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Aims Clinical practice guidelines restrict rhythm control therapy to patients with symptomatic atrial fibrillation (AF). The EAST-AFNET 4 trial demonstrated that early, systematic rhythm control improves clinical outcomes compared to symptom-directed rhythm control. Methods and results This prespecified EAST-AFNET 4 analysis compared the effect of early rhythm control therapy in asymptomatic patients (EHRA score I) to symptomatic patients. Primary outcome was a composite of death from cardiovascular causes, stroke, or hospitalization with worsening of heart failure or acute coronary syndrome, analyzed in a time-to-event analysis. At baseline, 801/2633 (30.4%) patients were asymptomatic [mean age 71.3 years, 37.5% women, mean CHA2DS2-VASc score 3.4, 169/801 (21.1%) heart failure]. Asymptomatic patients randomized to early rhythm control (395/801) received similar rhythm control therapies compared to symptomatic patients [e.g. AF ablation at 24 months: 75/395 (19.0%) in asymptomatic; 176/910 (19.3%) symptomatic patients, P = 0.672]. Anticoagulation and treatment of concomitant cardiovascular conditions was not different between symptomatic and asymptomatic patients. The primary outcome occurred in 79/395 asymptomatic patients randomized to early rhythm control and in 97/406 patients randomized to usual care (hazard ratio 0.76, 95% confidence interval [0.6; 1.03]), almost identical to symptomatic patients. At 24 months follow-up, change in symptom status was not different between randomized groups (P = 0.19). Conclusion The clinical benefit of early, systematic rhythm control was not different between asymptomatic and symptomatic patients in EAST-AFNET 4. These results call for a shared decision discussing the benefits of rhythm control therapy in all patients with recently diagnosed AF and concomitant cardiovascular conditions (EAST-AFNET 4; ISRCTN04708680; NCT01288352; EudraCT2010-021258-20).

Aims Patients with cardiac disease are considered high risk for poor outcomes following hospitalization with COVID-19. The primary aim of this study was to evaluate heterogeneity in associations between various heart disease subtypes and in-hospital mortality. Methods and results We used data from the CAPACITY-COVID registry and LEOSS study. Multivariable Poisson regression models were fitted to assess the association between different types of pre-existing heart disease and in-hospital mortality. A total of 16 511 patients with COVID-19 were included (21.1% aged 66–75 years; 40.2% female) and 31.5% had a history of heart disease. Patients with heart disease were older, predominantly male, and often had other comorbid conditions when compared with those without. Mortality was higher in patients with cardiac disease (29.7%; n = 1545 vs. 15.9%; n = 1797). However, following multivariable adjustment, this difference was not significant [adjusted risk ratio (aRR) 1.08, 95% confidence interval (CI) 1.02–1.15; P = 0.12 (corrected for multiple testing)]. Associations with in-hospital mortality by heart disease subtypes differed considerably, with the strongest association for heart failure (aRR 1.19, 95% CI 1.10–1.30; P Conclusion Considerable heterogeneity exists in the strength of association between heart disease subtypes and in-hospital mortality. Of all patients with heart disease, those with heart failure are at greatest risk of death when hospitalized with COVID-19. Serious cardiac complications are rare during hospitalization.

Background New methods to identify patients who truly benefit from primary prophylactic implantable cardioverter defibrillation (ICD) are urgently needed. T-wave alternans (TWA) represents a beat-to-beat fluctuation in the morphology of the ST-segment and T-wave. It has been shown to associate with arrhythmogenesis of heart and sudden cardiac death [1]. We hypothised that TWA might associate with benefit from ICD implantation in primary prevention. Methods In EU-CERT-ICD study, we prospectively enrolled 2327 primary prophylactic ICD candidates from 15 European countries. A 24-hours Holter-monitoring was taken from all recruited patients at enrolment. TWA was assessed from Holter-monitoring using MMA method with Getemed Cardioday software. To assess the benefit from ICD treatment, we used outcomes all-cause mortality, appropriate shock and survival benefit. We conducted Cox regression model, competing risk regression model and propensity score adjusted Cox regression model. TWA was assessed both as contiguous variable and with cut-off points Results Final cohort included 1,734 valid T-wave alternans samples, 1,211 patients with ICD and 523 control patients with conservative treatment, with mean follow-up time 2.3 years. TWA Conclusion T-wave alternans is poorly prognostic in primary prophylactic ICD patients. Altough it may predict life-threatening arrhythmias and sudden cardiac death in several patient populations, it cannot be used in assessing benefit from implantable cardioverter defibrillator in primary prevention among patients with ejection fraction ≤35%. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Community's 7th Framework Program FP7/2007-2013

