Implantable defibrillators-cardioverters Research Papers - Academia.edu (original) (raw)

The European Society of Cardiology heart failure guidelines firmly recommend regular physical activity and structured exercise training (ET), but this recommendation is still poorly implemented in daily clinical practice outside specialized centres and in the real world of heart failure clinics. In reality, exercise intolerance can be successfully tackled by applying ET. We need to encourage the mindset that breathlessness may be evidence of signalling between the periphery and central haemodynamic performance and regular physical activity may ultimately bring about favourable changes in myocardial function, symptoms, functional capacity, and increased hospitalization-free life span and probably survival. In this position paper, we provide practical advice for the application of exercise in heart failure and how to overcome traditional barriers, based on the current scientific and clinical knowledge supporting the beneficial effect of this intervention.

- by
- •
- Social Sciences, Physical Activity, Exercise therapy, Heart Failure

High Defibrillation Thresholds in Transvenous Biphasic Implantable Defibrillators: Clinical Predictors and Prognostic Implications. The aim of this study was to identify clinical characteristics that distinguish patients with high DFTs and assess the prognostic implication. DFTs testing is a lengthy, potentially painful, and a hazardous process. Little information is available concerning the identification of patients with high DFT who undergo ICD surgery with transvenous leads and biphasic energy. This study analyzed 968 patients from two separate clinical studies who received a Medtronic cardioverter defibrillator from January 1995 through November 1999 and who had DFT testing measured by a binary search protocol. Compared to 865 patients with low defibrillation thresholds (<18 J), the 103 patients with high thresholds (≥18 J) had a lower LVEF (34 ± 16.7 vs 38.3 ± 16.2%, P = 0.01), a worse NYHA functional class (23% Class I, 43% Class II, 29% Class III, 5% Class IV vs. 27% Class I, 55% Class II, 17% Class III, 1% Class IV, P < 0.0001), had bypass surgery less often (10.7 vs 27.5%, P < 0.0001), used amiodarone within the past 6 weeks (42.7 vs 27.2%, P = 0.002), and had a history of ventricular fibrillation more often (44.7 vs 33.1%, P = 0.02). Information concerning the number of shocks delivered was available in 345 (35%) patients; 23 were in the high DFT group and 322 were in the low DFT group.

Clinical trials have helped clarify the role of cardiac resynchronization therapy (CRT) in patients with heart failure. Early trials demonstrated reduction in mortality and heart failure hospitalization in patients with electrical dyssynchrony and moderate to severe functional impairment, 1,2 and more recent trials showed that these benefits extend to heart failure patients even with mild symptoms. 3,4 Most patients with a class 1 or 2 indication for CRT 5 also have an appropriate indication for an implantable cardioverterdefibrillator (ICD) on the basis of the presence of ischemic or nonischemic cardiomyopathy, 6,7 so the vast majority of CRT is delivered via a CRT with defibrillator (CRT-D). In fact, the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy (MADIT-CRT) study randomized 1820 patients with cardiomyopathy of any etiology with left ventricular ejection fraction ≤30%, QRS duration ≥130 ms, and mild heart failure (New York Heart Association class I or II) to either standard ICD or CRT-D, and it showed that CRT-D leads to improved outcome compared with ICD alone in this population. 4 The MADIT-CRT study design has enabled the investigators to also examine the effect of CRT on ventricular arrhythmic events. In a recent report, this group showed that CRT-D was associated with a 29% reduction in the risk of a first episode of ventricular tachyarrhythmic events compared with ICD alone. 8 Importantly, this arrhythmia risk reduction was not homogeneous across the entire study population. Among patients with left bundle branch block (LBBB), CRT-D conferred a 42% reduction in the risk of first arrhythmic event compared with standard ICD, but in non-LBBB patients, CRT-D provided no such advantage, a finding that mirrors the general lack of clinical response to CRT seen in non-LBBB patients. 9 Conversely, one might wonder what effect arrhythmic events have on subsequent outcome in CRT-D treated patients compared with that in standard ICD recipients. In this issue of HeartRhythm, Kutyifa et al 10 addresses this very question, once again taking the advantage of the rich database provided by the MADIT-CRT trial. These investigators sought to evaluate the prognostic value of ventricular tachyarrhythmias, categorized as slow ventricular tachycardia

