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Implantable Defibrillators (implantable + defibrillator)
Selected AbstractsPsychological Intervention Following Implantation of an Implantable Defibrillator: A Review and Future RecommendationsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2007SUSANNE S. PEDERSEN Ph.D. Background:The medical benefits of the implantable cardioverter defibrillator (ICD) are unequivocal, but a subgroup of patients experiences emotional difficulties following implantation. For this subgroup, some form of psychological intervention may be warranted. This review provides an overview of current evidence on the efficacy of psychological intervention in ICD patients and recommendations for future research. Methods:We searched the PubMed and PsycInfo databases in the period between January 1980 and April 2007, using a set of a priori determined keywords. Based on the search and a hand search of the reference lists of the included articles, we identified nine studies that fulfilled the inclusion criteria. Results:The majority of studies used a randomized controlled trial design, but studies varied considerably in sample size, response, attrition rate, and type of intervention. However, most interventions were multifactorial, using cognitive behavioral therapy as one of the mainstays of treatment. Overall, psychological interventions seem to have little impact on shocks and heart rate variability. Some studies found a decrease in depressive symptoms and gains in quality of life, but the most notable effects are seen in improved exercise capacity and reductions in anxiety. Effect sizes for changes in anxiety in the intervention group ranged from small to large compared to small in the usual care group, using Cohen's effect size index. Conclusions:Preliminary evidence from small-scale intervention trials suggests that psychological intervention is worthwhile in ICD patients. Nevertheless, large-scale, well-designed trials are warranted to substantiate these findings. A multifactorial approach using a cognitive behavioral component paired with exercise training is likely to be the most successful. [source] Runaway Implantable Defibrillator,A Rare Complication of Radiation TherapyPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2007EMEC M.D., F.A.C.C., JAN N A case of a patient with runaway implantable cardioverter defibrillator (ICD) due to radiation therapy of a lung cancer is reported. This manifested as poorly tolerated wide complex tachycardia due to inappropriate rapid ventricular pacing, The event terminated with polymorphic VT, which inhibited pacing and ceased spontaneously before ICD discharge. The likely cause was corruption of device random access memory by ionizing radiation. [source] The Dual Chamber and VVI Implantable Defibrillator (DAVID) TrialPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 7p1 2003Bruce L. Wilkoff Introduction: The devices used to prove the benefit of ICD therapy had only VVI pacing but most current ICD devices provide dual chamber pacing therapy. The DAVID trial sought to measure the impact of dual chamber pacing at 70 bpm (DDDR-70) vs. ventricular backup pacing at 40 bpm (VVI-40) in patients with standard indications for ICD implantation but without indications for bradycardia pacing. Methods: This single-blind, multicenter, parallel-group, randomized clinical trial enrolled 506 patients with indications for ICD therapy between 10/2000 and 9/2002. All patients had an LVEF ,0.40, no indication for pacemaker therapy and no persistent atrial arrhythmias. ICDs with dual chamber, rate-responsive pacing capability were implanted and programmed to VVI-40 or DDDR-70. Results: The combined endpoint of mortality or hospitalization for congestive heart failure (CHF) at one year was 16.1% (VVI-40) vs. 26.7% (DDDR-70), (p , 0.03), mortality 6.5% vs. 10.1% (p , 0.15) and CHF hospitalization 13.3% vs. 22.5% (p , 0.07). Conclusion: For ICD patients, DDDR-70 pacing exhibits no clinical advantage over VVI-40 pacing and may increase CHF and mortality. [source] Device-Related Infection Among Patients With Pacemakers and Implantable Defibrillators: Incidence, Risk Factors, and ConsequencesJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2010PABLO B. NERY M.D. Risk Factors and Complications of Pacemaker and ICD Infection.,Background: Device-related infection is a major limitation of device therapy for cardiac arrhythmia. Methods: The authors analyzed the incidence and risk factors for