Showing papers on "Implantable cardioverter-defibrillator published in 2013"

2013 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy : The Task Force on cardiac pacing and resynchronization therapy of the European Society of Cardiology (ESC). Developed in collaboration with the European Heart Rhythm Association (EHRA)

Abstract: ### Abbreviations 1st AV : First-degree atrioventricular block AF : atrial fibrillation AT : atrial tachyarrhythmia ATP : Anti-tachycardia pacing AV : atrioventricular BBB : bundle branch block CHF : congestive heart failure CI : confidence interval CPG : Committee for Practice Guidelines CRT : cardiac resynchronization therapy CRT-D : cardiac resynchronization therapy and defibrillator CRT-P : cardiac resynchronization therapy and pacemaker ECG : electrocardiogram EDMD : Emery-Dreifuss muscular dystrophy EF : ejection fraction EPS : electrophysiological study ESC : European Society of Cardiology HCM : hypertrophic cardiomyopathy HF : heart failure HR : hazard ratio HV : His-ventricular ICD : implantable cardioverter defibrillator ILR : implantable loop recorder IVCD : intraventricular conduction delay LBBB : left bundle branch block LQTS : long QT syndrome LV : left ventricular LVEF : left ventricular ejection fraction LVSD : left ventricular systolic dysfunction MR : mitral regurgitation MRI : magnetic resonance imaging NYHA : New York Heart Association PM : pacemaker OR : odds ratio QALY : quality-adjusted life year RBBB : right bundle branch block RCT : randomized controlled trial RV : right ventricular SB : sinus bradycardia SNRT : sinus node recovery time SR : sinus rhythm SSS : sick sinus syndrome TAVI : transcatheter aortic valve implantation VF : ventricular fibrillation VT : ventricular tachycardia VV : interventricular (delay) ### Acronyms of the trials referenced in the recommendations or reported in the tables ADEPT : ADvanced Elements of Pacing Randomized Controlled Trial ADOPT : Atrial Dynamic Overdrive Pacing Trial AOPS : Atrial Overdrive Pacing Study APAF : Ablate and Pace in Atrial Fibrillation ASSERT : ASymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the Atrial Fibrillation Reduction Atrial Pacing Trial ATTEST : ATrial Therapy Efficacy and Safety Trial AVAIL CLS/CRT : AV Node Ablation with CLS and CRT Pacing Therapies for Treatment of AF trial B4 : Bradycardia detection in Bundle Branch Block BELIEVE : Bi vs. Left Ventricular Pacing: an International Pilot Evaluation on Heart Failure Patients with Ventricular Arrhythmias BIOPACE : Biventricular pacing for atrioventricular block to prevent cardiac desynchronization BLOCK-HF : Biventricular versus right ventricular pacing in patients with AV block B-LEFT : Biventricular versus LEFT Univentricular Pacing with ICD Back-up in Heart Failure Patients CARE-HF : CArdiac REsynchronization in Heart Failure CLEAR : CLinical Evaluation on Advanced Resynchronization COMBAT : COnventional vs. Biventricular Pacing in Heart Failure and Bradyarrhythmia COMPANION : COmparison of Medical Therapy, Pacing and Defibrillation in Heart Failure DANPACE : DANish Multicenter Randomized Trial on Single Lead Atrial PACing vs. Dual Chamber Pacing in Sick Sinus Syndrome DECREASE-HF : The Device Evaluation of CONTAK RENEWAL 2 and EASYTRAK 2: Assessment of Safety and Effectiveness in Heart Failure FREEDOM : Optimization Study Using the QuickOpt Method GREATER-EARTH : Evaluation of Resynchronization Therapy for Heart Failure in Patients with a QRS Duration GREATER Than 120 ms LESSER-EARTH : Evaluation of Resynchronization Therapy for Heart Failure in Patients with a QRS Duration Lower Than 120 ms HOBIPACE : HOmburg BIventricular PACing Evaluation IN-CHF : Italian Network on Congestive Heart Failure ISSUE : International Study on Syncope of Unexplained Etiology MADIT : Multicenter Automatic Defibrillator Trial MIRACLE : Multicenter InSync RAndomized CLinical Evaluation MOST : MOde Selection Trial in Sinus-Node Dysfunction MUSTIC : MUltisite STimulation In Cardiomyopathies OPSITE : Optimal Pacing SITE PACE : Pacing to Avoid Cardiac Enlargement PAVE : Left Ventricular-Based Cardiac Stimulation Post AV Nodal Ablation Evaluation PATH-CHF : PAcing THerapies in Congestive Heart Failure II Study Group PIPAF : Pacing In Prevention of Atrial Fibrillation Study PIRAT : Prevention of Immediate Reinitiation of Atrial Tachyarrhythmias POT : Prevention Or Termination Study PREVENT-HF : PREventing VENTricular Dysfunction in Pacemaker Patients Without Advanced Heart Failure PROSPECT : PRedictors Of Response to Cardiac Resynchronization Therapy RAFT : Resynchronization–Defibrillation for Ambulatory Heart Failure Trial RethinQ : Cardiac REsynchronization THerapy IN Patients with Heart Failure and Narrow QRS REVERSE : REsynchronization reVErses Remodelling in Systolic left vEntricular dysfunction SAFARI : Study of Atrial Fibrillation Reduction SCD HeFT : Sudden Cardiac Death in Heart Failure Trial SMART-AV : The SMARTDelay Determined AV Optimization: a Comparison with Other AV Delay Methods Used in Cardiac Resynchronization Therapy SYDIT : The SYncope DIagnosis and Treatment SYNPACE : Vasovagal SYNcope and PACing TARGET : TARgeted Left Ventricular Lead Placement to Guide Cardiac Resynchronization Therapy THEOPACE : Effects of Oral THEOphylline and of Permanent PACEmaker on the Symptoms and Complications of Sick Sinus Syndrome VASIS-PM : VAsovagal Syncope International Study on PaceMaker therapy V-HeFT : Vasodilator in HEart Failure Trial VPSII : Second Vasovagal Pacemaker Study (VPS II) Additional references are mentioned with ‘w’ in the main text and can be found on the online addenda along with 5 figures (1, 6, 7, 9, 11, 12) and 10 tables (3, 4, 5, 9, 11, 12, 19, 21, 22, 23). They are available on the ESC website only at http://www.escardio.org/guidelines-surveys/esc-guidelines/Pages/cardiac-pacing-and-cardiac-resynchronisation-therapy.aspx Guidelines summarize and evaluate all available evidence, at the time of the writing process, on a …