Background Myocardial infarction (MI) results in altered mechanical loading and changes in the cardiac electrical properties. The infarct border zone is pro-arrhythmic but the exact role of mechano-electrical coupling remains unclear. Objective We studied spatial electrical heterogeneity in MI animals during acute afterload increase using a novel E-field methodology for high resolution mapping of local activation-repolarization intervals (ARI) in vivo. Methods Anterior-septal MI was induced in five domestic pigs by 120-minute occlusion of the left anterior descending artery followed by reperfusion. This led to an infarct size of 17.7±2.1% of the left ventricle. After 1 month, electro-anatomical mapping was performed before and during an acute afterload challenge induced by partially inflating a balloon in the descending aorta. A non-contact recording of a 64-electrode array was translated to 2048 non-contact electrograms distributed over the left ventricle. The non-contact electrograms were processed to determine the ARIs using a custom-made algorithm, previously validated against monophasic action potential recordings. Based on the contact map we defined border zone (BZ, voltage 0.5 to 1.5 mV) and remote (>1.5mV) regions. Heterogeneity was defined as the interquartile range (IQR) of ARIs in fixed neighborhoods of 1cm radius (figure 1A) and analyzed in 10 segments (5 BZ and 5 remote) of a modified version of the AHA model (49 segments by dividing the 16 non-apical segments). Other segments were discarded due to artefacts mainly caused by the array touching the septal and apical wall. Results Acute afterload challenge resulted in an increase of the systolic left ventricular pressure of 41.7±5.4% and increased left ventricular repolarization heterogeneity (IQR 4.03±1.23ms baseline to 4.85±1.38ms during inflation, p=0.004). There was a significant increase in heterogeneity in both BZ (4.78±1.60ms to 5.64±1.66ms, p=0.020) and remote (2.24±0.17ms to 3.00±0.86ms, p=0.034) regions (figure 1B). The IQR in the infarct BZ was higher compared to the remote zone at rest (4.78±1.60ms vs 2.24±0.17ms, p=0.010) as well as during inflation (5.64±1.66ms vs 3.00±0.86ms, p=0.008) (figure 1B). Both BZ and remote regions responded equally to acute afterload (p for interaction = 0.803). Conclusion Increased afterload leads to increased repolarization heterogeneity. This heterogeneity is higher in the infarct BZ. These alterations could provide a functional substrate for reentry. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): KU Leuven - C1 funding