cardiac device infection (CDI) among consecutive patients implanted with pacemaker (PM) or implantable cardioverter defibrillator (ICD) (including cardiac resynchronization therapy devices) at a tertiary health center in Hamilton, Ontario, Canada. Most patients with device-related infections were identified by an internal infection control system that reports any positive wound and blood cultures following surgery, between 2005 and the present. A retrospective review of patient records was also performed for all patients who received an ICD or PM between July 1, 2003 and March 20, 2007. Results: A total of 24 infections were identified among 2,417 patients having device surgery (1%). Fifteen of these infections (60%) were diagnosed within 90 days of the last surgical procedure. Univariate analysis showed that patients presenting with CDI were more likely to have had a device replacement, rather than a new implant, had more complex devices (dual/triple chamber vs single), and were more likely to have had a prior lead dislodgement. Multivariate analysis found device replacement (P = 0.02) and cardiac resynchronization therapy (CRT)/dual-chamber devices (P = 0.048) to be independent predictors of infection. One patient developed septic pulmonary emboli after having laser-assisted lead extraction. No patient died and 22 patients received a new device. Conclusion: CDI occurs in about 1% of cases in high volume facilities. Pulse generator replacement surgery and dual- or triple-chamber device implantation were associated with a significantly increased risk of infection. (J Cardiovasc Electrophysiol, Vol. pp. 786-790, July 2010) [source] Electrocardiographic Findings, Device Therapies, and Comorbidities in Octogenarian Implantable Defibrillator RecipientsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2010JAMES D. DANIELS M.D. Implantable Defibrillators in Octogenarians.,Background: The use of implantable cardioverter-defibrillators (ICDs) in octogenarians is poorly defined. Objective: To assess baseline electrocardiographic (ECG) findings, arrhythmia episodes, and development of severe nonarrhythmic illness or death in patients aged ,80 years at ICD implantation, and to compare them with younger patients. Methods: Medical records and device interrogations for 199 patients ,70 years old who underwent ICD implantation were reviewed. Patients were divided into 3 groups based on age at the time of implant: age 70,74 (group 1; 88 patients), age 75,79 (group 2; 67 patients), and age ,80 (group 3; 44 patients). Results: ECGs: Octogenarians were more likely to have sinus bradycardia (SB) (P = 0.047) and left bundle branch block (LBBB) (P = 0.043) compared to younger patients. There was no difference among groups in the proportion of patients with atrial fibrillation or any degree of AV block. Therapies: There was no difference between age groups in any therapy (P = 0.78), appropriate therapy (P = 0.54), or inappropriate therapy (P = 0.21) per patient-year. There was no difference between groups in time-to-first therapy of any type (P = 0.71). Nonarrhythmic death/morbidity: There was no difference between groups in time to death or serious illness. Conclusion: Our study is the first to evaluate in detail the therapies received by octogenarians after ICD placement. The higher incidence of SB and LBBB might influence the number of pacing sites in octogenarian patients. Very elderly patients have similar rates of arrhythmic episodes and development of severe comorbidities as septuagenarians, and they should not be denied ICD implantation based solely on age. (J Cardiovasc Electrophysiol, Vol. 21, pp. 236,241, March 2010) [source] Analysis of Implantable Cardioverter Defibrillator Therapy in the Antiarrhythmics Versus Implantable Defibrillators (AVID) TrialJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2003RICHARD C. KLEIN M.D. Introduction: The implantable cardioverter defibrillator (ICD) is commonly used to treat patients with documented sustained ventricular tachycardia (VT) or ventricular fibrillation (VF). Arrhythmia recurrence rates in these patients are high, but which patients will receive a therapy and the forms of arrhythmia recurrence (VT or VF) are poorly understood. Methods and Results: The therapy delivered by the ICD was examined in 449 patients randomized to ICD therapy in the Antiarrhythmics Versus Implantable Defibrillators (AVID) Trial. Events triggering ICD shocks or antitachycardia pacing (ATP) were reviewed for arrhythmia diagnosis, clinical