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Background: The objectives of the study were to describe positron emission tomography (PET) parameters, using the tracers O-15-water at rest/stress, C-11-acetate, and C-11-HED, with regard to nonsustained ventricular tachycardia (NSVT) in hypertrophic cardiomyopathy (HCM). PET offers quantitative assessment of pathophysiology throughout the left ventricular segments, including the endocardium/epicardium. The potential use PET in risk stratification remains to be elucidated. NSVT provides a marker for sudden cardiac death. Methods: Patients with a validated diagnosis of HCM who had an implantable cardioverter-defibrillator were interrogated at 12 months and independently of PET-examinations. Results: In total, 25 patients (mean age 56.8 +/- 12.9 years, 76% males) were included and 10 reported NSVT. Mean myocardial blood flow (MBF) at rest was 0.91 ml/g/min and decreased at stress, 1.59 ml/ g/min. The mean gradient (endocardium/epicardium quotient) at rest was 1.14 +/- 0.09, while inverse at stress (mean 0.92 +/- 0.16). Notably, MBF gradient at stress was significantly lower in patients with NSVT (p = 0.022) and borderline at rest (p = 0.059) while global MBF at rest and stress were not. Mean myocardial oxygen consumption (MVO2) was 0.088 ml/g/min (higher in NSVT, p = 0.023) and myocardial external efficiency 18.5%. Using C-11-HED, the mean retention index was 0.11 min (1) and a higher volume of distribution (p = 0.089) or transmural gradient of clearance rate (p = 0.061) or lower clearance rate (p = 0.052) showed a tendency of association of NSVT. Conclusions: The endocardium/epicardium MBF gradient at stress is significantly lower in HCM patients with NSVT. This provides a novel approach to further refine risk stratification of sudden cardiac death.

Background: The number of implantable cardioverter defibrillator (ICD) infections is increasing due to an increased number of ICD implants, higher-risk patients, and more frequent replacement procedures, which carry a higher risk of infection. Reducing the morbidity, mortality, and cost of ICD-related infections requires an understanding of the current rate of this complication and its predictors. Methods: The Shock Implant Evaluation Trial (SIMPLE) trial randomized 2500 ICD recipients to defibrillation testing or not. Over an average of 3.1 years, patients were seen every 6 months and examined for evidence of ICD infection, which was defined as requiring device removal and/or intravenous antibiotics. Results: Within 24 months, 21 patients (0.8%) developed infection. Fourteen patients (67%) with infection presented within 30 days, 20 patients by 12 months, and only 1 patient beyond 12 months. Univariate analysis demonstrated that patients with primary electrical disorders (3 patients, P = 0.009) and those with a secondary prevention indication (13 patients, P = 0.0009) were more likely to develop infection. Among the 2.2% of patients who developed an ICD wound hematoma, 10.4% developed an infection. Among the 8.3% of patients requiring an ICD reintervention, 1.9% developed an infection. Conclusions: This cohort of ICD recipients at high-volume centres have a low risk of device-related infection. However; strategies to reduce wound hematoma and the need for ICD reintervention could further reduce the rate of infection., Contexte: L’incidence des cas d’infection du défibrillateur cardioverteur implantable (DCI) augmente en raison du nombre accru d’implantations, de l’emploi de ces dispositifs chez des patients exposés à un risque très élevé et de l’augmentation de la fréquence des interventions de remplacement, qui sont associées à un plus grand risque d’infections. Pour parvenir à réduire la morbidité, la mortalité et les coûts associés aux infections liées à un DCI, il faut connaître la fréquence de cette complication et les facteurs qui permettent de la prédire. Méthodologie: Lors de l’essai S hock Impl ant E valuation Trial (SIMPLE), 2 500 patients ayant reçu un DCI ont été répartis aléatoirement en deux groupes, l’un subissant des tests de défibrillation et l’autre, non. Sur une période de 3,1 ans en moyenne, les patients ont été vus en consultation tous les 6 mois et examinés à la recherche de signes d’infection du DCI, définie comme étant une infection exigeant le retrait du dispositif et/ou l’administration d’antibiotiques par voie intraveineuse. Résultats: Au total, 21 patients (0,8 %) ont présenté une infection dans les 24 mois suivant l’implantation. Quatorze patients (67 %) ont présenté une infection dans les 30 jours suivant l’intervention; à 12 mois, 20 patients avaient présenté une infection. Un seul patient a présenté une infection plus de 12 mois après l’intervention. Les résultats d’une analyse univariée ont démontré qu’une infection était plus probable chez les patients qui présentaient un trouble électrique primaire (3 patients, p = 0,009) et chez ceux qui avaient reçu un dispositif en prévention secondaire (13 patients, p = 0,0009). Parmi les patients qui présentaient un hématome après l’implantation du DCI (2,2 %), 10,4 % ont présenté une infection. Parmi les patients qui ont eu besoin d’une nouvelle intervention relative au DCI (8,3 %), 1,9 % ont présenté une infection. Conclusions: Les patients de cette cohorte ayant reçu un DCI dans des établissements à haut

