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IntroductionImplantable cardioverter-defibrillators (ICDs) can prevent sudden cardiac death due to ventricular arrhythmias in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). The aim of our study was to assess the cumulative burden, evolution and potential triggers of appropriate ICD shocks during long-term follow-up, which may help to reduce and further refine individual arrhythmic risk in this challenging disease.MethodsThis retrospective cohort study included 53 patients with definite ARVC according to the 2010 Task Force Criteria from the multicentre Swiss ARVC Registry with an implanted ICD for primary or secondary prevention. Follow-up was conducted by assessing all available patient records from patient visits, hospitalisations, blood samples, genetic analysis, as well as device interrogation and tracings.ResultsFifty-three patients (male 71.7%, mean age 43±2.2 years, genotype positive 58.5%) were analysed during a median follow-up of 7.9 (IQR 10) years. In 29 (54.7%) patients, 177 appropriate ICD shocks associated with 71 shock episodes occurred. Median time to first appropriate ICD shock was 2.8 (IQR 3.6) years. Long-term risk of shocks remained high throughout long-term follow-up. Shock episodes occurred mainly during daytime (91.5%, n=65) and without seasonal preference. We identified potentially reversible triggers in 56 of 71 (78.9%) appropriate shock episodes, the main triggers representing physical activity, inflammation and hypokalaemia.ConclusionThe long-term risk of appropriate ICD shocks in patients with ARVC remains high during long-term follow-up. Ventricular arrhythmias occur more often during daytime, without seasonal preference. Reversible triggers are frequent with the most common triggers for appropriate ICD shocks being physical activity, inflammation and hypokalaemia in this patient population.

Background Since the body of evidence addressing the coagulation derangements caused by Coronavirus disease (COVID-19) has been constantly growing, we investigated whether pre-hospitalization oral anticoagulation (OAC) or in-hospital heparin treatment could have a protective role among COVID-19 patients. Method In this cohort study, consecutive COVID-19 patients admitted to four different Italian Institutions were enrolled. Baseline demographic, clinical, laboratory, and radiological characteristics, as well as in-hospital treatment and outcomes were evaluated. The primary outcome was mortality. Results A total of 844 COVID-19 patients were enrolled as study cohort, n = 65 (7.7%) taking OACs prior to hospitalization. Regarding clinical outcomes, OAC patients developed acute hypoxemic respiratory failure (AHRF) more frequently than non-OAC patients as well as presenting a higher mortality rate (44.6% vs 19.8%, p, Highlights • Evidence on a prothrombotic asset caused by COVID-19 has been constantly growing. • In our cohort, OACs appeared to be ineffective in reducing mortality rate. • Heparin resulted to be a useful treatment when lung disease was sufficiently severe. • Microthrombosis may have a crucial role in COVID-19. • Due to the relatively small sample size of OAC patients included, larger studies are needed.

The absence of pacing capabilities may reduce the appeal of subcutaneous implantable cardioverter-defibrillator (S-ICD) devices for patients at risk for conduction disorders or with antitachycardia pacing (ATP)/cardiac resynchronization (CRT) requirements. Reports of rates of S-ICD to transvenous implantable cardioverter-defibrillator (TV-ICD) system switch in real-world scenarios are limited.The purpose of this study was to investigate the need for a subsequent transvenous (TV) device in patients implanted with an S-ICD and its predictors.All patients implanted with an S-ICD were enrolled from the multicenter, real-world iSUSI (International SUbcutaneouS Implantable cardioverter defibrillator) Registry. The need for a TV device and its clinical reason, and appropriate and inappropriate device therapies were assessed. Logistic regression with Firth penalization was used to assess the association between baseline and procedural characteristics and the overall need for a subsequent TV device.A total of 1509 patients were enrolled (age 50.8 ± 15.8 years; 76.9% male; 32.0% ischemic; left ventricular ejection fraction 38% [30%-60%]). Over 26.5 [13.4-42.9] months, 155 (10.3%) and 144 (9.3%) patients experienced appropriate and inappropriate device therapies, respectively. Forty-one patients (2.7%) required a TV device (13 bradycardia; 10 need for CRT; 10 inappropriate shocks). Body mass index (BMI)30 kg/mA low rate (2.7%) of conversion from S-ICD to a TV device was observed at follow-up, with need for antibradycardia pacing, ATP, or CRT being the main reasons. BMI30 kg/m

Several studies in literature have shown that 90% of emboli related to non-valvular atrial fibrillation originate from left atrial appendage. Percutaneous closure or surgical exclusion of left atrial appendage in patients with high bleeding and high cardioembolic risk is currently a well established procedure in literature, clinical practice and guidelines. Knowledge of different techniques of left atrial appendage closure is necessary to individualize the procedure according to the patient anatomy and pre-procedural imaging evaluations. In this review the authors will evaluate different left atrial appendage closure systems and the different pre and intra procedural imaging methods.

High-resolution scar characterization using late gadolinium enhancement cardiac magnetic resonance imaging (LGE-CMR) is useful for guiding ventricular arrhythmia (VA) treatment. However, imaging study quality may be degraded by breath-holding difficulties, arrhythmias, and implantable cardioverter-defibrillators (ICDs). We evaluated the effect of image quality on left ventricle (LV) base to apex scar interpretation in pre-VA ablation LGE-CMR. 43 consecutive patients referred for VA ablation underwent gradient-recalled-echo LGE-CMR. In ICD patients (n = 24), wide-bandwidth inversion-recovery suppressed ICD artifacts. In non-ICD patients, single-shot steady-state free-precession LGE-CMR could also be performed to reduce respiratory motion/arrhythmia artifacts. Study quality was assessed for adequate/limited scar interpretation due to cardiac/respiratory motion artifacts, ICD-related artifacts, and image contrast. 28% of non-ICD patients had studies where image quality limited scar interpretation in at least one image compared to 71% of ICD patient studies (p = 0.012). A median of five image slices had limited quality per ICD patient study, compared to 0 images per non-ICD patient study. Poorer quality in ICD patients was largely due to motion-related artifacts (54% ICD vs 6% non-ICD studies, p = 0.001) as well as ICD-related image artifacts (25% of studies). In VA ablation patients with ICDs, conventional CMR protocols frequently have image slices with limited scar interpretation, which can limit whole-heart scar assessment. Motion artifacts contribute to suboptimal image quality, particularly in ICD patients. Improved methods for motion and ICD artifact suppression may better delineate high-resolution LGE scar features of interest for guiding VA ablation.

