Implantable Cardioverter-defibrillator Implantation For Primary Prevention Research Articles

Rapid-rate nonsustained ventricular tachycardias in high-risk dilated cardiomyopathy patients.

Nonsustained ventricular tachycardia (NSVT) occurs frequently in patients with dilated cardiomyopathy (DCM), especially in high-risk patients. The role of rapid-rate NSVT (RR-NSVT) documented by an implantable cardioverter-defibrillator (ICD) in DCM patients has not been fully explored. This study aimed to determine the relationship between RR-NSVT and the occurrence of ventricular tachyarrhythmias (VTAs) in DCM patients with ICD. From December 2000 to December 2017, 136 DCM patients received ICD or cardiac resynchronization therapy defibrillator (CRT-D) implantation for primary or secondary prevention of VTAs. Based on the occurrence of documented RR-NSVT, patients were classified into RR-NSVT (-) or RR-NSVT (+) groups. During the median follow-up of 4.5 years, 50.0% (68/136) patients experienced ≥1 episode, and 25.0% (34/136) patients experienced ≥3 episodes of RR-NSVT. Event-free survival for VTAs was significantly higher in the RR-NSVT (-) group, whereas those for heart failure admission and cardiovascular mortality were comparable between groups. In the multivariate Cox regression analysis, any RR-NSVT showed a positive association with the occurrence of VTAs (hazard ratio: 5.087; 95% confidence interval: 2.374-10.900; P<.001). In RR-NSVT (+) patients, a cluster (≥3 times/6 months) and frequent pattern (≥3 runs/day) of RR-NSVT were observed in 42.6% (29/68) and 30.9% (21/68) patients, respectively, who showed further increased incidence of VTAs. In DCM patients with ICD/CRT-D, 50.0% patients experienced at least one episode of RR-NSVT. RR-NSVT documentation showed a positive association with subsequent occurrence of VTAs, suggesting the importance of constructive arrhythmia management for patients with RR-NSVT.

Recommendations of the current guidelines for implantable cardioverter-defibrillator implantation in patients with hypertrophic cardiomyopathy: Debate still exists.

Sudden cardiac death (SCD) related to ventricular arrhythmias is the most disastrous consequence of hypertrophic cardiomyopathy (HCM). Hence, clinicians seek to identify the highest risk patients that have the greatest potential to benefit from an implantable cardioverter-defibrillator (ICD) for primary prevention; nonetheless, this is where controversies begin as the 2011 American College of Cardiology Foundation/American Heart Association and the 2014 European Society of Cardiology guidelines have significant discrepancies. These guidelines propose clinically and statistically oriented algorithms, respectively, for SCD risk stratification of patients with HCM and recommendation to implantation of primary prevention ICD. The differences between these guidelines have resulted in confusion among care practitioners and patients alike. In this communication, we tried to criticize the statistical viewpoint in terms of clinical outcomes and suggest the more beneficial model.

Comparison of Mortality and Readmission in Non-Ischemic Versus Ischemic Cardiomyopathy After Implantable Cardioverter-Defibrillator Implantation

Data is lacking on the contemporary risk of death and readmission following implantable cardioverter-defibrillator (ICD) implantation in patients with non-ischemic cardiomyopathies (NICM) compared with ischemic cardiomyopathies (ICM) in a large nationally representative cohort. We performed a retrospective cohort study using the National Cardiovascular Data Registry ICD Registry linked with Medicare claims from April 1, 2010 to December 31, 2013. We established a cohort of NICM and ICM patients with a left ventricular ejection fraction ≤35% who received a de novo, primary prevention ICD. We compared mortality and readmission using Kaplan-Meier curves and Cox proportional hazard regressions models. We also evaluated temporal trends in mortality. In 31,044 NICM and 68,458 ICM patients with a median follow up of 2.4 years, 1-year mortality was significantly higher in ICM patients (12.3%) compared with NICM (7.9%, p < 0.001). The higher mortality in ICM patients remained significant after adjustment for covariates (hazard ratio [HR] 1.40; 95% confidence interval [CI] 1.36 to 1.45), and was consistent in subgroup analyses. These findings were consistent across the duration of the study. ICM patients were also significantly more likely to be readmitted for all causes (adjusted HR 1.15, CI 1.12 to 1.18) and for heart failure (adjusted HR 1.25, CI 1.21 to 1.31). In conclusion, the risks of mortality and hospital readmission after primary prevention ICD implantation were significantly higher in patients with ICM compared with NICM which was consistent across all patient subgroups tested and over the duration of the study.

Arrhythmic event prediction in patients with heart failure and reduced ejection fraction.

