Implantable loop recorders in patients with Brugada syndrome: the BruLoop study.

BACKGROUND AND AIMS: Available data on continuous rhythm monitoring by implantable loop recorders (ILRs) in patients with Brugada syndrome (BrS) are scarce. The aim of this multi-centre study was to evaluate the diagnostic yield and clinical implication of a continuous rhythm monitoring strategy by ILRs in a large cohort of BrS patients and to assess the precise arrhythmic cause of syncopal episodes. METHODS: A total of 370 patients with BrS and ILRs (mean age 43.5 ± 15.9, 33.8% female, 74.1% symptomatic) from 18 international centers were included. Patients were followed with continuous rhythm monitoring for a median follow-up of 3 years. RESULTS: During follow-up, an arrhythmic event was recorded in 30.7% of symptomatic patients [18.6% atrial arrhythmias (AAs), 10.2% bradyarrhythmias (BAs), and 7.3% ventricular arrhythmias (VAs)]. In patients with recurrent syncope, the aetiology was arrhythmic in 22.4% (59.3% BAs, 25.0% VAs, and 15.6% AAs). The ILR led to drug therapy initiation in 11.4%, ablation procedure in 10.9%, implantation of a pacemaker in 2.5%, and a cardioverter-defibrillator in 8%. At multivariate analysis, the presence of symptoms [hazard ratio (HR) 2.5, P = .001] and age >50 years (HR 1.7, P = .016) were independent predictors of arrhythmic events, while inducibility of ventricular fibrillation at the electrophysiological study (HR 9.0, P < .001) was a predictor of VAs. CONCLUSIONS: ILR detects arrhythmic events in nearly 30% of symptomatic BrS patients, leading to appropriate therapy in 70% of them. The most commonly detected arrhythmias are AAs and BAs, while VAs are detected only in 7% of cases. Symptom status can be used to guide ILR implantation.

Implantable cardioverter defibrillator use in arrhythmogenic right ventricular cardiomyopathy in North America and Europe.

BACKGROUND AND AIMS: Implantable cardioverter-defibrillators (ICDs) are critical for preventing sudden cardiac death (SCD) in arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aims to identify cross-continental differences in utilization of primary prevention ICDs and survival free from sustained ventricular arrhythmia (VA) in ARVC. METHODS: This was a retrospective analysis of ARVC patients without prior VA enrolled in clinical registries from 11 countries throughout Europe and North America. Patients were classified according to whether they received treatment in North America or Europe and were further stratified by baseline predicted VA risk into low- (<10%/5 years), intermediate- (10%-25%/5 years), and high-risk (>25%/5 years) groups. Differences in ICD implantation and survival free from sustained VA events (including appropriate ICD therapy) were assessed. RESULTS: One thousand ninety-eight patients were followed for a median of 5.1 years; 554 (50.5%) received a primary prevention ICD, and 286 (26.0%) experienced a first VA event. After adjusting for baseline risk factors, North Americans were more than three times as likely to receive ICDs {hazard ratio (HR) 3.1 [95% confidence interval (CI) 2.5, 3.8]} but had only mildly increased risk for incident sustained VA [HR 1.4 (95% CI 1.1, 1.8)]. North Americans without ICDs were at higher risk for incident sustained VA [HR 2.1 (95% CI 1.3, 3.4)] than Europeans. CONCLUSIONS: North American ARVC patients were substantially more likely than Europeans to receive primary prevention ICDs across all arrhythmic risk strata. A lower rate of ICD implantation in Europe was not associated with a higher rate of VA events in those without ICDs.

Pulsed field ablation technology for pulmonary vein and left atrial posterior wall isolation in patients with persistent atrial fibrillation.

