete endovascular/endocardial approach was adopted consisting of positioning a bipolar pacing and sensing lead in the right ventricular (RV) apex with intravascular redundancy forming a loop in the inferior vena cava (IVC), and a caval coil placed in the IVC. Sensing values (7,8 mV), pacing threshold (0.5,0.6 V/0.5 msec), and defibrillation testing (case 1 = 10 J, case 2 = 20 J) were all acceptable. During follow-up, in both cases ICD intervened correctly. In one case, 16 months after implantation, because of change in the IVC coil-active can vector, the IVC coil was effectively repositioned to a more distal position. Conclusion: A complete endovascular/endocardial ICD implantation technique in early childhood is both feasible and safe. This approach avoids thoracotomy and ensures ICD therapy efficacy. [source] Supraventricular Arrhythmia Induction by an Implantable Cardioverter Defibrillator in a Patient with Hypertrophic CardiomyopathyPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 3 2010FARIBORZ AKBARZADEH M.D. A 23-year-old woman with obstructive hypertrophic cardiomyopathy and history of frequent unexplained syncope had undergone implantable cardioverter defibrillator implantation. She had experienced frequent inappropriate shocks since implantation due to T-wave oversensing. After one of the syncopal attacks, she was found to have an atrioventricular (AV)-reentrant tachycardia, induced by a high-voltage shock, with rapid degeneration to atrial fibrillation and then ventricular fibrillation. The AV-reentrant tachycardia was believed to be the cause of both syncopal attacks and inappropriate shocks. The patient has been asymptomatic after ablation of the accessory pathway. To the best of our knowledge, this is the first report of induction of an AV-reentrant tachycardia by a high-voltage implantable cardioverter defibrillator shock. (PACE 2010; 33:372,376) [source] Depression and Anxiety Status of Patients with Implantable Cardioverter Defibrillator and Precipitating FactorsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 6 2006AHMET KAYA BILGE Background: Implantable cardioverter defibrillators (ICDs) are life-saving devices in treatment of life-threatening arrhythmia. We evaluate the emotional status of Turkish patients with ICD and try to explain factors that affect emotional status of the patients. Methods: Ninety-one patients with previously implanted ICD were included in the study. Follow-up periods, presence of ICD shock, shock frequency, time of the recent shock, age, and gender were noted. Depression and anxiety scores were evaluated according to Hospital Anxiety and Depression (HAD) chart. Results: Mean anxiety and depression scores were found as 9.1 ± 5.3 and 7.2 ± 5.1, respectively. According to HAD charts, 42 patients (46%) had anxiety and 37 patients (41%) had depression. Depression scores indicated significant difference between subgroups divided on the basis of follow-up periods (P = 0.026) and on the basis of time of recent shock (P = 0.028). There was significant difference in anxiety scores (P = 0.016) between patients with ICD shocks and patients with no shocks. When the patients were divided into subgroups according to shock frequency, both depression (P = 0.024) and anxiety (P = 0.016) scores presented significant difference. In female patients, depression and anxiety scores were found significantly higher compared to male patients (P = 0.046 and P = 0.016, respectively). In multivariate analysis, gender and shock frequency were found as predictors for anxiety scores (P = 0.019 and P = 0.044, respectively). However same analysis revealed no predictive factor for depression score. Conclusion: Our study indicates presence of depression and anxiety in nearly half of the patients with ICD. Consultation with psychiatry should be a part of the treatment for patients with ICD, especially for those who constitute high-risk groups. [source] Strategy for Safe Performance of Magnetic Resonance Imaging on a Patient with Implantable Cardioverter DefibrillatorPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2006CLAAS PHILIP NAEHLE Clinically indicated magnetic resonance imaging (MRI) of the brain was safely performed at 1.5 T on a patient with an implantable cardioverter defibrillator (ICD). The ICD was reprogrammed to detection only, and imaging hardware and protocols were modified to minimize radiofrequency power deposition to the ICD system. The integrity of the ICD system was verified immediately post-MRI and after 6 weeks, including an ICD test with induction of ventricular fibrillation. This case demonstrates that in exceptional circumstances, in carefully selected patients, and using special precautions, an MRI exam of the brain may be possible in patients with ICDs. [source] Alternating Preventricular and Postventricular Atrial Far-Field Sensing by a Dual Chamber Cardioverter DefibrillatorPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2005S. SERGE