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Background: Repeated procedures involving the cardiac implantable electronic device (CIED) pocket increase the infection risk, and the extent of pocket adhesions may prolong the procedure time. Few data on pocket histology at the time of CIED replacement are available.Objective: The purpose of this study was to describe CIED pocket histology in a cohort of patients undergoing CIED replacement or upgrade.Methods: All consecutive patients undergoing CIED replacement or upgrade at our center between November 2019 and May 2020 were enrolled. Subclinical pocket infection was ruled out by physical inspection and laboratory parameters before the procedure. Pocket tissue specimens from the anterior and posterior pockets were obtained intraoperatively. A systematic histological analysis of capsular thickness, fibrous connective tissue, neovascularization, inflammation, and calcifications was performed.Results: Thirty patients (6 women, 20%) were enrolled. The mean capsular thickness was 0.8 ± 0.3 mm in the anterior wall and 1.1 ± 0.4 mm in the posterior wall. Subcapsular fibrosis was mild and multifocal in the anterior wall and moderate and focal in the posterior wall. Neovascularization was focal in most cases, and vessel remodeling mainly involved the tunica media. Chronic inflammation was usually mild and nongranulomatous, and in a quarter of cases, subacute exudative fibrous inflammation was detected in the posterior pocket wall.Conclusion: The CIED pocket is a histopathologically dynamic environment, given the coexistence of both a subacute foreign body response and fibrous tissue growth, implying continuous remodeling due to an injury-repair mechanism. Strategies to interact with foreign body response might minimize inflammatory pocket activity, especially device encapsulation by tight fibrous tissue, and possibly complications related to repeated CIED procedures. [ABSTRACT FROM AUTHOR]

In the present article, we will focus on the pharmacologic treatment of atrial flutter aimed either at restoring/maintaining sinus rhythm or controlling the ventricular response during tachyarrhythmia. To provide a comprehensive description we will start discussing the electroanatomic substrate underlying the development of atrial flutter and the complex relationship with atrial fibrillation. We will then describe the available drugs for the treatment of atrial flutter on the bases of their electrophysiological effects and data from available clinical studies. We will conclude by discussing the general principles of rhythm and rate control treatment during atrial flutter. [ABSTRACT FROM AUTHOR]

Background: Sleep apnea, as measured by polysomnography, is associated with adverse outcomes in heart failure. The DASAP-HF (Diagnosis and Treatment of Sleep Apnea in Patient With Heart Failure) study previously demonstrated that the respiratory disturbance index (RDI) computed by the ApneaScan algorithm (Boston Scientific) accurately identifies severe sleep apnea in implantable cardioverter-defibrillator (ICD) patients.Objective: The purpose of the long-term study phase was to assess the incidence of clinical events after 24 months and investigate the association with RDI values.Methods: Patients with left ventricular ejection fraction ≤35% implanted with an ICD were enrolled and followed-up for 24 months. The RDI calculated at 1 month after implantation was used to stratify patients (below or above 30 episodes/h). The endpoints were all-cause death and a combination of all-cause death or cardiovascular hospitalization.Results: Of the 265 enrolled patients, 224 had usable RDI values. Severe sleep apnea (RDI ≥30 episodes/h) was diagnosed in 115 patients (51%). These patients were more frequently male (84% vs 72%; P = .030) and had higher creatinine levels. During median follow-up of 25 months, 19 patients (8%) died. Cardiovascular hospitalizations were reported in 19 patients (8%). The risk of all-cause death was higher in patients with RDI ≥30 episodes/h (hazard ratio [HR] 3.33; 95% confidence interval [CI] 1.35-8.21; P = .023), as well as the risk of all-cause death or cardiovascular hospitalization (HR 1.94; 95% CI 1.01-3.76; P = .048). At multivariate analysis, independent predictors of death were RDI ≥30 episodes/h (HR 4.02; 95% CI 1.16-13.97; P = .029) and creatinine levels (HR 2.36; 95% CI 1.26-4.42; P = .008).Conclusion: In heart failure patients implanted with an ICD, higher RDI values are associated with death and cardiovascular hospitalizations. Device-detected severe sleep apnea independently predicts death. [ABSTRACT FROM AUTHOR]