INTRODUCTION: Limited data exist on pulsed-field ablation (PFA) in patients with persistent atrial fibrillation (PeAF) undergoing left atrial posterior wall isolation (LAPWI). METHODS: The Advanced TecHnologies For SuccEssful AblatioN of AF in Clinical Practice (ATHENA) prospective registry included consecutive patients referred for PeAF catheter ablation at 9 Italian centers, treated with the FARAPULSETM-PFA system. The primary efficacy and safety study endpoints were the acute LAPWI rate, freedom from arrhythmic recurrences and the incidence of major periprocedural complications. Patients undergoing pulmonary vein isolation (PVI) alone, PWI + LAPWI and redo procedures were compared. RESULTS: Among 249 patients, 21.7% had long-standing PeAF, 79.5% were male; mean age was 63 ± 9 years. LAPWI was performed in 57.6% of cases, with 15.3% being redo procedures. Median skin-to-skin times (PVI-only 68 [60-90] vs. PVI + LAPWI 70 [59-88] mins) did not differ between groups. 45.8% LAPWI cases were approached with a 3D-mapping system, and 37.3% with intracardiac echocardiography. LAPWI was achieved in all patients by means of PFA alone, in 88.8% cases at first pass. LAPWI was validated either by an Ultrahigh-density mapping system or by recording electrical activity + pacing maneuvers. No major complications occurred, while 2.4% minor complications were detected. During a median follow-up of 273 [191-379] days, 41 patients (16.5%) experienced an arrhythmic recurrence after the 90-day blanking period, with a mean time to recurrence of 223 ± 100 days and no differences among ablation strategies. CONCLUSION: LAPWI with PFA demonstrates feasibility, rapidity, and safety in real-world practice, offering a viable alternative for PeAF patients. LAPWI is achievable even with a fluoroscopy-only method and does not significantly extend overall procedural times.

Sex differences among subcutaneous implantable cardioverter-defibrillator recipients: a propensity-matched, multicentre, international analysis from the i-SUSI project.

AIMS: Women have been historically underrepresented in implantable cardioverter-defibrillator (ICD) trials. No data on sex differences regarding subcutaneous ICDs (S-ICD) carriers have been described. Aim of our study was to investigate sex-related differences among unselected S-ICD recipients. METHODS AND RESULTS: Consecutive patients enrolled in the multicentre, international i-SUSI registry were analysed. Comparisons between sexes were performed using a 1:1 propensity matching adjusted analysis for age, body mass index (BMI), left ventricular function, and substrate. The primary outcome was the rate of appropriate shocks during follow-up. Inappropriate shocks and other device-related complications were deemed secondary outcomes. A total of 1698 patients were extracted from the i-SUSI registry; 399 (23.5%) were females. After propensity matching, two cohorts of 374 patients presenting similar baseline characteristics were analysed. Despite similar periprocedural characteristics and a matched BMI, women resulted at lower risk of conversion failure as per PRAETORIAN score (73.4% vs. 81.3%, P = 0.049). Over a median follow-up time of 26.5 [12.7-42.5] months, appropriate shocks were more common in the male cohort (rate/year 3.4% vs. 1.7%; log-rank P = 0.049), while no significant differences in device-related complications (rate/year: 6.3% vs. 5.8%; log-rank P = 0.595) and inappropriate shocks (rate/year: 4.3% vs. 3.1%; log-rank P = 0.375) were observed. After controlling for confounders, sex remained significantly associated with the primary outcome (aHR 1.648; CI 0.999-2.655, P = 0.048), while not resulting predictor of inappropriate shocks and device-related complications. CONCLUSION: In a propensity-matched cohort of S-ICD recipients, women are less likely to experience appropriate ICD therapy, while not showing higher risk of device-related complications. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT0473876.

Impact of ventricular tachycardia ablation in subcutaneous implantable cardioverter defibrillator carriers: a multicentre, international analysis from the iSUSI project.

