Background: The Subcutaneous ICD (S-ICD) is safe and effective for sudden cardiac death prevention. However, patients in previous S-ICD studies had fewer comorbidities, less left ventricular dysfunction and received more inappropriate shocks (IAS) than in typical transvenous (TV)-ICD trials. The UNTOUCHED trial was designed to evaluate the IAS rate in a more typical, contemporary ICD patient population implanted with the S-ICD using standardized programming and enhanced discrimination algorithms. Methods: Primary prevention patients with left ventricular ejection fraction (LVEF) ≤ 35% and no pacing indications were included. Generation 2 or 3 S-ICD devices were implanted and programmed with rate-based therapy delivery for rates ≥ 250 beats per minute (bpm) and morphology discrimination for rates ≥200 and < 250 bpm. Patients were followed for 18 months. The primary endpoint was the IAS free rate compared to a 91.6% performance goal, derived from the results for the ICD-only patients in the MADIT-RIT study. Kaplan-Meier analyses were performed to evaluate event-free rates for IAS, all cause shock, and complications. Multivariable proportional hazard analysis was performed to determine predictors of endpoints. Results: S-ICD implant was attempted in 1116 patients and 1111 patients were included in post-implant follow-up analysis. The cohort had a mean age of 55.8±12.4 years, 25.6% women, 23.4% black race, 53.5% with ischemic heart disease, 87.7% with symptomatic heart failure and a mean LVEF of 26.4±5.8%. Eighteen-month freedom from IAS was 95.9% (Lower confidence limit LCL 94.8%). Predictors of reduced incidence of IAS were implanting the most recent generation of device, using the three-incision technique, no history of atrial fibrillation, and ischemic etiology. The 18-month all cause shock free rate was 90.6% (LCL 89.0%), meeting the prespecified performance goal of 85.8%. Conversion success rate for appropriate, discrete episodes was 98.4%. Complication free rate at 18 months was 92.7%. Conclusions: This study demonstrates high efficacy and safety with contemporary S-ICD devices and programming despite the relatively high incidence of co-morbidities in comparison to earlier S-ICD trials. The inappropriate shock rate (3.1% at one year) is the lowest reported for the S-ICD and lower than many TV ICD studies using contemporary programming to reduce IAS. Clinical Trial Registration: URL https://clinicaltrials.gov Unique Identifier NCT02433379

The European Heart Rhythm Association charged the present writing committee with the task of producing a consensus document on training and accreditation for transvenous extraction of chronically implanted pacing and defibrillator leads.^1,2 The core curriculum for the European Heart Rhythm Specialist includes implantation of heart rhythm devices but does not specifically mandate learning and accreditation for extraction techniques.³ The lack of such recommendations is related to the limited number of extractions available for training purposes and attaining competency. The present document focuses on the rising burden and the increasing complexity of techniques of lead extraction with an emphasis on the critical issues of training, accreditation, and documentation of results. There is also an educational component felt necessary to include by the Task Force in view of the specialized and emerging nature of this field. Where appropriate, a European perspective is presented and paediatric aspects are treated separately. The aim is to complement two recently published documents, one from the Heart Rhythm Society (HRS)⁴ on facilities, training, indications, and management of transvenous lead extraction and the other from the American Heart Association on device-related infections.⁵ The indications for lead extraction have not changed since these publications and are therefore not covered in this present document.

Objective To assess long-term outcomes and predictors of mortality in patients treated according to current recommendations for cardiac implantable electronic device (CIED) infection. Design Two-group matched cohort study. Setting Tertiary-care institution. Patients Consecutive patients admitted for CIED infection between 2004 and 2008 were prospectively enrolled. Study subjects were matched to a cohort of uninfected CIED patients by age, sex and type of device. Interventions In all infected patients, the therapeutic approach consisted of complete hardware removal whenever possible, antimicrobial therapy, and implantation of a new device, if indicated. Patients were systematically followed, with standardised outcomes assessment. Main outcome measures All-cause mortality and predictors of long-term mortality. Results 197 patients were included and matched 1:1 to controls. Pocket infections were present in 41.1% and definite or suspected infective endocarditis in 58.9%. Total or subtotal hardware removal was achieved in 98.5% of cases. Median follow up was 25 months (12–70). Mortality rates in the study group and controls were 14.3% vs 11.0% (NS) at 1 year and 35.4% vs 27.0% (p=NS) at 5 years. Independent predictors of long-term mortality were older age (HR=1.09, p<0.001), cardiac resynchronisation therapy (HR=3.70, p=0.001), thrombocytopenia (HR=5.10, p=0.003) and renal insufficiency (HR=2.66, p=0.006). In patients with reimplanted devices, epicardial right ventricular pacemakers were associated with higher mortality (HR=2.85, p=0.034). Conclusion In patients with CIED infection managed by recommended therapy, long-term mortality rates are similar to comparable controls. Independent predictors include patient and disease-related factors, in addition to implantation of right ventricular epicardial pacemakers.

Adenosine is a nucleoside that impacts the cardiovascular system via the activation of its membrane receptors, named A₁R, A_2AR, A_2BR and A₃R. Adenosine is released during hypoxia, ischemia, beta-adrenergic stimulation or inflammation and impacts heart rhythm and produces strong vasodilation in the systemic, coronary or pulmonary vascular system. This review summarizes the main role of adenosine on the cardiovascular system in several diseases and conditions. Adenosine release participates directly in the pathophysiology of atrial fibrillation and neurohumoral syncope. Adenosine has a key role in the adaptive response in pulmonary hypertension and heart failure, with the most relevant effects being slowing of heart rhythm, coronary vasodilation and decreasing blood pressure. In other conditions, such as altitude or apnea-induced hypoxia, obstructive sleep apnea, or systemic hypertension, the adenosinergic system activation appears in a context of an adaptive response. Due to its short half-life, adenosine allows very rapid adaptation of the cardiovascular system. Finally, the effects of adenosine on the cardiovascular system are sometimes beneficial and other times harmful. Future research should aim to develop modulating agents of adenosine receptors to slow down or conversely amplify the adenosinergic response according to the occurrence of different pathologic conditions.

Cardioneuroablation has emerged as a potential alternative to cardiac pacing in selected cases with vasovagal reflex syncope, extrinsic vagally induced sinus bradycardia-arrest or atrioventricular block. The technique was first introduced decades ago, and its use has risen over the past decade. However, as with any intervention, proper patient selection and technique are a prerequisite for a safe and effective use of cardioneuroablation therapy. This document aims to review and interpret available scientific evidence and provide a summary position on the topic.