Implantable cardioverter defibrillator (ICD) is an effective treatment to reduce mortality in patients with symptomatic heart failure and left ventricular ejection fraction (LVEF) 35% or less. LVEF presents a low sensitivity for predicting arrhythmic events. Aim of this study was to identify predictors of sustained ventricular arrhythmias (SVAs), overall and according to the cause of heart failure. Single-center, retrospective, cohort study of 193 patients (51 nonischemic and 142 ischemic) with chronic heart failure and LVEF less than 35% who had received ICD for primary prevention of sudden cardiac death. We collected clinical data, echocardiographic parameters and SVAs detected by the ICD. During a median follow-up of 1440 days, 32 (16.2%) patients had SVAs. SVAs incidence was similar in patients with nonischemic (15.6%) and ischemic cause of heart failure (16.9%). Hypertension, diabetes, chronic renal failure, atrial fibrillation, chronic obstructive pulmonary disease, New York Heart Association class at least III were predictors at univariate analysis of SVAs. A clinical score, assigning one point to each of these variables, was associated with a significantly increased risk of SVAs [odds ratio for each point increase = 1.92, 95% confidence interval 1.40-2.65, P < 0.0001, area under the curve (AUC) 0.73], with 72% sensitivity and 60% specificity for a cutoff at least three and remained significant in nonischemic (AUC 0.84) and ischemic (AUC 0.68) patients. Our study shows the benefit of ICD implantation in primary prevention and its independency of cause. A simple clinical score, based on comorbidities, identifies patients with more benefits from ICD implantation.

P575Usefulness of late gadolinium enhancement cardiac magnetic resonance to predict appropriate therapies in implantable cardioverter defibrillator patients in primary prevention

Abstract Funding Acknowledgements No funding acknowledgements OnBehalf VT and sudden cardiac death Background The scar and the amount of border zone measured by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) has been proposed as an independent predictor of ventricular arrhythmias in patients with ischemic and non-ischemic cardiomyopathy. However, at the present time, the guidelines are based only on the ejection fraction to recommend an implantable cardioverter defibrillator (ICD) in primary prevention, and only a minority of these patients receive appropriate therapies. So, prevention needs to be improved. Purpose To identify predictors of appropriate therapies in patients with a primary prevention ICD using cardiac magnetic resonance imaging and a dedicated software (ADAS-3D) to characterize the scar. Methods All consecutive patients who underwent a LGE-MR prior to ICD implantation in primary prevention were prospectively included. Clinical and cardiac imaging characteristics were collected. The myocardium was segmented with ADAS-3D software in 10 layers (from endocardium to epicardium). The scar, border zone, core and conducting channels were automatically measured in grams by the software. Results Since 2008 to 2017, 206 patients were included. Mean age was 67 +/- 28 years, 80% men, mean ejection fraction 26%+/-9, 52% with ischemic cardiomyopathy and 48% non-ischemic. The primary endpoint was appropriate therapies and/or sudden cardiac death (SCD). Median follow-up was 46,33 months. 46 patients (22%) reached the primary endpoint. Greater scar mass (36,05 grams vs 21,5 grams; HR 1.04; 95% CI (1.03-1-05), p &amp;lt;0.001), core mass (9,8 grams vs 5,6 grams; HR 1.06; 95% CI (1.04-1-09), p &amp;lt;0.001), border zone mass (26,2 grams vs 15,9 grams; HR 1.05; 95% CI (1.04-1-09), p &amp;lt;0.001) and channel mass (3,0 grams vs 1,6 grams; HR 1.15 95% CI (1.06-1.25), p &amp;lt;0.001) were associated with appropriate therapies and SCD. A border zone mass &amp;gt;5.3 grams was independently associated with the primary endpoint (HR: 4.77; 95% CI (1.15-19.73), p = 0.03). Conclusions The amount of border zone, core and channel mass measured by LGE-MR and ADAS software are independent predictors of appropriate therapies and SCD in patients with ICD in primary prevention. Abstract Figure. Scar characterization

Automated electrocardiographic quantification of myocardial scar in patients undergoing primary prevention implantable cardioverter-defibrillator implantation: Association with mortality and subsequent appropriate and inappropriate therapies

Myocardial scarring from infarction or nonischemic fibrosis forms an arrhythmogenic substrate. The Selvester QRS score has been developed to estimate myocardial scar from the 12-lead electrocardiogram. We aimed to assess the value of an automated version of the Selvester QRS score for the prediction of implantable cardioverter-defibrillator (ICD) therapy and death in patients undergoing primary prevention ICD implantation. Unselected patients undergoing primary prevention ICD implantation were included in this retrospective, observational, multicenter study. The QRS score was calculated automatically from a digital standard preimplantation 12-lead electrocardiogram and was correlated to the occurrence of death and appropriate and inappropriate shocks during follow-up. Analyses were performed in groups defined by QRS duration < 130 ms vs ≥ 130 ms. Overall, 1047 patients (872 [83%] men; median age 64 years IQR [55-71]) with ischemic (648, 62%) or nonischemic (399, 38%) cardiomyopathy were included. The median QRS duration was 123 ms (interquartile range [IQR] 111-157 ms), and the median QRS score was 5 (IQR 2-8). The QRS duration was <130 ms in 59% and ≥130 ms in 41%. During a median follow-up of 45 months (IQR 24-72 months), a QRS score of ≥5 was independently associated with a significantly higher risk of mortality (hazard ratio [HR] 1.67; 95% confidence interval [CI] 1.05-2.66; P = .031) and appropriate (HR 1.83; 95% CI 1.07-3.14; P = .028) and inappropriate (HR 2.32; 95% CI 1.04-5.17; P= .039) shocks in patients with QRS duration ≥ 130 ms. No association of the QRS score and outcome was observed in patients with QRS duration < 130 ms (P > .05). The automatically calculated Selvester QRS score, an indicator of myocardial scar burden, predicts mortality and appropriate and inappropriate shocks in patients undergoing primary prevention ICD implantation with a prolonged QRS duration.