AIMS: Catheter ablation (CA) of ventricular tachycardia (VT) has become an important tool to improve clinical outcomes in patients with appropriate transvenous implantable cardioverter defibrillator (ICD) shocks. The aim of our analysis was to test whether VT ablation (VTA) impacts long-term clinical outcomes even in subcutaneous ICD (S-ICD) carriers. METHODS AND RESULTS: International Subcutaneous Implantable Cardioverter Defibrillator (iSUSI) registry patients who experienced either an ICD shock or a hospitalization for monomorphic VT were included in this analysis. Based on an eventual VTA after the index event, patients were divided into VTA+ vs. VTA- cohorts. Primary outcome of the study was the occurrence of a combination of device-related appropriate shocks, monomorphic VTs, and cardiovascular mortality. Secondary outcomes were addressed individually. Among n = 1661 iSUSI patients, n = 211 were included: n = 177 experiencing ICD shocks and n = 34 hospitalized for VT. No significant differences in baseline characteristics were observed. Both the crude and the yearly event rate of the primary outcome (5/59 and 3.8% yearly event rate VTA+ vs. 41/152 and 16.4% yearly event rate in the VTA-; log-rank: P value = 0.0013) and the cardiovascular mortality (1/59 and 0.7% yearly event rate VTA+ vs. 13/152 and 4.7% yearly event rate VTA-; log-rank P = 0.043) were significantly lower in the VTA + cohort. At multivariate analysis, VTA was the only variable remaining associated with a lower incidence of the primary outcome [adjusted hazard ratio 0.262 (0.100-0.681), P = 0.006]. CONCLUSION: In a real-world registry of S-ICD carriers, the combined study endpoint of arrhythmic events and cardiovascular mortality was lower in the patient cohort undergoing VTA at long-term follow-up. CLINICALTRIALS.GOV IDENTIFIER: NCT0473876.

Left ventricular functional recovery after atrial fibrillation catheter ablation in heart failure: a prediction model.

AIMS: Management of patients with atrial fibrillation (AF) and concomitant heart failure (HF) remains complex. The Antwerp score, based on four parameters [QRS >120 ms (2 points), known aetiology (2 points), paroxysmal AF (1 point), severe atrial dilation (1 point)] adequately estimated the probability of left ventricular ejection fraction (LVEF) recovery after AF ablation in a single-centre cohort. The present study aims to externally validate this prediction model in a large European multi-centre cohort. METHODS AND RESULTS: A total of 605 patients (61.1 ± 9.4 years, 23.8% females, 79.8% with persistent AF) with HF and impaired LVEF (<50%) undergoing AF ablation in 8 European centres were retrospectively identified. According to the LVEF changes at 12-month echocardiography, 427 (70%) patients fulfilled the '2021 Universal Definition of HF' criteria for LVEF recovery and were defined as 'responders'. External validation of the score yielded good discrimination and calibration {area under the curve 0.86 [95% confidence interval (CI) 0.82-0.89], P < .001; Hosmer-Lemeshow P = .29}. Patients with a score < 2 had a 93% probability of LVEF recovery as opposed to only 24% in patients with a score > 3. Responders experienced more often positive ventricular remodelling [odds ratio (OR) 8.91, 95% CI 4.45-17.84, P < .001], fewer HF hospitalizations (OR 0.09, 95% CI 0.05-0.18, P < .001) and lower mortality (OR 0.11, 95% CI 0.04-0.31, P < .001). CONCLUSION: In this multi-centre study, a simple four-parameter score predicted LVEF recovery after AF ablation in patients with HF and discriminated clinical outcomes. These findings support the use of the Antwerp score to standardize shared decision-making regarding AF ablation referral in future clinical studies.

Cardiac Magnetic Resonance and Cardiac Implantable Electronic Devices: Are They Truly Still "Enemies"?

The application of cardiac magnetic resonance (CMR) imaging in clinical practice has grown due to technological advancements and expanded clinical indications, highlighting its superior capabilities when compared to echocardiography for the assessment of myocardial tissue. Similarly, the utilization of implantable cardiac electronic devices (CIEDs) has significantly increased in cardiac arrhythmia management, and the requirements of CMR examinations in patients with CIEDs has become more common. However, this type of exam often presents challenges due to safety concerns and image artifacts. Until a few years ago, the presence of CIED was considered an absolute contraindication to CMR. To address these challenges, various technical improvements in CIED technology, like the reduction of the ferromagnetic components, and in CMR examinations, such as the introduction of new sequences, have been developed. Moreover, a rigorous protocol involving multidisciplinary collaboration is recommended for safe CMR examinations in patients with CIEDs, emphasizing risk assessment, careful monitoring during CMR, and post-scan device evaluation. Alternative methods to CMR, such as computed tomography coronary angiography with tissue characterization techniques like dual-energy and photon-counting, offer alternative potential solutions, although their diagnostic accuracy and availability do limit their use. Despite technological advancements, close collaboration and specialized staff training remain crucial for obtaining safe diagnostic CMR images in patients with CIEDs, thus justifying the presence of specialized centers that are equipped to handle these type of exams.