symptoms, activity at the onset of the arrhythmia, and appropriateness and results of therapy. Both shock and ATP therapies were frequent by 2 years, with 68% of patients receiving some therapy or having an arrhythmic death. An appropriate shock was delivered in 53% of patients, and ATP was delivered in 68% of patients who had ATP activated. The first arrhythmia treated in follow-up was diagnosed as VT (63%), VF (13%), supraventricular tachycardia (18%), unknown arrhythmia (3%), or due to ICD malfunction or inappropriate sensing (3%). Acceleration of an arrhythmia by the ICD occurred in 8% of patients who received any therapy. No physical activity consistently preceded arrhythmias, nor did any single clinical factor predict the symptoms of the arrhythmia. Conclusion: Delivery of ICD therapy in AVID patients was common, primarily due to VT. Inappropriate ICD therapy occurred frequently. Use of ICD therapy as a surrogate endpoint for death in clinical trials should be avoided. (J Cardiovasc Electrophysiol, Vol. 14, pp. 940-948, September 2003) [source] Temporal Patterns of Atrial Arrhythmia Recurrences in Patients with Implantable Defibrillators: Implications for Assessing Antiarrhythmic TherapiesJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2002LINA A. SHEHADEH M.S. Temporal Patterns of Atrial Arrhythmias.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 < 0.015) and not taking (17/22 patients; P < 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. [source] Impaired Detection of Ventricular Tachyarrhythmias by a Rate-Smoothing Algorithm in Dual-Chamber Implantable Defibrillators: Intradevice InteractionsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2002MICHAEL GLIKSON M.D. Rate-Smoothing Algorithm in ICD.Introduction: Rate smoothing is an algorithm initially designed to prevent rapid changes in pacemaker rates. In this study, we sought to determine the potential of the rate-smoothing mechanism in preventing detection of ventricular tachyarrhythmias. Methods and Results: Clinical testing of rate smoothing was performed at the time of defibrillator arrhythmia induction in 16 patients with implantable defibrillators during 65 episodes of ventricular tachyarrhythmias. We also performed simulator-based testing to assess detection of ventricular tachycardia between 170 and 220 beats/min with systematic sequential change of rate-smoothing percent, AV delay, and maximal rate. During clinical testing of 54 ventricular fibrillation/polymorphic ventricular tachyarrhythmia episodes, there were no cases of nondetection and 3 episodes (5%) of minimally delayed detection. Of 10 monomorphic ventricular tachyarrhythmias, 6 had either delayed (2 cases) or absent (4 cases) detection. During simulator testing, complex interrelationships were demonstrated in AV delay, upper rate, and rate-smoothing percent in determining the severity of the effect on detection. Generally, long AV delay, higher upper rate, and smaller (more aggressive) rate smoothing were associated with increased risk of ventricular tachyarrhythmia underdetection. Importantly, use of parameters that impaired detection was always accompanied by a programmer warning message. Conclusion: Rate smoothing may result in delay or failure of ventricular tachycardia detection. It is important to consider warning messages when programming rate smoothing and to test for appropriate detection when rate smoothing is used despite warning messages. [source] Implantable Defibrillators in Children: From Whence to ShockJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2001RICHARD A. FRIEDMAN M.D. [source] Analysis of the Pattern of Initiation of Sustained Ventricular Arrhythmias in Patients with Implantable DefibrillatorsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2000ERIC TAYLOR M.D. Initiation of Sustained Ventricular Arrhythmias. Introduction: The purpose of this study was to analyze the pattern of initiation of sustained ventricular arrhythmias in patients with varying types of underlying structural heart disease. Methods and Results: The study group consisted of 90 patients with an implantable cardioverter defibrillator. Cardiovascular diagnoses included coronary artery disease in 64 patients (71%). The patients were divided into four groups based on the type and severity of structural heart disease. Two hundred sixty episodes of sustained ventricular arrhythmias were analyzed. The mean coupling interval of the initiating heat of all ventricular arrhythmias was 523 ± 171 