BAROLD No abstract is available for this article. [source] Persistent Left Superior Vena Cava-Inferior Vena Caval Communication Complicating Implantation of an Implantable Cardioverter DefibrillatorPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 11 2005SANJEEV GOYAL A persistent left superior vena cava has been observed in 0.3% of the general population on autopsy. Its presence can complicate left-sided device implantation. Commonly, a LSVC connects to the right atrium via the coronary sinus. A LSVC-accessory hemiazygous-hemiazygous-inferior vena caval communication has not been described previously. The presence of such a congenital venous anomaly will prohibit a left-sided device implant. [source] Electrical Interference from an Abdominal Muscle Stimulator Unit on an Implantable Cardioverter Defibrillator:PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2003Report of Two Consecutive Cases Two consecutive cases are presented of patients with ICDs in whom the use of commercial units for muscle stimulation for abdominal training caused interference with the device, mimicked cardiac signals, and resulted in inappropriate treatment shock delivery. (PACE 2003; 26:1292,1293) [source] Inhibition of Bradycardia Pacing and Detection of Ventricular Fibrillation Due to Far-Field Atrial Sensing in a Triple Chamber ImplantablePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2002DIRK VOLLMANN VOLLMANN, D., et al.: Inhibition of Bradycardia Pacing and Detection of Ventricular Fibrillation Due to Far-Field Atrial Sensing in a Triple Chamber Implantable Cardioverter Defibrillator. Oversensing of intracardiac signals or myopotentials may cause inappropriate ICD therapy. Reports on far-field sensing of atrial signals are rare, and inappropriate ICD therapy due to oversensing of atrial fibrillation has not yet been described. This report presents a patient with a triple chamber ICD and a history of His-bundle ablation who experienced asystolic ventricular pauses and inappropriate detection of ventricular fibrillation due to far-field oversensing of atrial fibrillation. Several factors contributed to the complication, which resolved after reduction of the ventricular sensitivity. [source] Washing Machine Associated 50 Hz Detected As Ventricular Fibrillation by An Implanted Cardioverter DefibrillatorPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 8 2001XAVIER SABATÉ SABATÉ, X., et al.: Washing Machine Associated 50 Hz Detected As Ventricular Fibrillation by An Implanted Cardioverter Defibrillator. This case report describes a patient with an automatic ICD who suffered a defibrillation shock without warning symptoms. An electrical interference can be observed in the stored EGM of the episode. The patient explained that the moment he felt the shock he was touching a washing machine. After correct grounding of this machine the patient did not suffer more inappropriate shocks. [source] Use of a Single Coil Transvenous Electrode with an Abdominally Placed Implantable Cardioverter Defibrillator in ChildrenPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2000PETER S. FISCHBACH While transvenous defibrillator electrode placement avoiding a thoracotomy is preferable, electrode size, a large intercoil spacing, and the need for subclavicular device placement preclude this approach in most children. We investigated a single RV coil to an abdominally placed active can ICD device. Five children ages 8,16 years (weight 21,50 kg, mean 35 kg) underwent ICD placement. Placement of a single coil Medtronic model 6932 or 6943 electrode was performed via the left subclavian vein approach and the electrode positioned in the RV apex with the coil lying along the RV diaphragmatic surface. The ICD (Medtronic Micro Jewel II model 7223Cx) was implanted in a left abdominal pocket with the lead tunneled from the infraclavicular region to the pocket. Implant DFTs were ± 15 J using a biphasic waveform. DFTs rechecked within 3-month postimplant were unchanged. Lead impedance at implant ranged from 38 to 56 ,, mean 51 ,. Follow-up was 3,21 months (total 82 months) with no electrode dislodgment. lead fractures, or inappropriate discharges. Two of the five patients have had successful appropriate ICD discharges. Transvenous ICD electrode placement can be performed in children as small as 20 kg with the device implanted in a cosmetically acceptable abdominal pocket that is well tolerated. Excellent DFTs can be achieved. This approach avoids a thoracotomy in all but the smallest child, does not require subclavicular placement of the device, and avoids use of a second intravascular coil. [source] ABCD (Alternans Before Cardioverter Defibrillator)CLINICAL CARDIOLOGY, Issue 2 2007Article first published online: 26 FEB 200 No abstract is available for this article. [source] Remote Monitoring of Implantable Cardioverter Defibrillators versus Quarterly Device Interrogations in