SEARS, S.F., ET AL.: Assessing the Psychosocial Impact of the ICD: A National Survey of Implantable Cardioverter Defibrillator Health Care Providers. The implantable cardioverter defibrillator (ICDJ provides a survival advantage over antiarrhythmic medications for patients with life-threatening ventricular arrhythmias. However, the effect of ICD therapy on quality-of-life and psychosocial functioning are not as well understood. Health care providers (e.g., physicians, nursesj can serve as a valuable source of information related to these ICD outcomes. The purpose of this study was to investigate health care provider perceptions regarding: (1) the quality-of-life and psychosocial functioning of their ICD recipients, (2) the concerns or problems reported by ICD recipients, and (3) the degree of provider comfort in managing these concerns. The final sample of health care providers (n = 261) rated ICD recipients' global quality-of-life and psychosocial functioning, and specific concerns about health care, lifestyle, special population adjustment, marital and family adjustment, and emotional well-being. With regard to quality-of-life, health care providers reported that the majority of ICD recipients were functioning better (38%) or about the same (47%J than before implantation. However, health care providers reported that 15% of recipients experienced worse quality-of-life postimplantation. Similarly, health care providers indicated that 10%-20% of ICD recipients experienced worse emotional functioning and strained family relationships. Moreover, issues related to driving, dealing with ICD shocks, and depression were the most common ICD recipient concerns. Significant differences were noted between physicians and nurses/other health care professionals on a wide range of psychosocial issues. Health care providers generally reported the most comfort dealing with traditional medical issues (i.e., patient adherence), and the least comfort in managing emotional well-being issues (e.g., depression and anxietyj. These results suggest that routine attention to ICD quality-of-life and psychosocial outcomes is indicated for health care providers who care for ICD recipients. (PACE 2000; 23:939-945) implantable cardioverter defibrillator, patient care, health care providers, psychosocial adjustment, quality-of-life

- by Samuel Sears
- •
- Biomedical Engineering, Quality of life, Treatment Outcome, Emotions
- by Soko Setoguchi Iwata
- •
- Dialysis, Treatment Outcome, Cardiovascular disease, Comorbidity

Angioplasty. This case describes another example of inappropriate implantable defibrillator shock. We also show that this phenomenon resulted from electromagnetic current traveling down a coronary wire during coronary angioplasty. (PACE... more

- by Mark Marieb
- •
- Biomedical Engineering, Electrocardiography, Heart rate, Artifacts

and ‡University of Michigan, Ann Arbor, Michigan Background: Following high-profile device failures, the Heart Rhythm Society emphasized the need for postmarketing surveillance by recommending that physicians return all explanted devices to the manufacturer for analysis. Methods: We conducted a national survey of electrophysiologists (EPs) regarding recovery for analysis of explanted pacemakers and implantable cardioverter defibrillators (devices), and attitudes toward devicespecific advance directives to facilitate return of devices. Online survey invitations were sent in four waves from December 2008 to June 2009 to 300 e-mail addresses from the Heart Rhythm Society member database. Results: From 250 invitations, there were 95 responses (38%). Demographics included average age 50 years (range, 31-87); 95% male; 81% Caucasian. Only 23% reported returning all explanted devices to the manufacturers. Of all the respondents, 32% discarded >10 devices/year as medical waste, 42% stored devices in a box in the electrophysiology lab, and 10% donated at least 1 device/year to charity for reuse overseas. Sixty-seven percent felt that it would not be helpful to have an advance directive specifying what the patient would want done with their device postmortem.

- by Sachin Logani
- •
- Biomedical Engineering, United States, Reuse, Clinical Sciences

Allergic reactions to endoprostheses are uncommon and reported in association with orthopaedic, dental, endovascular and other implanted devices. Hypersensitivity reactions to the biomaterials used in endovascular prostheses are among the infrequent reactions that may lead to local or systemic complications following cardiovascular therapeutic interventions. This article reviews potential immunotoxic effects of commonly used biomaterials. Reports of putative hypersensitivity reactions to endovascular devices, including coronary stents, perforated foramen occluders, pacemakers and implantable cardioverter defibrillators are also reviewed.