Aims The aim of the study was to describe ECG modifications and arrhythmic events in COVID-19 patients undergoing hydroxychloroquine (HCQ) therapy in different clinical settings. Methods and results COVID-19 patients at seven institutions receiving HCQ therapy from whom a baseline and at least one ECG at 48+ h were available were enrolled in the study. QT/QTc prolongation, QT-associated and QT-independent arrhythmic events, arrhythmic mortality, and overall mortality during HCQ therapy were assessed. A total of 649 COVID-19 patients (61.9 ± 18.7 years, 46.1% males) were enrolled. HCQ therapy was administrated as a home therapy regimen in 126 (19.4%) patients, and as an in-hospital-treatment to 495 (76.3%) hospitalized and 28 (4.3%) intensive care unit (ICU) patients. At 36–72 and at 96+ h after the first HCQ dose, 358 and 404 ECGs were obtained, respectively. A significant QT/QTc interval prolongation was observed (P < 0.001), but the magnitude of the increase was modest [+13 (9–16) ms]. Baseline QT/QTc length and presence of fever (P = 0.001) at admission represented the most important determinants of QT/QTc prolongation. No arrhythmic-related deaths were reported. The overall major ventricular arrhythmia rate was low (1.1%), with all events found not to be related to QT or HCQ therapy at a centralized event evaluation. No differences in QT/QTc prolongation and QT-related arrhythmias were observed across different clinical settings, with non-QT-related arrhythmias being more common in the intensive care setting. Conclusion HCQ administration is safe for a short-term treatment for patients with COVID-19 infection regardless of the clinical setting of delivery, causing only modest QTc prolongation and no directly attributable arrhythmic deaths.

IMPORTANCE: A high burden of premature ventricular contractions (PVCs) at disease diagnosis has been associated with an overall higher risk of ventricular arrhythmias in arrhythmogenic right ventricular cardiomyopathy (ARVC). Data regarding dynamic modification of PVC burden at follow-up with Holter monitoring and its impact on arrhythmic risk in ARVC are scarce. OBJECTIVE: To describe changes in the PVC burden and to assess whether serial Holter monitoring is dynamically associated with sustained ventricular arrhythmias during follow-up in patients with ARVC. DESIGN, SETTINGS, AND PARTICIPANTS: In this cohort study, patients with a definite ARVC diagnosis, available Holter monitoring results at disease diagnosis, and at least 2 additional results of Holter monitoring during follow-up were enrolled from 6 ARVC registries in North America and Europe. Data were collected from June 1 to September 15, 2021. MAIN OUTCOMES AND MEASURES: The association between prespecified variables retrieved at each Holter monitoring follow-up (ie, overall PVC burden; presence of sudden PVC spikes, defined as absolute increase in PVC burden ≥5000 per 24 hours or a relative ≥75% increase, with an absolute increase of ≥1000 PVCs; presence of nonsustained ventricular tachycardia [NSVT]; and use of β-blockers and class III antiarrhythmic drugs) and sustained ventricular arrhythmias occurring within 12 months after that Holter examination was assessed using a mixed logistical model. RESULTS: In 169 enrolled patients with ARVC (mean [SD] age, 36.3 [15.0] years; 95 men [56.2%]), a total of 723 Holter examinations (median, 4 [IQR, 4-5] per patient) were performed during a median follow-up of 54 (IQR, 42-63) months and detected 75 PVC spikes and 67 sustained ventricular arrhythmias. The PVC burden decreased significantly from the first to the second Holter examination (mean, 2906 [95% CI, 1581-4231] PVCs per 24 hours; P

Absorbable antibacterial envelopes (AAEs) are currently recommended in patients undergoing a transvenous ICD implantation in cases at high risk of infection, who are now preferably implanted with a subcutaneous ICD (S-ICD). Nevertheless, experiences using a combined approach with S-ICD and AAE have not been reported. The aim of our study was to evaluate this strategy in patients at very high risk of infection.Twenty-five patients were implanted with the S-ICD+AAE using our combined approach, restricted to patients who would fit our decisional flow algorithm identifying very high-risk patients. Patients were followed up 1 month after discharge and every 6 months thereafter. Complications were defined as device-related events requiring medical or surgical intervention for resolution and/or device reprogramming.Twenty-five patients (92% males, mean age 58.5±14.1 years) were implanted with the S-ICD device and the AAE using our combined approach. The most common high-infective risk factors were diabetes requiring insulin treatment (80%) and CKD requiring hemodialysis (48%), with 7 (28%) patients presenting with more than 2 risk factors. A single mild early post-operative hematoma was observed that was managed conservatively with a spontaneous resolution. Despite a very high-risk cohort, only a single late pocket infection was detected and solved conservatively with antibiotic therapy.The preliminary data of this proof-of-concept study show how a combined deployment of AAE and S-ICD in selected patients at very high risk of infection is a safe and feasible technique and may offer a reliable treatment option in specific and selected clinical settings.

Aims Pulmonary vein isolation (PVI) either by balloon devices or radiofrequency forms the cornerstone of invasive atrial fibrillation (AF) treatment. Although equally effective cryoballoon (CB)-based PVI offers shorter procedure duration and a better safety profile. Beside the worldwide established Arctic Front Advance system, a novel CB device, POLARx, was recently introduced. This CB incorporates unique features, which may translate into improved efficacy and safety. However, multicentre assessment of periprocedural efficacy and safety is lacking up to date. Methods and results A total of 317 patients with paroxysmal or persistent AF were included and underwent POLARx CB-based PVI in 6 centres from Germany and Italy. Acute efficacy and safety were assessed in this prospective multicenter observational study. In 317 patients [mean age: 64 ± 12 years, 209 of 317 (66%) paroxysmal AF], a total of 1256 pulmonary veins (PVs) were identified and 1252 (99,7%) PVs were successfully isolated utilizing mainly the short tip POLARx CB (82%). The mean minimal CB temperature was −57.9 ± 7°C. Real-time PVI was registered in 72% of PVs. The rate of serious adverse events was 6.0% which was significantly reduced after a learning curve of 25 cases (9.3% vs. 3.0%, P = 0.018). The rate of recurrence-free survival after mean follow-up of 226 ± 115 days including a 90-day blanking period was 86.1%. Conclusion In this large multicentre assessment, the novel POLARx CB shows a promising efficacy and safety profile after a short learning curve.