Background: Biventricular endocardial pacing (BiV ENDO) is a therapy for heart failure patients who cannot receive transvenous epicardial cardiac resynchronization therapy (CRT) or have not responded adequately to CRT. BiV ENDO CRT can be delivered by a new wireless LV ENDO pacing system (WiSE-CRT system; EBR Systems, Sunnyvale, CA), without the requirement for lifelong anticoagulation.Objective: The purpose of this study was to assess the safety and efficacy of the WiSE-CRT system during real-world clinical use in an international registry.Methods: Data were prospectively collected from 14 centers implanting the WiSE-CRT system as part of the WiCS-LV Post Market Surveillance Registry. (ClinicalTrials.gov Identifier: NCT02610673).Results: Ninety patients from 14 European centers underwent implantation with the WiSE-CRT system. Patients were predominantly male, age 68.2 ± 10.5 years, left ventricular ejection fraction 30.6% ± 8.9%, mean QRS duration 180.7 ± 27.0 ms, and 40% with ischemic etiology. Successful implantation and delivery of BiV ENDO pacing was achieved in 94.4% of patients. Acute (<24 hours), 1- to 30-day, and 1- to 6-month complications rates were 4.4%, 18.8%, and 6.7%, respectively. Five deaths (5.6%) occurred within 6 months (3 procedure related). Seventy percent of patients had improvement in heart failure symptoms.Conclusion: BiV ENDO pacing with the WiSE-CRT system seems to be technically feasible, with a high success rate. Three procedural deaths occurred during the study. Procedural complications mandate adequate operator training and implantation at centers with immediately available cardiothoracic and vascular surgical support. [ABSTRACT FROM AUTHOR]

Implantable cardioverter-defibrillator (ICD) represents the main tool for prevention of sudden cardiac death. Different kinds of postimplant complications have been described; however, little is known about shoulder functional impairment and its impact on quality of life. Patients with standard indications for elective prepectoral subcutaneous ICD insertion were enrolled during a 1-year period. The impact of ICD implantation on shoulder motility, pain, general disability, and quality of life was evaluated prospectively at baseline, and after 2 weeks, 3 months, 1 year, and 5 years using the Constant score, the Numeric Pain Rating Scale, the Disabilities of the Arm, Shoulder, and Hand scale, and the Short Form-36 Health Survey questionnaire. A total of 50 patients underwent insertion of single, dual chamber, or biventricular ICDs. Two weeks after implantation, functional impairment and mild pain were observed in ipsilateral shoulder movements, with a reduction in the Short Form-36 Health Survey score. Shoulder functional impairment improved at the third-month evaluations, with almost normalization at 1-year and 5-year assessments, as well as pain and quality of life. Prepectoral subcutaneous ICD implantation may be associated with ipsilateral shoulder functional impairment that regresses partially after 3 months and completely at 1-year and 5-year assessments. The less invasive implantation technique and the relatively small size of modern ICDs, independently from types and volumes, may be relevant to the degree of postimplantation shoulder functional impairment and recovery time. Shoulder function should be assessed at routine checks, especially soon after ICD implantation because of potential functional impairment and subsequent impact on quality of life. [ABSTRACT FROM AUTHOR]

Background: At the time of subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation, successful termination of ventricular fibrillation (VF) is confirmed. A previous study reported cases of prolonged time to therapy during defibrillation testing.Objectives: We sought to evaluate the time to therapy, identify possible predictors of delay, and investigate the impact of delayed therapy on VF conversion.Methods: We analyzed consecutive patients with S-ICDs who underwent initial conversion testing at a shock energy of 65 J in 53 Italian centers.Results: We analyzed 570 patients (467 [82%] male; mean age 48 ± 15 years; mean body mass index 25 ± 6 kg/m2; mean ejection fraction 47% ± 17%). General anesthesia was used in 165 (29%) of patients, with sub- or intermuscular positioning of the generator in (422; 74%). Cardioversion was successful at 65 J in 557 (97.7%) of patients. In 12 patients (2.1%) the shock did not convert VF, and in 1 patient the shock was not delivered because of noise from entrapped subcutaneous air. All failures were successfully managed by reprogramming or repositioning the device. The mean time to therapy was 15 ± 3 seconds, and it exceeded 18 seconds in 51 patients (9%). Independent predictors of delayed therapy (18 seconds) were ejection fraction (odds ratio [OR] 0.98; 95% confidence interval [CI] 0.96-0.99; P = .016) and a 2× gain programmed (OR 3.66; 95% CI 1.44-9.30; P = .006). Effectiveness at 65 J was not associated with time to therapy (OR 1.13; 95% CI 0.97-1.32; P = .122).Conclusion: In this analysis of a large population of patients with S-ICDs, delayed therapy during defibrillation testing occurred less frequently than previously reported and had no effect on VF conversion success. Delayed therapies seemed more common when a vector with a 2× gain was programmed. [ABSTRACT FROM AUTHOR]