Safety and Efficacy of a Totally Subcutaneous Implantable-Cardioverter Defibrillator

Abstract: Background—The most frequent complications associated with implantable cardioverter-defibrillators (ICDs) involve the transvenous leads. A subcutaneous implantable cardioverter-defibrillator (S-ICD) has been developed as an alternative system. This study evaluated the safety and effectiveness of the S-ICD System (Cameron Health/Boston Scientific) for the treatment of life-threatening ventricular arrhythmias (ventricular tachycardia/ventricular fibrillation). Methods and Results—This prospective, nonrandomized, multicenter trial included adult patients with a standard indication for an ICD, who neither required pacing nor had documented pace-terminable ventricular tachycardia. The primary safety end point was the 180-day S-ICD System complication-free rate compared with a prespecified performance goal of 79%. The primary effectiveness end point was the induced ventricular fibrillation conversion rate compared with a prespecified performance goal of 88%, with success defined as 2 consecutive ventricular fib...

Outcome After Implantation of a Cardioverter-Defibrillator in Patients With Brugada Syndrome

Abstract: Background—Implantable cardioverter-defibrillator indications in Brugada syndrome remain controversial, especially in asymptomatic patients. Previous outcome data are limited by relatively small nu...

Strain echocardiography improves risk prediction of ventricular arrhythmias after myocardial infarction.