A few limited case series have shown that the subcutaneous implantable cardioverter-defibrillator (S-ICD) system is safe for teenagers and young adults, but a large-scale analysis currently is lacking.The purpose of this study was to compare mid-term device-associated outcomes in a large real-world cohort of S-ICD patients, stratified by age at implantation.Two propensity-matched cohorts of teenagers + young adults (≤30 years old) and adults (30 years old) were retrieved from the ELISIR Registry. The primary outcome was the comparison of inappropriate shock rate. Complications, freedom from sustained ventricular arrhythmias, and overall and cardiovascular mortality were deemed secondary outcomes.Teenagers + young adults represented 11.0% of the entire cohort. Two propensity-matched groups of 161 patients each were used for the analysis. Median follow-up was 23.1 (13.2-40.5) months. In total, 15.2% patients experienced inappropriate shocks, and 9.3% device-related complications were observed, with no age-related differences in inappropriate shocks (16.1% vs 14.3%; P = .642) and complication rates (9.9% vs 8.7%; P = .701). At univariate analysis, young age was not associated with increased rates of inappropriate shocks (hazard ratio [HR] 1.204 [0.675-2.148]: P = .529). At multivariate analysis, use of the SMART Pass algorithm was associated with a strong reduction in inappropriate shocks (adjusted HR 0.292 [0.161-0.525]; P.001), whereas arrhythmogenic right ventricular cardiomyopathy (ARVC) was associated with higher rates of inappropriate shocks (adjusted HR 2.380 [1.205-4.697]; P = .012).In a large multicenter registry of propensity-matched patients, use of the S-ICD in teenagers/young adults was safe and effective. The rates of inappropriate shocks and complications between cohorts were not significantly different. The only predictor of increased inappropriate shocks was a diagnosis of ARVC.

Aims In arrhythmogenic cardiomyopathy (ACM), sustained ventricular tachycardia (VT) typically displays a left bundle branch block (LBBB) morphology while a right bundle branch block (RBBB) morphology is rare. The present study assesses the VT morphology in ACM patients with sustained VT and their clinical and genetic characteristics. Methods and results Twenty-six centres from 11 European countries provided information on 954 ACM patients who had ≥1 episode of sustained VT spontaneously documented during patients’ clinical course. Arrhythmogenic cardiomyopathy was defined according to the 2010 Task Force Criteria, and VT morphology according to the QRS pattern in V1. Overall, 882 (92.5%) patients displayed LBBB-VT alone and 72 (7.5%) RBBB-VT [alone in 42 (4.4%) or in combination with LBBB-VT in 30 (3.1%)]. Male sex prevalence was 79.3%, 88.1%, and 56.7% in the LBBB-VT, RBBB-VT, and LBBB + RBBB-VT groups, respectively (P = 0.007). First RBBB-VT occurred 5 years after the first LBBB-VT (46.5 ± 14.4 vs 41.1 ± 15.8 years, P = 0.011). An implanted cardioverter-defibrillator was more frequently implanted in the RBBB-VT (92.9%) and the LBBB + RBBB-VT groups (90%) than in the LBBB-VT group (68.1%) (P Conclusion RBBB-VT accounts for a significant proportion of sustained VTs in ACM. Sex and type of pathogenic mutations were associated with VT type, female sex with LBBB + RBBB-VT, and DSP mutation with RBBB-VT.

BACKGROUND: Cardiac implantable electronic device (CIED) implantation rates as well as the clinical and procedural characteristics and outcomes in patients with known active coronavirus disease 2019 (COVID-19) are unknown. OBJECTIVE: The purpose of this study was to gather information regarding CIED procedures during active COVID-19, performed with personal protective equipment, based on an international survey. METHODS: Fifty-three centers from 13 countries across 4 continents provided information on 166 patients with known active COVID-19 who underwent a CIED procedure. RESULTS: The CIED procedure rate in 133,655 hospitalized COVID-19 patients ranged from 0 to 16.2 per 1000 patients (P

No data on the add-on sacubitril/valsartan (S/V) therapy among cardiac resynchronization therapy with a defibrillator (CRT-D) nonresponder patients are currently available in literature. We conducted a prospective observational study including 190 CRT-D nonresponder patients with symptomatic heart failure with reduced ejection fraction despite the optimal medical therapy from at least 1 year. The primary endpoint was the rate of additional responders (left ventricular end-systolic volume reduction >15%) at 12 months from the introduction of S/V therapy. At the end of the 12 months follow-up, 37 patients (19.5%) were deemed as "additional responders" to the combination use of CRT + S/V therapy. The only clinical predictor of additional response was a lower left ventricular ejection fraction [OR 0.881 (0.815-0.953), P = 0.002] at baseline. At 12 months follow-up, there were significant improvements in heart failure (HF) symptoms and functional status [New York Heart Association 2 (2-3) vs. 1 (1-2), P < 0.001; physical activity duration/day: 10 (8-12) vs. 13 (10-18) hours, P < 0.001]. Compared with the 12 months preceding S/V introduction, there were significant reductions in the rate of HF rehospitalization (35.5% vs. 19.5%, P < 0.001), in atrial tachycardia/atrial fibrillation burden [6.0 (5.0-8.0) % vs. 0 (0-2.0) %, P < 0.001] and in the proportions of patients experiencing ventricular arrhythmias (21.6% vs. 6.3%; P < 0.001). Our results indicate that S/V add-on therapy in CRT-D nonresponder patients is associated with 19.5% of additional responders, a reduction in HF symptoms and rehospitalizations, AF burden, and ventricular arrhythmias.

Background Ventricular arrhythmias (VAs) represent a critical issue with regard to sports eligibility assessment in athletes. The ideal diagnostic evaluation of competitive and leisure-time athletes with complex VAs has not been clearly defined. Objective The purpose of this study was to assess the clinical implications of invasive electrophysiological assessments and endomyocardial biopsy (EMB) among athletes with VAs. Methods We evaluated 227 consecutive athletes who presented to our institutions after being disqualified from participating in sports because of VAs. After noninvasive tests, electrophysiological study (EPS), electroanatomic mapping (EAM), and EAM- or cardiac magnetic resonance imaging–guided EMB was performed, following a prespecified protocol. Sports eligibility status was redefined at 6-month follow-up. Results From our sample, 188 athletes (82.8%) underwent EAM and EPS, and 42 (15.2%) underwent EMB. A diagnosis of heart disease could be formulated in 30% of the study population (67/227; 95% confidence interval [CI] 0.24–0.36) after noninvasive tests; in 37% (83/227; 95% CI 31%–43%) after EPS and EAM; and in 45% (102/227; 95% CI 39%–51%) after EMB. In the subset of athletes undergoing EMB, invasive diagnostic workup allowed diagnostic reclassification of half of the athletes (n = 21 [50%]). Reclassification was particularly common among subjects without definitive findings after noninvasive evaluation (n = 23; 87% reclassified). History of syncope, abnormal echocardiogram, presence of late gadolinium enhancement, and abnormal EAM were linked to sports ineligibility at 6-month follow-up. Conclusion A comprehensive invasive workup provided additional diagnostic elements and could improve the sports eligibility assessment of athletes presenting with VAs. The extensive invasive evaluation presented could be especially helpful when noninvasive tests show unclear findings.