- by golara honari
- •
- Immunology, Stents, Allergens, Clinical Sciences

provides the superior access needed for removal of large lesions in the posterior maxilla. The Le Fort I down-fracture is a routine procedure in oral and maxillofacial surgery. Its postoperative morbidity is low, and the results are predictable, without changes to the occlusion after surgery. The Le Fort I down-fracture approach also gives an excellent view of the entire maxillary sinus, allowing well-visualized, safe, and thorough removal of the tumor.

- by Nicholas THEODOTOU
- •
- Dentistry, Treatment, Electrocardiography, Dental Local Anesthesia
- by Mary Walsh and +1
- •
- Biomedical Engineering, Treatment Outcome, Risk assessment, Adolescent

ARIAS, MA, PUCHOL, A., COLCHERO, T., PACHÓN, M., CASTELLANOS, E. and RODRÍGUEZ-PADIAL, L.(2010), An Appropriate Implantable Cardioverter-Defibrillator Shock Triggering Unusual Phenomenons. Pacing and Clinical Electrophysiology, 33: ...

- by Giovanni Grossi and +1
- •
- Dentistry, Electromagnetic Interference, Electrocardiography, Ultrasonics

Background Biventricular (BiV) stimulation is the preferred means of delivering cardiac resynchronization therapy (CRT), although left ventricular (LV)-only stimulation might be as safe and effective. B-LEFT HF is a prospective, multicenter, randomized, double-blind study aimed to examine whether LV-only is noninferior to BiV pacing regarding clinical and echocardiographic responses. Methods B-LEFT HF randomly assigned 176 CRT-D recipients, in New York Heart Association class III or IV, with an LV ejection fraction ≤35% and QRS ≥130 milliseconds, to a BiV (n = 90) versus LV (n = 86) stimulation group. Clinical status and echocardiograms were analyzed at baseline and 6 months after CRT-D implant to test the noninferiority of LV-only compared with BiV stimulation. Results The proportion of responders was in line with current literature on CRT, with improvement in heart failure composite score in 76.2% and 74.7% of patients in BiV and LV groups, respectively. Comparing LV versus BiV pacing, the small differences in response rates and corresponding 95% CI indicated that LV pacing was noninferior to BiV pacing for a series of response criteria (combination of improvement in New York Heart Association and reverse remodeling, improvement in heart failure composite score, reduction in LV end-systolic volume of at least 10%), both at intention-to-treat and at per-protocol analysis. Conclusions Left ventricular-only pacing is noninferior to BiV pacing in a 6-month follow-up with regard to clinical and echocardiographic responses. Left ventricular pacing may be considered as a clinical alternative option to BiV pacing.

- by Nicolas Delarche
- •
- Treatment Outcome, Medicine, Echocardiography, Heart Failure
- by Marc Vanderheyden
- •
- Cardiology, Telemedicine, Heart Failure, Heart rate

Small-diameter implantable cardioverter-defibrillator (ICD) leads have been introduced into clinical practice to facilitate the implantation procedure. Despite their expected benefits, the reliability of these leads has proven to be questionable. The main purpose of our study is to investigate the impact of ICD lead diameter (≤8 F versus >8 F) on long-term lead durability.

For patients at the end of life, active automatic implantable cardioverter-defibrillators (AICDs) may no longer achieve the treatment goals present at the time of implantation. It is possible to deactivate AICDs in patients with terminal and life-limiting diagnoses, thereby preventing the pain and distress of nontherapeutic discharge. This article presents a moral argument for the right of such patients to have their AICDs deactivated. It then explains that hospice and home care agencies have an obligation to address AICD deactivation at a policy level and offers recommendations for doing so.