Introduction Atrial Fibrillation (AF) is associated with an increased risk of stroke that can be mitigated with anticoagulation therapy. Opportunistic screening for AF for primary stroke prevention is recommended in subjects above 65. However, the paroxysmal and asymptomatic nature of AF hampers early detection with a single time point screening. Multiple time point measurements are superior to single time point measurements for the detection of AF. New technologies such as photoplethysmography (PPG) enable large scale AF screening with repetitive measurements at low-cost using only a smartphone. Purpose To explore an entirely online AF screening program in subjects with an elevated stroke risk. Methods The Belgian Heart Rhythm Association launched a digital marketing campaign, to promote AF screening during “The Belgian Week of the Heart Rhythm”. Candidates were referred to an online questionnaire to calculate their CHADS-VASC score. Subjects older than 18 with a CHADS-VASC score of 2 or more were allowed to enter the screening program. AF screening was performed with a PPG-based smartphone application. A 60-second PPG trace is captured by placing a fingertip on the smartphone's camera. The smartphone application analyses the PPG trace with an artificial intelligence software. Subjects were instructed to perform measurement twice daily and while experiencing symptoms over the course of 7 days. Measurements were classified as AF or non-AF by the algorithm and were reviewed by medical technicians. Results Of the 12.602 candidates who completed the questionnaire, 6.020 subjects met the inclusion criteria and were offered screening. However, only 2.111 (35%) participated in the screening program. The mean age of participants was 63±11 years, 37.3% was male, median CHADS-VASC was 2 (2–3). 257 participants (12.2%) were previously known with AF. In total 25.362 PPG recordings of 60 seconds were performed of which 258 demonstrated AF. AF was detected in 56 participants (2.7%). This was a new finding in 36 participants (1.7%) meaning that 64.3% of participants demonstrating AF were not previously known with AF. The number needed to screen was 58.6 to detect AF in a population without a history of AF and the number needed to invite was 167.2. Only 20 participants (7.8%) with a history of AF demonstrated AF during the screening program. Conclusions AF screening in subjects with an elevated stroke risk is feasible with an entirely online screening program without the need for medical hardware or medical personnel with an acceptable number needed to screen. However, this approach failed to target subjects in the highest age groups and since almost two thirds of the subjects interested in the screening program failed to commence screening, approaches to increase this response (specifically in high-risk groups) needs to be explored. Funding Acknowledgement Type of funding sources: None.

Background Although many adults with congenital heart disease (CHD) still die prematurely, end-of-life care for these patients receives limited attention. There are indications that current care provision at the end of life is burdensome, expensive, and not in line with patients' needs and preferences. We sought to analyse end-of-life care in adult CHD patients to determine whether health services need to be optimized. Purpose This study aimed to describe patterns of healthcare consumption of adults with CHD who died in the last year of life. Methods This retrospective mortality follow-back study used data of the BELgian COngenital heart disease Database combining Administrative and Clinical data (BELCODAC), including individually linked healthcare claims, death certificates and clinical data from adults with CHD in Flanders (Belgium). For this study, adults with CHD who died between 2007 and 2016 from any cause except sudden death, accident or violence, were selected for inclusion. Accidental, violent, and sudden deaths were identified based on causes of death and healthcare use in the last 3 months of life. Healthcare consumption was based on nomenclature codes derived from healthcare claims data. Results A total of 327 eligible patients (median age: 58 y; 54% women; 43% mild CHD; 45% moderate CHD; 11% complex CHD; 49% cardiovascular cause of death) were identified. During the last year of life, healthcare use increased substantially (Fig. 1). During the last month of life, 54% of patients were hospitalised, 55% visited the emergency department, and 15% were admitted to an intensive care unit at least once (Fig. 2). A total of 8% and 5% of patients underwent heart surgery or catherization in the last month of life, respectively. Furthermore, 70% of patients had at least one encounter with a general practitioner and 11% with a CHD specialist in the last month of life. Specialist palliative care was provided to 13% of patients in the last month of life. When looking at the subgroup of patients with CHD that died due to a cardiovascular cause, proportions of patients that were hospitalised or had visits at the emergency department or intensive care unit in the last month of life were similar (Fig. 2). However, these patients underwent more heart surgeries (11%) and catherizations (8%), had more encounters with CHD specialists (15%), and received remarkably less specialized palliative care (4%) in the last month of life. Conclusion Resource utilization increased substantially during the last year of life, resulting in high acute healthcare consumption in the last month of life. It is remarkable that only a minority of patients received palliative care, especially when looking at patients who died due to a cardiovascular cause. Our findings motivate the need to assess if and how end-of-life is planned for adults with CHD. Future studies using qualitative analyses and survey methodology are needed to optimize the management of end-of-life care. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Research Foundation Flanders, European Society of Cardiology, Koning Boudewijnstichting, National Foundation on Research in Pediatric Cardiology, Swedish Research Council for Health, Working Life and Welfare-FORTE