A Novel Approach to Cardiac Magnetic Resonance Scar Characterization in Patients Affected by Cardiac Amyloidosis: A Pilot Study.

Background and Objectives: Cardiac magnetic resonance (CMR) imaging has become an essential instrument in the study of cardiomyopathies; it has recently been integrated into the diagnostic workflow for cardiac amyloidosis (CA) with remarkable results. An additional emerging role is the stratification of the arrhythmogenic risk by scar analysis and the possibility of merging these data with electro-anatomical maps. This is made possible by using a software (ADAS 3D, Galgo Medical, Barcelona, Spain) able to provide 3D heart models by detecting fibrosis along the whole thickness of the myocardial walls. Little is known regarding the applications of this software in the wide spectrum of cardiomyopathies and the potential benefits have yet to be discovered. In this study, we tried to apply the ADAS 3D in the context of CA. Materials and Methods: This study was a retrospectively analysis of consecutive CMR imaging of patients affected by CA that were treated in our center (Marche University Hospital). Wherever possible, the data were processed with the ADAS 3D software and analyzed for a correlation between the morphometric parameters and follow-up events. The outcome was a composite of all-cause mortality, unplanned cardiovascular hospitalizations, sustained ventricular arrhythmias (VAs), permanent reduction in left ventricular ejection fraction, and pacemaker implantation. The secondary outcomes were the need for a pacemaker implantation and sustained VAs. Results: A total of 14 patients were deemed eligible for the software analysis: 8 patients with wild type transthyretin CA, 5 with light chain CA, and 1 with transthyretin hereditary CA. The vast majority of imaging features was not related to the composite outcome, but atrial wall thickening displayed a significant association with both the primary (p = 0.003) and the secondary outcome of pacemaker implantation (p = 0.003). The software was able to differentiate between core zones and border zones of scars, with the latter being the most extensively represented in all patients. Interestingly, in a huge percentage of CMR images, the software identified the highest degree of core zone fibrosis among the epicardial layers and, in those patients, we found a higher incidence of the primary outcome, without reaching statistical significance (p = 0.18). Channels were found in the scar zones in a substantial percentage of patients without a clear correlation with follow-up events. Conclusions: CMR imaging plays a pivotal role in cardiovascular diagnostics. Our analysis shows the feasibility and applicability of such instrument for all types of CA. We could not only differentiate between different layers of scars, but we were also able to identify the presence of fibrosis channels among the different scar zones. None of the data derived from the ADAS 3D software seemed to be related to cardiac events in the follow-up, but this might be imputable to the restricted number of patients enrolled in the study.

Programmed Ventricular Stimulation as an Additional Primary Prevention Risk Stratification Tool in Arrhythmogenic Right Ventricular Cardiomyopathy: A Multinational Study.