- by Timothy Kirk
- •
- Nursing, Home Care, End of life, Hospice Care
- by Hardwin Mead
- •
- Stroke, Congestive Heart Failure, Telemetry, Atrial Fibrillation

A prospective analysis was carried out on a group of irradiated patients with pacemakers or implantable cardioverter-defibrillators to identify any relationship between the various types of devices and physical and dosimetric parameters.... more

- by Michele Stasi
- •
- Informed Consent, Prospective studies, Electromagnetic Fields, Heart

maker-ICD Interactions. Numerous types of interactions between pacemakers und implantable curdioverter defibrillators (ICDs) have been described. Pacemaker outputs preventing appropriate detection of ventricular tachycardia or ventricular fibrillution by the ICD is one of the more serious. Asvnchronous pacemaker activity during ventricular arrhythmias may be caused by either nonsensing of the arrhvthmia or by noise reversion, which is an algorithm that causes the pacemaker to switch to asynchronous pacing when repetitive sensing at a high rate occurs. We analyzed the mechanisms underlying asynchronous pacemaker activity in ventricular arrhythmias using pacemaker telemetry during the arrhythmia. Thirtynine induced arrhythmias from 26 different procedures in 19 patients with both pacemakers and ICDs were analyzed. Of the 39 arrhythmias, asynchronous pacemaker activity occurred in 16. The underlying mechanism was nonsensing in 4 episodes and noise reversion in 12 episodes. Clinically significant interference with detection arose on three occasions. Conditions favoring the occurrence of noise reversion include specific pacemaker models, arrhythmia cycle lengths in the range causing noise reversion of the individual pacemaker model, long noise sampling periods, and VVI pacing mode. Noise reversion can be diagnosed by telemetering the pacemaker marker channel during ventricular arrhvthmias as a part of routine pacemaker-ICD interaction evaluation. It can be prevented or minimized by programming short ventricular refractory periods or using pacemakers with shoii retriggerable refractory periods.

- by Stephen Hammill
- •
- Biomedical Engineering, Electrocardiography, Electricity, Prospective studies

Among the most compelling challenges facing cardiologists today is identification of which patients are at highest risk for sudden death. Automatic implantable cardioverter-defibrillators are now indicated in many of these patients, yet the role of noninvasive risk stratification in classifying patients at high risk is not well defined. The purpose of this review is to evaluate the various electrocardiographic (ECG) techniques that appear to have potential in assessment of risk for arrhythmia. The resting ECG (premature ventricular contractions, QRS duration, damage scores, QT dispersion, and ST segment and T wave abnormalities), T wave alternans, late potentials identified on signal-averaged ECGs, and heart rate variability are explored. Unequivocal evidence to support the widespread use of any single noninvasive technique is lacking; further research in this area is needed. It is likely that a combination of risk evaluation techniques will have the greatest predictive power in enabling identification of patients most likely to benefit from device therapy. (Curr Probl Cardiol 2004;29:357-432.) O ver the past decade advances in technology have provided cardiologists with improved therapeutic options for patients at risk for sudden cardiac death (SCD). The automatic implantable cardioverter-defibrillator (ICD) has changed the landscape of electrophys-

- by euan ashley
- •
- Risk assessment, Electrocardiography, Heart rate variability, Sudden Death

Implantable cardioverter defibrillators (ICDs) have evolved from the treatment of last resort to the gold standard therapy for patients at high risk for ventricular tachyarrhythmias. High-risk patients include those who have survived life-threatening arrhythmias, and individuals with cardiac diseases who are at risk for such arrhythmias, but are symptomless. Use of an ICD will affect the patient's quality of life. Some drugs can substantially affect defibrillator function and efficacy, and possible drug-device interactions should be considered. Patients with ICDs may encounter cell phones, antitheft detectors, and many other sources of potential electromagnetic Interference. In addition to treating ventricular tachyarrhythmias, new defibrillators provide full featured dual chamber pacing, and could treat atrial arrhythmias, and congestive heart failure by means of biventricular pacing.