Introduction Leadless right ventricular (RV) pacing has been recently proposed as alternative to conventional pacemakers (PM's). While RV pacing with a conventional PM is known to cause deterioration of left ventricular (LV) and RV systolic function over time, the effects of leadless PM's are currently under-explored. In this prospective and randomized study, we hypothesized that the effect of leadless RV pacing over time on both LV and RV systolic function is not inferior to conventional RV pacing. Methods Fifty-one age-matched patients with a guideline indication for a PM were prospectively recruited and randomized to undergo implantation of either (i) a leadless PM, or (ii) a conventional PM. Patients underwent echocardiography prior to (BL), and at 6 and 12 months (M6 & M12) after PM implantation. All imaging after implantation was performed during active pacing. Analysis included LV ejection fraction (LVEF), LV global longitudinal strain (GLS), and RV free wall (FW) strain. Results Twenty-seven patients were implanted with a leadless PM, while twenty-four received a conventional PM. Median age was 82 (80–87) years. At BL, average LVEF and LV GLS were normal and similar in both groups. At M12, both LVEF (−12%) and LV GLS strain (−5%) decreased significantly in both study groups (ANOVA p0.05). Median pacing percentage was 68.2% and similar in both study groups (at all time-points p>0.05). Conclusions Both patients with leadless and conventional PM's demonstrate a decrease in LV and RV systolic function, 12 months after implantation. While LV function decrease was similar between both groups, RV function decrease was most prominent in patients treated with conventional PM's. Our data suggest that leadless pacing is not inferior to conventional pacing with regard to the effect on cardiac function. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Research Foundation Flanders (FWO) post-doc grant

Background Pulsed field ablation (PFA) is a novel non-thermal energy source to conduct catheter ablation of atrial fibrillation (AF). However, real-world multi-center data regarding acute procedural efficacy and safety is sparse. Purpose To study acute procedural success and safety in patients undergoing PFA for catheter ablation of AF in a multicenter registry. Methods Consecutive paroxysmal and persistent AF patients undergoing PFA-based catheter ablation using a multispline catheter were enrolled. The cohort included first and repeat ablation procedures. Procedural parameters, acute success and in-hospital safety were evaluated. A follow-up of all patients was conducted. Results Five German centers enrolled a total of 154 patients undergoing PFA in this study. Mean age was 68±12 years, median CHA2DS2-VASc Score was 3 (Q1-Q3: 2–4). Patients suffered from paroxysmal AF (n=55; 36%), persistent AF (n=93; 60%) and consecutive atrial tachycardias (AT) due to previous CA (n=6; 4%). The median left atrial (LA) PFA and total procedure times were 33 (Q1-Q3: 24–53) and 90 (Q1-Q3: 73–116) minutes, respectively. Mean LA PFA fluoroscopy and total fluoroscopy times were 12.1±5.5 and 20.2±8.7 minutes. Of all 154 procedures, 130 (84%) were index ablation procedures with isolation of pulmonary veins (PVI) only and 24 (16%) were repeat procedures (including re-PVI and ablation of consecutive AT). Acute PV reconnection following primary PVI and the initial set of PFA-applications was found in 20/130 (15%) patients, necessitating additional PFA ablation. Finally, successful PFA-guided PVI was achieved in all patients. Additional PFA lesion sets (including LA posterior wall isolation, anterior ablation, mitral isthmus ablation) were applied in 17/154 (11%) patients. Complications occurred in a total of 6/154 (3.8%) patients (including three groin site complications, two pericardial tamponades, one transient coronary spasm without sequela). The follow up data is still being assessed and will be provided by the time of the ESC 2022 meeting. Conclusion PFA performed in patients with atrial fibrillation demonstrates high acute procedural success rates and a favorable safety profile in this first real-world multicenter registry. Funding Acknowledgement Type of funding sources: None.

