Recurrences after Pulsed Field Ablation of Atrial Fibrillation: Incidence, Mechanisms, Predictors, and Comparison with Thermal Energy.

Pulsed Field Ablation (PFA) is the latest and most intriguing technology for catheter ablation of atrial fibrillation, due to its capability to generate irreversible and cardiomyocytes-selective electroporation of cell membranes by delivering microsecond-lasting high-voltage electrical fields, leading to high expectations. The first trials to assess the clinical success of PFA, reported an arrhythmia-free survival at 1-year of 78.5%, while other trials showed less enthusiastic results: 66.2% in paroxysmal and 55.1% in persistent AF. Nevertheless, real world data are encouraging. The isolation of pulmonary veins with PFA is easily achieved with 100% acute success. Systematic invasive remapping showed a high prevalence of durable pulmonary vein isolation at 75 and 90 days (range 84-96%), which were significatively lower in redo procedures (64.3%). The advent of PFA is prompting a reconsideration of the role of the autonomic nervous system in AF ablation, as PFA-related sparing of the ganglionated plexi could lead to the still undetermined effect on late arrhythmias' recurrences. Moreover, a new concept of a blanking period could be formulated with PFA, according to its different mechanism of myocardial injury, with less inflammation and less chronic fibrosis. Finally, in this review, we also compare PFA with thermal energy.

In vivo Lesion Index (LSI) validation in percutaneous radiofrequency catheter ablation.

INTRODUCTION: Lesion Index (LSI) has been developed to predict lesion efficacy during radiofrequency (RF) catheter ablation. However, its value in predicting lesions size has still to be established. The aim of our study was to assess the lesions size reproducibility for prespecified values of LSI reached during RF delivery in an in vivo beating heart. METHODS: Ablation lesions were created with different values of LSI in seven domestic pigs by means of a contact force-sensing catheter (TactiCathTM , Abbott). Lesions were identified during RF delivery by means of a three-dimensional mapping system (EnSiteTM Precision, Abbott) and measured after heart explantation. Histology was carried out after gross examination on the first three lesions to confirm the accuracy of the macroscopic evaluation. RESULTS: A total of 64 myocardial lesions were created. Thirty-nine lesions were excluded from the analysis for the following reasons: histological confirmation of macroscopic lesion measurement (n = 3), transmurality (n = 24), unfavorable anatomic position (n = 10), not macroscopically identifiable (n = 2). In a final set of 25 nontransmural lesions, injury width and depth were, respectively, 4.6 ± 0.6 and 2.6 ± 0.8 mm for LSI = 4, 7.3 ± 0.8 and 4.7 ± 0.6 mm for LSI = 5, and 8.6 ± 1.2 and 7.2 ± 1.1 mm for LSI = 6. A strong linear correlation was observed between LSI and lesion width (r = .87, p < .00001) and depth (r = .89, p < .00001). Multiple linear regression analysis identified LSI as the only ablation parameter that significantly predicted lesion width (p < .001) and depth (p < .001). CONCLUSION: In our in vivo study, LSI proved highly predictive of lesion size and depth.

Anticoagulation after catheter ablation of atrial fibrillation: An unnecessary evil? A systematic review and meta-analysis.

BACKGROUND: Anticoagulation in patients with atrial fibrillation (AF) is currently based on clinical parameters (CHA2 DS 2 -VASc score) that have been shown to predict cerebrovascular events (CVE). Controversy exists as to whether CVE risk persists unmodified after successful catheter ablation, as observational studies suggest a lower risk of CVE. Current guidelines recommend continued oral anticoagulation (OAC) based on the CHA 2 DS 2 -VASc score risk profile. METHODS: We conducted a systematic literature review of all studies published up to July 31, 2018, that reported CVE after catheter ablation of AF and compared patients on or off OAC. Random-effects models were used to demonstrate the risk of CVE and major bleeding in on-OAC vs off-OAC patients. This analysis was further stratified by CHADS2 and CHA 2 DS 2 -VASc score. RESULTS: We retained 16 studies, 10 prospective cohort and 6 retrospective cohort, that met inclusion criteria, and which enrolled 25 177 patients: 13 166 off-OAC and 12 011 on-OAC. No significant difference in the incidence of CVE emerged between on-OAC and off-OAC patients after AF ablation (risk ratio, 0.66; confidence interval [CI], 0.38, 1.15). Similar results were found after stratification by CHADS2 and CHA 2 DS 2 -VASc score. Off-OAC patients suffered significantly less bleeding than those on OAC (RR, 0.17; CI, 0.09, 0.34). Of note, the percentage of patients with AF recurrence impacts the treatment effect in the two groups ( P = 0.001). CONCLUSIONS: In this metanalysis, the risk-benefit ratio favored the suspension of OAT after successful AF ablation even in patients at moderate-high risk. Whether the reported results can be extended also to non-vitamin K antagonist oral anticoagulants warrants further investigations.