Hypertrophic cardiomyopathy is the most common cardiogenetic disease affecting 1/500–1/1 000 individuals. Dyspnea is common but chest pain, dizziness or fainting may also cause considerable limitation for the patient. The diagnosis can be suspected from ECG. Echocardiography confirms hypertrophy of at least 15 mm, usually in the septum. If the obstruction of the outflow tract is severe, myectomy or alcohol ablation can relieve symptoms. Genetic evaluation of family members is advisable. To reduce symptoms, betablockers are used; verapamil or disopyramide are alternatives. Atrial fibrillation is often prevalent and requires special attention concerning anticoagulation and rhythm or rate control. An end-stage heart failure warrants advanced treatment options such as cardiac resynchronization therapy, ventricular assist devices or heart transplant. Sudden cardiac death is unpredictable and evaluation of risk markers is important to identify potential candidates for an implantable defibrillator.

Background Risk stratification of sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM) is mainly based on evaluations from patients at highly specialized centers. Aim To evaluate risk markers for appropriate implantable cardioverter defibrillator (ICD) therapy in an unselected, nationwide cohort of HCM. MethodsPatients with an ICD due to HCM were identified from the Swedish ICD Registry since its start in 1995, merged with Patient Register data, and medical records were retrieved. Risk markers for ventricular arrhythmias leading to appropriate ICD therapy were analyzed using Cox proportional hazard ratio (HR). Results Of 321 patients (70.1% males), at least one appropriate therapy occurred in 77 (24.0%) during a mean follow-up of 5.4 years (5.3% per year; primary prevention 4.5%, secondary prevention 7.0%). Cumulative incidences at 1 year, 3 years, and 5 years were 8.1%, 15.3%, and 21.3%, respectively. Cardioversion effectively restored rhythm in 52% of the first episode and antitachycardia pacing was sufficient in the remaining. For the whole cohort, ejection fraction (EF) <50% (HR 2.63; P < 0.001) was associated with appropriate ICD therapy. In primary prevention, patients with established risk markers experienced appropriate therapy; atrial fibrillation (AF; HR 2.54; P = 0.010), EF < 50% (HR 2.78; P = 0.004), and nonsustained ventricular tachycardia (HR 1.80; P = 0.109) had the highest HR, and wall thickness 30 mm, syncope, exercise blood pressure response, or family history of SCD had weaker associations. Conclusion ICD therapy successfully terminates ventricular arrhythmias in HCM. In addition to conventional risk markers, a history of AF or EF < 50% may be considered in risk stratification.