Abstract: Objectives The aim of this study was to test the hypothesis that strain echocardiography might improve arrhythmic risk stratification in patients after myocardial infarction (MI). Background Prediction of ventricular arrhythmias after MI is challenging. Left ventricular ejection fraction (LVEF) Methods In this prospective, multicenter study, 569 patients >40 days after acute MI were included, 268 of whom had ST-segment elevation MIs and 301 non–ST-segment elevation MIs. By echocardiography, global strain was assessed as average peak longitudinal systolic strain from 16 left ventricular segments. Time from the electrocardiographic R-wave to peak negative strain was assessed in each segment. Mechanical dispersion was defined as the standard deviation from these 16 time intervals, reflecting contraction heterogeneity. Results Ventricular arrhythmias, defined as sustained ventricular tachycardia or sudden death during a median 30 months (interquartile range: 18 months) of follow-up, occurred in 15 patients (3%). LVEFs were reduced (48 ± 17% vs. 55 ± 11%, p 35% (p Conclusions Mechanical dispersion by strain echocardiography predicted arrhythmic events independently of LVEF in this prospective, multicenter study of patients after MI. A combination of mechanical dispersion and global strain may improve the selection of patients after MI for implantable cardioverter-defibrillator therapy, particularly in patients with LVEFs >35% who did not fulfill current implantable cardioverter-defibrillator indications.

Risk stratification for implantable cardioverter defibrillator therapy: the role of the wearable cardioverter-defibrillator

Abstract: The benefit of implantable cardioverter-defibrillator (ICD) therapy depends upon appropriate evaluation of a persisting risk of sudden death and estimation of the patient's overall survival. Assessment of a stable and unchangeable arrhythmogenic substrate is often difficult. Structural abnormality and ventricular dysfunction, the two major risk parameters, may recover, and heart failure symptoms can improve so that ICD therapy may not be indicated. Risk stratification can take time while the patient continues to be at high risk of arrhythmic death, and patients may need temporary bridging by a defibrillator in cases of interrupted ICD therapy. The wearable cardioverter-defibrillator (WCD) combines a long-term electrocardiogram (ECG)-monitoring system with an external automatic defibrillator. The LIfeVest® (ZOLL, Pittsburgh, PA, USA) is composed of a garment, containing two defibrillation patch electrodes on the back, and an elastic belt with a front-defibrillation patch electrode and four non-adhesive ECG electrodes, connected to a monitoring and defibrillation unit. The WCD is a safe and effective tool to terminate ventricular tachycardia/ventricular fibrillation events, unless a conscious patient withholds shock delivery. It may be used in patients in the early phase after acute myocardial infarction with poor left ventricular function, after acute coronary revascularization procedures (percutaneous coronary intervention or coronary artery bypass grafting) and reduced left ventricular ejection fraction (≤35%), in patients with acute heart failure in non-ischaemic cardiomyopathy of uncertain aetiology and prognosis. The WCD may be helpful in subjects with syncope of assumed tachyarrhythmia origin or in patients with inherited arrhythmia syndromes. The WCD may replace ICD implantation in patients waiting for heart transplantation or who need a ventricular-assist device. This review describes the technical details and characteristics of the WCD, discusses its various potential applications, and reports the currently available experience with the wearable defibrillator.

Implantable Cardioverter Defibrillators in Patients with Cardiac Amyloidosis

Abstract: ICD in Cardiac AmyloidosisBackground Cardiac amyloidosis (CA) is associated with increased risk of sudden cardiac arrest. Although ICD therapy improves survival in patients with cardiomyopathy due to other etiologies, the benefit of ICD therapy in patients with CA is unclear in large part due to limited data on the precise mechanism of sudden cardiac arrest and selection of patients with cardiac amyloidosis for ICD therapy. Objective The objective was to determine the benefit of ICD therapy in cardiac amyloidosis. Methods We reviewed all ICD implant indications, procedures, and therapies, of CA patients evaluated at Mayo Clinic between 2000 and 2009. Results A total of 53 patients with CA (33 AL, 10 senile, 9 familial, and 1 AA) who underwent ICD implantation were included. Indication for ICD implantation was for primary prevention of sudden cardiac arrest in 41 (77%) patients and secondary prevention in 12 (23%) patients. The rate of appropriate ICD shocks was 32% in the first year and was observed almost exclusively in AL amyloidosis patients, occurring in 15 patients (12 AL amyloidosis, 2 senile, 1 AA). Appropriate ICD shocks were more frequent in patients with prior sudden cardiac arrest or sustained ventricular arrhythmias (secondary prevention indication), and less frequent in patients who presented with decreased ejection fraction or syncope. Conclusions A high rate of appropriate ICD shocks was observed especially in patients with AL-type amyloidosis. However, appropriate ICD therapy did not translate into overall survival benefit, suggesting that selection of patients with CA who might be candidates for ICD is imprecise.

