Background: Electroanatomic voltage mapping (EVM) is a promising modality for guiding endomyocardial biopsies (EMBs). However, few data support its feasibility and safety. We now report the largest cohort of patients undergoing EVM-guided EMBs to show its diagnostic yield and to compare it with a cardiac magnetic resonance (CMR)–guided approach. Methods: We included 162 consecutive patients undergoing EMB at our institution from 2010 to 2019. EMB was performed in pathological areas identified at EVM and CMR. CMR and EVM sensitivity and specificity regarding the identification of pathological substrates of myocardium were evaluated according to EMB results. Results: Preoperative CMR showed late gadolinium enhancement in 70% of the patients, whereas EVM identified areas of low voltage in 61%. Right (73%), left (19%), or both ventricles (8%) underwent sampling. EVM proved to have sensitivity similar to CMR (74% versus 77%), with specificity being 70% and 47%, respectively. In 12 patients with EMB-proven cardiomyopathy, EVM identified pathological areas that had been undetected at CMR evaluation. Sensitivity of pooled EVM and CMR was as high as 95%. EMB analysis allowed us to reach a new diagnosis, different from the suspected clinical diagnosis, in 39% of patients. The complications rate was low, mostly related to vascular access, with no patients requiring urgent management. Conclusions: EVM proved to be a promising tool for targeted EMB because of its sensitivity and specificity for identification of myocardial pathological substrates. EVM was demonstrated to have accuracy similar to CMR. EVM and CMR together conferred a positive predictive value of 89% on EMB.

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. 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). 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. On the upper side, the four variables included in the score and their respective weight is shown. The score was evaluated in 605 heart failure (HF) patients with impaired (<50%) left ventricular ejection fraction (LVEF) undergoing atrial fibrillation (AF) catheter ablation (CA), recruited from 8 European centres. Based on the 2021 universal definition of HF, 12-month post-procedural LVEF improvement was observed in 427 (70%) patients (Responders). Responders were identified if: (i) in case of baseline LVEF between 40% and 50%: LVEF improvement to more than ≥50%; (ii) in case of baseline LVEF 40%. In this external evaluation study, the score accurately predicted the response rate [area under the curve (AUC) 0.859, P < .001] with a good calibration (P = .296), as shown on the lower right side. In the lower left side, the specific response rate stratified according to the score value is represented.

Background - Arrhythmogenic left ventricular cardiomyopathy (ALVC) is an under-characterized phenotype of arrhythmogenic cardiomyopathy involving the LV ab initio. ALVC was not included in the 2010 International Task Force Criteria (ITFC) for arrhythmogenic right ventricular cardiomyopathy diagnosis and data regarding this phenotype are scarce. Methods - clinical characteristics were reported from all consecutive patients diagnosed with ALVC, defined as a LV isolated late gadolinium enhancement (LGE) and fibro-fatty replacement (FFR) at cardiac magnetic resonance (CMR) plus genetic variants associated with ARVC and/or of an endomyocardial biopsy (EMB) showing FFR complying with the 2010 ITFC in the LV. Results - twenty-five ALVC patients (53 [48-59] years, 60% male) were enrolled. T-wave inversion in infero-lateral and left precordial leads were the most common ECG abnormalities. Overall arrhythmic burden at study inclusion was 56%. CMR showed LV LGE in the LV lateral and/or posterior basal segments in all patients. In 72% of the patients an invasive evaluation was performed, in which electroanatomical voltage mapping (EVM) and EVM-guided EMB showed low endocardial voltages and FFR in areas of LGE presence. Genetic variants in desmosomal genes (desmoplakin and desmoglein-2) were identified in 12/25 of the cohort presenting pathogenic/likely-pathogenic variants. A definite/borderline 2010 ITFC ARVC diagnosis was reached only in 11/25 patients. Conclusions - ALVC presents with a preferential involvement of the lateral and/or postero-lateral basal LV and is associated mostly with variants in desmoplakin and desmoglein-2 genes. An amendment to the current ITFC is reasonable to better diagnose ALVC patients.

Background: Left atrial substrate may have mechanistic relevance for ablation of atrial fibrillation (AF). We sought to analyze the relationship between low‐voltage zones (LVZs), transition zones, and AF recurrence in patients undergoing pulmonary vein isolation. Methods and Results: We conducted a prospective multicenter study on consecutive patients undergoing pulmonary vein isolation‐only approach. LVZs and transition zones (0.5–1 mV) were analyzed offline on high‐density electroanatomical maps collected before pulmonary vein isolation. Overall, 262 patients (61±11 years, 31% female) with paroxysmal (130 pts) or persistent (132 pts) AF were included. After 28 months of follow‐up, 73 (28%) patients experienced recurrence. An extension of more than 5% LVZ in paroxysmal AF and more than 15% in persistent AF was associated with recurrence (hazard ratio [HR], 4.4 [95% CI, 2.0–9.8], P <0.001 and HR, 1.9 [95% CI, 1.1–3.7], P =0.04, respectively). Significant association was found between LVZs and transition zones and between LVZs and left atrial volume index (LAVI) (both P <0.001). Thirty percent of patients had significantly increased LAVI without LVZs. Eight percent of patients had LVZs despite normal LAVI. Older age, female sex, oncological history, and increased AF recurrence characterized the latter subgroup. Conclusions: In patients undergoing first pulmonary vein isolation, the impact of LVZs on outcomes occurs with lower burden in paroxysmal than persistent AF, suggesting that not all LVZs have equal prognostic implications. A proportional area of moderately decreased voltages accompanies LVZs, suggesting a continuous substrate instead of the dichotomous division of healthy or diseased tissue. LAVI generally correlates with LVZs, but a small subgroup of patients may present with disproportionate atrial remodeling, despite normal LAVI.

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. 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. 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. 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. In our large cohort of 370 Brugada syndrome (BrS) patients from 18 international centers monitored continuously with an implantable loop recorder (ILR) for 3 years, 25.4% of the patients experienced an arrhythmic event (per-patient analysis). Specifically, 16% experienced an atrial arrhythmia, 5% a ventricular arrhythmia (VA), and 8% a bradyarrhythmia (per-event analysis). The occurrence of arrhythmic syncope in the whole cohort was 8.6% (32/370). The induction of ventricular fibrillation (VF) during an electrophysiological (EP) study emerged as the only predictor of VAs in this cohort. The clinical implications are detailed in the lower right part of the figure (SCD, sudden cardiac death; PM, pacemaker; ICD, implantable cardioverter-defibrillator; Drugs include anti-arrhythmic drugs and anticoagulants; CA, catheter ablation for atrial arrhythmias or VAs).