Prospective European survey on atrial fibrillation ablation: clinical characteristics of patients and ablation strategies used in different countries.

BACKGROUND: Atrial fibrillation (AF) ablation is widely adopted. Our aim was to conduct a prospective multicenter survey to verify patients' characteristics, approaches, and technologies adopted across Europe. METHODS AND RESULTS: A total of 35 centers in 12 countries actively participated in the study and 940 patients (median age 60 years) were enrolled. AF was paroxysmal, persistent, and long-lasting persistent in 52.4%, 36%, and 11.6% of patients, respectively; 95.5% of patients were symptomatic and 91.4% were refractory to antiarrhythmic therapy. Redo procedures were performed in 20.9%. Pulmonary vein isolation (PVI) emerged as the cornerstone of ablative therapy and has been performed in 98.7% of procedures, with confirmation of PVI in 92.9% of cases. The ablation of nonparoxysmal AF was not generally limited to isolating the PVs and several adjunctive approaches are adopted, particularly in the case of long-lasting persistent AF. Linear lesions or elimination of complex fractionated atrial electrograms were more frequently added. Circular mapping catheters and imaging techniques were seen to be used in about two-thirds of cases. Radiofrequency energy was delivered through open irrigated catheters in 68% of cases. CONCLUSIONS: European centers are largely following the recommendations of the guidelines and the expert consensus documents for AF ablation. AF ablation is mainly performed in relatively young patients with symptomatic drug refractory AF and no or minimal heart disease. Patients with paroxysmal AF are the most frequently treated with a quite uniform ablative approach across Europe. A less standardized approach was observed in nonparoxysmal AF patients.

Systematic Review on S-ICD Lead Extraction.

BACKGROUND AND PURPOSE: Subcutaneous implantable cardioverter defibrillators (S-ICDs) have emerged in recent years as a valid alternative to traditional transvenous ICDs (TV-ICDs). Therefore, the number of S-ICD implantations is rising, leading to a consequent increase in S-ICD-related complications sometimes requiring complete device removal. Thus, the aim of this systematic review is to gather all the available literature on S-ICD lead extraction (SLE), with particular reference to the type of indication, techniques, complications and success rate. METHODS: Studies were identified by searching electronic databases (Medline via PubMed, Scopus and Web of Science) from inception to 21 November 2022. The search strategy adopted was developed using the following key words: subcutaneous, S-ICD, defibrillator, ICD, extraction, explantation. Studies were included if they met both of the following criteria: (1) inclusion of patients with S-ICD; (2) inclusion of patients who underwent SLE. RESULTS: Our literature search identified 238 references. Based on the abstract evaluation, 38 of these citations were considered potentially eligible for inclusion, and their full texts were analyzed. We excluded 8 of these studies because no SLE was performed. Eventually, 30 studies were included, with 207 patients who underwent SLE. Overall, the majority of SLEs were performed for non-infective causes (59.90%). Infection of the device (affecting either the lead or the pocket) was the cause of SLE in 38.65% of cases. Indication data were not available in 3/207 cases. The mean dwelling time was 14 months. SLEs were performed using manual traction or with the aid of a tool designed for transvenous lead extraction (TLE), including either a rotational or non-powered mechanical dilator sheath. CONCLUSIONS: SLE is performed mainly for non-infective causes. Techniques vary greatly across different studies. Dedicated tools for SLE might be developed in the future and standard approaches should be defined. In the meantime, authors are encouraged to share their experience and data to further refine the existing variegated approaches.

[Management of infections in patients with cardiac implantable electronic devices]. / La gestione delle infezioni nei pazienti portatori di dispositivi impiantabili.

Implantation of pacemakers and cardiac defibrillators is a life-saving treatment but can put our patients at risk of infections, increasing morbidity and mortality and prolonging hospitalization with a significant financial healthcare burden. A preventive strategy is crucial but, while several strategies such as administration of intravenous antibiotic therapy before implantation are well recognized, other uncertainties remain. The main gaps regard the use of periprocedural measures, including antibacterial envelope to prevent device infection, the appropriate management of antithrombotic therapy before and after device implantation and timing of device reimplantation. To address these issues, some important randomized clinical trials and a European Heart Rhythm Association consensus document have recently been published. The aim of this article is to review current knowledge on the management of infections in patients with cardiac implantable electronic devices to help not only electrophysiologists, but also physicians in their daily practice.