AimsImplantable defibrillators (ICDs) successfully terminate ventricular arrhythmias in hypertrophic cardiomyopathy (HCM), protect against bradycardia, and monitor atrial arrhythmias. This may alter the natural history and causes of death.MethodsThis nationwide observational longitudinal retrospective study of all HCM patients implanted during 1995-2012 obtained data from the Swedish ICD Registry, the National Patient Register, the Cause of Death Register, and were validated by review of medical records.ResultsOf 342 patients (mean age 51.8 years, 70.8% males), 45 died during a total follow-up of 1847 years (mean 5.4 years). Mean age at death was 68.2 years (range 21-83 years; 12 were 75 years). Mean follow-up time among the deceased was 4.9 years (quartiles 1.4-7.4 years). All-cause mortality was higher in HCM patients compared with the age and sex-matched Swedish general population (standardized mortality ratio 3.4; 95% confidence interval 2.4-4.5; P<0.001). Main cause of death was heart failure (n=27), stroke (n=5), cancer (n=3), myocardial infarction (n=2), sepsis (n=2), and others (n=4). Two patients died suddenly, one after the ICD was turned off because of inappropriate shocks, and one patient whose device system was removed after infection. HCM was the main cause of death in 76% of the cases, mainly because of progressive heart failure.ConclusionFor HCM patients, ICDs almost eliminate premature arrhythmic death and result in a shift to heart failure as the cause of death in the majority of cases. Still, mortality in HCM patients remains elevated and management of heart failure and comorbidities must be improved to increase survival.

Background: Health-related quality of life (HRQL) in hypertrophic cardiomyopathy (HCM) patients with implantable cardioverter-defibrillators (ICDs) is largely unknown. The aim was to assess HRQL, including comparisons between groups, using the questionnaire SF-36, and compare it to a Swedish age-and sex-matched population. Methods and Results: Validated data on adult HCM patients with ICDs were used. The SF-36 response rate was 82.5 % and 245 patients (mean age 55.9 years, 70.2 % men) were analyzed using the Mann-Whitney U-test, t-test, Spearman correlation and effect size calculations. In all SF-36 domains the patients' score was lower (p-value of <0.0001) than norms except for bodily pain. The general health domain showed the highest effect size (0.77) and the impact was more pronounced in the SF-36 physical component summary score (0.62) than the mental component summary score (0.46). Older age was correlated with lower scores on the physical component and higher scores on the mental component. Atrial fibrillation and/or systolic heart failure were associated with worse physical health. HRQL was similar in primary vs secondary prevention cases. Inappropriate ICD shock was associated with worse mental health while appropriate therapy trended toward better mental health. Conclusion: HCM patients with ICDs suffer from poor HRQL regardless of age, sex, or primary vs secondary prevention indication. Atrial fibrillation and systolic heart failure are determinants of poor physical health. Inappropriate shocks, but not appropriate therapies, are associated with poorer mental health.

Fredrik Gadler,1 Yao Ding,2 Nathalie Verin,3 Martin Bergius,4 Jeffrey D Miller,5 Gregory M Lenhart,5 Mason W Russell5 1Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden; 2Truven Health Analytics, an IBM Company, Bethesda, MD, USA; 3Boston Scientific Corporation, Hemel Hempstead, Hertfordshire, UK; 4Boston Scientific Nordic AB, Helsingborg, Sweden; 5Truven Health Analytics, an IBM Company, Cambridge, MA, USA Objective: The objective of this study was to quantify the impact that longer battery life of cardiac resynchronization therapy defibrillator (CRT-D) devices has on reducing the number of device replacements and associated costs of these replacements from a Swedish health care system perspective.Methods: An economic model based on real-world published data was developed to estimate cost savings and avoided device replacements for CRT-Ds with longer battery life compared with devices with industry-standard battery life expectancy. Base-case comparisons were performed among CRT-Ds of three manufacturers – Boston Scientific Corporation, St. Jude Medical, and Medtronic – over a 6-year time horizon, as per the available clinical data. As a sensitivity analysis, we evaluated CRT-Ds as well as single-chamber implantable cardioverter defibrillator (ICD-VR) and dual-chamber implantable cardioverter defibrillator (ICD-DR) devices over a longer 10-year period. All costs were in 2015 Swedish Krona (SEK) discounted at 3% per annum.Results: Base-case analysis results show that up to 603 replacements and up to SEK 60.4 million cumulative-associated costs could be avoided over 6 years by using devices with extended ­battery life. The pattern of savings over time suggests that savings are modest initially but increase rapidly beginning in the third year of follow-up with each year’s cumulative savings two to three times the previous year. Evaluating CRT-D, ICD-VR, and ICD-DR devices together over a