Background The incidence and prevalence of atrial fibrillation (AF) increases with age. With an ageing general population, a 2.3-fold rise in AF prevalence is expected. Catheter ablation has emerged as an effective treatment option for rhythm control therapy. However, very elderly patients (≥80 years old) have been excluded in landmark clinical trials. Current data regarding the safety and efficacy of catheter ablation in the very elderly is therefore sparse. Purpose Due to the growing demand to manage AF in an increasingly ageing population, we investigated the safety and efficacy of catheter ablation in this particular patient population. Methods Patients with symptomatic paroxysmal, persistent and long-standing persistent AF aged ≥80 years undergoing catheter ablation, including first and re-ablation procedures in a single centre, were analysed retrospectively. Catheter ablation involved pulmonary vein isolation (PVI) using radiofrequency, cryoballoon and pulsed field ablation as energy sources. Re-ablation procedures included re-PVI and consecutive atrial tachycardia ablation including atrial lines and/or ablation of complex fractionated atrial electrograms (CFAE) in persistent AF. Endpoints included acute procedural success (complete isolation of pulmonary veins and/or non-inducibility in the case of atrial tachycardia), major complications and early arrhythmia-recurrence. Results A total of eighty-eight patients (mean age 83.1±1.9 years, mean CHA2DS2-VASc-Score 4.4±1, mean left ventricular ejection fraction 56.7±7%, direct oral anticoagulation 92.1%, vitamin-K antagonists 7.9%) were included from January 2021 to October 2021. Fifty cases (56.8%) involved PVI as an index procedure (radiofrequency 58%, n=29/50, cryoballoon 36%, n=18/50, pulsed field ablation 6%, n=3/50). Thirty-eight procedures (43.2%) involved re-ablation procedures (Re-PVI 60.5%, n=23/38, linear lesions 65.8%, n=25/38, atrial tachycardia ablation 26.3%, n=10/38 and ablation of CFAE 15.8%, n=6/38). Acute procedural success was achieved in 87/88 patients (98.9%). Major complications included stroke (n=1/88, 1.1%), pericardial tamponade (n=1/88, 1.1%) and bradycardia with subsequent pacemaker implantation (n=3/88, 3.4%). No further major complications were documented. In 13/88 patients (14.8%) early arrhythmia-recurrence occurred (38.5%, n=5/13 after the index procedure and 61.5%, n=8/13 after re-ablation) during the 90-day blanking period. Conclusions Catheter ablation for atrial fibrillation in the very elderly shows favourable acute success and low complication rates. Long term success of catheter ablation and superiority to rate control in this patient population is unknown and requires investigation in the future. Funding Acknowledgement Type of funding sources: None.

Aims The EUropean Comparative Effectiveness Research to Assess the Use of Primary ProphylacTic Implantable Cardioverter-Defibrillators (EU-CERT-ICD), a prospective investigator-initiated, controlled cohort study, was conducted in 44 centres and 15 European countries. It aimed to assess current clinical effectiveness of primary prevention ICD therapy. Methods and results We recruited 2327 patients with ischaemic cardiomyopathy (ICM) or dilated cardiomyopathy (DCM) and guideline indications for prophylactic ICD implantation. Primary endpoint was all-cause mortality. Clinical characteristics, medications, resting, and 12-lead Holter electrocardiograms (ECGs) were documented at enrolment baseline. Baseline and follow-up (FU) data from 2247 patients were analysable, 1516 patients before first ICD implantation (ICD group) and 731 patients without ICD serving as controls. Multivariable models and propensity scoring for adjustment were used to compare the two groups for mortality. During mean FU of 2.4 ± 1.1 years, 342 deaths occurred (6.3%/years annualized mortality, 5.6%/years in the ICD group vs. 9.2%/years in controls), favouring ICD treatment [unadjusted hazard ratio (HR) 0.682, 95% confidence interval (CI) 0.537–0.865, P = 0.0016]. Multivariable mortality predictors included age, left ventricular ejection fraction (LVEF), New York Heart Association class Conclusion In contemporary ICM/DCM patients (LVEF ≤35%, narrow QRS), primary prophylactic ICD treatment was associated with a 27% lower mortality after adjustment. There appear to be patients with less survival advantage, such as older patients or diabetics.