Clinic: Results from a Randomized Pilot Clinical TrialJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 5 2010M.H.S., SANA M. AL-KHATIB M.D. ICD: Remote Monitoring Versus Clinic Interrogations.,Introduction: Remote monitoring is increasingly becoming the new standard of care for implantable cardioverter defibrillator (ICD) follow-up. We sought to determine whether remote monitoring of ICDs improves patient outcomes compared with quarterly device interrogations in clinic. Methods and Results: In this single-center pilot clinical trial, adult patients with an ICD were randomly assigned to remote monitoring versus quarterly device interrogations in clinic. The primary endpoint was a composite of cardiovascular hospitalization, emergency room visit for a cardiac cause, and unscheduled visit to the electrophysiology clinic for a device-related issue at 1 year. We also examined health-related quality of life, costs, and patient satisfaction with their ICD care. Of 151 patients enrolled in this trial, 76 were randomized to remote monitoring and 75 to quarterly device interrogations in clinic. There was no significant difference in the primary endpoint (32% in the remote monitoring arm vs 34% in the control arm; P = 0.8), mortality, or cost between the 2 arms. Quality of life and patient satisfaction were significantly better in the control arm than in the remote monitoring arm at 6 months (83 [25th, 75th percentiles 70, 90] vs 75 [50, 85]; P = 0.002 and 88 [75, 100] vs 75 [75, 88]; P = 0.03, respectively), but not at 12 months. Conclusion: We showed no significant reduction in cardiac-related resource utilization with remote monitoring of ICDs. However, given the small number of patients in our study, the real clinical and health economics impact of remote monitoring needs to be verified by a large, multicenter, randomized clinical trial. (J Cardiovasc Electrophysiol, Vol. 21, pp. 545-550, May 2010) [source] Implantable Cardioverter Defibrillators: Do Women Fare Worse Than Men?JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2009Gender Comparison in the INTRINSIC RV Trial Introduction: Due to limited enrollment of women in previous trials, there is a paucity of data comparing outcome and arrhythmic events in men versus women with implantable cardioverter defibrillators (ICDs). Methods and Results: We analyzed outcome of patients in the INTRINSIC RV (Inhibition of Unnecessary RV Pacing with AV Search Hysteresis in ICDs) trial based on gender. Women comprised 19% (293/1530) of the INTRINSIC RV population. Compared with men, women were less likely to have coronary disease, ischemic cardiomyopathy, and hyperlipidemia, and were more likely to have congestive heart failure and diabetes. Women were less likely to receive beta blockers and ACE inhibitors, and more likely to receive diuretics. Over 10.8 ± 3.5 months of follow-up, unadjusted mortality was higher in women than men (6.8% vs 4.1%, P = 0.04). Heart failure hospitalizations occurred in 7.9% of women versus 5.7% of men (P = 0.13). After adjustment for baseline differences and drug therapy, there was no significant difference in mortality between men and women. Adverse events were observed more often in women. There were no gender differences in the percentage of patients receiving appropriate or inappropriate ICD shocks. Conclusions: In INTRINSIC RV, women receiving ICDs differed from men regarding baseline characteristics and drug therapy. After adjusting for baseline differences and medical therapy, there were no differences in heart failure hospitalization, survival, or ICD shock therapy during follow-up. Apparent undertreatment of heart failure and greater frequency of adverse advents in women receiving ICDs warrant further investigation. [source] Predictors of All-Cause Mortality for Patients with Chronic Chagas' Heart Disease Receiving Implantable Cardioverter Defibrillator TherapyJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2007AUGUSTO CARDINALLI-NETO M.D., Ph.D. Background: Implantable Cardioverter Defibrillators (ICD) have sporadically been used in the treatment of either Sustained Ventricular Tachycardia (VT) or Ventricular Fibrillation (VF) in Chagas' disease patients. This study aimed at determining predictors of all-cause mortality for Chagas' disease patients receiving ICD therapy. Methods and Results: Ninety consecutive patients were entered the study. Mean left ventricular ejection fraction was 47 ± 13%. Twenty-five (28%) patients had no left ventricular systolic dysfunction. After device implantation, all patients were given amiodarone (mean daily dose = 331, 1 ± 153,3 mg), whereas a B-Blocking agent was given to 37 (40%) out of 90 patients. Results: A total of 4,274 arrhythmias were observed on stored electrogram in 64 (71%) out of 90 patients during the study period; SVT was observed in 45 out of 64 (70%) patients, and VF in 19 (30%) out of 64 patients. Twenty-six (29%) out of 90 patients