Background: Coagulopathy, in the form of either venous or arterial thromboembolism, is one of the most severe sequelae of coronavirus disease (COVID-19) and has been associated with poorer outcomes. However, the role of therapeutic anticoagulation (tAC) or prophylactic anticoagulation (pAC) in COVID-19 patients has not been definitely established. Therefore, the aim of this systematic review and meta-analysis was to gather all the available real-world data in the field and to provide a reliable effect size of the effect on mortality of tAC compared to pAC in COVID-19 patients. Methods: Real-world studies (RWS) were identified by searching electronic databases from inception to 31th October 2021. Randomized controlled trials were excluded. Mortality and bleedings were considered as primary and secondary outcomes, respectively. Results: 10 RWS and 5541 patients were included in the analysis. Overall, tAC was associated with lower mortality (HR=0.62, 95% CI 0.54-0.71). There was asymmetry at the funnel plot suggesting publication bias, that was not confirmed at the Egger test (p=0.07). For the secondary endpoint, there was a non-statistically significant tendency for more bleedings in patients treated with tAC compared to pAC (RR=1.75, 95% CI 0.81-3.81). Conclusions: Our meta-analysis, based on RWS and adjusted estimates of risk, suggests a survival benefit of tAC over pAC in COVID-19 patients in the real world.

The feasibility and effectiveness of virtual visits (VVs) for cardiac electrophysiology patients are still unknown. We aimed to assess the feasibility and effectiveness of VVs as compared to in-person visits, and to describe patient experience with virtual care in clinical electrophysiology. We prospectively enrolled patients scheduled to receive a clinical electrophysiology evaluation, dividing them in two groups: a VV group and an in-person visit group. Outcomes of interest were: (1) improvement in symptoms after the index visit, (2) disappearance of remote monitoring (RM) alerts at follow-up, (3) necessity of urgent hospitalization and (4) patient satisfaction measured by the Patient Satisfaction Questionnaire-18 (PSQ-18). This study included 162 patients in the VV group and 185 in the in-office visit group. As compared to in-person visits, VVs resulted in a similar reduction in RM alerts (51.5% vs. 43.2%, p-value 0.527) and in symptomatic patient rates (73.6% vs. 56.9%, p-value 0.073) at follow-up, without differences in urgent hospitalization rates (p-value 0.849). Patient satisfaction with VVs was higher than with in-person evaluation (p-value < 0.012). VVs proved to be as feasible and as effective as in-person visits, with high patient satisfaction. A hybrid model of care including VVs and in-person visits may become the new standard of care after the COVID-19 pandemic is over.

Supplemental Digital Content is available in the text., Background: Cryoballoon-based pulmonary vein isolation (PVI) has emerged as an effective treatment for atrial fibrillation. The most frequent complication during cryoballoon-based PVI is phrenic nerve injury (PNI). However, data on PNI are scarce. Methods: The YETI registry is a retrospective, multicenter, and multinational registry evaluating the incidence, characteristics, prognostic factors for PNI recovery and follow-up data of patients with PNI during cryoballoon-based PVI. Experienced electrophysiological centers were invited to participate. All patients with PNI during CB2 or third (CB3) and fourth-generation cryoballoon (CB4)-based PVI were eligible. Results: A total of 17 356 patients underwent cryoballoon-based PVI in 33 centers from 10 countries. A total of 731 (4.2%) patients experienced PNI. The mean time to PNI was 127.7±50.4 seconds, and the mean temperature at the time of PNI was −49±8°C. At the end of the procedure, PNI recovered in 394/731 patients (53.9%). Recovery of PNI at 12 months of follow-up was found in 97.0% of patients (682/703, with 28 patients lost to follow-up). A total of 16/703 (2.3%) reported symptomatic PNI. Only 0.06% of the overall population showed symptomatic and permanent PNI. Prognostic factors improving PNI recovery are immediate stop at PNI by double-stop technique and utilization of a bonus-freeze protocol. Age, cryoballoon temperature at PNI, and compound motor action potential amplitude loss >30% were identified as factors decreasing PNI recovery. Based on these parameters, a score was calculated. The YETI score has a numerical value that will directly represent the probability of a specific patient of recovering from PNI within 12 months. Conclusions: The incidence of PNI during cryoballoon-based PVI was 4.2%. Overall 97% of PNI recovered within 12 months. Symptomatic and permanent PNI is exceedingly rare in patients after cryoballoon-based PVI. The YETI score estimates the prognosis after iatrogenic cryoballoon-derived PNI. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03645577. Graphic Abstract: A graphic abstract is available for this article.

Aims Micra-VR transcatheter pacing system (TPS) has shown strong stability of electrical parameters over time. Nevertheless, a small percentage of patients develops high pacing threshold (PT) (>1 V@0.24 ms) which can decrease the longevity of battery. Our study sought to investigate the intraoperative electrical parameters able to predict device electrical performances during the time. Methods and results Patients (pts) implanted with Micra-VR TPS from March 2018 to January 2021 were prospectively considered at the Cardiology Department of Spedali Civili Hospital (Brescia) and Luigi Sacco Hospital (Milan). R-wave sensing amplitude (mV), pacing impedance (Ohm), and PT (V@0.24 ms) were recorded twice: upon Micra final positioning, and after removal of the delivery system. All pts received a follow-up visit at 1- and 12-month after discharge. Electrical parameters were recorded at each visit. A total of 93 pts underwent Micra-VR implantation were enrolled. When compared to the first assessment, R-wave amplitude increased of 19.1% at second control performed after 13 ± 4 min (+1.71 ± 0.2 mV, 95% CI: 1.4–2.02; P < 0.001). Conversely, PT significantly decreased of 22.1% at 12-month follow-up respect to baseline (−0.22 ± 0.03 V, 95% CI: −0.13 to − 0.31; P < 0.001) (Figure 1). Among patients with high PT, acute increase of R-wave sensing of 1.5 mV after 14 ± 4 min significantly predicted PT normalization (≤1 V@0.24 ms) 12 months post-implant (R = 0.72, 95% CI: 0.13–0.33, P < 0.001) (Figure 2), with a sensitivity of 87.5% (95% CI: 0.61–0.98) and a specificity of 88.8% (95% CI: 0.51–0.99) (Figure 3). Conclusions A 1.5 mV increase in R-wave amplitude at implant time is predictive of PT normalization ( 536 Figure

Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy, which is associated with life-threatening ventricular arrhythmias. Approximately 60% of patients carry a putative disease-causing genetic variant, but interpretation of genetic test results can be challenging. The aims of this study were to systematically reclassify genetic variants in patients with ARVC and to assess the impact on ARVC diagnosis. Methods: This study included patients from the Multicenter Zurich ARVC Registry who hosted a genetic variant deemed to be associated with the disease. Reclassification of pathogenicity was performed according to the modified 2015 American College of Medical Genetics criteria. ARVC diagnosis (categories: definite, borderline, possible) based on the 2010 Task Force Criteria was reclassified after genetic readjudication. Results: In 79 patients bearing 80 unique genetic variants, n=47 (58.8%) genetic variants were reclassified, and reclassification was judged to be clinically relevant in n=33 (41.3%). Variants in plakophilin-2 ( PKP2 ) were shown to reclassify less frequently as compared with other genes ( PKP2 , n=1, 8.3%; desmosomal non- PKP2 , n=20, 66.7%; nondesmosomal, n=26, 68.4%; P =0.001for overall comparison; PKP2 versus desmosomal non- PKP2, P =0.001; PKP2 versus nondesmosomal, P Conclusions: Given that approximately half of genetic variants were reclassified, with 10.1% of patients losing their definite disease status, accurate determination of variant pathogenicity is of utmost importance in the diagnosis of ARVC.

Cryoballoon (CB) and laser-balloon (LB) catheter ablation (CA) has been demonstrated to achieve durable and effective pulmonary vein isolation (PVI). Only one head-to-head comparison with an intermittent rhythm monitor strategy is currently available. The aim of this study was to compare acute and long-term outcomes of CB and LB atrial fibrillation ablation procedures, by using a continuous rhythm monitoring strategy.This was a prospective two-arm nonrandomized propensity-matched observational trial that compared the outcomes of atrial fibrillation (AF) ablation using LB and CB techniques. To evaluate AF recurrences, an implantable cardiac monitor (ICM) was implanted before hospital discharge to detect atrial tachyarrhythmia (ATA) recurrences.A total of 110 propensity-matched patients undergoing AF ablation with an LB (n = 55) or with a CB system (n = 55) were enrolled (paroxysmal AF 57.3%). Procedural time (LB: 87 [73-104] vs. CB 90 [70-130] min; p = 0.264) and fluoroscopy time did not differ. No differences in ATA recurrences were observed at 12 months (LB-30.9% vs. CB-29.1% and LB-45.5% vs. CB-38.2%; log-rank 0.539). As for AF burden, the 12-month median was 0 [0-1] vs. 0 [0-3]% (p = 0.127) in the LB and CB groups, respectively. When considering only PeAF patients, the median 12-month ATA burden was 26 [18.5-40.5] vs. 29 [26-35]% (p = 0.919) for the LB and CB patients, respectively.In a propensity-matched cohort undergoing AF ablation, arrhythmia outcomes assessed by continuous rhythm monitoring did not differ between LB and CB, with an overall low ATA burden. The only predictor of recurrences was persistent AF. There was no difference in procedure or fluoroscopy time.

SYNOPSIS Coronavirus disease 2019 (COVID-19) could have a direct or indirect effect on the cardiovascular system. To detect cardiac involvement, trans-thoracic echocardiography (TTE), as a widely available and cost-effective tool, is highly recommended and can provide important information that can affect the clinical management of COVID-19 patients. Despite that, considering the risk of equipment contamination and personnel exposure, mainly focused echocardiographic evaluations instead of complete examination are recommended and the use of portable devices easy to disinfect with offline reporting is highly suggested. Accordingly, cardiac imaging examination should be considered only when it could change the clinical management or be lifesaving for the patients. COVID-19, through different mechanisms, could affect different sections of the heart and it is useful to analyze them separately during an echocardiographic examination. Regarding the left ventricle, the SARS-CoV-2 infection could lead to acute myocardial infarction, tako-tsubo syndrome and in particular acute myocarditis. The impairment of the pulmonary circulation and the higher prevalence of pulmonary embolism in these patients explain and correlate with some pathological findings as right ventricular systolic dysfunction and direct or indirect signs of pulmonary hypertension, which could easily be assessed by echocardiography and with notable prognostic meaning. Some reports also described acute pericarditis and cardiac effusion during SARS-COV-2 infection and echocardiography is the first recommended diagnostic tool to evaluate the pericardial involvement, especially to exclude signs of cardiac tamponade that rapidly deteriorate the clinical state of the patients. However, available echocardiographic data on COVID-19 patients are scarce and actually does not provide definite evidence and more studies are certainly needed to better evaluate this topic.

Background: Atrial arrhythmias are present in up to 20% of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). Catheter ablation (CA) is an effective treatment for atrial arrhythmias in the general population. Data regarding CA for atrial arrhythmias in ARVC are scarce. Objective: To assess the safety and efficacy of CA for atrial arrhythmias in patients with ARVC. Methods: In this international collaborative effort, all patients with a definite diagnosis of ARVC undergoing CA for atrial fibrillation (AF), focal atrial tachycardia (AT), or cavotricuspid isthmus (CTI)-dependent atrial flutter (AFl) were extracted from twelve ARVC registries. Demographic, periprocedural, and long-term arrhythmic outcome data were collected. Results: Thirty-seven patients were enrolled in the study (age 50.2 ± 16.6 years, male 84%, CHA2DS2VASc 1 (1,2), HAS-BLED 0 (0–2)). The arrhythmia leading to CA was AF in 23 (62%), focal left AT in 5 (14%), and CTI-dependent AFl in 9 (24%). Acute procedural success was achieved in all procedures but one (n = 1 focal left AT, 97% acute success). The median follow-up period was 27 (13–67) months, and 96%, 74%, and 61% of patients undergoing AF ablation were free from any atrial arrhythmia recurrence after a single procedure at 6 months, 12 months, and last follow-up, respectively. After focal AT ablation, freedom from atrial arrhythmia recurrence was 80%, 80%, and 60% at 6 months, 12 months, and last follow-up, respectively. All patients undergoing CTI ablation were free from atrial arrhythmia recurrences at 6 months, with 89% single-procedural arrhythmic freedom at last follow-up. One major complication (2.7%, PV stenosis requiring PV stenting) occurred. Conclusions: CA is safe and effective in managing atrial arrhythmias in patients with ARVC, with success rates comparable to the general population.