msec. The coupling interval of the initiating beat was longer in patients with impaired ventricular function, particularly those with nonischemic dilated cardiomyopathy. The prematurity index was similar regardless of the type of underlying structural heart disease. However, the prematurity index was shorter in patients with polymorphic ventricular tachycardia (VT) compared to those with monomorphic VT. A pause was observed more commonly before the onset of polymorphic VT/ventricular fibrillation than sustained monomorphic VT. Two hundred twenty-two (85%) of the arrhythmia episodes were initiated by a late-coupled premature beat, 33 (13%) were initiated by an early-coupled premature beat, and 5 episodes (2%) were initiated with a short-long-short sequence. The patttern of initiation of the ventricular arrhythmias was similar in all patient groups and for both monomorphic and polymorphic tachycardias. Conclusion: These findings demonstrate that sustained ventricular arrhythmias typically are initiated by late-coupled ventricular premature depolarizations, regardless of the type or severity of underlying structural heart disease or resultant arrhythmia. [source] Predictors of Early Mortality in Patients Age 80 and Older Receiving Implantable DefibrillatorsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 8 2010DREW ERTEL M.D. Background: There are no upper age restrictions for implantable defibrillators (ICDs) but their benefit may be limited in patients , 80 years with strong competing risks of early mortality. Risk factors for early (1-year) mortality in ICD recipients , 80 years of age have not been established. Methods: Two-center retrospective cohort study to assess predictors of one-year mortality in ICD recipients , 80 years of age. Results: Of 2,967 ICDs implanted in the two centers from 1990,2006, 225 (7.6%) patients were ,80 years of age and followed-up at one of the two centers. Mean age was 83.3 ± 3.1 years and follow-up time 3.3 ± 2.6 years. Median survival was 3.6 years (95% confidence interval 2.3,4.9). Multivariate predictors of 1-year mortality included ejection fraction (EF) , 20% and the absence of beta-blocker use. Actuarial 1-year mortality of ICD recipients , 80 with an EF , 20% was 38.2% versus 13.1% in patients 80+ years with an EF > 20% and 10.6% for patients < 80 years with an EF , 20% (P < 0.001 for both). There was no significant difference in the risk of appropriate ICD therapy between those patients 80+ years with EF above and below 20%. Conclusion: In general, patients , 80 years of age who meet current indications for ICD implantation live sufficiently long to warrant device implantation based on anticipated survival alone. However, those with an EF , 20% have a markedly elevated 1-year mortality with no observed increase in appropriate ICD therapy, thus reducing the benefit of device implantation in this population. (PACE 2010; 981,987) [source] Sleep-Disordered Breathing in Recipients of Implantable DefibrillatorsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2009WOLFRAM GRIMM M.D. Study Objectives: To examine the prevalence and clinical significance of sleep-disordered breathing in patients with implantable cardioverter defibrillators (ICD). Methods and Results: Overnight sleep studies were performed in 129 ICD recipients who had no history of sleep apnea. The mean left ventricular ejection fraction (LVEF) was 29 ± 11%. Mild, moderate, and severe sleep apnea was diagnosed in the presence of an apnea/hypopnea index (AHI) of 5,15/h, 15.1,30/h, and >30/h, respectively. No sleep apnea was present in 49 patients (38%), 57 (44%) had central sleep apnea (CSA), and 23 patients (18%) had obstructive sleep apnea (OSA). Mild, moderate, and severe sleep apnea were present in 25%, 31%, and 44% of patients with CSA, compared with 52%, 22%, and 26% of patients with OSA (P < 0.05). LVEF was similar in patients with versus without OSA or CSA. Patients with CSA were significantly older and had a higher prevalence of ischemic cardiomyopathy than patients without sleep apnea. Conclusions: Previously undiagnosed CSA is common in ICD recipients. Severely disordered breathing during sleep was more prevalent among patients with CSA than patients with OSA. This prospective, observational study will examine the long-term clinical significance of sleep-disordered breathing in ICD recipients. [source] High Quality Performance of Pacemakers and Implantable DefibrillatorsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2002PAUL