had no arrhythmia. Fifty-eight (64%) out of 90 patients received appropriate shock, whereas Antitachycardia Pacing was delivered to 58 (64%) out of 90 patients. There were 31 (34%) deaths during the study period. Five patients were lost to follow up. Sudden cardiac death affected 2 (7%) out of 26 patients, whereas pump failure death was detected in the remaining 24 (93%) patients. Number of shocks per patient per 30 days was the only independent predictor of mortality. Conclusion: Number of shocks per patient per 30 days predicts outcome in Chagas' disease patients treated with ICD. [source] Cigarette Smoking and the Risk of Supraventricular and Ventricular Tachyarrhythmias in High-Risk Cardiac Patients with Implantable Cardioverter DefibrillatorsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2006ILAN GOLDENBERG M.D. Introduction: Nicotine elevates serum catecholamine concentration and is therefore potentially arrhythmogenic. However, the effect of cigarette smoking on arrhythmic risk in coronary heart disease patients is not well established. Methods and Results: The risk of appropriate and inappropriate defibrillator therapy by smoking status was analyzed in 717 patients who received an implantable cardioverter defibrillator (ICD) in the Multicenter Automatic Defibrillator Implantation Trial-II. Compared with patients who had quit smoking before study entry (past smokers) and patients who had never smoked (never smokers), patients who continued smoking (current smokers) were significantly younger and generally had more favorable baseline clinical characteristics. Despite this, the adjusted hazard ratio (HR) for appropriate ICD therapy for fast ventricular tachycardia (at heart rates ,180 b.p.m) or ventricular fibrillation was highest among current smokers (HR = 2.11 [95% CI 1.11,3.99]) and intermediate among past smokers (HR = 1.57 [95% CI 0.95,2.58]), as compared with never smokers (P for trend = 0.02). Current smokers also exhibited a higher risk of inappropriate ICD shocks (HR = 2.93 [95% CI 1.30,6.63]) than past (HR = 1.91 [95% CI 0.97,3.77]) and never smokers (P for trend = 0.008). Conclusions: In patients with ischemic left ventricular dysfunction, continued cigarette smoking is associated with a significant increase in the risk of life-threatening ventricular tachyarrhythmias and inappropriate ICD shocks induced by rapid supraventricular arrhythmias. Our findings stress the importance of complete smoking cessation in this high-risk population. [source] Implantable Cardioverter Defibrillators in Pediatric Patients:JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 1 2005Off-Label Devices for Orphan Diseases No abstract is available for this article. [source] Supraventricular Arrhythmias in Children and Young Adults with Implantable Cardioverter DefibrillatorsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2001BARRY A. LOVE M.D. SVT in Pediatric ICD Recipients.Introduction: Rapidly conducted supraventricular tachycardias (SVTs) can lead to inappropriate device therapy in implantable cardioverter defibrillator (ICD) patients. We sought to determine the incidence of SVTs and the occurrence of inappropriate ICD therapy due to SVT in a pediatric and young adult population. Methods and Results: We undertook a retrospective review of clinical course, Holter monitoring, and ICD interrogations of patients receiving ICD follow-up at our institution between March 1992 and December 1999. Of 81 new ICD implantations, 54 eligible patients (median age 16.5 years, range 1 to 48) were identified. Implantation indications included syncope and/or spontaneous/inducible ventricular arrhythmia with congenital heart disease (30), long QT syndrome (9), structurally normal heart (ventricular tachycardia/ventricular fibrillation [VT/VF]) (7), and cardiomyopathies (7). Sixteen patients (30%) received a dual-chamber ICD. SVT was recognized in 16 patients, with 12 of 16 having inducible or spontaneous atrial tachycardias. Eighteen patients (33%) received , 1 appropriate shock(s) for VT/VF; 8 patients (15%) received inappropriate therapy for SVT. Therapies were altered after an inappropriate shock by increasing the detection time or rate and/or increasing beta-blocker dosage. No single-chamber ICD was initially programmed with detection enhancements, such as sudden onset, rate stability, or QRS discriminators. Only one dual-chamber defibrillator was programmed with an atrial discrimination algorithm. Appropriate ICD therapy was not withheld due to detection parameters or SVT discrimination programming. Conclusion: SVT in children and young adults with ICDs is common. Inappropriate shocks due to SVT can be curtailed even without dual-chamber devices or specific SVT discrimination algorithms. [source] Are Routine Arrhythmia Inductions Necessary in Patients with Pectoral Implantable Cardioverter Defibrillators?JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2000MICHAEL