Usefulness of Serum Free Thyroxine Concentration to Predict Ventricular Arrhythmia Risk in Euthyroid Patients With Structural Heart Disease

The aim of the present study was to determine whether free thyroxine (FT4) and calculated thyroid parameters predict the incidence of ventricular arrhythmias in euthyroid heart failure patients with implantable cardioverter-defibrillators (ICD). In this open-label prospective cohort study, 115 consecutive euthyroid patients (mean age 62.9 ± 1.3 years; 87% male; ischemic cardiomyopathy 63%) scheduled for primary prevention ICD implantation or exchange were enrolled. Serum concentrations of thyrotropin (thyroid-stimulating hormone) and FT4 were measured 1 day before device operation. Primary and secondary end points were defined as occurrence of appropriate ICD therapy (AIT) and cardiovascular death, respectively. During a mean follow-up of 1,191 ± 35 days, 24 patients (21%) experienced AIT, and cardiovascular death was observed in 10 patients (9%). Patients with AIT had higher FT4 concentrations compared with those without AIT (18.9 ± 0.48 vs 16.2 ± 0.22 pmol/L, p <0.001). FT4 was an independent predictor of AIT in an adjusted Cox regression (hazard ratio = 1.47, p <0.001). Kaplan-Meier analysis demonstrated that Jostel's thyroid-stimulating hormone index, reflecting the central component of the hypothalamus-pituitary-thyroid loop, and SPINA-GT as surrogate markers for thyroid's secretory capacity predicted AIT incidences. None of the indices predicted cardiovascular death. In conclusion, FT4 concentration predicts an increased incidence of ventricular arrhythmias in euthyroid patients receiving ICDs for primary prevention. Our data suggest that both impending primary hyperthyroidism and an increased thyroid homeostasis set point may increase the rate of AIT in this patient population.

Clinical and Hospital Factors Affecting Treatment with Primary Prevention Implantable Cardioverter-Defibrillators in Ischemic Cardiomyopathy Patients.

PurposeImplantable cardioverter defibrillators (ICD) are the standard of care for primary prevention (PP) in patients with ischemic cardiomyopathy (ICM). However, PP ICD implantation is underused in Asian countries. This study investigated ICD implantation rates and factors associated with appropriate PP ICD implants for ICM.Materials and MethodsIn this prospective multicenter observational registry (ADVANCE-ICM registry), ICM patients who were eligible for PP ICD were screened and enrolled. Factors associated with appropriate ICD implantation, including hospital and clinical factors, were investigated.ResultsOf the 1453 ICM patients eligible for PP ICD [1111 male; median age, 71.0 (61.0–78.0) years], only 76 (5.2%) patients underwent ICD implantation. Among hospital factors, a non-monetary incentive for referral (72.4% vs. 52.9%, p=0.001) and total hospital system score (6.0 vs. 5.0, p=0.013) were higher in the ICD than in the no-ICD group. In multivariate analysis, total hospital system score [odds ratio (OR), 1.28; 95% confidence interval (CI), 1.10–1.50] was an independent factor for predicting ICD implantation, along with clinical factors, including high New York Heart Association class (≥III: OR, 7.29; 95% CI, 2.97–17.87) and younger age (<70 years: OR, 2.14; 95% CI, 1.30–3.53).ConclusionPP ICD implantation for ICM patients is underused in Korea. Hospital factors were important for improving PP ICD implantation rate, suggesting that new screening and referral systems for ICM patients would improve the PP ICD implantation rate (Clinical trial registration No. NCT03590925).