A validation study of the 2003 American College of Cardiology/European Society of Cardiology and 2011 American College of Cardiology Foundation/American Heart Association risk stratification and treatment algorithms for sudden cardiac death in patients with hypertrophic cardiomyopathy

Abstract: Aims Sudden cardiac death (SCD) is a common mode of death in hypertrophic cardiomyopathy (HCM), but identification of patients who are at a high risk of SCD is challenging as current risk stratification guidelines have never been formally validated. The objective of this study was to assess the power of the 2003 American College of Cardiology (ACC)/European Society of Cardiology (ESC) and 2011 ACC Foundation (ACCF)/American Heart Association (AHA) SCD risk stratification algorithms to distinguish high risk patients who might be eligible for an implantable cardioverter defibrillator (ICD) from low risk individuals. Methods and results We studied 1606 consecutively evaluated HCM patients in an observational, retrospective cohort study. Five risk factors (RF) for SCD were assessed: non-sustained ventricular tachycardia, severe left ventricular hypertrophy, family history of SCD, unexplained syncope and abnormal blood pressure response to exercise. During a follow-up period of 11 712 patient years (median 6.6 years), SCD/appropriate ICD shock occurred in 20 (3%) of 660 patients without RF (annual rate 0.45%), 31 (4.8%) of 636 patients with 1 RF (annual rate 0.65%), 27 (10.8%) of 249 patients with 2 RF (annual rate 1.3%), 7 (13.7%) of 51 patients with 3 RF (annual rate 1.9%) and 4 (40%) of 10 patients with ≥4 RF (annual rate 5.0%). The risk of SCD increased with multiple RF (2 RF: HR 2.87, p≤0.001; 3 RF: HR 4.32, p=0.001; ≥4 RF: HR 11.37, p Conclusions The risk of SCD increases with the aggregation of RF. The 2003 ACC/ESC and 2011 ACCF/AHA guidelines distinguish high from low risk individuals with limited power.

Personalized management of atrial fibrillation

Abstract: The management of atrial fibrillation (AF) has seen marked changes in past years, with the introduction of new oral anticoagulants, new antiarrhythmic drugs, and the emergence of catheter ablation as a common intervention for rhythm control. Furthermore, new technologies enhance our ability to detect AF. Most clinical management decisions in AF patients can be based on validated parameters that encompass type of presentation, clinical factors, electrocardiogram analysis, and cardiac imaging. Despite these advances, patients with AF are still at increased risk for death, stroke, heart failure, and hospitalizations. During the fourth Atrial Fibrillation competence NETwork/European Heart Rhythm Association (AFNET/EHRA) consensus conference, we identified the following opportunities to personalize management of AF in a better manner with a view to improve outcomes by integrating atrial morphology and damage, brain imaging, information on genetic predisposition, systemic or local inflammation, and markers for cardiac strain. Each of these promising avenues requires validation in the context of existing risk factors in patients. More importantly, a new taxonomy of AF may be needed based on the pathophysiological type of AF to allow personalized management of AF to come to full fruition. Continued translational research efforts are needed to personalize management of this prevalent disease in a better manner. All the efforts are expected to improve the management of patients with AF based on personalized therapy.

Personalized management of atrial fibrillation: Proceedings from the fourth Atrial Fibrillation competence NETwork/European Heart Rhythm Association consensus conference.

Abstract: The management of atrial fibrillation (AF) has seen marked changes in past years, with the introduction of new oral anticoagulants, new antiarrhythmic drugs, and the emergence of catheter ablation as a common intervention for rhythm control. Furthermore, new technologies enhance our ability to detect AF. Most clinical management decisions in AF patients can be based on validated parameters that encompass type of presentation, clinical factors, electrocardiogram analysis, and cardiac imaging. Despite these advances, patients with AF are still at increased risk for death, stroke, heart failure, and hospitalizations. During the fourth Atrial Fibrillation competence NETwork/European Heart Rhythm Association (AFNET/EHRA) consensus conference, we identified the following opportunities to personalize management of AF in a better manner with a view to improve outcomes by integrating atrial morphology and damage, brain imaging, information on genetic predisposition, systemic or local inflammation, and markers for cardiac strain. Each of these promising avenues requires validation in the context of existing risk factors in patients. More importantly, a new taxonomy of AF may be needed based on the pathophysiological type of AF to allow personalized management of AF to come to full fruition. Continued translational research efforts are needed to personalize management of this prevalent disease in a better manner. All the efforts are expected to improve the management of patients with AF based on personalized therapy.