GLIKSON M.D. Routine Arrhythmia Inductions in Patients with ICDs. Introduction: The value of ventricular arrhythmia inductions as part of routine implantable cardioverter defibrillator (ICD) follow-up in new-generation pectoral ICDs is unknown Methods and Results: We performed a retrospective analysis of a prospectively collected database analyzing data from 153 patients with pectoral ICDs who had routine arrhythmia inductions at predismissal, and 3 months and 1 year after implantation. Routine predismissal ventricular fibrillation (VF) induction yielded important findings in 8.8% of patients, all in patients with implantation defibrillation threshold (DFT) , 15 J or with concomitant pacemaker systems. At 3 months and 1 year, routine VF induction yielded important findings in 5.9% and 3.8% of tested patients, respectively, all in patients who had high DFT on prior testing. Ventricular tachycardia (VT) induction at predismissal, and 3 months and 1 year after implantation resulted in programming change in 37.4%, 28.1%, and 13.8% of tested patients, almost all in patients with inducible VT on baseline electrophysiologic study and clinical episodes since implantation. Conclusion: Although helpful in identifying potentially important ICD malfunctions, routine arrhythmia inductions during the first year after ICD implantation may not be necessary in all cases. VF inductions have a low yield in patients with previously low DFTs who lack concomitant pacemakers. VT inductions have a low yield in patients without baseline Inducible VT and in the absence of clinical events. Definite recommendations regarding patient selection must await larger prospective studies as well as consensus in the medical community about what comprises an acceptable risk justifying avoidance of the costs and inconveniences of routine arrhythmia inductions. [source] Age-Specific Differences in Women with Implantable Cardioverter Defibrillators: An International Multi Center StudyPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2008LAUREN D. VAZQUEZ M.S. Background: Common psychological adjustment difficulties have been identified for groups of implantable cardioverter defibrillator patients, such as those who are young (<50 years old), have been shocked, and are female. Specific aspects and concerns, such as fears of death or shock and body image concerns, that increase the chance of distress, have not been examined in different aged female implantable cardioverter defibrillator (ICD) recipients. The aim of the study was to investigate these areas of adjustment across three age groups of women from multiple centers. Methods: Eighty-eight female ICD patients were recruited at three medical centers: Shands Hospital at the University of Florida, Brigham and Women's Hospital in Boston, and Royal North Shore Hospital in Sydney, Australia. Women completed individual psychological assessment batteries, measuring the constructs of shock anxiety, death anxiety, and body image concerns. Medical record review was conducted for all patients regarding cardiac illnesses and ICD-specific data. Results: Multivariate and univariate analyses of variance revealed that younger women reported significantly higher rates of shock and death anxiety (Pillai's F = 3.053, P = 0.018, ,2p= 0.067) and significantly greater body image concerns (Pillai's F = 4.198, P = 0.018, ,2p= 0.090) than middle- and older-aged women. Conclusions: Women under the age of 50 appear to be at greater risk for the development of psychosocial distress associated with shock anxiety, death anxiety, and body image. Clinical-based strategies and interventions targeting these types of adjustment difficulties in younger women may allow for improved psychosocial and quality of life outcomes. [source] Mechanisms of Ventricular Fibrillation Initiation in MADIT II Patients with Implantable Cardioverter DefibrillatorsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2008RYAN ANTHONY M.D. Background:The availability of stored intracardiac electrograms from implantable defibrillators (ICDs) has facilitated the study of the mechanisms of ventricular tachyarrhythmia onset. This study aimed to determine the patterns of initiation of ventricular fibrillation (VF) in Multicenter Automatic Defibrillator Implantation Trial (MADIT) II patients along with associated electrocardiogram (ECG) parameters and clinical characteristics. Methods:Examination of stored electrograms enabled us to evaluate the rhythm preceding each episode of VF and to calculate (intracardiac) ECG parameters including QT, QT peak (QTp), coupling interval, and prematurity index. Results:Sixty episodes of VF among 29 patients (mean age 64.4 ± 2.5 years) were identified. A single ventricular premature complex (VPC) initiated 46 (77%) episodes whereas a short-long-short (SLS) sequence accounted for 14 (23%) episodes. Of the 29 patients studied, 23 patients had VF episodes preceded by a VPC only, two