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

IMPORTANCE Renal denervation can reduce cardiac sympathetic activity that may result in an antiarrhythmic effect on atrial fibrillation. OBJECTIVE To determine whether renal denervation when added to pulmonary vein isolation enhances long-term antiarrhythmic efficacy. DESIGN, SETTING, AND PARTICIPANTS The Evaluate Renal Denervation in Addition to Catheter Ablation to Eliminate Atrial Fibrillation (ERADICATE-AF) trial was an investigator-initiated, multicenter, single-blind, randomized clinical trial conducted at 5 referral centers for catheter ablation of atrial fibrillation in the Russian Federation, Poland, and Germany. A total of 302 patients with hypertension despite taking at least 1 antihypertensive medication, paroxysmal atrial fibrillation, and plans for ablation were enrolled from April 2013 to March 2018. Follow-up concluded in March 2019. INTERVENTIONS Patients were randomized to either pulmonary vein isolation alone (n = 148) or pulmonary vein isolation plus renal denervation (n = 154). Complete pulmonary vein isolation to v an end point of elimination of all pulmonary vein potentials; renal denervation using an irrigated-tip ablation catheter delivering radiofrequency energy to discrete sites in a spiral pattern from distal to proximal in both renal arteries. MAIN OUTCOMES AND MEASURES The primary end point was freedom from atrial fibrillation, atrial flutter, or atrial tachycardia at 12 months. Secondary end points included procedural complications within 30 days and blood pressure control at 6 and 12 months. RESULTS Of the 302 randomized patients (median age, 60 years [interquartile range, 55-65 years]; 182 men [60.3%]), 283 (93.7%) completed the trial. All successfully underwent their assigned procedures. Freedom from atrial fibrillation, flutter, or tachycardia at 12 months was observed in 84 of 148 (56.5%) of those undergoing pulmonary vein isolation alone and in 111 of 154 (72.1%) of those undergoing pulmonary vein isolation plus renal denervation (hazard ratio, 0.57; 95% CI, 0.38 to 0.85; P = .006). Of 5 prespecified secondary end points, 4 are reported and 3 differed between groups. Mean systolic blood pressure from baseline to 12 months decreased from 151 mm Hg to 147 mm Hg in the isolation-only group and from 150 mm Hg to 135 mm Hg in the renal denervation group (between-group difference, −13 mm Hg; 95% CI, −15 to −11 mm Hg; P < .001). Procedural complications occurred in 7 patients (4.7%) in the isolation-only group and 7 (4.5%) of the renal denervation group. CONCLUSIONS AND RELEVANCE Among patients with paroxysmal atrial fibrillation and hypertension, renal denervation added to catheter ablation, compared with catheter ablation alone, significantly increased the likelihood of freedom from atrial fibrillation at 12 months. The lack of a formal sham-control renal denervation procedure should be considered in interpreting the results of this trial.

Metoprolol and ivabradine exert a similar effect on resting HR in patients with IST. Ivabradine seems to be more effective to relieve symptoms during exercise or daily activity.

Patients with nonischemic cardiomyopathy and patients with tachyarrhythmic complications have more extensive MTWA possibly reflecting more extensive myocardial damage and a higher arrhythmia propensity.