Early Risk of Mortality After Coronary Artery Revascularization in Patients With Left Ventricular Dysfunction and Potential Role of the Wearable Cardioverter Defibrillator

Abstract: Background— Implantation of implantable cardioverter defibrillator for prevention of sudden cardiac death is deferred for 90 days after coronary revascularization, but mortality may be highest early after cardiac procedures in patients with ventricular dysfunction. We determined mortality risk in postrevascularization patients with left ventricular ejection fraction ≤35% and compared survival with those discharged with a wearable cardioverter defibrillator (WCD). Methods and Results— Hospital survivors after surgical (coronary artery bypass graft surgery) or percutaneous (percutaneous coronary intervention [PCI]) revascularization with left ventricular ejection fraction ≤35% were included from Cleveland Clinic and national WCD registries. Kaplan–Meier, Cox proportional hazards, propensity score-matched survival, and hazard function analyses were performed. Early mortality hazard was higher among 4149 patients discharged without a defibrillator compared with 809 with WCDs (90-day mortality post–coronary artery bypass graft surgery 7% versus 3%, P =0.03; post-PCI 10% versus 2%, P <0.0001). WCD use was associated with adjusted lower risks of long-term mortality in the total cohort (39%, P <0.0001) and both post–coronary artery bypass graft surgery (38%, P =0.048) and post-PCI (57%, P <0.0001) cohorts (mean follow-up, 3.2 years). In propensity-matched analyses, WCD use remained associated with lower mortality (58% post–coronary artery bypass graft surgery, P =0.002; 67% post-PCI, P <0.0001). Mortality differences were not attributable solely to therapies for ventricular arrhythmia. Only 1.3% of the WCD group had a documented appropriate therapy. Conclusions— Patients with left ventricular ejection fraction ≤35% have higher early compared to late mortality after coronary revascularization, particularly after PCI. As early hazard seemed less marked in WCD users, prospective studies in this high-risk population are indicated to confirm whether WCD use as a bridge to left ventricular ejection fraction improvement or implantable cardioverter defibrillator implantation can improve outcomes after coronary revascularization.

Rate, causes, and impact on patient outcome of implantable device complications requiring surgical revision: large population survey from two centres in Italy.

Abstract: Aims The long-term impact of implantable device-related complications on the patient outcome has not been thoroughly evaluated. The aims of this retrospective, bi-centre study were to analyse the rate and nature of device-related complications requiring surgical revision in a large series of patients undergoing device implantation, elective generator replacement and pacing system upgrade and to systematically assess the impact of such complications on patient outcome and healthcare utilization. Methods and results Data from 2671 consecutive procedures (1511 device implantations, 1034 elective generator replacements, and 126 pacing system upgrades) performed between January 2006 and March 2011 were retrospectively analysed. The outcome measures recorded were complication-related mortality, number of re-operations, need for complex surgical procedures, number of re-hospitalizations, and additional hospital treatment days. Over a median follow-up of 27 months, the overall rate of complications was 2.8% per procedure-year [9.5% in cardiac resynchronisation therapy (CRT) device implantation, 6.1% in pacing system upgrade, 3.5% in implantable cardioverter defibrillator implantation, 1.7% in pacemaker implantation, and 1.7% in generator replacement). The procedure with the highest risk of complications was CRT device implantation (odds ratio: 6.6; P < 0.001); these complications primarily involved coronary sinus lead dislodgement and device infection. Patients with complications had a significantly higher number of device-related hospitalizations (2.3 ± 0.6 vs. 1.0 ± 0.1; P < 0.001) and hospital treatment days (15.7 ± 25.1 vs. 3.6 ± 1.1; P < 0.001) than those without complications. Device infection was the complication with the greatest negative impact on patient outcome. Conclusion Cardiac resynchronisation therapy implantation was the procedure with the highest risk of complications requiring surgical revision. Complications were associated with substantial clinical consequences and a significant increase in the number and length of hospitalizations.