Background: Large-scale studies evaluating long-term recurrence rates in both idiopathic and non-idiopathic PVC catheter ablation (CA) patients have not been reported. Objective: To evaluate the efficacy and safety of idiopathic and non-idiopathic PVC CA, investigating the predictors of acute and long-term efficacy. Methods: This retrospective multicentric study included 439 patients who underwent PVC CA at three institutions from April-2015 to December-2021. Clinical success at 6 months’ follow-up, defined as a reduction of at least 80% of the pre-procedural PVC burden, was deemed the primary outcome. The secondary aims of the study were: clinical success at the last available follow-up, predictors of arrhythmic recurrences at long-term follow-up, and safety outcomes. Results: The median age was 51 years, with 24.9% patients being affected suffering from structural heart disease. The median pre-procedural PVC burden was 20.1%. PVCs originating from the RVOT were the most common index PVC observed (29.1%), followed by coronary cusp (CC) and non-outflow tract (OT) LV PVCs (23.1% and 19.0%). The primary outcome at 6 months was reached in 85.1% cases, with a significant reduction in the 24 h% PVC burden (−91.4% [−83.4; −96.7], p < 0.001); long-term efficacy was observed in 82.1% of cases at almost 3-year follow-up. The presence of underlying structural heart disease and non-OT LV region origin (aHR 1.77 [1.07–2.93], p = 0.027 and aHR = 1.96 [1.22–3.14], p = 0.005) was independently associated with recurrences. Conclusion: CA of both idiopathic and non-idiopathic PVCs showed a very good acute and long-term procedural success rate, with an overall low complication. Predictors of arrhythmic recurrence at follow-up were underlying structural heart disease and non-OT LV origin.

INTRODUCTION The PRAETORIAN score (PS) was developed to assess the implant position and predict defibrillation success of the subcutaneous implantable cardioverter defibrillators (S-ICD). The main critique moved to the routine use of PS has been its postprocedural timing, that limits its usefulness on procedure guidance. The aim of this proof-of-concept study was to assess the feasibility of an intraprocedural use of PS. METHODS Forty consecutive patients undergoing S-ICD implantation were enrolled. Intraprocedural PS (IP-PS) obtained with fluoroscopy before closure of the pocket and postprocedural PS (PP-PS) obtained with two-views chest X-ray were compared. Intraprocedural data and PS were compared with the historic cohorts of the involved institutions. RESULTS When assessing IP-PS and PP-PS, a complete overall agreement was observed (100%, 1.00-κ; p

Complete atrioventricular block (CAVB) is a total dissociation between the atrial and ventricular activity, in the absence of atrioventricular conduction. Several diseases may result in CAVB in the pediatric and young-adult population. Permanent right ventricular (RV) pacing is required in permanent CAVB, when the cause is neither transient nor reversible. Continuous RV apical pacing has been associated with unfavorable outcomes in several studies due to the associated ventricular dyssynchrony. This study aims to summarize the current literature regarding CAVB in the pediatric and young adult population and to explore future treatment perspectives.

High pacing threshold (HPT) and very high pacing threshold (VHPT) are known to have a negative impact on leadless pacemaker battery longevity, representing the most common reason for device repositioning. In this study, we evaluated if intraoperative electrical parameters recorded during Micra™ VR implant would be able to predict device performance during follow-up (FU).A total of 93 patients undergoing Micra™ VR implant were retrospectively considered. Patients were enrolled in the study if electrical assessment was performed at least twice at implant, at Micra™ final positioning and after removal of the delivery system. All patients received a FU visit at 1 and 12 month after discharge. R-wave sensing amplitude, pacing threshold (PT), and impedance were recorded at each visit.When compared to the first assessment, R-wave sensing amplitude increased by 19.1% after 13 ± 4 min (+ 1.71 ± 0.2 mV, 95% CI 1.4 to 2.02; p .001). Conversely, there was a significant PT decrease of 22.1% at 12-month FU (- 0.22 ± 0.03 V, 95% CI - 0.13 to - 0.31; p .001). Among patients with HPT, acute increase of R-wave sensing of 1.5 mV after 14 ± 4 min predicted a significant reduction of PT below 1 V/0.24, at 12-month post-implant (R = 0.72, 95% CI 0.13 to 0.33, p .001), with a sensitivity of 87.5% (95% CI 0.61-0.98) and a specificity of 88.8% (95% CI 0.51-0.99).A 1.5-mV increase in R-wave amplitude at implant is predictive of PT normalization ( 1.0 V/0.24 ms) at 12-month FU. This finding may have practical implications for device repositioning in case of HPT recording at implant.

Severe acute respiratory syndrome coronavirus 2 infection in children mainly shows a milder course. In complicated cases, it is unknown whether inflammation is predictive of disease severity, as in adults. Moreover, cardiac involvement is anecdotally described. We report the case of a 2-month-old infant with severe acute respiratory syndrome coronavirus 2 infection presenting with fever, tachycardia and elevated interleukin-6, who was diagnosed with myocarditis and treated with immunoglobulins.

BACKGROUND Multipoint pacing (MPP) may improve clinical outcomes in patients with cardiac resynchronization therapy defibrillators (CRT-D), but its impact on battery longevity in a real-world population has not been investigated in large trials. OBJECTIVE Compare projected battery longevity in CRT-D patients with and without MPP during long-term follow-up. METHODS The Italian registry on multipoint left ventricular pacing (IRON-MPP) is a prospective, multicenter registry of patients implanted with MPP-capable CRT-D devices. Projected battery longevity during follow-up was compared for patients with MPP (MPP ON) vs single-site (MPP OFF) left ventricular pacing at CRT-D implantation. A sub-analysis excluded crossover patients with MPP activation or deactivation occurring after implantation. A second sub-analysis excluded patients with a right or left ventricular pacing amplitude >2.5 V. RESULTS Out of 237 CRT-D patients (71 ± 9 years, 81% male) followed for 1.9 ± 0.8 years, 102 (43%) had MPP ON at implantation. Programmed atrial and ventricular outputs and percentage of pacing were similar between groups. MPP was associated with a 0.44 years reduction in projected battery longevity (P = .03) during long-term follow-up. Results were similar for the first and second sub-analyses, with a 0.57 years (P

Background We sought to evaluate the additional value of left atrial appendage (LAA) 3D printing derived from computed tomography (CCT) in determining the size for LAA occlusion (LAAO) devices as compared to standard measurement by using occurrence of LAA leak as endpoint. Methods We evaluated 6 patients with LAA leak (cases) and 14 matched patients without LAA leak (controls) after LAAO. For each group, a patient-specific 3D printed model of LAA was manufactured using CT pre-operative images. The size recommended by the 3D printed model was compared with the size of the implanted device. Results Compared to the 3D printed model, 55% of the devices were underestimated, the two sizing approaches agreed in 35% of the patients, while the 3D printed model overestimated the size in 10% of patients. The prevalence of LAA leak was significantly higher in the subset of patients with underestimation of prosthesis implanted with the standard approach as compared to the other patients (p = 0.019). Conclusion 3D printing of the LAA may provide additional value to standard practice for LAAO device prosthesis sizing with the potential impact to reduce LAA leak.