Background: The subcutaneous implantable cardioverter-defibrillator (S-ICD) does not require the insertion of any leads into the cardiovascular system.Objective: The aims of the study were to describe current practice and to measure outcomes associated with S-ICD or standard single-chamber transvenous ICD (TV-ICD) use after TV-ICD explantation.Methods: We analyzed all consecutive patients who underwent transvenous extraction of an ICD and subsequent implantation of an S-ICD or a single-chamber TV-ICD at 12 Italian centers from 2011 to 2017.Results: A total of 229 patients were extracted and subsequently reimplanted with an S-ICD (90; 39%) or a single-chamber TV-ICD (139; 61%). S-ICD implantation increased from 9% in 2011 to 85% in 2017 (P < .001). Patients reimplanted with an S-ICD were younger (53 ± 13 years vs 60 ± 18 years; P = .011) and more frequently had undergone extraction owing to infection (73% vs 52%; P < .001). The rates of complications at follow-up were comparable between groups (hazard ratio 0.97; 95% confidence interval 0.49-1.92; P = .940). No lead failures, systemic infections, or system-related deaths occurred in the S-ICD group. In the TV-ICD group, 1 lead fracture occurred and 2 systemic infections were reported, resulting in death in 1 case. In the S-ICD group, the rate of complications was lower when the generator was positioned in a sub- or intermuscular pocket (hazard ratio 0.21; 95% confidence interval 0.05-0.87; P = .048).Conclusion: Our results show an increasing use of S-ICD over the years in patients undergoing TV-ICD explantation. An S-ICD is preferably adopted in young patients, mostly in the case of infection. The complication rate was comparable between groups and decreased when a sub- or intermuscular S-ICD generator position was adopted. [ABSTRACT FROM AUTHOR]

Background: Sleep apnea (SA) is a relevant issue in the management of patients with heart failure for risk stratification and for implementing treatment strategies.Objective: The purpose of this study was to evaluate in patients with implantable cardioverter-defibrillators (ICDs) the performance of the respiratory disturbance index (RDI) computed by the ApneaScan algorithm (Boston Scientific Inc., Natick, MA) as a discriminator of severe SA.Methods: ICD-indicated patients with left ventricular ejection fraction ≤35% were enrolled. One month after implantation, patients underwent a polysomnographic study. We evaluated the accuracy of the RDI for the prediction of severe SA (apnea-hypopnea index [AHI] ≥30 episodes/h) and the agreement between RDI and AHI during the sleep study night.Results: Two hundred sixty-five patients were enrolled to obtain the required sample of 173 patients with AHI and RDI data for analysis. The mean AHI was 21 ± 15 episodes/h and severe SA was diagnosed in 38 patients (22%), while the mean RDI was 33 ± 13 episodes/h. On the basis of the receiver operating characteristic curve analysis of RDI values, the area under the curve was 0.77 (95% confidence interval [CI] 0.70-0.83; P < .001). At an RDI value of 31 episodes/h, severe SA was detected with 87% (95% CI 72%-96%) sensitivity and 56% (95% CI 48%-66%) specificity. RDI closely correlated with AHI recorded during the same night (r = 0.74; 95% CI 0.57-0.84; P < .001), and the Bland-Altman agreement analysis revealed a bias of 11 episodes/h, with limits of agreement being -10 to 32 episodes/h.Conclusion: The RDI accurately identified severe SA and demonstrated good agreement with AHI. Therefore, it may serve as an efficient tool for screening patients at risk of SA. [ABSTRACT FROM AUTHOR]