patients with SLS only, and four patients with both VPC and SLS-initiated episodes. There were no significant differences between initiation patterns in regards to the measured ECG parameters; a faster heart rate with SLS initiation (mean RR prior to VF of 655 ± 104 ms for SLS and 744 ± 222 ms for VPC) approached significance (P = 0.06). The two patients with SLS only were not on ,-blockers compared to 83% of the VPC patients. Conclusion:Ventricular fibrillation is more commonly initiated by a VPC than by a SLS sequence among the MADIT II population. Current pacing modes designed to prevent bradycardia and pause-dependent arrhythmias are unlikely to decrease the incidence of VPC-initiated episodes of VF. [source] A Clinical Risk Score to Predict the Time to First Appropriate Device Therapy in Recipients of Implantable Cardioverter DefibrillatorsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 3 2007HAITHAM HREYBE M.D. Background:To develop a risk score to predict the occurrence of appropriate defibrillator [implantable cardioverter-defibrillator (ICD)] therapies. A simple clinical score predicting the risk of appropriate ICD therapy is lacking. Methods:A Cox regression model was developed from a database of ICD patients at a single tertiary center to predict the time to appropriate ICD therapy defined as shock or antitachycardia pacing. A risk score was derived from this model using half of the database and was validated using the other half. Results:A total of 399 patients were entered into the database between July 2001 and February 2004. There were no statistically significant differences between the derivation (n = 200) and validation (n = 199) groups in any of the demographic or clinical variables recorded. The risk score included three independent variables: indication for ICD implantation (P = 0.03), serum creatinine level (P = 0.015), and QRS width (P = 0.028). The observed risk scores were highly predictive of time to ICD therapy in the validation group (P = 0.02). Conclusion:We describe a new clinical risk score that predicts the time to appropriate device therapy in ICD recipients of a single tertiary center hospital. The performance of this risk score needs to be investigated prospectively in a larger patient population. [source] Remote, Wireless, Ambulatory Monitoring of Implantable Pacemakers, Cardioverter Defibrillators, and Cardiac Resynchronization Therapy Systems: Analysis of a Worldwide DatabasePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2007ARNAUD LAZARUS M.D. Study Objective: To describe the daily routine application of a new telemonitoring system in a large population of cardiac device recipients. Methods: Data transmitted daily and automatically by a remote, wireless Home MonitoringÔ system (HM) were analyzed. The average time gained in the detection of events using HM versus standard practice and the impact of HM on physician workload were examined. The mean interval between device interrogations was used to compare the rates of follow-up visits versus that recommended in guidelines. Results: 3,004,763 transmissions were made by 11,624 recipients of pacemakers (n = 4,631), defibrillators (ICD; n = 6,548), and combined ICD + cardiac resynchronization therapy (CRT-D) systems (n = 445) worldwide. The duration of monitoring/patient ranged from 1 to 49 months, representing 10,057 years. The vast majority (86%) of events were disease-related. The mean interval between last follow-up and occurrence of events notified by HM was 26 days, representing a putative temporal gain of 154 and 64 days in patients usually followed at 6- and 3-month intervals, respectively. The mean numbers of events per patient per month reported to the caregivers for the overall population was 0.6. On average, 47.6% of the patients were event-free. The mean interval between follow-up visits in patients with pacemakers, single-chamber ICDs, dual chamber ICDs, and CRT-D systems were 5.9 ± 2.1, 3.6 ± 3.3, 3.3 ± 3.5, and 1.9 ± 2.9 months, respectively. Conclusions: This broad clinical application of a new monitoring system strongly supports its capability to improve the care of cardiac device recipients, enhance their safety, and optimize the allocation of health resources. [source] The Impact of Catecholamines on Defibrillation Threshold in Patients with Implanted Cardioverter DefibrillatorsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 11 2005JAMES S. KALUS Objectives: To determine the effect of physiologic catecholamine concentrations on the defibrillation threshold (DFT) in patients with implanted cardioverter defibrillators. Background: DFT is the minimum energy delivered by an implanted cardioverter defibrillator that successfully converts ventricular fibrillation. DFT testing is performed under conscious sedation. Since activities of daily living enhance sympathetic tone substantially over these nadir levels, it is important to explore the impact of