BACKGROUND: A novel risk calculator based on clinical characteristics and noninvasive tests that predicts the onset of clinical sustained ventricular arrhythmias (VA) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) has been proposed and validated by recent studies. It remains unknown whether programmed ventricular stimulation (PVS) provides additional prognostic value. METHODS: All patients with a definite ARVC diagnosis, no history of sustained VAs at diagnosis, and PVS performed at baseline were extracted from 6 international ARVC registries. The calculator-predicted risk for sustained VA (sustained or implantable cardioverter defibrillator treated ventricular tachycardia [VT] or fibrillation, [aborted] sudden cardiac arrest) was assessed in all patients. Independent and combined performance of the risk calculator and PVS on sustained VA were assessed during a 5-year follow-up period. RESULTS: Two hundred eighty-eight patients (41.0±14.5 years, 55.9% male, right ventricular ejection fraction 42.5±11.1%) were enrolled. At PVS, 137 (47.6%) patients had inducible ventricular tachycardia. During a median of 5.31 [2.89-10.17] years of follow-up, 83 (60.6%) patients with a positive PVS and 37 (24.5%) with a negative PVS experienced sustained VA (P<0.001). Inducible ventricular tachycardia predicted clinical sustained VA during the 5-year follow-up and remained an independent predictor after accounting for the calculator-predicted risk (HR, 2.52 [1.58-4.02]; P<0.001). Compared with ARVC risk calculator predictions in isolation (C-statistic 0.72), addition of PVS inducibility showed improved prediction of VA events (C-statistic 0.75; log-likelihood ratio for nested models, P<0.001). PVS inducibility had a 76% [67-84] sensitivity and 68% [61-74] specificity, corresponding to log-likelihood ratios of 2.3 and 0.36 for inducible (likelihood ratio+) and noninducible (likelihood ratio-) patients, respectively. In patients with a ARVC risk calculator-predicted risk of clinical VA events <25% during 5 years (ie, low/intermediate subgroup), PVS had a 92.6% negative predictive value. CONCLUSIONS: PVS significantly improved risk stratification above and beyond the calculator-predicted risk of VA in a primary prevention cohort of patients with ARVC, mainly for patients considered to be at low and intermediate risk by the clinical risk calculator.

Microelectrode voltage mapping for substrate assessment in catheter ablation of ventricular tachycardia: A dual-center experience.

INTRODUCTION: The assessment of the ventricular myocardial substrate critically depends on the size of mapping electrodes, their orientation with respect to wavefront propagation, and interelectrode distance. We conducted a dual-center study to evaluate the impact of microelectrode mapping in patients undergoing catheter ablation (CA) of ventricular tachycardia (VT). METHODS: We included 21 consecutive patients (median age, 68 [12], 95% male) with structural heart disease undergoing CA for electrical storm (n = 14) or recurrent VT (n = 7) using the QDOT Micro catheter and a multipolar catheter (PentaRay, n = 9). The associations of peak-to-peak maximum standard bipolar (BVc ) and minibipolar (PentaRay, BVp ) with microbipolar (BVµMax ) voltages were respectively tested in sinus rhythm with mixed effect models. Furthermore, we compared the features of standard bipolar (BE) and microbipolar (µBE) electrograms in sinus rhythm at sites of termination with radiofrequency energy. RESULTS: BVµMax was moderately associated with both BVc (ß = .85, p < .01) and BVp (ß = .56, p < .01). BVµMax was 0.98 (95% CI: 0.93-1.04, p < .01) mV larger than corresponding BVc , and 0.27 (95% CI: 0.16-0.37, p < .01) mV larger than matching BVp in sinus rhythm, with higher percentage differences in low voltage regions, leading to smaller endocardial dense scar (2.3 [2.7] vs. 12.1 [17] cm2 , p < .01) and border zone (3.2 [7.4] vs. 4.8 [20.1] cm2 , p = .03) regions in microbipolar maps compared to standard bipolar maps. Late potentials areas were nonsignificantly greater in microelectrode maps, compared to standard electrode maps. At sites of VT termination (n = 14), µBE were of higher amplitude (0.9 [0.8] vs. 0.4 [0.2] mV, p < .01), longer duration (117 [66] vs. 74 [38] ms, p < .01), and with greater number of peaks (4 [2] vs. 2 [1], p < .01) in sinus rhythm compared to BE. CONCLUSION: microelectrode mapping is more sensitive than standard bipolar mapping in the identification of viable myocytes in SR, and may facilitate recognition of targets for CA.

Incidence of ventricular arrhythmias related to COVID infection and vaccination in patients with Brugada syndrome: Insights from a large Italian multicenter registry based on continuous rhythm monitoring.