Transthyretin-mediated (ATTR) amyloidosis is a progressive, multisystem, fatal disease. Treatment options for patients with ATTR amyloidosis with cardiomyopathy are currently limited, with only the TTR stabilizer tafamidis approved for this population. Patisiran, an IV RNAi therapeutic, is approved for the treatment of hereditary ATTR amyloidosis with polyneuropathy. The safety and efficacy of patisiran in patients with wild-type or hereditary ATTR amyloidosis with cardiomyopathy is being investigated in the ongoing APOLLO-B study (NCT03997383). Reduction of TTR protein levels by patisiran provides benefit in patients with ATTR amyloidosis with cardiomyopathy. Patients were 18–85 yrs old with evidence of cardiac amyloidosis by echocardiography, and either ATTR amyloid by tissue biopsy or fulfilling nonbiopsy diagnostic criteria for ATTR amyloidosis with cardiomyopathy. Medical history of heart failure (HF) due to ATTR amyloidosis with ≥1 prior hospitalization for HF or current clinical evidence of HF was also required. Patients were randomized (1:1) to patisiran IV 0.3 mg/kg or placebo Q3W for 12 months. The primary endpoint was change from baseline in 6-MWT at Month 12 (M12) with patisiran vs placebo. Secondary endpoints to M12 included the effect of patisiran vs placebo on health status and quality of life (KCCQ-OS score), and death and hospitalization outcomes. APOLLO-B enrolled 360 patients (patisiran, n=181; placebo, n=179): median age (range), 76.0 (41, 85) yrs; male, 89%; wtATTR, 80%. Baseline characteristics were consistent between patients on tafamidis at baseline (91/360 [25%]) and those who were not. Patisiran achieved a rapid and sustained reduction in serum TTR, irrespective of baseline tafamidis treatment. At M12, patisiran showed a significant benefit vs placebo in the 6-MWT (median [95% CI] change from baseline: patisiran, -8.15 [-16.42, 1.50]; placebo, -21.35 [-34.05, -7.52]; Hodges-Lehmann estimate of median difference: 14.69 [0.69, 28.69]; p=0.0162) and KCCQ-OS (LS mean [SEM] change from baseline: patisiran, 0.300 [1.263]; placebo, -3.408 [1.277]; LS mean [SEM] difference: 3.709 [1.796]; p=0.0397). Consistent benefits with patisiran in 6-MWT and KCCQ-OS were observed across predefined patient subgroups. Time to first event of all-cause hospitalization, urgent HF visit, or death directionally favored patisiran vs placebo (HR [95% CI], 0.839 [0.557, 1.263]), as did all-cause mortality (HR [95% CI], 0.355 [0.110, 1.138]), but all composite outcomes endpoints did not achieve significance over 12 months. Patisiran was well tolerated; most AEs were mild or moderate in severity, and there were no cardiac safety concerns. Benefits at 12 months were observed with patisiran vs placebo in functional capacity, and health status and quality of life in patients with ATTR amyloidosis with cardiomyopathy, with consistency across clinically important subgroups. The efficacy and safety of patisiran continues to be studied in the APOLLO-B open-label extension. [ABSTRACT FROM AUTHOR]

Background: Current recommendations require a QRS duration of ≥120 ms as a condition for prescribing cardiac resynchronization therapy (CRT). This study was designed to test the hypothesis that patients with heart failure (HF) of ischemic origin, current indications for defibrillator implantation, and QRS <120 ms may benefit from CRT in the presence of marked mechanical dyssynchrony. Methods and Results: Patients with intraventricular dyssynchrony on echocardiography were randomly assigned to CRT or dual-chamber defibrillator implantation (CRT defibrillator and dual-chamber implantable cardioverter-defibrillator arm, respectively). The primary end point was the HF clinical composite response, which scores patients as improved, unchanged, or worsened. The secondary end point was the cumulative survival from HF hospitalization and HF death. An additional secondary end point was the composite of HF hospitalization, HF death, and spontaneous ventricular fibrillation. Twenty-three of 56 patients with CRT defibrillator showed an improvement in their clinical composite response at 1 year, compared with 9 of 55 patients with dual-chamber implantable cardioverter-defibrillator (41% versus 16%; P=0.004). After a median follow-up of 16 months, the CRT defibrillator arm showed a nonsignificant higher survival from HF hospitalization and HF death (P=0.077), and a significantly higher survival from the combined end point of HF hospitalization, HF death, and spontaneous ventricular fibrillation (P=0.028). Conclusions: In this comparison of CRT defibrillator and dual-chamber implantable cardioverter-defibrillator, CRT improved clinical status in some patients with ischemic cardiomyopathy, mild-to-moderate symptoms, narrow QRS duration, and mechanical dyssynchrony on echocardiography. Clinical Trial Registration: URL: http://clinicaltrials.gov. Unique identifier: NCT01577446. [ABSTRACT FROM AUTHOR]