Rationale and design of the SERVE‐HF study: treatment of sleep‐disordered breathing with predominant central sleep apnoea with adaptive servo‐ventilation in patients with chronic heart failure

Abstract: Aims Central sleep apnoea/Cheyne–Stokes respiration (CSA/CSR) is a risk factor for increased mortality and morbidity in heart failure (HF). Adaptive servo-ventilation (ASV) is a non-invasive ventilation modality for the treatment of CSA/CSR in patients with HF. Methods SERVE-HF is a multinational, multicentre, randomized, parallel trial designed to assess the effects of addition of ASV (PaceWave™, AutoSet CS™; ResMed) to optimal medical management compared with medical management alone (control group) in patients with symptomatic chronic HF, LVEF ≤45%, and predominant CSA. The trial is based on an event-driven group sequential design, and the final analysis will be performed when 651 events have been observed or the study is terminated at one of the two interim analyses. The aim is to randomize ∼1200 patients to be followed for a minimum of 2 years. Patients are to stay in the trial up to study termination. The first patient was randomized in February 2008 and the study is expected to end mid 2015. The primary combined endpoint is the time to first event of all-cause death, unplanned hospitalization (or unplanned prolongation of a planned hospitalization) for worsening (chronic) HF, cardiac transplantation, resuscitation of sudden cardiac arrest, or appropriate life-saving shock for ventricular fibrillation or fast ventricular tachycardia in implantable cardioverter defibrillator patients. Perspectives The SERVE-HF study is a randomized study that will provide important data on the effect of treatment with ASV on morbidity and mortality, as well as the cost-effectiveness of this therapy, in patients with chronic HF and predominantly CSA/CSR. Trial registration ISRCTN19572887

Implantable cardioverter defibrillators in arrhythmogenic right ventricular dysplasia/cardiomyopathy: Patient outcomes, incidence of appropriate and inappropriate interventions, and complications

Abstract: Background— Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is a cardiomyopathy characterized by ventricular arrhythmias and an abnormal right ventricle. Implantable cardioverter defibrillator (ICD) therapy may prevent sudden cardiac death in patients with ARVD/C. Currently, an overview of outcomes, appropriate and inappropriate interventions, and complications of ICD therapy in ARVD/C is lacking. Methods and Results— A literature search was performed to identify studies reporting outcome and complications in patients with ARVD/C who underwent ICD implantation. Of 641 articles screened, 24 studies on 18 cohorts were eligible for inclusion. In case of multiple publications on a cohort, the most recent publication was included in the meta-analysis. There were 610 patients (mean age, 40.4 years; 42% women), who had an ICD for primary or secondary prevention of sudden cardiac death. Risk factors for sudden cardiac death were presyncope (61%), syncope (31%), previous cardiac arrest (14%), ventricular tachycardia (58%), and ventricular fibrillation (6%). Antiarrhythmic medication consisted mostly of β-blockers (38%), amiodarone (14%), or sotalol (30%). During the 3.8-year follow-up, annualized cardiac mortality rate was 0.9%, annualized noncardiac mortality rate was 0.8%, and annualized heart transplant rate was 0.9%. The annualized appropriate and inappropriate ICD intervention rates were 9.5% and 3.7%, respectively. ICD-related complications consisted of difficult lead placement (18.4%), lead malfunction (9.8%), infection (1.4%), lead displacement (3.3%), and any complication (20.3%). Conclusions— Cardiac and noncardiac mortality rates after ICD implantation in patients with ARVD/C are low. Appropriate ICD interventions occur at a rate of 9.5%/y. Inappropriate ICD interventions and complications lead to considerable ICD-related morbidity.

Implantable cardioverter-defibrillator shocks: epidemiology, outcomes, and therapeutic approaches.