INTRODUCTION: Brugada syndrome (BrS) has a dynamic ECG pattern that might be revealed by certain conditions such as fever. We evaluated the incidence and management of ventricular arrhythmias (VAs) related to COVID-19 infection and vaccination among BrS patients carriers of an implantable loop recorder (ILR) or implantable cardioverter-defibrillator (ICD) and followed by remote monitoring. METHODS: This was a multicenter retrospective study. Patients were carriers of devices with remote monitoring follow-up. We recorded VAs 6 months before COVID-19 infection or vaccination, during infection, at each vaccination, and up to 6-month post-COVID-19 or 1 month after the last vaccination. In ICD carriers, we documented any device intervention. RESULTS: We included 326 patients, 202 with an ICD and 124 with an ILR. One hundred and nine patients (33.4%) had COVID-19, 55% of whom developed fever. Hospitalization rate due to COVID-19 infection was 2.76%. After infection, we recorded only two ventricular tachycardias (VTs). After the first, second, and third vaccines, the incidence of non-sustained ventricular tachycardia (NSVT) was 1.5%, 2%, and 1%, respectively. The incidence of VT was 1% after the second dose. Six-month post-COVID-19 healing or 1 month after the last vaccine, we documented NSVT in 3.4%, VT in 0.5%, and ventricular fibrillation in 0.5% of patients. Overall, one patient received anti-tachycardia pacing and one a shock. ILR carriers had no VAs. No differences were found in VT before and after infection and before and after each vaccination. CONCLUSIONS: From this large multicenter study conducted in BrS patients, followed by remote monitoring, the overall incidence of sustained VAs after COVID-19 infection and vaccination is relatively low.

Implantable defibrillator-detected heart failure status predicts ventricular tachyarrhythmias.

INTRODUCTION: The prediction of ventricular tachyarrhythmias among patients with implantable cardioverter defibrillators is difficult with available clinical tools. We sought to assess whether in patients with heart failure (HF) and reduced ejection fraction with defibrillators, physiological sensor-based HF status, as summarized by the HeartLogic index, could predict appropriate device therapies. METHODS: Five hundred and sixty-eight consecutive HF patients with defibrillators (n = 158, 28%) or cardiac resynchronization therapy-defibrillators (n = 410, 72%) were included in this prospective observational multicenter analysis. The association of both HeartLogic index and its physiological components with defibrillator shocks and overall appropriate therapies was assessed in regression and time-dependent Cox models. RESULTS: Over a follow-up of 25 (15-35) months, 122 (21%) patients received an appropriate device therapy (shock, n = 74, 13%), while the HeartLogic index crossed the threshold value (alert, HeartLogic ≥ 16) 1200 times (0.71 alerts/patient-year) in 370 (65%) subjects. The occurrence of ≥1 HeartLogic alert was significantly associated with both appropriate shocks (Hazard ratios [HR]: 2.44, 95% confidence interval [CI]: 1.49-3.97, p = .003), and any appropriate defibrillator therapies. In multivariable time-dependent Cox models, weekly IN-alert state was the strongest predictor of appropriate defibrillator shocks (HR: 2.94, 95% CI: 1.73-5.01, p < .001) and overall therapies. Compared with stable patients, patients with appropriate shocks had significantly higher values of HeartLogic index, third heart sound amplitude, and resting heart rate 30-60 days before device therapy. CONCLUSION: The HeartLogic index is an independent dynamic predictor of appropriate defibrillator therapies. The combined index and its individual physiological components change before the arrhythmic event occurs.

Catheter ablation approach and outcome in HIV+ patients with recurrent atrial fibrillation.

INTRODUCTION: Earlier studies have shown a clear association between severity of human immunodeficiency virus (HIV) infection and incident atrial fibrillation (AF). We present the long-term outcome of catheter ablation (CA) and electrophysiological characteristics in HIV+ AF patients. METHODS: This study evaluated 1438 consecutive AF patients [31 (2.15%) with HIV and 1407 (97.8%) without HIV diagnosis] undergoing their first CA at our center. A total of 31 HIV patients and 31 controls were generated by propensity matching, based on calculated risk factor scores, using a logistic model. During first procedure, all received isolation of pulmonary vein (PV) + posterior wall and superior vena cava. Non-PV triggers, defined as ectopic triggers originating from sites other than PVs, were identified at the redo ablation with high-dose isoproterenol challenge. RESULTS: Clinical characteristics were not different between the groups. When compared to the control, by the end of 5 years after the first procedure, recurrence was significantly greater in HIV group [100% vs. 54%, p < .001]. Among patients that underwent redo ablation non-PV triggers were higher in HIV group [93.5% vs. 54%, p < .001], and most frequently originated from the coronary sinus [67.7% vs. 45.2%, p < .001] and left atrial appendage [41.9% vs. 25.8%, p < .001]. After focal ablation of non-PV trigger, no difference in arrhythmia recurrence between two groups [80.6% vs. 87.1%, p = .753] at 1-year follow up was found. CONCLUSION: Our findings suggest that non-PV triggers are highly prevalent in HIV+ AF patients resulting in higher rate of the mid- and long-term arrhythmia recurrence.