Background: Phrenic stimulation (PS) may hinder left ventricular (LV) pacing. We prospectively observed its prevalence in consecutive patients with cardiac resynchronization therapy (CRT) devices. Methods and Results: In the years 2003 to 2006, 197 patients received a CRT device. PS and LV threshold measurements were carried out at implantation and at 6-month follow-up. LV reverse remodeling was assessed by echocardiography before implantation and at follow-up. LV lead placement was lateral/posterolateral in 86% of patients. Both PS and LV reverse remodeling occurred most frequently at the lateral/posterolateral LV pacing sites (P<0.001). PS was detected in 73 (37%) of patients and was clinically relevant in 41 (22%). The detection of PS at implantation had a poor sensitivity, as it occurred only in left lateral or sitting position in 27 patients. Ten patients (5%) underwent repeated surgery and 4 (2%) had their CRT turned off because of PS. At follow-up, we could manage PS noninvasively in 32 patients with a small PS-LV threshold difference: in 20 by cathode programmability (3 also thanks to automatic management of LV output) and in 12 (without cathode programmability) by programming the LV output as threshold +1 V. Conclusions: PS may seriously hinder CRT. A bipolar LV lead and cathode programmability are mandatory to avoid PS by changing the LV pacing vector at target sites for CRT. LV stability at target sites despite PS should also be pursued by these means. The automatic adjustment of LV pacing output is complementary in patients with a small PS-LV threshold difference. [ABSTRACT FROM AUTHOR]

Background: Shock pain has limited the acceptance of the implantable atrial cardioverter and is a complication of ventricular implantable cardioverter-defibrillator therapy. Rounding off of the peak of a shock waveform reduces pain. Whether the pain reduction results from reduction in the peak voltage or from the rounding has not been established. In other words, does reducing the extreme dV/dt (voltage derivative) of the conventional truncated exponential capacitive discharge waveform reduce pain?Objectives: The purpose of this study was to compare the relative contributions of peak voltage and waveform shape to pain.Methods: We compared rounded and conventional waveforms with equal peak voltages. Eighty-five shocks of 50 to 500 V were delivered to 10 patients requiring atrial cardioversion for persistent atrial fibrillation. The patient touched an analog pain scale (0-15 cm) and orally reported a pain score on a scale from 0 to 5. An observer scored thoracic contractions on a scale from 0 to 5.Results: No differences between the rounded and conventional waveform on any scale were noted for either univariate or multivariate analyses. However, all three response scales were strongly predicted by voltage with r(2) = 0.77 (oral), r(2) = 0.86 (analog), and r(2) = 0.85 (contraction) after correcting for patient variability and including a log voltage term.Conclusions: Patient pain perception was determined primarily by waveform peak voltage and not by the rounding, per se. [ABSTRACT FROM AUTHOR]

Patients undergoing CRT upgrades are more likely to suffer from severe heart failure (HF) and less likely to show reverse LV remodelling than patients undergoing de novo implants. WiSE-CRT provides endocardial pacing and has many advantages over epicardial CRT, which may result in higher rates of clinical and echocardiographic response following CRT upgrades. To determine whether WiSE-CRT would improve outcomes in patients undergoing CRT upgrades. All patients undergoing a CRT upgrade with WiSE-CRT were analysed. Patients were followed-up for 6 months and considered CRT responders if (A) they had an improvement in LVESV≥15% and (B) had improvement in clinical composite score (CCS); alive, no HF hospitalisations, improvement in NYHA or improvement in global assessment. 38 patients analysed, demographics: 68.1±11.3 years, 84.2% male and 60.5% non-ischaemic. All patients had the system successfully implanted, no major complications and 1 (2.6%) patient developed a pneumothorax treated conservatively. During follow-up, 2 patients died from cardiovascular causes, 1 patient withdrew from the study and all the remaining patients had successful biventricular pacing. Following WiSE-CRT there was a significant improvement in NYHA (2.4±0.6 vs. 2.0±0.7, p =0.002) and LV remodelling (Figure 1). 74.3% of patients had improvement in CCS and 66.7% had improvement in LVESV≥15%,. Patients undergoing CRT upgrades with a WiSE-CRT have excellent outcomes with evidence of reverse LV remodelling and clinical improvement. Further studies are required to directly compare outcomes between epicardial and endocardial CRT upgrades. [ABSTRACT FROM AUTHOR]