Background Data on the optimal treatment strategy for antiarrhythmic drug therapy (AAD) after atrial fibrillation (AF) catheter ablation are inconsistent. While AAD potentially stabilizes sinus rhythm, it also increases the patients' treatment burden. Methods Patients from the prospective German Ablation Registry (n=3275) discharged with or without AAD after AF catheter ablation were compared regarding long-term success, cardiovascular events and patient reported outcome. Results In patients with paroxysmal AF (n=2138) recurrence and rehospitalization rates did not differ when discharged with (n=1051) or without (n=1087) AAD (recurrence: adjusted odds ratio (OR) 1.13, 95% confidence interval (CI) [0.95–1.35]; rehospitalization: OR 1.08, 95% CI [0.90–1.30]). The reablation rate was higher and reduced treatment satisfaction was reported more often in those discharged with AAD (reablation: OR 1.30, 95% CI [1.05–1.61]; reduced treatment satisfaction: OR 1.76, 95% CI [1.20–2.58]). Similar rates of recurrences, rehospitalisations, reablations and treatment satisfaction were found in patients with persistent AF (n=1137) discharged with (n=641) or without (n=496) AAD (recurrence: OR 1.22, 95% CI [0.95–1.56]; rehospitalization: OR 1.16, 95% CI [0.90–1.50]; reablation: OR 1.21, 95% CI [0.91–1.61]; treatment satisfaction: OR 1.24, 95% CI [0.74–2.08]). The incidence of cardiovascular events and mortality did not differ at follow-up in paroxysmal and persistent AF patients discharged with or without AAD. Conclusion The rates of recurrences, cardiovascular events and mortality did not differ between patients discharged with or without AAD after AF catheter ablation. However, AAD should be considered carefully in patients with paroxysmal AF, in whom it was associated with a higher reablation rate and reduced treatment satisfaction. Funding Acknowledgement Type of funding sources: None.

Background Myocardial infarction (MI) results in a regional scar, with a border zone (BZ) of surviving myocytes interspersed with fibrosis providing an anatomical substrate for re-entry. Heterogeneous repolarization within the BZ may add a functional component aggravating re-entrant arrhythmias. Purpose We studied BZ heterogeneity and developed novel methodology for high resolution mapping of local in vivo activation-repolarization intervals (ARI) within the BZ and for studying the relation to cellular action potential (AP) profiles of cells isolated from the BZ. Methods Anterior-septal myocardial infarction was induced in 5 domestic pigs by 120-minute occlusion of the left anterior descending artery followed by reperfusion (18.9±4.7% of the left ventricle). After 1-month, electro-anatomical mapping was performed. Contact mapping was used to define the BZ (bipolar voltage 0.5–1.5mV). A non-contact recording of a 64-electrode array was translated to 2048 non-contact electrograms distributed over the LV. The non-contact electrograms were processed to determine the ARIs using a custom-made algorithm, validated against monophasic action potential recordings. After 2–4 days recovery, single cardiomyocytes were enzymatically isolated from the anterior-septal BZs and remote regions. Cardiomyocytes were field stimulated at 1Hz at 37°C and cellular AP duration (APD) was optically recorded (fluorescent voltage-sensitive dye Di-8-Annepps). Results In vivo, regional ARIs tended to be longer in the BZs than remote. ARI heterogeneity, quantified as the standard deviation of ARIs in a neighborhood of 1cm radius, was increased in the BZ (anterior BZ: 3.4±1.0 ms, P=0.052, septal BZ: 3.6±1.7 ms, P=0.027 vs remote: 2.0±0.5 ms). Cellular APD was measured in large population samples (>100 cells per region in each pig) and was longer in BZ myocytes compared to the remote region. Cellular APD heterogeneity, measured as the standard deviation within cell population samples pooled by region per animal, was increased in the BZ (anterior BZ: 105.9±17.0 ms, P=0.0010; septal BZ: 98.1±20.8 ms, P=0.0127 vs remote: 73.9±8.6 ms). Cell APD correlated to in vivo ARI (R2=0.34, P=0.021) and cellular heterogeneity correlated strongly with in vivo heterogeneity (R2=0.67, P=0.002). Conclusion In the BZ of MI, in vivo regional heterogeneity adds a functional substrate for re-entry that may result from heterogeneous cellular remodeling and increased cell-cell APD variability. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): KU Leuven BOF-C1 “Blood pressure induced premature ventricular beats as triggers for ventricular arrhythmia in ischemic cardiomyopathy”