Primary prevention of sudden cardiac death in patients with tetralogy of Fallot with implantable cardioverter defibrillator: Insights from the DAI-T4F study

Ventricular arrhythmias and sudden death are feared late complications in patients with tetralogy of Fallot. Selection of candidates for primary prevention implantable cardioverter defibrillator (ICD) remains challenging. To identify patients with tetralogy of Fallot at high-risk of sudden cardiac death in primary prevention. The DAI-T4F study is an ongoing national French registry including all patients with tetralogy of Fallot and ICD ( NCT03837574 ). Information have been collected prospectively since 2010. Cox proportional hazard models were used to identify factors associated with appropriate ICD therapies. Among 134 patients enrolled, 47 (35.1%) underwent ICD implantation for primary prevention (median age 49.1 years, 76.6% males). At baseline, 20 (42.6%) patients had NSVT, 17 (36.2%) had altered LVEF ≤ 35%, 16 (34.0%) had positive programmed ventricular stimulation, and 16 (34.0%) had QRS duration ≥ 180ms. During a median (IQR) follow-up duration of 5.3 (2.1–8.0) years, 14 (29.8%) patients had at least one appropriate ICD therapy. The annual incidence of appropriate ICD therapies were 2.8%, 4.6%, 6.3%, and 8.6% in patients with none, one, two, or ≥ three of these factors ( P for trend = 0.145). None of predictors, considered isolated, was significantly associated with ICD appropriate therapies. Patients with non-sustained ventricular tachycardia (NSVT) and positive programmed ventricular stimulation had a significant increased risk of ICD appropriate therapies (HR = 3.8, 95% CI: 1.1–14.3, P = 0.035), as well as patients with NSVT and QRSd ≥ 180 ms (HR = 7.2, 95% CI: 1.6–32.7, P = 0.003). No patient with severe altered LVEF without other risk factor had appropriate ICD therapy. Our data illustrate that specific risk stratification and primary prevention for sudden cardiac death in patients with tetralogy of Fallot may be improved. The value of a severely altered LVEF appears low in the absence of other risk factors.

Long-term follow-up of implantable cardioverter-defibrillators in children: Indications and outcomes.

Validation data of the use of implantable cardioverter-defibrillators (ICD) in the pediatric population is insufficient, with limited follow-up periods. The aim of the study was to report on 17 years of experience with implantable cardioverter-defibrillator (ICD) therapy in children and young adults. This retrospective review included patients below the age of 18 years at the time of ICD implantation between May 2000 and December 2017. For the statistical analysis, the sample was divided into groups by gender and the type of indications for ICD implantation (primary vs secondary prevention). The study group included 20 children (8 female, 12 male) who underwent ICD implantation for primary or secondary prevention of sudden cardiac death (SCD). The average age at the time of the initial procedure was 15.6 years (range: 3.8-17.7 years). Primary electrical disease (PED) was present in 9 patients, cardiomyopathy (CMP) in 9 and 2 others had congenital heart defects (CHDs). The median follow-up time was 6.7 years (range: 0.4-12.5 years). The outcomes of ICD therapy were analyzed. No differences between the sexes were found in terms of treatment strategy effectiveness (p > 0.05). The girls were more often treated as primary prevention (p = 0.009). After implantation, all the patients were on optimal pharmacotherapy. Alltogether there were 126 ICD interventions in 11 patients, including 23 inadequate interventions (IA) in 2 children (18.2%).Three children (15%) died due to electrical storms. In the per-procedure analysis, the overall freedom rate from ICD lead replacement was 90%, 80% and 57% at 1, 5 and 10 years of observation, respectively. Implantable cardioverter-defibrillator implantation indications in children are more heterogeneous in comparison to adult population. In the pediatric population undergoing ICD implantation, the treatment strategy is influenced by gender. The rate of inappropriate ICD discharges (IA) in our group of pediatric patients was low. Rigorous pharmacotherapy and individual ICD programming seemed of paramount importance. Lead malfunctions LF constituted the most prevalent complication observed.

The SHIFT model combines clinical, electrocardiographic and echocardiographic parameters to predict sudden cardiac death in hypertrophic cardiomyopathy

IntroductionLimitations have been pointed out in the clinical risk prediction model for sudden cardiac death (SCD) of the European Society of Cardiology (ESC), which is recommended for hypertrophic cardiomyopathy (HCM) patients. The aim of this study was to determine the SCD risk of the HCM patients enrolled in a Portuguese nationwide registry and to develop a new SCD risk prediction model applicable to our population. Methods and resultsThe cohort consisted of 1022 patients (mean age 53.2±16.4 years, 59% male) enrolled in a Portuguese national HCM registry. During the follow-up period (median five years), 19 patients (1.9%) died suddenly or had aborted SCD or appropriate implantable cardioverter-defibrillator (ICD) shock therapy. Through a Cox proportional hazards model, four variables were independently associated with SCD or equivalent: unexplained Syncope, Heart failure signs, Interventricular septum thickness ≥19 mm and FragmenTed QRS complex. These predictors were included in the SHIFT model and individual risk probabilities of SCD at five years were estimated. This model was internally validated using bootstrapping. The C-index of the SHIFT model was 0.81 (95% CI: 0.77-0.83) and the C-index of the ESC model (performed in a subgroup of 349 HCM patients) was 0.77 (95% CI: 0.73-0.81) (p=0.246). ConclusionThe SHIFT model may potentially provide prognostic value and contribute to the clinical decision-making process for ICD implantation for primary prevention of SCD.