A. LEVINE No abstract is available for this article. [source] Prevention of sudden cardiac deathCLINICAL CARDIOLOGY, Issue S1 2005Eric N. Prystowsky M.D. Abstract It is often unclear why some patients suffer sudden cardiac death (SCD), or even what risk factors correlate best with the syndrome. This review describes current thinking on the prevention of SCD. Most studies have focused on the prevention of potentially fatal ventricular arrhythmias in patients post myocardial infarction (MI). While pharmacotherapy has a role in the prevention of SCD in patients post MI, the interpretation of drug trials can be problematic. This is because not all patients participating in such trials received optimized medical therapy by today's standards. As a result, trial outcomes for new therapies may not reflect their true efficacy when they are added to a background of best medical care. The two principal prophylactic modalities for SCD studied to date are antiarrhythmic drug therapy and use of an implantable cardioverter defibrillator (ICD). At the present time, antiarrhythmic drugs, such as the class III agent amiodarone, seem to display relatively limited efficacy for the primary prevention of sudden death in most patients post MI. Most clinical trials have found that ICD therapy has a significant mortality benefit in patients at high risk for ventricular arrhythmias. This has been demonstrated in primary prevention trials, and in secondary prevention trials such as Antiarrhythmics Versus Implantable Defibrillators (AVID), which studied patients who survived a near-fatal ventricular arrhythmia. Based on an analysis of secondary prevention trials, the single patient characteristic that best predicted an advantage of ICD therapy over antiarrhythmic drug therapy was a left ventricular (LV) ejection fraction , 35%. Cardiac resynchronization therapy has been established as having a mortality benefit in patients with dyssynchronous LV contraction associated with dilated cardiomyopathy. [source] Home Monitoring in Patients with Implantable Cardiac Devices: Is There a Potential Reduction of Stroke Risk?JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2009Results from a Computer Model Tested Through Monte Carlo Simulations Introduction: Patients with pacemakers and implantable defibrillators (ICD) may experience asymptomatic atrial fibrillation (AF), detected with a delay depending on the in-person follow-up schedule. Home monitoring (HM) remote control with automatic alerts for AF may drive early anticoagulation, potentially reducing stroke risk. Methods and Results: A sample of 136 pacemaker (103) and ICD (33) patients with or without cardiac resynchronization therapy not taking anticoagulation at implant were monitored remotely with HM. Upon HM alerts for AF, patients were recalled to update therapy. Two-year data were entered in a computer Monte Carlo model, simulating 4,000 virtual subjects with the same AF and CHADS2 stroke risk distribution of our real population. Simulations reproduced a 2-year follow-up. Two thousand subjects were supposed to be followed with HM (HM group) and 2,000 with standard in-person follow-up (SF group) at 3, 6, 9, or 12 months. Two-year Kaplan-Meier cumulative probability of ,24-hour AF was 15.6% (95%CI 8.5,23.3%); the AF-related symptom rate was 27% and the median CHADS2 score was 2. As a result of simulations, stroke incidence in case of AF was 2.3 ± 1.1% in the HM group and 2.4 ± 1.1%, 2.5 ± 1.2%, 2.7 ± 1.2%, and 2.9 ± 1.3% in the SF group with 3-, 6-, 9-, and 12-month follow-up programs, with odds ratios of 0.97 (95%CI 0.93,1.01), 0.91 (0.88,0.95), 0.87 (0.84,0.90), and 0.82 (0.79,0.85) (HM better if odds ratios <1), respectively. Conclusions: Daily HM potentially reduces the stroke risk by 9% to 18% with respect to SF with intervisit intervals of 6 to 12 months. [source] Impaired Detection of Ventricular Tachyarrhythmias by a Rate-Smoothing Algorithm in Dual-Chamber Implantable Defibrillators: Intradevice InteractionsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2002MICHAEL GLIKSON M.D. Rate-Smoothing Algorithm in ICD.Introduction: Rate smoothing is an algorithm initially designed to prevent rapid changes in pacemaker rates. In this study, we sought to determine the potential of the rate-smoothing mechanism in preventing detection of ventricular tachyarrhythmias. Methods and Results: Clinical testing of rate smoothing was performed at the time of defibrillator arrhythmia induction in 16 patients with implantable