Arrhythmic risk stratification in arrhythmogenic right ventricular cardiomyopathy.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heritable cardiomyopathy characterized by a predominantly arrhythmic presentation. It represents the leading cause of sudden cardiac death (SCD) among athletes and poses a significant morbidity threat in the general population. As a causative treatment for ARVC is still not available, the placement of an implantable cardioverter defibrillator represents the current cornerstone for SCD prevention in this setting. Thanks to international ARVC-dedicated efforts, significant steps have been achieved in recent years towards an individualized, patient-centred risk stratification approach. A novel risk calculator algorithm estimating the 5-year risk of arrhythmias of patients with ARVC has been introduced in clinical practice and subsequently validated. The purpose of this article is to summarize the body of evidence that has allowed the development of this tool and to discuss the best way to implement its use in the care of an individual patient.

How an innovative catheter with temperature control and very high-power, short-duration ablation changed our approach to the treatment of persistent atrial fibrillation.

Ablation targets of persistent atrial fibrillation remain poorly understood nowadays: due to structural alterations of the left atrium, isolation of the pulmonary veins alone has proved ineffective. New ablation targets such as the posterior wall, coronary sinus, and left atrial appendage were then sought. A new catheter (QDOT Micro™) has recently been released, which has the potential to increase the safety and efficacy of the procedure: it is connected to a new radiofrequency generator that allows for temperature-controlled ablation by reducing power and increasing irrigation with the increase in tissue temperature and allows to deliver power up to 90 W for few seconds (very high-power short-duration).

Arrhythmic risk prediction in arrhythmogenic right ventricular cardiomyopathy: external validation of the arrhythmogenic right ventricular cardiomyopathy risk calculator.

AIMS: Arrhythmogenic right ventricular cardiomyopathy (ARVC) causes ventricular arrhythmias (VAs) and sudden cardiac death (SCD). In 2019, a risk prediction model that estimates the 5-year risk of incident VAs in ARVC was developed (ARVCrisk.com). This study aimed to externally validate this prediction model in a large international multicentre cohort and to compare its performance with the risk factor approach recommended for implantable cardioverter-defibrillator (ICD) use by published guidelines and expert consensus. METHODS AND RESULTS: In a retrospective cohort of 429 individuals from 29 centres in North America and Europe, 103 (24%) experienced sustained VA during a median follow-up of 5.02 (2.05-7.90) years following diagnosis of ARVC. External validation yielded good discrimination [C-index of 0.70 (95% confidence interval-CI 0.65-0.75)] and calibration slope of 1.01 (95% CI 0.99-1.03). Compared with the three published consensus-based decision algorithms for ICD use in ARVC (Heart Rhythm Society consensus on arrhythmogenic cardiomyopathy, International Task Force consensus statement on the treatment of ARVC, and American Heart Association guidelines for VA and SCD), the risk calculator performed better with a superior net clinical benefit below risk threshold of 35%. CONCLUSION: Using a large independent cohort of patients, this study shows that the ARVC risk model provides good prognostic information and outperforms other published decision algorithms for ICD use. These findings support the use of the model to facilitate shared decision making regarding ICD implantation in the primary prevention of SCD in ARVC.

Etiology and device therapy in complete atrioventricular block in pediatric and young adult population: Contemporary review and new perspectives.

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.

Stepwise endo-/epicardial catheter ablation for atrial fibrillation: The Mediterranea approach.