5968Adherence to driving restrictions among patients with an implantable cardioverter defibrillator: insights from a nationwide register-linked survey study

Abstract Background Patients with an implantable cardioverter defibrillator (ICD) are restricted from driving following initial implantation or ICD shock. It is unclear how many patients are aware of, and adhere to, these restrictions. Purpose To investigate knowledge of, and adherence to, private and professional driving restrictions in a nationwide cohort of ICD patients. Methods A questionnaire was distributed to all living Danish residents ≥18 years who received a first-time ICD between 2013 and 2016 (n=3,913). During this period, Danish guidelines recommended 1 week driving restriction following ICD implantation for primary prevention, and 3 months following either ICD implantation for secondary prevention or appropriate ICD shock, and permanent restriction of professional driving and driving of large vehicles (&gt;3.5 metric tons). Questionnaires were linked with relevant nationwide registries. Logistic regression was applied to identify factors associated with non-adherence. Results Of 2,741 questionnaire respondents, 92% (n=2,513) held a valid private driver's license at time of ICD implantation (85% male; 46% primary prevention indication; median age: 67 years (IQR: 59–73)). Of these, 7% (n=175) were actively using a professional driver's license for truck driving (n=73), bus driving (n=45), taxi driving (n=22), large vehicle driving for private use (n=54), or other purposes (n=32) (multiple purposes allowed). Only 42% of primary prevention patients, 63% of secondary prevention patients, and 72% of patients who experienced an appropriate ICD shock, recalled being informed of any driving restrictions. Only 45% of professional drivers recalled being informed about specific professional driving restrictions (Figure). Most patients (93%, n=2,344) resumed private driving after ICD implantation, more than 30% during the driving restriction period: 34% of primary prevention patients resumed driving within 1 week, 43% of secondary prevention patients resumed driving within 3 months, and 30% of patients who experienced an appropriate ICD shock resumed driving within 3 months. Professional driving was resumed by 35%. Patients who resumed driving within the restricted periods were less likely to report having received information about driving restrictions (all p&lt;0.001) (Figure). In a multiple logistic regression model, non-adherence was predicted by reporting non-receipt of information about driving restrictions (OR: 3.34, CI: 2.27–4.03), as well as male sex (OR: 1.53, CI: 1.17–2.01), age ≥60 years (OR: 1.20, CI: 1.02–1.64), receipt of a secondary prevention ICD (OR: 2.2, CI: 1.80–2.62), and being the only driver in the household (OR: 1.29, CI: 1.05–1.57). Conclusion In this nationwide survey study, many ICD patients were unaware of the driving restrictions, and many ICD patients, including professional drivers, resumed driving within the restricted periods. More focus on communicating driving restrictions might improve adherence. Acknowledgement/Funding Danish Heart Foundation, Arvid Nilsson Foundation, Fraenkels Mindefond

5204Primary prevention of sudden cardiac death in patients with tetralogy of Fallot with implantable cardioverter defibrillator: insights from the DAI-T4F study

Abstract Background Ventricular arrhythmias and sudden death are feared late complications in patients with tetralogy of Fallot. Selection of candidates for primary prevention implantable cardioverter defibrillator (ICD) remains challenging in this population. Non-sustained ventricular tachycardia (NSVT), altered left ventricular ejection fraction (LVEF), positive programmed ventricular stimulation, and enlarged QRS are currently used for risk stratification. Purpose To identify high-risk patients with tetralogy of Fallot in the setting of primary prevention of sudden cardiac death. Methods The DAI-T4F study is a large ongoing national French registry including all patients with tetralogy of Fallot and ICD (NCT03837574). Information have been collected prospectively since 2010 with annual update. Baseline patient characteristics and clinical events during the follow-up were analyzed with central adjudication. Cox proportional hazard models were used to identify factors associated with appropriate ICD therapies. Results Among 134 patients enrolled, 47 (35.1%) underwent ICD implantation for primary prevention (median age 49.1 years, 76.6% males). At baseline, 20 (42.6%) patients had NSVT, 17 (36.2%) had severe altered LVEF ≤35%, 16 (34.0%) had positive programmed ventricular stimulation, and 16 (34.0%) had QRS duration ≥180ms. Overall, 20 (42.6%), 15 (31.9%), and 6 (12.8%) patients had respectively one, two, or ≥ three of these risk factors. Six (12.8%) patients were implanted for other indications. During a median (IQR) follow-up duration of 5.3 (2.1–8.0) years, 14 (29.8%) patients had at least one appropriate ICD therapy. The annual incidence of appropriate ICD therapies were 2.8%, 4.6%, 6.3%, and 8.6% in patients with none, one, two, or ≥ three of these factors (p for trend = 0.145). None of predictors, considered isolated, was significantly associated with ICD appropriate therapies. Patients with non-sustained ventricular tachycardia (NSVT) and positive programmed ventricular stimulation had a significant increased risk of ICD appropriate therapies (HR=3.8, 95% CI: 1.1–14.3, p=0.035), as well as patients with NSVT and QRSd ≥180 ms (HR=7.2, 95% CI: 1.6–32.7, p=0.003). No patient with severe altered LVEF without other risk factor had appropriate ICD therapy. Patients with congestive heart failure and/or altered LVEF had a higher risk of non-sudden death or cardiac transplantation (HR=14.4, 95% CI: 1.8–112.7, p&lt;0.001). Seventeen (36.2%) patients experienced at least one ICD-related complication. Conclusions Our data illustrate that specific risk stratification and primary prevention for sudden cardiac death in patients with tetralogy of Fallot may be improved. The value of a severely altered LVEF appears low in the absence of other risk factors, and combination of different predictors is essential. The high rate of complications as well as consideration of competing risk situation have to be integrated in the benefit-risk equation.