Background The combined left atrial appendage closure (LAAC) and cryoenergy pulmonary vein isolation (PVI) procedure has been proven safe and effective in managing stroke in patients with nonvalvular atrial fibrillation (AF), although most data refer to procedures performed using radiofrequency as the main energy source. Objective The purpose of this study was to evaluate long-term follow-up of patients with AF undergoing concomitant LAAC and cryoenergy PVI. Methods Patients undergoing LAAC and cryoballoon PVI at our institution were enrolled. At 3, 6, and 24 months from the index procedure, we determined the atrial arrhythmia recurrence rate, the extent of LAAC, and the rate of cerebrovascular/bleeding events. Results Forty-nine patients (mean age 69 ± 8 years; 32/49 (67%) men; CHA2DS2-VASc score 2.8 ± 1.2; HAS-BLED score 3 ± 1) with a guideline-recommended LAAC indication were included. Acute PVI and complete LAAC were achieved in 100% of patients. All patients completed at least 24 months of follow-up. At 8 weeks and 6 months, complete or satisfactory ( Conclusion Concomitant cryoballoon ablation and LAAC procedures appear safe and effective at long-term follow-up, with high antithrombotic drug withdrawal rates at 24 months.

Background Nowadays, transvenous lead extraction (TLE) is considered an essential technique in lead management strategy. Since 2011, a multidisciplinary approach was undertaken in our centre involving electrophysiologists, cardiac surgeons and anaesthesiologists to improve cross- unit cooperation and minimize complications and mortality. The present paper reports procedural outcomes and complications of our lead extraction experience. Methods We retrospectively collected and analysed data from all consecutive patients undergoing cardiac implantable electronic device leads TLE at the IRCCS Centro Cardiologico Monzino between January 2011 and November 2017. Results One-hundred fifty patients (111 males, 68 ± 13 years) underwent extraction procedures. The most common extraction indication were infections (86.7%) and TLE was carried out by laser-based approach in 88 (58.6%) patients, by mechanical dilating sheaths in 58 (38.7%) patients and by a combined approach (TLE + open surgical intervention) in 4 (2.7%) patients. Procedural success was obtained in 146 (97.3%) cases with only 3 (2.0%) major complications with 2 cases of structural injury with tamponade requiring emergent median sternotomy. Open surgery extraction was required in 4 patients, after an attempt to TLE, due to leads strict adhesion to cardiac or vascular structures, whereas in 5 (3.3%) cases, the treatment of choice was a combined approach consisting in transvenous leads extraction followed by planned surgery. Conclusions TLE is a complex procedure that sometimes leads to fatal complications. In our single center experience, a multidisciplinary approach involving electrophysiologist, cardiac surgeon, anaesthesiologist in an operating room allows a safer approach and major complications treatment.

Background To date, only a few comparisons between subcutaneous implantable cardioverter-defibrillator (S-ICD) patients undergoing and those not undergoing defibrillation testing (DT) at implantation (DT+ vs DT–) have been reported. Objective The purpose of this study was to compare long-term clinical outcomes of 2 propensity-matched cohorts of DT+ and DT– patients. Methods Among consecutive S-ICD patients implanted across 17 centers from January 2015 to October 2020, DT– patients were 1:1 propensity-matched for baseline characteristics with DT+ patients. The primary outcome was a composite of ineffective shocks and cardiovascular mortality. Appropriate and inappropriate shock rates were deemed secondary outcomes. Results Among 1290 patients, a total of 566 propensity-matched patients (283 DT+; 283 DT–) served as study population. Over median follow-up of 25.3 months, no significant differences in primary outcome event rates were found (10 DT+ vs 14 DT–; P = .404) as well as for ineffective shocks (5 DT– vs 3 DT+; P = .725). At multivariable Cox regression analysis, DT performance was associated with a reduction of neither the primary combined outcome nor ineffective shocks at follow-up. A high PRAETORIAN score was positively associated with both the primary outcome (hazard ratio 3.976; confidence interval 1.339–11.802; P = .013) and ineffective shocks alone at follow-up (hazard ratio 19.030; confidence interval 4.752–76.203; P = .003). Conclusion In 2 cohorts of strictly propensity-matched patients, DT performance was not associated with significant differences in cardiovascular mortality and ineffective shocks. The PRAETORIAN score is capable of correctly identifying a large percentage of patients at risk for ineffective shock conversion in both cohorts.

Recently, the Food and Drug Administration issued a recall for the subcutaneous implantable cardioverter-defibrillator (S-ICD) because of the possibility of lead ruptures and accelerated battery depletion.The aim of this study was to evaluate device-related complications over time in a large real-world multicenter S-ICD cohort.Patients implanted with an S-ICD from January 2015 to June 2020 were enrolled from a 19-institution European registry (Experience from the Long-term Italian S-ICD registry [ELISIR]; ClinicalTrials.gov identifier NCT0473876). Device-related complication rates over follow-up were collected. Last follow-up of patients was performed after the Boston Scientific recall issue.A total of 1254 patients (median age 52.0 [interquartile range 41.0-62.2] years; 973 (77.6%) men; 387 (30.9%) ischemic) was enrolled. Over a follow-up of 23.2 (12.8-37.8) months, complications were observed in 117 patients (9.3%) for a total of 127 device-related complications (23.6% managed conservatively and 76.4% required reintervention). Twenty-seven patients (2.2%) had unanticipated generator replacement after 3.6 (3.3-3.9) years, while 4 (0.3%) had lead rupture. Body mass index (hazard ratio [HR] 1.063 [95% confidence interval 1.028-1.100]; P.001), chronic kidney disease (HR 1.960 [1.191-3.225]; P = .008), and oral anticoagulation (HR 1.437 [1.010-2.045]; P = .043) were associated with an increase in overall complications, whereas older age (HR 0.980 [0.967-0.994]; P = .007) and procedure performed in high-volume centers (HR 0.463 [0.300-0.715]; P = .001) were protective factors.The overall complication rate over 23.2 months of follow-up in a multicenter S-ICD cohort was 9.3%. Early unanticipated device battery depletions occurred in 2.2% of patients, while lead fracture was observed in 0.3%, which is in line with the expected rates reported by Boston Scientific.