- by Michael Glikson
- •
- Quality of life, Electrocardiography, Lancet, Electromagnetic phenomena

Background Studies of the association between obesity, and total mortality and cardiovascular events in patients with coronary artery disease (CAD) have shown contradictory results. We undertook a systematic review to determine the extent... more

- by Claudia Tabini
- •
- Obesity, Mortality, Automated External defibrillator, Survivors
- by Eugene Crystal
- •
- Biomedical Engineering, Europe, United States, Risk factors

The aim of this study was to determine whether defibrillation waveform duration adjustment with single-coil defibrillation leads can be used to increase the proportion of patients with satisfactory defibrillation thresholds (DFTs). A retrospective analysis of the DFT levels for 105 patients with implantable cardioverter-defibrillator devices and a single-coil defibrillation lead was performed. Two groups of patients were compared: 34 patients who had undergone waveform tuning (group A) and 71 patients with a fixed-tilt waveform (group B). Additional data including demographics, etiology, New York Heart Association functional class, left ventricular ejection fraction, high-voltage lead impedance and medications were gathered to determine what effect these variables had on the DFT levels. Of the 34 patients who had undergone waveform adjustment (group A), 27 (79%) were found to have satisfactory DFTs, while 41 (58%) of the 71 patients with fixed-tilt devices (group B) had satisfactory DFTs. Waveform duration adjustment was found to significantly increase the proportion of patients with satisfactory DFTs (p = 0.03).

- by Adam Budzikowski
- •
- Cardiology, Treatment Outcome, Electrocardiography, Aged

Ventrikuläre Tachykardien (VT) mit Ursprung im His-Purkinje-System können bei Patienten mit und ohne strukturelle Herzerkrankung auftreten. Bei Ersteren stellen die Schenkeltachykardien (englisch "bundle branch reentrant ventricular tachycardia") die häufigste Form dieser VT dar. Diese Makroreentrytachykardien entstehen auf dem Boden einer Leitungsverzögerung im His-Purkinje-System (vorbestehender Linksschenkelblock) und können durch Ablation des rechten Tawara-Schenkels kuriert werden. Die weitere Prognose hängt von der kardialen Grunderkrankung ab.

While no simple electrical descriptor provides a good measure of defibrillation efficacy, the waveform parameters that most directly influence defibrillation are voltage and duration. Voltage is a critical parameter for defibrillation because its spatial derivative defines the electrical field that interacts with the heart. Similarly, waveform duration is a critical parameter because the shock interacts with the heart for the duration of the waveform. Shock energy is the most often cited metric of shock strength and an ICD’s capacity to defibrillate, but it is not a direct measure of shock effectiveness. Despite the physiological complexities of defibrillation, a simple approach in which the heart is modeled as passive resistor–capacitor (RC) network has proved useful for predicting efficient defibrillation waveforms. The model makes two assumptions: (1) The goal of both a monophasic shock and the first phase of a biphasic shock is to maximize the voltage change in the membrane at the end of the shock for a given stored energy. (2) The goal of the second phase of a biphasic shock is to discharge the membrane back to the zero potential, removing the charge deposited by the first phase. This model predicts that the optimal waveform rises in an exponential upward curve, but such an ascending waveform is difficult to generate efficiently. ICDs use electronically efficient capacitive-discharge waveforms, which require truncation for effective defibrillation. Even with optimal truncation, capacitive-discharge waveforms require more voltage and energy to achieve the same membrane voltage than do square waves and ascending waveforms. In ICDs, the value of the shock output capacitance is a key intermediary in establishing the relationship between stored energy—the key determinant of ICD size—and waveform voltage as a function of time, the key determinant of defibrillation efficacy. The RC model predicts that, for capacitive-discharge waveforms, stored energy is minimized when the ICD’s system time constant τ s equals the cell membrane time constant τ m, where τ s is the product of the output capacitance and the resistance of the defibrillation pathway. Since the goal of phase two is to reverse the membrane charging effect of phase one, there is no advantage to additional waveform phases. The voltages and capacitances used in commercial ICDs vary widely, resulting in substantial disparities in waveform parameters. The development of present biphasic waveforms in the 1990s resulted in marked improvements in defibrillation efficacy. It is unlikely that substantial improvement in defibrillation efficacy will be achieved without radical changes in waveform design.