Abstract: Importance Implantable cardioverter-defibrillators (ICDs) have revolutionized the approach to the prevention of sudden cardiac death and are commonly used in a wide range of high-risk patients, including the large population of patients with severe left ventricular systolic dysfunction. The benefit of these devices derives from their therapies, including both antitachycardia pacing and high-energy shocks. However, although these therapies may be life saving, devices can also deliver inappropriate shocks. Objective To review ICD therapies (shocks and antitachycardia pacing), their effects on health outcomes, and current methods to reduce these therapies. Evidence Review We reviewed clinical evidence on ICD shocks and reference lists of retrieved articles. We also examined literature about the methods of reducing ICD therapy. Findings Both appropriate and inappropriate ICD shocks are common and are associated with an adverse effect on health outcomes, quality of life, and mortality. Several methods are available to reduce the risk of inappropriate ICD therapies. Conclusions and Relevance Implantable cardioverter-defibrillators reduce the risk of sudden cardiac death and prolong life in selected populations; however, many patients will receive an ICD shock, either appropriate or inappropriate. It is imperative that patients be counseled regarding this risk and adverse outcomes associated with shocks. Reduction of ICD shock should be individualized to ensure that patients receiving these devices experience the maximal benefits of therapy while minimizing the adverse consequences.

Left Cardiac Sympathetic Denervation in Long QT Syndrome Analysis of Therapeutic Nonresponders

Abstract: Background— Long QT syndrome (LQTS) is a potentially lethal but highly treatable cardiac channelopathy. Treatment options include pharmacotherapy, device therapy, and left cardiac sympathetic denervation (LCSD). Here, we sought to determine the characteristics of LQTS patients who have had ≥1 LQTS-related breakthrough cardiac event (BCE) after LCSD. Methods and Results— We performed retrospective chart review for 52 consecutive patients (24 males; mean age at diagnosis, 10.0±10 years; mean QTc, 528±74 ms) with LQTS who underwent LCSD between 2005 and 2010 (mean age at LCSD, 14.1±10 years) and have been followed up for 3.6±1.3 years. A BCE was defined as either (1) an appropriate ventricular fibrillation-terminating implantable cardioverter defibrillator shock or (2) arrhythmogenic syncope, seizures, or aborted cardiac arrest after LCSD. Thirty-three patients (61%) had LCSD as primary prevention because of either high-risk assessment or β-blocker intolerance. So far, 12 of 52 (23%) patients (7 males) have experienced ≥1 BCE post LCSD. The clinical phenotype of patients with BCEs was significantly more severe than patients without a BCE. No BCEs were seen in patients undergoing LCSD for β-blocker intolerance (0/12 versus 17/40; P <0.001). Conclusions— Although a marked reduction in number of cardiac events is usually seen after LCSD, ≈50% of high-risk LQTS patients have experienced ≥1 post-LCSD breakthrough. Therefore, LCSD must not be viewed as curative or as an alternative in implantable cardioverter defibrillator for high-risk patients. Prophylactic LCSD may provide another option to counter a suboptimal quality of life resulting from medication-related side effects.

Late gadolinium enhancement cardiac magnetic resonance imaging for the prediction of ventricular tachyarrhythmic events: a meta-analysis.

Abstract: Aims Approaches to the risk stratification for sudden cardiac death (SCD) remain unsatisfactory. Although late gadolinium enhancement cardiac magnetic resonance imaging (LGE-CMR) for SCD risk stratification has been evaluated in several studies, small sample size has limited their clinical validity. We performed this meta-analysis to better gauge the predictive accuracy of LGE-CMR for SCD risk stratification. Methods and results Electronic databases and published bibliographies were systematically searched to identify studies evaluating the association between the extent of LV scar on LGE-CMR and ventricular arrhythmic events [SCD, resuscitated cardiac arrest, the occurrence of ventricular arrhythmias, or appropriate implantable cardioverter defibrillator (ICD) therapy]. Only studies enrolling patients with CAD or non-ischaemic cardiomyopathy were included. Summary estimates of the relative risk (RR) and likelihood ratios (LRs) were calculated using random effects models. Eleven studies comprising 1105 patients were identified. During a mean/median follow-up of 8.5–41 months 207 patients had ventricular arrhythmic events. Ventricular arrhythmic events were more common in patients with a greater extent of LV scar: RR 4.33 [95% confidence interval (CI) 2.98–6.29], positive LR 1.98 (95% CI 1.66–2.37), and negative LR 0.33 (95% CI 0.24–0.46). Conclusion The extent of LGE on CMR is strongly associated with the occurrence of ventricular arrhythmias in patients with reduced LVEF and may be a valuable risk stratification tool for identifying patients who will benefit from ICD therapy. However, uncertainties regarding clinical application persist and need to be addressed prior to introduction into broad clinical practice.