Prevalence of asymptomatic atrial fibrillation among multimorbid elderly patients: diagnostic implications.

Advancing age of the global population is one of the main reasons for the uprising trend in atrial fibrillation (AF) prevalence worldwide leading to a proper "AF epidemic". Strictly related to the increasing prevalence of AF in the elderly is the relevant burden of cardiac end extra-cardiac comorbidities that these patients show. Patients with AF are frequently asymptomatic (i.e., asymptomatic or silent AF) and thus the arrhythmia is generally underdiagnosed. Detainment of proper treatment in elderly and comorbid patients may potentially result in significant morbidity and mortality. Therefore, in recent years, several screening strategies (systematic vs opportunistic screening) for asymptomatic AF have been developed and early diagnosis of AF is an important treatment goal that can improve prognosis. This review will focus on the prevalence of asymptomatic AF in the elderly, frequently associated comorbidities, screening strategies, and implications for a correct AF diagnosis.

Therapeutic vs. prophylactic anticoagulation in COVID-19 patients: a systematic review and meta-analysis of real-world studies.

INTRODUCTION: 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. EVIDENCE ACQUISITION: Real-world studies (RWS) were identified by searching electronic databases from inception to 31st October, 2021. Randomized controlled trials were excluded. Mortality and bleedings were considered as primary and secondary outcomes, respectively. EVIDENCE SYNTHESIS: 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.

[Arrhythmias and sudden death in neuromuscular disorders]. / Aritmie e morte improvvisa nelle malattie neuromuscolari.

Neuromuscular diseases (NMD) are a broadly defined group of disorders that all involve injury or dysfunction of peripheral nerves, neuromuscular junction or muscle, often with dominant or recessive pattern of inheritance. Cardiac involvement is uncommon, in particular with cardiomyopathies and brady/tachyarrhythmias. The causes of cardiac involvement are unclear: replacement fibrosis, alteration of membrane permeability, sympathetic hyperactivity, or accumulation of toxic metabolites can play a role in the pathogenesis of cardiac disorders. The early diagnosis is of pivotal importance to prevent evolution of the disease: electrocardiographic alterations and arrhythmias, particularly if associated with family history for cardiomyopathy or sudden death, can be an early signal of cardiomyopathy associated with NMD. Genetic analysis can improve prognostic stratification, particularly related to arrhythmic risk, and guide to a tailored therapy.

Anticoagulation Issues in Patients with AF.

The evaluation of the risk of stroke for individual patients with atrial fibrillation (AF) is a crucial factor in the decision to provide anticoagulation therapy. Novel oral anticoagulants, as compared with warfarin, are associated with a lower or similar rate of stroke and systemic embolism and a lower rate of hemorrhagic stroke. These drugs are administered at a fixed dose, have a shorter peak action and half-life, and do not require international normalized ratio monitoring. After a successful AF ablation, oral anticoagulation therapy discontinuation seems to be feasible in patients with a CHADS2 score greater than or equal to 2 and normal left atrial (LA) function. However, larger prospective randomized trials are needed to confirm the safety of this strategy.

Bone-marrow-derived CXCR4-positive tissue-committed stem cell recruitment in human right ventricular remodeling.

The epicardium contributes to cardiac formation, particularly during embryogenesis. It remains to be seen if it is also involved in postnatal myocardial homeostasis. This study evaluates the topographic distribution of stem cells (c-Kit) and extracardiac progenitor cells (CXCR4+) and their contribution to ventricular remodeling in a model of pressure volume overload leading to right ventricle hypertrophy. Eleven specimens with hypoplastic left heart syndrome were evaluated and compared with 6 normal hearts from subjects matched for age and weight. All underwent Norwood procedure with the right ventricle becoming a systemic one, with pressure and volume overload leading to right ventricle remodeling. Transmural cardiac tissue samples from the right ventricle were analyzed by immunohistochemistry and morphometry. This is the first study to demonstrate that c-Kit-positive progenitor cells and tissue-committed stem cells (CXCR4+/CD45-) are higher in children with systemic right ventricle remodeling. We also show that the localization of cardiac progenitor and recruited CXCR4+ stem cells in the myocardium is site specific in hearts with right ventricle hypertrophy. These cells are mainly scattered in the interstitium of the epicardial layer. In contrast, myocyte proliferation is not a key process in right ventricular hypertrophy. Induced by the overexpression of SDF-1α by the myocardium, CXCR4 cell mobilization resembles SDF-1 homing factor distribution, showing transmural enhanced expression from the endocardium toward the epicardium. The study provides evidences of the site-specific epicardial localization of stem cells in a model of pressure/volume overload and suggests that the epicardium acts as a permissive niche in normal and pathologic conditions.