Background: The implantable cardioverter defibrillator (ICD) reduces mortality in patients at risk for life-threatening arrhythmias via high energy shock. The Florida Shock Anxiety Scale (FSAS) was developed to measure ICD patient shock-related anxiety. Initial psychometric evaluation revealed good reliability and validity. The purpose of this study was to examine the psychometrics of the FSAS in a large US sample of ICD patients. Methods: Participants were recruited via e-mail and the survey was completed online. Ultimately, 443 ICD patients (359 male and 421 White) completed the 10-item FSAS. Results: Means for FSAS were comparable to previously published data (M = 15.18, SD = 6.5). Interitem reliability was good (Cronbach's α = 0.89). The FSAS was negatively correlated with single-item measures of emotional well-being (r = -0.378, P < 0.01), sense of security (r = -0.365, P < 0.01), perceived general health (r = -0.185, P < 0.01), and quality of life (r = -0.216, P < .01), demonstrating discriminant validity. Convergent validity was supported through significant correlations with number of shocks (r = 0.464, P < 0.01) and reported disruptiveness of shock (r = 0.484, P < 0.01). Confirmatory factor analysis revealed that a single (second-order) factor model (χ 2 [34] = 75.34, P < 0.05, comparative fit index = 0.98, root mean-square error of approximation = 0.05) had the best fit.

- by Garrett Hazelton and +1
- •
- Biomedical Engineering, Assessment, Psychometrics, Risk assessment
- by Roberto Grimaldi
- •
- Biomedical Engineering, Neuromodulation, Quality of life, Treatment Outcome

Fellows should possess an understanding of the basic cellular and molecular mechanisms of electrophysiology. These concepts include the cellular and molecular bases for electrical function of the heart under normal and pathophysiologic conditions, the mechanisms responsible for the development of arrhythmias, and the actions of antiarrhythmic drugs.

- by Hasan Garan
- •
- Teaching, Curriculum, Atrial Fibrillation, Goals
- by Jose Luis
- •
- Algorithms, Comorbidity, Electrocardiography, Heart Failure

The purpose of these guidelines is to provide specific recommendations in regard to psychological activities in cardiac rehabilitation (CR). Based on scientific evidence and clinical experience, the present guidelines are targeted for psychologists working in the field of cardiac rehabilitation and for the core component of CR, as well as for the health care providers, insurers, policy makers and consumers. In the introduction, the framework of Italian cardiac rehabilitation and psychology as well as the methodology used are defined, in accordance with the recommendations of the National Guidelines Programme of the Italian Health Ministry. The first section illustrates the educational training and structural requirements necessary for psychologists intending to work in cardiac rehabilitation, and provides a summary of the principal models of organization. Section two describes the sequence of psychological activities based on the different phases of the process of care. The chapters...

- by Ornella Bettinardi
- •
- Program Evaluation, Psychotherapy, Family, Quality of life

JG Howlett, RS McKelvie, JMO Arnold, et al. Canadian Cardiovascular Society Cconsensus Conference guidelines on heart failure, update 2009: Diagnosis and management of right-sided heart failure, myocarditis, device therapy and recent... more

- by Michel White
- •
- Cardiology, Evidence Based Medicine, Exercise therapy, Heart Failure

Whilst the decision regarding defibrillator implantation in a patient with a familial sudden cardiac death syndrome is likely to be most significant for any particular individual, the clinical decision-making process itself is complex and requires interpretation and extrapolation of information from a number of different sources. This document provides recommendations for adult patients with the congenital Long QT syndromes, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, hypertrophic cardiomyopathy, and arrhythmogenic right ventricular cardiomyopathy. Although these specific conditions differ in terms of clinical features and prognosis, it is possible and logical to take an approach to determining a threshold for implantable cardioveter-defibrillator implantation that is common to all of the familial sudden cardiac death syndromes based on estimates of absolute risk of sudden death.