Heart failure (HF) patients undergoing CRT upgrades are more symptomatic and have lower rates of reverse LV remodelling compared with de novo implants. WiSE-CRT delivers endocardial LV pacing and has many advantages over epicardial CRT which can be particularly useful in this upgrade population. Currently, WiSE-CRT is reserved for patients considered high risk for epicardial CRT such as venous occlusion, risk of pocket infection and multiple co-morbidities placing patients at an increased risk. To determine whether patients undergoing high-risk CRT upgrades with WiSE-CRT had at least comparable outcomes to epicardial CRT upgrades. Consecutive patients undergoing epicardial CRT upgrades at Guy's and St Thomas' between 2014-2018 were compared with patients undergoing high-risk CRT upgrades with a WiSE-CRT. 95 patients were included; 58 epicardial and 37 endocardial CRT. Baseline demographics for epicardial vs. endocardial CRT upgrades include: 71.2±12.2 vs. 67.9±11.4 years (p= 0.098), 77.6±0.4 vs. 83.8±0.4% (p= 0.023) male, 39.7±0.5 vs. 37.8±0.5% (p =0.859) ischaemic, QRS 176.3±27.5 vs. 182.4±29.0ms (p =0.315) and LVEF 30.2±8.2 vs. 29.7±7.9% (p =0.796). At 6 month follow-up, epicardial CRT upgrades had an 81% improvement in clinical composite score (alive, no HF hospitalisations, improvement in NYHA or global assessment) and 78% had improvement following WiSE-CRT (p =0.784). There was a trend towards a non-significant improvement in LV remodelling following WiSE-CRT compared with epicardial CRT; 73.5±0.4 vs. 66.0±0.5% (p =0.367) of patients had an absolute change in LVEF≥5% and 69.0±0.5 vs. 52.8±0.5% (p =0.185) of patients had improvement in LVESV≥15%. Patients undergoing high-risk CRT upgrades with WiSE-CRT have comparable outcomes with those patients undergoing epicardial CRT upgrades. There is a tendency towards improved LV remodelling following WiSE-CRT, however further studies are required to determine if this reaches significance in a larger patient cohort. [ABSTRACT FROM AUTHOR]

The management of heart failure (HF) patients who are CRT non-responders (symptomatic and have no evidence of reverse LV remodelling following epicardial CRT) remains limited. Endocardial LV pacing is potentially superior to epicardial LV pacing as it allows faster electrical activation, more physiological and provides a greater selection of pacing sites enabling operators to avoid myocardial scar. The WiSE-CRT system was developed to provide endocardial LV pacing and may be particularly useful in CRT non-responders. To determine whether WiSE-CRT would improve patient outcomes in CRT non-responders. CRT non-responders who successfully had the WiSE-CRT system implanted were analysed. Patients were followed up for 6 months. 17 patients were analysed, baseline demographics: 68.2±7.9 years, 94.1% male, 41.1% ischaemic, NYHA 2.8±0.4, QRS 169.1±23.8ms and LVEF 25.6±8.0%. There were no acute complications and 1 patient developed a pocket haematoma during follow-up. 58.8% of patients had an improvement in their clinical composite score (alive, no HF hospitalisations, improvement in NYHA or patient global assessment), 53.3% had an improvement in LVESV of≥15% and 64.7% had an absolute increase in LVEF of ≥5% or improvement in LVESV of ≥15%. The management of CRT non-responders remains difficult with limited treatment options. Our analysis has shown that in this high-risk patient group, the WiSE-CRT system results in a considerable improvement in the clinical composite score and leads to reverse left ventricular remodelling. These encouraging results suggest an important role for the WiSE-CRT system in the management of CRT non-responders. [ABSTRACT FROM AUTHOR]