catecholamines on DFT. Methods: In this double-blind study, we determined DFT by the step-down method. Patients (n = 50) were stratified by beta-blocker use and then randomized to a 7-minute infusion of epinephrine, norepinephrine, or placebo. After study infusion, DFT testing was repeated. Changes in DFT with different study medications were compared. Subgroup analyses of the effects of catecholamines on DFT, based on beta-blocker use, were also performed. Results: Norepinephrine reduced DFT from baseline measurements by 22.6% (P = 0.008). Neither epinephrine nor placebo impacted DFT (P = 0.999, P = 0.317, respectively). In the subgroup analyses, DFT was reduced with norepinephrine regardless of beta-blocker use, while epinephrine reduced DFT among those receiving beta-blockers. No change in DFT was observed in either of the placebo subgroups. Conclusions: Elevation of plasma norepinephrine concentrations reduces the DFT, while elevations in epinephrine had no effect. Norepinephrine seems to reduce DFT regardless of beta-blocker therapy but epinephrine's effects are beta-blocker dependent. [source] Shock Coordinated with High Power of Morphology Electrogram Improves Defibrillation Success in Patients with Implantable Cardioverter DefibrillatorsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 9 2002ALEXANDER BERKOWITSCH BERKOWITSCH, A., et al.: Shock Coordinated with High Power of Morphology Electrogram Improves Defibrillation Success in Patients with Implantable Cardioverter Defibrillators. Animal studies have suggested that the success of defibrillation may depend on the properties of VF waveform obtained from the morphology electrogram (ME) at the time of the shock. The reliable identification of depolarization events in the fibrillatory signal can be achieved using adaptive estimation of the instantaneous signal power (P). The aim of this study was to investigate if a high P of the ME (PME) was related to ventricular DFT and if the upslope in ME can be associated with the depolarization event. A total of 575 VF (mean duration 10 s) episodes recorded and stored during ICD implantation in 77 patients with ventricular arrhythmias were used for analysis. The DFT was defined using a double step-down test. The values of PME immediately before pulse delivery (Pshock) and shock outcomes were registered. The differences between Pshock of successful and failed defibrillation were tested with the Mann-Whitney U test. The relationship between individual medians of Pshock (Pmed) and DFT was analyzed using the Kruskall-Wallis H-test. The coincidence between identified depolarization and upslope in ME was tested using the chi-square test. A P value of 0.05 was set for an error probability. The Pshock in case of failed defibrillation was significantly lower than Pshock in successful cases by the pulses of any strength (P < 0.001). The test revealed a significant inverse correlation between Pmed and DFT with P < 0.001. The depolarization corresponded to the upslope of ME in 85% of cases. This study demonstrated that a high value of instantaneous power of ME indicates the optimal time for shock delivery. The implementation of this algorithm in ICDs may improve the defibrillation efficacy. [source] Preliminary Results with the Simultaneous Use of Implantable Cardioverter Defibrillators and Permanent Biventricular Pacemakers: Implications for Device Interaction and DevelopmentPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 3 2000S. WALKER We report our preliminary experience with the combined use of implantable cardioverter defibrillutors (ICD) and biventricular pacemakers in six patients with heart failure and malignant ventricular arrhythmia. Two patients underwent ICD implantation for malignant ventricular arrhythmia after previous biventricular pacemaker implantation. One patient underwent biventricular pacemaker insertion for NYHA Class III heart failure after previous ICD implantation. Two patients underwent single device implantation. In the sixth patient, a combined implantation failed due to an inability to obtain a satisfactory left ventricular pacemaker lead position. The potential for device interaction was explored during implantation. In two patients a potentially serious interaction was discovered. Subsequent alterations in device configuration and programming prevented these interactions with long-term use. No complication of combined device use has been demonstrated during a mean follow-up of 2 months (range 1-4 months). Satisfactory ICD and pacemaker function has also been demonstrated. We conclude that combined device implantation may be feasible with currently available pacing technology and that further prospective studies are required in this area. [source] Electrophysiologist-Implanted Transvenous Cardioverter Defibrillators Using Local Versus General AnesthesiaPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2000ANTONIS S. MANOLIS With the