- by Michael Griffith
- •
- Clinical Sciences, Great Britain, Cardiac Arrhythmias, Sudden Cardiac Death

1.73 m 2 and high ACR had a four-fold higher risk of death than the reference group. They also found that normotensive individuals with preserved eGFR (≥ 90 ml/min/1.73 m 2 ) and moderately high ACR (30 to 299 mg/g) have an elevated risk of all-cause death [5]. The results are very similar to the results of our study. Therefore, to conclude that our results are inconsistent with the results of the previous studies may be the result of an incorrect interpretation of the results from the previous studies.

- by Fernando Cabrera-Bueno
- •
- Cardiology, Follow-up studies, Aged, Time Factors

Since its introduction as a clinical entity in 1992, the Brugada syndrome has progressed from being a rare disease to one that is second only to automobile accidents as a cause of death among young adults in some countries. Electrocardiographically characterized by a distinct ST-segment elevation in the right precordial leads, the syndrome is associated with a high risk for sudden cardiac death in young and otherwise healthy adults, and less frequently in infants and children. Patients with a spontaneously appearing Brugada ECG have a high risk for sudden arrhythmic death secondary to ventricular tachycardia/fibrillation. The ECG manifestations of Brugada syndrome are often dynamic or concealed and may be unmasked or modulated by sodium channel blockers, a febrile state, vagotonic agents, alpha-adrenergic agonists, beta-adrenergic blockers, tricyclic or tetracyclic antidepressants, a combination of glucose and insulin, hypo- and hyperkalemia, hypercalcemia, and alcohol and cocaine toxicity. In recent years, an exponential rise in the number of reported cases and a striking proliferation of articles defining the clinical, genetic, cellular, ionic, and molecular aspects of the disease have occurred. The report of the first consensus conference, published in 2002, focused on diagnostic criteria. The present report, which emanated from the second consensus conference held in September 2003, elaborates further on the diagnostic criteria and examines risk stratification schemes and device and pharmacological approaches to therapy on the basis of the available clinical and basic science data.

- by Domenico Corrado and +1
- •
- Biomedical Engineering, Risk assessment, Electrocardiography, Differential Diagnosis

Objective: To assess the value for improving risk stratification of measures, unadjusted and adjusted for heart rate, of heart rate variability (HRV) and heart rate turbulence (HRT) based on 2-to 24-h ambulatory electrocardiographic recordings; and to relate this to the decision to use an implantable cardiac defibrillator (ICD) and the attendant consequences on effectiveness and cost-effectiveness. Background: Risk stratification for high risk or low risk of lethal ventricular arrhythmic events, and hence for a decision about defibrillator implant, most commonly utilizes the left ventricular ejection fraction (LVEF). Electrocardiographic (ECG) approaches include 24-h ambulatory ECG recordings, with counts of ventricular premature contractions (VPCs), measures of heart rate variability (HRV), and heart rate turbulence (HRT). HRT has two components: turbulence onset (TO) and turbulence slope (TS). Methods and results: We evaluated the qualifying ambulatory ECG recordings from 744 patients in the active treatment arms of the Cardiac Arrhythmia Suppression Trial (CAST). Beat characteristics, VPC counts, normal-to-normal beat intervals, and time-domain measures of HRV and HRT were calculated. Tachograms were rescaled to a heart rate of 75 and the resulting bnormalizedQ measures evaluated as risk predictors for death, compared to unnormalized measures. Measures based on 2-h ECGs were also evaluated as risk predictors.

- by Kurt Ulm
- •
- Cardiology, Survival Analysis, Risk assessment, Electrocardiography
- by Suresh Neelagaru
- •
- Biomedical Engineering, Treatment Outcome, Feasibility Study, Heart Failure

Implantation of cardioverter-defibrillators in patients with limited venous access due to recurrent infections, thrombosis, or congenital anomalies can be challenging. For this subset of patients, we performed a video-assisted thoracoscopic intrapericardial implantation using standard shock electrodes and epicardial leads. The pulse generator was placed in pectoral or subcostal position. All pacing and sensing parameters and defibrillation thresholds were satisfactory and stable in time. No major complications were reported. Our limited experience suggests that this technique is a potential alternative in patients where endocardial implantation should be avoided.