Trends in the use of implantable cardioverter-defibrillators for prevention of sudden cardiac arrest: A South Korean nationwide population-based study.

The benefits of implantable cardioverter-defibrillators (ICDs) for the prevention of sudden cardiac arrest (SCA) are well established. However, a significant knowledge gap remains regarding current indications and utilization of ICDs in real-world settings in Asia. Patients who underwent ICD implantation in South Korea from 2007 to 2015 were identified using the Health Insurance Review and Assessment Service database. We investigated trends in use of ICD for the prevention of SCA. A total of 4649 ICDs were implanted during 9 years. ICDs were implanted in 1448 (31.2%) patients for primary prevention and in 3201 (68.8%) for secondary prevention. The proportion of ICDs for primary prevention increased from 6.1% in 2007 to 41.9% in 2015. Primary prevention was more frequent in older (≥40 years) recipients (34.4%vs. 14.6%, P<.0001). The rates of ICD implantation for primary prevention were highest for nonischemic dilated cardiomyopathy (55.1%) and lowest (9.7%) for inherited primary arrhythmia syndrome (IPAS). Our data showed a trend of progressively increasing rates of ICD implantation in Asia, especially for primary prevention of SCA. Primary prevention as an indication for ICD in patients with IPAS remained low.

Left Atrial Function Using Cardiovascular Magnetic Resonance Imaging Independently Predicts Life-Threatening Arrhythmias in Patients Referred to Receive a Primary Prevention Implantable Cardioverter Defibrillator

BackgroundIn this study we aimed to investigate left atrial (LA) function, measured from routine cine cardiovascular magnetic resonance imaging, to determine its value for the prediction of sudden cardiac death (SCD) or appropriate implantable cardioverter defibrillator (ICD) shock in patients who received primary prevention ICD implantation. MethodsWe studied 203 patients with ischemic or idiopathic nonischemic dilated cardiomyopathy who underwent cardiovascular magnetic resonance imaging before primary prevention ICD implantation. LA volumes were measured at end-diastole and end-systole from 4- and 2-chamber cine images, and LA emptying function (LAEF) calculated. Patients were followed for the primary composite end point of SCD or appropriate ICD shock. ResultsMean age was 61 ± 12 years with a mean left ventricular ejection fraction of 24 ± 7%. The mean LAEF was 27 ± 15% (range, 0.9%-73%). At a median follow-up of 1639 days, 35 patients (17%) experienced the primary composite outcome. LAEF was strongly associated with the primary outcome (P = 0.001); patients with an LAEF ≤ 30% experienced a cumulative event rate of 26.1% vs 5.7% (hazard ratio, 5.5; P < 0.001) in patients above this cutoff. This finding was maintained in multivariable analysis (hazard ratio, 4.7; P = 0.002) and was consistently shown in the ischemic and nonischemic dilated cardiomyopathy subgroups. ConclusionsLAEF is a simple, powerful, and independent predictor of SCD in patients being referred for primary prevention ICD implantation.

Therapy of ventricular arrhythmias in patients suffering from isolated left ventricular non-compaction cardiomyopathy.