Funding Acknowledgements Type of funding sources: None. Background The 2010 Task Force Criteria (TFC), although representing the current gold standard to diagnose arrhythmogenic right ventricular cardiomyopathy (ARVC), have not been tested to differentiate ARVC from the athlete’s heart. Furthermore, not all 6 diagnostic categories are easy to obtain. Purpose We hypothesized that atrial dimensions are useful to differentiate between both entities. Therefore, we developed a new diagnostic score based upon readily available clinical parameters including atrial dimensions on TTE to help distinguishing the athlete’s heart from ARVC in daily clinical practice. Methods In this observational study, 37 patients with definite ARVC (from the Zurich ARVC Program) were compared to 68 athletes. Base on ROC analysis, the following echocardiographic, laboratory and electrocardiographic parameters were included in the final score: indexed right/left atrial volumes (RAVI/LAVI ratio), NT-proBNP, RVOT measurements (PLAX and PSAX adjusted for BSA) on TTE, tricuspid annular motion velocity (TAM) on TTE, precordial electrocardiographic T-wave inversions and depolarization abnormalities according to the TFC. Results ARVC patients had a higher RAVI/LAVI ratio (1.78 ± 1.6vs0.95 ± 0.3,p Conclusions ARVC patients present with significantly larger RA as compared to athletes, resulting in a greater RAVI/LAVI ratio. Our novel diagnostic score includes readily available clinical parameters and has a high diagnostic accuracy to differentiate between ARVC and the athlete´s heart. Abstract Figure. Novel clinical score

Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): The Zurich ACM Program is supported by generous grants from the Georg and Bertha Schwyzer-Winniker Foundation, the Baugarten Foundation, Swiss National Science Foundation, Swiss Heart Foundation and Wild Foundation. This work is also supported by a Canadian Institutes of Health Research grant (FRN: 162402) and the Labatt Heart Centre and Waugh Family Innovation Funds, Caitlin Elizabeth Morris Memorial Fund, Alex Corrance Memorial Foundation and Meredith Cartwright. BACKGROUND Arrhythmogenic right ventricular cardiomyopathy (ARVC) has several phenocopies such as cardiac sarcoidosis (CS), idiopathic outflow tract ventricular tachycardia (OT-VT) and myocarditis. Differentiation between these entities can be challenging. Recently, we have identified diagnostic anti-desmoglein-2 autoantibodies (anti-DSG2 Abs) in patients with ARVC. PURPOSE We sought to examine whether anti-DSG2 Abs are also present in clinical phenocopies of ARVC. METHODS Anti-DSG2 Abs in sera of 25, 19 and 22 patients with sarcoidosis, OT-VT and myocarditis, respectively, were assessed by western blots and ELISA. Clinical and imaging parameters, as well as conventional biomarkers were correlated to detected anti-DSG2 Ab intensity levels. RESULTS Anti-DSG2 Abs, at various intensities, were identified in 6/25 (24%) patients with sarcoidosis, all presenting with CS, but were absent in patients with OT-VT and myocarditis. Cardiac 18F- fluorodeoxyglucose positron emission tomography (18F-FDG PET) was positive in all sarcoidosis patients with positive anti-DSG2 Abs, corresponding to a median PET maximum standardized uptake value (SUVmax) of 5.65 [IQR: 5.15 – 10.9]. In sarcoidosis patients without anti-DSG2 Abs, the SUVmax values were significantly lower with a median of 0 [IQR: 0 – 4] (p = 0.011). The Pearson correlation coefficient (R) was 0.188 (p = 0.039) indicating a positive correlation between cardiac 18F-FDG uptake and anti-DSG2 Abs. No significant correlation was detected for any of the other clinical parameters and biomarkers. CONCLUSIONS In addition to being present in ARVC, anti-DSG2 Abs are also found in CS, a common phenocopy of ARVC; conversely, anti-DSG2 Abs are absent in idiopathic OT-VT and myocarditis. Anti-DSG2 Ab levels positively correlate with myocardial disease activity in CS as indicated by cardiac 18F-FDG PET scanning. Abstract Figure. Central illustration

Background: Current guidelines recommend avoiding apical left ventricular (LV) pacing for cardiac resynchronization therapy (CRT). Aims: We investigated the feasibility of nonapical pacing with the current quadripolar LV lead technology. Methods: We analyzed consecutive patients who received CRT with an LV quadripolar lead. The post­­implantation position of each electrode of the LV lead was designated as basal, mid, or apical. The pacing capture threshold (PCT) and phrenic nerve stimulation (PNS) threshold were assessed for each electrode. Results: We enrolled 168 patients. A total of 8 CRT defibrillators were from Biotronik (with Sentus OTW QP leads), 98 were from Boston Scientific (with 21 Acuity X4 Spiral and 77 Acuity X4 Straight leads), and 62 from St. Jude Medical (with Quartet leads). The median (interquartile range) number of electrodes at nonapical segments per patient was 3 (1–4) with Biotronik Sentus leads, 4 (3–4) with spiral ­design Boston Scientific leads, 4 (3–4) with straight Boston Scientific leads, and 3 (3–4) with St. Jude Medical Quartet leads (P = 0.045). Three patients (38%) with Biotronik Sentus leads, 21 (100%) with spiral ­design Boston Scientific leads, 69 (90%) with straight ­design Boston Scientific leads, and 49 (79%) with St. Jude Medical Quartet leads (P < 0.001) had at least 1 electrode located at nonapical segments linked with a PNS ­PCT safety margin of more than 2 V. During the 6­month follow ­up, PNS was detected in 4 patients and was eliminated with reprogramming. No significant changes in PCT were detected during follow ­up. Conclusions: Quadripolar leads allowed nonapical pacing with acceptable electrical parameters in the majority of CRT recipients, although differences were found among the currently available devices.

Leadless pacemakers are an established treatment option for bradyarrhythmias. Similar to conventional transvenous pacemakers, satisfying pacing values during implantation are targeted for optimal long-term device function. The objective is to investigate the role of a local injury current (IC) in leadless pacemaker implantations.The IC, sensing value, capture threshold and impedance were collected in 30 consecutive patients receiving a leadless pacemaker.39 EGMs were recorded from 30 patients (including 9 device repositions). An IC was detected in 15 cases (38%). At implantation, the presence of an IC was associated with a significantly lower sensing (7.1 ± 3.7 mV vs 12.0 ± 4.0 mV; P = 0.004) and a higher capture threshold (median threshold 1.13 V at 0.24 ms [0.50-2.00] vs 0.50 V at 0.24 ms [0.25-0.75]; P = 0.002) and with a 26 fold higher likelihood of device repositioning compared to the absence of an IC (OR 26.3 [2.79-248], P 0.001). Patients with an IC in their final implant position had a lower sensing (9.3 ± 4.4 mV vs 13.6 ± 4.7 mV at implantation, P = 0.04), while the initially similar capture threshold was lower after 24 h in the IC group. After 2 weeks, all parameters were similar between the two groups.Our study shows that an IC can readily be observed during leadless pacemaker implantation associated with a lower sensing and a higher capture threshold at implantation but with similar to even better values during follow-up.