advent of smaller biphasic transvenous implantable Cardioverter defibrillators (ICDs) and the experience gained over the years, it is now feasible for electrophysioiogists to implant them safely in the abdominal or pectoral area without surgical assistance. Throughout the years, general anesthesia has been used as the standard technique of anesthesia for these procedures. However, use of local anesthesia combined with deep sedation only for defibrillation threshold (DFT) testing might further facilitate and simplify these procedures. The purpose of this study was to test the feasibility of using local anesthesia and compare it with the standard technique of general anesthesia, during implantation of transvenous ICDs performed by an electrophysiologist in the electrophysiology laboratory. For over 4 years in the electrophysiology laboratory, we have implanted transvenous ICDs in 90 consecutive patients (84 men and 6 women, aged 58 ± 15 years). Early on, general anesthesia was used (n = 40, group I), but in recent series (n = 50, group II) local anesthesia was combined with deep sedation for DFT testing. Patients had coronary (n = 58) or valvular (n = 4) disease, cardiomyopathy (n = 25) or no organic disease (n = 3), a mean left ventricular ejection fraction of 35%, and presented with ventricular tachycardia (n = 72) or fibrillation (n = 16), or syncope (n = 2). One-lead ICD systems were used in 74 patients, two-lead systems in 10 patients, andan AVICD in 6 patients. ICDs were implanted in abdominal (n = 17, all in group I) or more recently in pectoral (n = 73) pockets. The DFT averaged 9.7 ± 3.6 J and 10.2 ± 3.6 J in the two groups, respectively (P = NS) and there were no differences in pace-sense thresholds. The total procedural duration was shorter (2.1 ± 0.5 hours) in group II (all pectoral implants) compared with 23 pectoral implants of group I (2.9 ± 0.5 hours) (P < 0.0001). Biphasic devices were used in all patients and active shell devices in 67 patients; no patient needed a subcutaneous patch. There were six complications (7%), four in group I and two in group II: one pulmonary edema and one respiratory insufficiency that delayed extubation for 3 hours in a patient with prior lung resection, both probably related to general anesthesia, one lead insulation break that required reoperation on day 3, two pocket hematomas, and one pneumothorax. There was one postoperative arrhythmic death at 48 hours in group I. No infections occurred. Patients were discharged at a mean time of 3 days. All devices functioned well at predischarge testing. Thus, it is feasible to use local anesthesia for current ICD implants to expedite the procedure and avoid general anesthesia related cost and possible complications. [source] QT Variability during Rest and Exercise in Patients with Implantable Cardioverter Defibrillators and Healthy ControlsANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 1 2009Mark C. Haigney M.D. Background: Increased QT Variability (QTVI) is predictive of life threatening arrhythmias in vulnerable patients. The predictive value of QTVI is based on resting ECGs, and little is known about the effect of acute exercise on QTVI. The relation between QTVI and arrhythmic vulnerability markers such as T-wave alternans (TWA) has also not been studied. This study examined the effects of exercise on QTVI and TWA in patients with arrhythmic vulnerability. Methods: Digitized ECGs were obtained from 47 ICD patients (43 males; age 60.9 ± 10.1) and 23 healthy controls (18 males; age 59.7 ± 9.5) during rest and bicycle exercise. QTVI was assessed using a previously validated algorithm and TWA was measured as both a continuous and a categorical variable based on a priori diagnostic criteria. Results: QTVI increased with exercise in ICD patients (,0.79 ± 0.11 to 0.36 ± 0.08, P < 0.001) and controls (,1.50 ± 0.07 to ,0.19 ± 0.12, P < 0.001), and QTVI levels were consistently higher in ICD patients than controls during rest and exercise (P < 0.001). The magnitude of QTVI increase from baseline levels was not larger among ICD patients versus controls (P > 0.20). Among ICD patients, elevated exercise QTVI was related to lower LV ejection fraction and inducibility of ischemia (P < 0.05). QTVI at rest correlated with exercise TWA (r = 0.54, P = 0.0004). Conclusions: QT variability increases significantly with exercise, and exercise QTVI is related to other well-documented markers of arrhythmic vulnerability, including low ejection fraction, inducible ischemia, and TWA. Resting QTVI may be useful in the risk stratification of individuals incapable of performing standard exercise protocols. [source] ChemInform Abstract: Room Temperature Synthesis of the Larger Power, High Silver Density Cathode Material Ag4V2O6F2 for Implantable Cardioverter Defibrillators.CHEMINFORM, Issue 40 2009Thomas A. Albrecht Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] | ||||||||||||||||||||||||||||