Inappropriate ICD Shocks and Complications in HCM IntroductionThe expanded use of implantable cardioverter-defibrillators (ICDs) to prevent sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM) based on risk stratification in individuals without known previous ventricular arrhythmia is justified by an acceptable risk of device-related adverse events. Such complications, leading to surgical procedures or inappropriate electrical shocks, may impact mortality, morbidity, quality of life, and cost-effectiveness. Methods and ResultsFrom the Swedish ICD Registry, implants due to HCM since 1995 until November 2012 in patients aged 18 years were identified and medical records reviewed. Inappropriate ICD shock occurred in 14.3% (46 of 321 patients; mean follow-up 5.4 years) with a recurrent episode in 28.2% of them. In multivariable analysis, hazard ratio (HR) for atrial fibrillation was 3.5 (95% confidence interval 1.8-6.8; P < 0.001) but showed no significant association to male sex (HR = 0.77), age (HR = 0.99), secondary indication (HR = 1.02) or device, ICD-DR/CRTD vs. ICD-VR (HR 1.07). Inappropriate shocks were triggered by atrial fibrillation/flutter or ectopic tachycardia (56.5%), sinus tachycardia (14.5%), lead dysfunction (14.5%), and T-wave oversensing (13.0%). A reintervention, besides elective device replacement, occurred in 92 patients (totally 150 procedures). The majority were lead-related (70.0%) procedures, especially of the ICD lead. Reintervention was associated with female sex (HR = 1.6 P = 0.04). ConclusionInappropriate ICD shock triggered by atrial arrhythmias, lead dysfunction, or complications requiring surgical interventions, is a concern in HCM patients who will be eligible for long-term prevention of sudden death. Efforts to avoid adverse events and provide balanced risk-benefit information are important, especially in primary prevention.

OBJECTIVE: The main aim of this study was to identify foetal susceptibility genes on chromosome six for Ro/SSA autoantibody-mediated congenital heart block. SUBJECTS AND DESIGN: Single nucleotide polymorphism (SNP) genotyping of individuals in the Swedish Congenital Heart Block (CHB) study population was performed. Low-resolution HLA-A, -Cw and -DRB1 allele typing was carried out in 86 families comprising 339 individuals (86 Ro/SSA autoantibody-positive mothers, 71 fathers, 87 CHB index cases, and 95 unaffected siblings). RESULTS: A case-control comparison between index cases and population-based out-of-study controls (n=1710) revealed association of CHB with 15 SNPs in the 6p21.3 MHC locus at a chromosome-wide significance of p<2.59×10(-6) (OR 2.21-3.12). In a family-based analysis of association of SNP markers as well as distinct MHC class I and II alleles with CHB, HLA-DRB1*04 and HLA-Cw*05 variants were significantly more frequently transmitted to affected individuals (p<0.03 and p<0.05, respectively), while HLA-DRB1*13 and HLA-Cw*06 variants were significantly less often transmitted to affected children (p<0.04 and p<0.03). We further observed marked association of increased paternal (but not maternal) HLA-DRB1*04 transmission to affected offspring (p<0.02). CONCLUSIONS: HLA-DRB1*04 and HLA-Cw*05 were identified as novel foetal HLA allele variants that confer susceptibility to CHB in response to Ro/SSA autoantibody exposure, while DRB1*13 and Cw*06 emerged as protective alleles. Additionally, we demonstrated a paternal contribution to foetal susceptibility to CHB for the first time.