Non-compaction cardiomyopathy (NCCM) is associated with high rates of mortality and morbidity. Knowledge regarding risk stratification, arrhythmogenesis, therapy, and prognosis is limited. The aim of this study was to analyse the outcome of patients suffering from NCCM and ventricular arrhythmias (VAs) focusing on a treatment with implantable cardioverter-defibrillator (ICD) therapy and catheter ablation. We conducted a multicentre observational study on 18 patients with NCCM, who underwent ICD implantation for secondary (n = 12) and primary (n = 6) prevention. In patients with multiple symptomatic episodes of VAs catheter ablation was performed. During a follow-up of 62 ± 42 months, 12 patients (67%) presented with appropriate ICD therapies [ventricular tachycardia (VT): n = 8; ventricular fibrillation (VF): n = 4; VT/VF: n = 3]. Ten patients underwent catheter ablation for VT/VF. Solely endocardial ablation was conducted in eight patients, and in two patients endo- and epicardial ablation was performed within the same procedure. Acute procedural success was achieved in 9/10 patients. Ventricular tachycardia recurrence was observed in two patients and the median arrhythmia free interval was 9.5 months (interquartile range 5.3-21 months). One patient underwent reablation, four patients died due to the underlying NCCM, and one patient received a left ventricular assist device. Ventricular arrhythmias are common in patients suffering from NCCM and ICD therapy may be effective for primary and secondary prevention. In our cohort, consisting of patients with multiple VA episodes and recurrent ICD therapy, catheter ablation offered a safe and effective therapeutically option.

Association of cardiovascular magnetic resonance-derived circumferential strain parameters with the risk of ventricular arrhythmia and all-cause mortality in patients with prior myocardial infarction and primary prevention implantable cardioverter defibrillator

BackgroundImpaired left ventricular (LV) contraction and relaxation may further promote adverse remodeling and may increase the risk of ventricular arrhythmia (VA) in ischemic cardiomyopathy. We aimed to examine the association of cardiovascular magnetic resonance (CMR)-derived circumferential strain parameters for LV regional systolic function, LV diastolic function and mechanical dispersion with the risk of VA in patients with prior myocardial infarction and primary prevention implantable cardioverter defibrillator (ICD).MethodsPatients with an ischemic cardiomyopathy who underwent CMR prior to primary prevention ICD implantation, were retrospectively identified. LV segmental circumferential strain curves were extracted from short-axis cine CMR. For LV regional strain analysis, the extent of moderately and severely impaired strain (percentage of LV segments with strain between − 10% and − 5% and > − 5%, respectively) were calculated. LV diastolic function was quantified by the early and late diastolic strain rate. Mechanical dispersion was defined as the standard deviation in delay time between each strain curve and the patient-specific reference curve. Cox proportional hazard ratios (HR) (95%CI) were calculated to assess the association between LV strain parameters and appropriate ICD therapy.ResultsA total of 121 patients (63 ± 11 years, 84% men, LV ejection fraction (LVEF) 27 ± 9%) were included. During a median (interquartile range) follow-up of 47 (27;69) months, 30 (25%) patients received appropriate ICD therapy. The late diastolic strain rate (HR 1.1 (1.0;1.2) per − 0.25 1/s, P = 0.043) and the extent of moderately impaired strain (HR 1.5 (1.0;2.2) per + 10%, P = 0.048) but not the extent of severely impaired strain (HR 0.9 (0.6;1.4) per + 10%, P = 0.685) were associated with appropriate ICD therapy, independent of LVEF, late gadolinium enhancement (LGE) scar border size and acute revascularization. Mechanical dispersion was not related to appropriate ICD therapy (HR 1.1 (0.8;1.6) per + 25 ms, P = 0.464).ConclusionsIn an ischemic cardiomyopathy population referred for primary prevention ICD implantation, the extent of moderately impaired strain and late diastolic strain rate were associated with the risk of appropriate ICD therapy, independent of LVEF, scar border size and acute revascularization. These findings suggest that disturbed LV contraction and relaxation may contribute to an increased risk of VA after myocardial infarction.

Meta-Analysis of Clinical Outcome After Implantable Cardioverter-Defibrillator Implantation in Patients With BrugadaSyndrome.

This study sought to summarize the clinical outcome of implantable cardioverter-defibrillator (ICD) therapy in patients with Brugada syndrome. Brugada syndrome is characterized by cardiac conduction abnormalities and a high risk of ventricular arrhythmias that may result in sudden cardiac death. A complete overview of clinical outcome, appropriate and inappropriate interventions, and complications after ICD therapy in patients with Brugada syndrome is lacking. The online MEDLINE database was searched for published reports and yielded 828 studies on outcome and complications after ICD therapy in patients with Brugada syndrome. After careful evaluation, 22 studies including a total of 1,539 patients were included in the meta-analysis. In total, 1,539 patients (mean age 45 years, 18% women) underwent ICD implantation for primary (79%) or secondary (21%) prevention of sudden cardiac death. During a mean follow-up of 4.9 years, the appropriate and inappropriate ICD intervention rates were 3.1 and 3.3 per 100 person-years, respectively. The cardiac mortality rate was 0.03 per 100 person-years and noncardiac mortality rate was 0.3 per 100 person-years. ICD-related complications per 100 person-years consisted of lead malfunction (1.6), psychological complication (1.3), infection (0.6), lead dislocation (0.4), and any complication (0.6). Patients with Brugada syndrome judged to be at high risk for ventricular arrhythmia may significantly benefit from ICD therapy, which is associated with an appropriate ICD intervention rate of 3.1 per 100 person-years and low cardiac and noncardiac mortality rates. Inappropriate ICD interventions and ICD-related complications may lead to considerable morbidity.