defibrillators during 65 episodes of ventricular tachyarrhythmias. We also performed simulator-based testing to assess detection of ventricular tachycardia between 170 and 220 beats/min with systematic sequential change of rate-smoothing percent, AV delay, and maximal rate. During clinical testing of 54 ventricular fibrillation/polymorphic ventricular tachyarrhythmia episodes, there were no cases of nondetection and 3 episodes (5%) of minimally delayed detection. Of 10 monomorphic ventricular tachyarrhythmias, 6 had either delayed (2 cases) or absent (4 cases) detection. During simulator testing, complex interrelationships were demonstrated in AV delay, upper rate, and rate-smoothing percent in determining the severity of the effect on detection. Generally, long AV delay, higher upper rate, and smaller (more aggressive) rate smoothing were associated with increased risk of ventricular tachyarrhythmia underdetection. Importantly, use of parameters that impaired detection was always accompanied by a programmer warning message. Conclusion: Rate smoothing may result in delay or failure of ventricular tachycardia detection. It is important to consider warning messages when programming rate smoothing and to test for appropriate detection when rate smoothing is used despite warning messages. [source] Distribution of Patients, Paroxysmal Atrial Tachyarrhythmia Episodes: Implications for Detection of Treatment EfficacyJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2001WILLIAM F. KAEMMERER Ph.D. Distribution of Paroxysmal Atrial Tachyarrhythmia Episodes.Introduction: Clinical trials of treatments for paroxysmal atrial tachyarrhythmia (pAT) often compare different treatment groups using the time to first episode recurrence. This approach assumes that the time to the first recurrence is representative of all times between successive episodes in a given patient. We subjected this assumption to an empiric test. Methods and Results: Records of pAT onsets from a chronologic series of 134 patients with dual chamber implantable defibrillators were analyzed; 14 had experienced > 10 pAT episodes, which is sufficient for meaningful statistical modeling of the time intervals between episodes. Episodes were independent and randomly distributed in 9 of 14 patients, but a fit of the data to an exponential distribution, required by the stated assumption, was rejected in 13 of 14. In contrast, a Weibull distribution yielded an adequate goodness of fit in 5 of the 9 cases with independent and randomly distributed data. Monte Carlo methods were used to determine the impact of violations of the exponential distribution assumption on clinical trials using time from cardioversion to first episode recurrence as the dependent measure. In a parallel groups design, substantial loss of power occurs with sample sizes < 500 patients per group. In a cross-over design, there is insufficient power to detect a 30% reduction in episode frequency even with 300 patients. Conclusion: Clinical trials that rely on time to first episode recurrence may be considerably less able to detect efficacious treatments than may have been supposed. Analysis of multiple episode onsets recorded over time should be used to avoid this pitfall. [source] Predictors of Early Mortality in Patients Age 80 and Older Receiving Implantable DefibrillatorsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 8 2010DREW ERTEL M.D. Background: There are no upper age restrictions for implantable defibrillators (ICDs) but their benefit may be limited in patients , 80 years with strong competing risks of early mortality. Risk factors for early (1-year) mortality in ICD recipients , 80 years of age have not been established. Methods: Two-center retrospective cohort study to assess predictors of one-year mortality in ICD recipients , 80 years of age. Results: Of 2,967 ICDs implanted in the two centers from 1990,2006, 225 (7.6%) patients were ,80 years of age and followed-up at one of the two centers. Mean age was 83.3 ± 3.1 years and follow-up time 3.3 ± 2.6 years. Median survival was 3.6 years (95% confidence interval 2.3,4.9). Multivariate predictors of 1-year mortality included ejection fraction (EF) , 20% and the absence of beta-blocker use. Actuarial 1-year mortality of ICD recipients , 80 with an EF , 20% was 38.2% versus 13.1% in patients 80+ years with an EF > 20% and 10.6% for patients < 80 years with an EF , 20% (P < 0.001 for both). There was no significant difference in the risk of appropriate ICD therapy