- by jan nijs
- •
- Treatment Outcome, Adolescent, Child, Young Adult

Background: The incidence of venous lesions following transvenous cardiac device implantation is high. Previous implantation of temporary leads ipsilateral to the permanent devices, and a depressed left ventricular ejection fraction have been associated with an increased risk of venous lesions, though the effects of preventive strategies remain controversial. This randomized trial examined the effects of warfarin in the prevention of these complications in high-risk patients. Method: Between February 2004 and September 2007, we studied 101 adults who underwent a first cardiac device implantation, and who had a left ventricular ejection fraction ≤0.40, or a temporary pacing system ipsilateral to the permanent implant, or both. After device implantation, the patients were randomly assigned to warfarin to a target international normalized ratio of 2.0-3.5, or to placebo. Clinical and laboratory evaluations were performed regularly up to 6 months postimplant. Venous lesions were detected at 6 months by digital subtraction venography. Results: Venous obstructions of various degrees were observed in 46 of the 92 patients (50.0%) who underwent venography. The frequency of venous obstructions was 60.4% in the placebo, versus 38.6% in the warfarin group (P = 0.018), corresponding to an absolute risk reduction of 22% (relative risk = 0.63; 95% confidence interval = 0.013-0.42). Conclusions: Warfarin prophylaxis lowered the frequency of venous lesions after transvenous devices implantation in high-risk patients. (PACE 2009; 32:S247-S251) cardiac pacing, pacing complication, venous thrombosis, warfarin, anticoagulation, randomized trial

Arrhythmias play a significant role in the mortality and morbidity as well as hospitalizations of patients who carry a diagnosis of congestive heart failure. With improving survival in a world of novel medications and devices, an understanding of the pathophysiology and management of these arrhythmias is crucial. Majority of the basic heart failure medications such as beta--blockers, angiotensin converting enzyme inhibitors/aldosterone receptor blockers and aldosterone antagonists play a pivotal role in prevention of sudden cardiac deaths which can be a direct/indirect result of these arrhythmias. Anti-arrhythmic drugs and implantable cardioverter--defibrillators were also beneficial in selected patients. Innovative electrophysiological techniques need to be considered in special situations. (Cardiol J 2012; 19, 6: 567-577)

- by Venkata Mukku
- •
- Cardiology, General Practice, Evidence Based Medicine, Treatment Outcome

Inappropriate shocks have been an important issue post-implantable cardioverter-defibrillator (ICD) implantation. Moreover, inappropriate ICD shocks are associated with increased mortality. The objective of this study was to evaluate the feasibility of catheter ablation therapy for atrial tachyarrhythmias (ATa) responsible for inappropriate ICD shocks. Among 108 consecutive patients who underwent ICD implantations, 22, 5, and 3 experienced inappropriate ICD shocks due to ATa, sinus tachycardia, and T-wave oversensing, respectively. Among the 22 patients with ATa, 18 patients (55 ± 10 years, 15 men, structural heart disease in 9) underwent catheter ablation of ATa causing inappropriate shocks. The median duration between the ICD implantation and first inappropriate shock was 10.0 (3.0-24.5) months. The ATa were atrial fibrillation (AF), atrial flutter (AFL), and atrioventricular nodal reentrant tachycardia in 14, 2, and 2 patients, respectively. One patient underwent an atrioventricular nodal ablation for persistent AF associated with a venous anomaly. Among 13 patients who underwent pulmonary vein antrum isolation, 10 (76.9%) were free from AF for a median of 21.0 (13-37.3) months after an average of 1.3 ± 0.5 procedures. In four patients with AFL or a supraventricular tachycardia, none had any arrhythmia recurrence for a median of 6.0 (3.3-93.5) months after a cavotricuspid isthmus or slow pathway ablation, respectively. There were no procedural complications. During the median follow-up of 19.0 (9.5-37.3) months after the last procedure, no patients experienced any inappropriate shocks. Catheter ablation is a feasible therapeutic option for treating ATa responsible for inappropriate shock(s) in patients with ICD.

- by Yoshito Iesaka
- •
- Atrial Fibrillation, Clinical Sciences, Aged, Retrospective Studies