Systematic Review for the 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society.

Although large randomized clinical trials have found that primary prevention use of an implantable cardioverter-defibrillator (ICD) improves survival in patients with cardiomyopathy and heart failure symptoms, patients who receive ICDs in practice are often older and have more comorbidities than patients who were enrolled in the clinical trials. In addition, there is a debate among clinicians on the usefulness of electrophysiological study for risk stratification of asymptomatic patients with Brugada syndrome. Our analysis has 2 objectives. First, to evaluate whether ventricular arrhythmias (VAs) induced with programmed electrostimulation in asymptomatic patients with Brugada syndrome identify a higher risk group that may require additional testing or therapies. Second, to evaluate whether implantation of an ICD is associated with a clinical benefit in older patients and patients with comorbidities who would otherwise benefit on the basis of left ventricular ejection fraction and heart failure symptoms. Traditional statistical approaches were used to address 1) whether programmed ventricular stimulation identifies a higher-risk group in asymptomatic patients with Brugada syndrome and 2) whether ICD implantation for primary prevention is associated with improved outcomes in older patients (>75 years of age) and patients with significant comorbidities who would otherwise meet criteria for ICD implantation on the basis of symptoms or left ventricular function. Evidence from 6 studies of 1138 asymptomatic patients were identified. Brugada syndrome with inducible VA on electrophysiological study was identified in 390 (34.3%) patients. To minimize patient overlap, the primary analysis used 5 of the 6 studies and found an odds ratio of 2.3 (95% CI: 0.63-8.66; P=0.2) for major arrhythmic events (sustained VAs, sudden cardiac death, or appropriate ICD therapy) in asymptomatic patients with Brugada syndrome and inducible VA on electrophysiological study versus those without inducible VA. Ten studies were reviewed that evaluated ICD use in older patients and 4 studies that evaluated unique patient populations were identified. In our analysis, ICD implantation was associated with improved survival (overall hazard ratio: 0.75; 95% confidence interval: 0.67-0.83; P<0.001). Ten studies were identified that evaluated ICD use in patients with various comorbidities including renal disease, chronic obstructive pulmonary disease, atrial fibrillation, heart disease, and others. A random effects model demonstrated that ICD use was associated with reduced all-cause mortality (overall hazard ratio: 0.72; 95% confidence interval: 0.65-0.79; P<0.0001), and a second "minimal overlap" analysis also found that ICD use was associated with reduced all-cause mortality (overall hazard ratio: 0.71; 95% confidence interval: 0.61-0.82; P<0.0001). In 5 studies that included data on renal dysfunction, ICD implantation was associated with reduced all-cause mortality (overall hazard ratio: 0.71; 95% confidence interval: 0.60-0.85; P<0.001).

Mortality outcome and predictive risk factors for death in patients with heart failure and reduced ejection fraction who declined implantable cardioverter defibrillator implantation in Singapore.

BackgroundThere have been conflicting data regarding the risk of sudden cardiac death (SCD) in Asian population with reduced left ventricular ejection fraction (LVEF). We aim to study mortality outcome and its risk predictors in patients with reduced LVEF who declined an implantable cardioverter defibrillator (ICD) implantation and assess whether current ICD guidelines for primary prevention are applicable to the population in Singapore.MethodsThis prospective observational study involved 240 consecutive patients who fulfilled the ACC/AHA/HRS criteria for ICD implantation for primary prevention of SCD but declined ICD implantation. Baseline characteristics and mortality outcomes through May 2017 were collected via case‐note review after a mean follow‐up of 44.8 ± 16.6 months.ResultsMajority of our patients were Chinese (71.3%), followed by Malays (16.2%) and Indians (10.8%). Mean age (±SD) was 61 ± 10 years, and 84% were male. Majority were in New York Heart Association (NYHA) functional classes I (46.7%) and II (46.3%). Over a mean follow‐up of 44.8 ± 16.6 months, all‐cause mortality rate was 34.6%. Diabetes mellitus (HR = 1.57; 95% CI, 1.01‐2.44; P = 0.047) and chronic kidney disease (CKD; HR = 1.95; 95% CI, 1.17‐3.23; P = 0.010) were independent predictors of mortality. Patients in NYHA classes II (HR = 2.15; 95% CI, 1.32‐3.50; P = 0.002) and III (HR = 2.82; 95% CI, 1.34‐5.96; P = 0.007) showed higher risk of death.ConclusionThe mortality rate was comparable with major primary prevention trials. ICD guideline recommendations for primary prevention may thus be applicable to our local population. Patients with diabetes, CKD, and poorer NYHA status exhibited higher mortality rates.