BACKGROUND: Outcomes of catheter ablation (CA) among patients with nonparoxysmal atrial fibrillation (AF) are largely disappointing. OBJECTIVE: We sought to evaluate the feasibility, effectiveness, and safety of a single-stage stepwise endo-/epicardial approach in patients with persistent/longstanding-persistent AF. METHODS: We enrolled 25 consecutive patients with symptomatic persistent (n = 4) or longstanding-persistent (n = 21) AF and at least one prior endocardial procedure, who underwent CA using an endo-/epicardial approach. Our anatomical stepwise protocol included multiple endocardial as well as epicardial (Bachmann's bundle [BB] and ligament of Marshall ablations) components, and entailed ablation of atrial tachycardias emerging during the procedure. The primary outcome was freedom from any AF/atrial tachycardia episode after a 3-month blanking period. The secondary outcome was patients' symptom status during follow-up. RESULTS: The stepwise endo-/epicardial approach allowed sinus rhythm restoration in 72% of patients, either directly (n = 6, 24%) or after AF organization into atrial tachycardia (n = 12, 48%). BB's ablation was commonly implicated in arrhythmia termination. After a median follow-up of 266 days (interquartile range, 96 days), survival free from AF/atrial tachycardia was 88%. Antiarrhythmic drugs could be discontinued in 22 patients (88%). As compared to baseline, more patients were asymptomatic at 9-month follow-up (0% vs. 56%, p = .02). Five patients (20%) developed mild medical complications, whereas one subject (4%) had severe kidney injury requiring dialysis. CONCLUSION: A single-stage endo-/epicardial CA resulted in favorable rhythm and symptom outcomes in a cohort of patients with symptomatic persistent/longstanding-persistent AF and one or more prior endocardial procedures. Epicardial ablation of BB was commonly implicated in procedural success.

Intraprocedural PRAETORIAN score for early assessment of S-ICD implantation: A proof-of-concept study.

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 < .001). When assessing a per-step agreement, a very high-degree of concordance in evaluating Step 1 of the PS was observed (95%, 0.81-κ; p < .001). A complete agreement in Step 2-3 (100%, 1.00-κ; p < .001) of the PS was reported. In comparison with our historical cohort, procedural time in the IP-PS cohort did not increase (45 [41-52] vs. 45 [39-49] min; p = .351) while the expected increase in fluoroscopy time resulted scarce (15 [10-15] s). CONCLUSION: An IP-PS can be reliably obtained using fluoroscopy guidance during S-ICD implantation, without a significant increase in procedural duration and may serve as guidance for implanting physicians, to avoid postprocedural S-ICD repositioning, leading to patient discomfort and significantly enhancing infective risks. IP-PS showed a very high agreement with the PP-PS obtained from two-views chest X-ray.

Cardiac Biomarkers and Autoantibodies in Endurance Athletes: Potential Similarities with Arrhythmogenic Cardiomyopathy Pathogenic Mechanisms.

The "Extreme Exercise Hypothesis" states that when individuals perform training beyond the ideal exercise dose, a decline in the beneficial effects of physical activity occurs. This is due to significant changes in myocardial structure and function, such as hemodynamic alterations, cardiac chamber enlargement and hypertrophy, myocardial inflammation, oxidative stress, fibrosis, and conduction changes. In addition, an increased amount of circulating biomarkers of exercise-induced damage has been reported. Although these changes are often reversible, long-lasting cardiac damage may develop after years of intense physical exercise. Since several features of the athlete's heart overlap with arrhythmogenic cardiomyopathy (ACM), the syndrome of "exercise-induced ACM" has been postulated. Thus, the distinction between ACM and the athlete's heart may be challenging. Recently, an autoimmune mechanism has been discovered in ACM patients linked to their characteristic junctional impairment. Since cardiac junctions are similarly impaired by intense physical activity due to the strong myocardial stretching, we propose in the present work the novel hypothesis of an autoimmune response in endurance athletes. This investigation may deepen the knowledge about the pathological remodeling and relative activated mechanisms induced by intense endurance exercise, potentially improving the early recognition of whom is actually at risk.