between those patients 80+ years with EF above and below 20%. Conclusion: In general, patients , 80 years of age who meet current indications for ICD implantation live sufficiently long to warrant device implantation based on anticipated survival alone. However, those with an EF , 20% have a markedly elevated 1-year mortality with no observed increase in appropriate ICD therapy, thus reducing the benefit of device implantation in this population. (PACE 2010; 981,987) [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] Safety and Acceptability of Implantation of Internal Cardioverter-Defibrillators Under Local Anesthetic and Conscious SedationPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 8 2007DAVID J. FOX B.M.Sc., M.B.Ch.B., M.R.C.P. Background: Implantation and testing of implantable defibrillators (ICDs) using local anesthetic and conscious sedation is widely practiced; however, some centers still use general anesthesia. We assessed safety and patient acceptability for implantation of defibrillators using local anesthetic and conscious sedation. Methods: The records of 500 consecutive device implants from two UK cardiac centers implanted under local anesthetic and conscious sedation from January 1996 to December 2004 were reviewed. Procedure time, left ventricular ejection fraction (LVEF) sedative dosage (midazolam), analgesic dosage (fentanyl or diamorphine), requirement for drug reversal, and respiratory support were recorded. Patient acceptability of the procedure was also assessed. Results: Of 500 implants examined, 387 were ICDs, 88 were biventricular ICDs, and 25 were generator changes. Patients with biventricular-ICDs had significantly longer (mean ± SD) procedure times 129.7 ± 7.6 minutes versus 63.3 ± 32.3 minutes; P < 0.0001 and lower LVEF 24.4 ± 8.4% versus 35.7 ± 15.4%; P < 0.0001. There were no differences in the doses (mean ± SD) of midazolam 8.9 ± 3.5 mg versus 8.0 ± 3.1 mg; P = NS, diamorphine 4.3 ± 2.0 mg versus 3.8 ± 1.7 mg; P = NS or fentanyl 94.4 ± 53.7 mcg versus 92.2 ± 48.6 mcg; P = NS, between the two groups. There were no deaths or tracheal intubations in either group. Acceptability was available for 373 of 500 (75%) patients, 41 of 373 (11%) described "discomfort," but from these 41 patients only 14 of 373 (3.8%) declined a second procedure under the same conditions. Conclusions: Implantation of defibrillators under local anesthetic and sedation is safe and acceptable to patients. General anesthesia is no longer routinely required for implantation of defibrillators. [source] Alternans in QRS Amplitude During Ventricular TachycardiaPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2002PHILIPPE MAURY MAURY, P., et al.: Alternans in QRS Amplitude During Ventricular Tachycardia. Although the value of T wave alternans as an index of electrical instability has been extensively investigated, little is known about QRS alternans during VT. Intracardiac electrograms of 111 episodes of spontaneous monomorphic regular VT retrieved from implantable defibrillators in 25 patients were retrospectively selected. Three beat series, representing the total amplitudes and amplitudes from baseline to summit and from baseline to lower point of 16 or 32 successive QRS complexes before deliverance of electrical therapy were generated for each episode. Spectral analysis was then performed using the fast Fourrier transform. VT was considered as alternans if the magnitude of the spectral power at the 0.5-cycle/beat frequency was greater than the mean ± 3 SD of the noise in at least one of the three spectral curves. QRS alternans was present in 23 (20%) of 111 episodes and in 9 (36%) of 25 patients. Alternans was not related to the VT cycle length, QRS duration, QRS amplitude, signal amplification, nor to clinical variables. Alternans was more frequently detected in unipolar configuration and when a higher number of complexes was included in analysis. Failure of antitachycardia pacing was more frequent in case of alternans VT (50% vs 75% success in non-alternans VT, P = 0.05). Spontaneous termination before deliverance of therapy occurred in 16 nonalternans VT but never in alternans episodes (P = 0.02). Alternans in QRS amplitude is a relatively common finding during VT and could be associated with failure of antitachycardia pacing and lack of spontaneous termination. Lower efficacy of electrical therapies in case of QRS alternans must be confirmed in a way to improve the effectiveness of antitachycardia pacing. [source] | ||||||||||