Background/Introduction Multidisciplinary teams (MDT) are an integral part of cardiology. In sports cardiology wide area of expertise is required to differentiate between extraordinary pathophysiological adaption and pathology. In Addition, expertise-based sports advice should be prescribed with great care considering the great impact on (professional) sports careers. Specific guidelines for the composition of MDT's for sports cardiology are currently lacking. We established a sports cardiology MDT in April 2020 (Amsterdam UMC), consisting of experts in the fields of sports medicine, cardiogenetics and paediatric cardiology, cardiovascular imaging and electrophysiology, with bi-monthly meetings. Cases were contributed from cardiologists or referred nationally for expertise with patients/athletes varying from recreational to elite-level sports. Purpose To describe our infrastructure and utilization of a sports cardiology MDT, and to justify the need for a sports cardiology MDT. Methods We retrospectively analysed all MDT reviewed cases (from April 2020 to April 2021), and collected follow-up data 1 year after initial MDT review. Data were classified according to type/level of sports. We compared diagnosis and/or reason for referral and sports advice at initial MDT application and after panel review. In addition we abstracted data on occurrence of cardiac symptoms and/or cardiac events, and adherence to sports advice. Results 112 cases underwent MDT review, with a mean age of 32 (SD 16.0) years. In total 12% were women, 38% professional athletes, and 30% engaged in high dynamic/low static sports. Reasons for referral were personalised sports advice in 48%, expert opinion in 28%, and abnormal ECG/CMR/CPX in 24%. The diagnosis was revised in 55% (n=61), main groups; 1) suspicion of (non-specified) cardiomyopathy (CMP) to no cardiac pathology in 20% (n=12), and 2) “cardiac abnormalities with no clear diagnosis” to “no cardiac pathology” in 36% (n=22) (Figure 1). Sports advice was revised to more personalized sports advice in 30% (n=34) (Figure 2), main groups; no restriction to no peak load/specific maximum load in 38% (n=13), and no restrictions to no competitive sports in 26% (n=9). At 1 year follow-up, the (sports) advice was adhered in 99,98% (n=111), and cases with no sports restrictions reported no cardiac symptoms in 99% (n=72/73), and no major acute cardiovascular events in 100% (73/73). No further revisions of diagnoses were found to have taken place. Conclusion Our experience with a comprehensive, sports cardiology MDT demonstrates that such an approach is feasible, and leads to more personalised treatment- and sports advice in athletes. Medium-term adherence to sports advice given is high. A team-based approach also leads to a higher percentage definitive diagnoses. Our findings serve as a proof-of-concept of the added value of the sports cardiology team in care for athletes and patients who wish to engage in sports and exercise. Funding Acknowledgement Type of funding sources: Other. Main funding source(s): Dutch Olympic Committee*Dutch Sports Federation (NOC*NSF)Amsterdam Movement Sciences (AMS) Figure 1. Revised diagnosis before and after panel review (N=61)Figure 2. Revised sports advice before and after panel review (N=34)

Introduction In Belgium ICD implantation is restricted to 23 centers. A previous analysis of our group based on aggregated results per center showed that 3y mortality varied significantly between centers ranging from 7.5 to 23.4%. Multivariate analysis demonstrated that volume, infection rate and a higher proportion of implantations in primary prevention were predictors of 3y-mortality. These findings needed to be confirmed on a patient level since they could be caused by inter-patient rather than inter-hospital differences. Methods The QERMID-ICD database is a retrospective database of all patients implanted with an ICD in Belgium managed by the governmental health care institution (RIZIV/INAMI). Participation is mandatory for reimbursement. We analyzed data of 9896 new implantations performed between 2010 and 2016. Following patient characteristics were available: demographics (gender, NYHA class, primary vs secondary prevention, underlying heart disease, type of device, QRS duration, age and ejection fraction (EF)), comorbidities (atrial fibrillation, diabetes, COPD, neurological disease, oncological disease and renal failure), volume of center (low < median of 65 primo-implantations/year vs high >65 implantations/year) and the average income of the arrondissement in which the patient lived (low income < p25, median p25-p75, high > p75). The primary endpoint was 3y-mortality. Chi-squared test and Mann-Whitney U test with correction for multiple testing were used and multivariate logistic regression was performed to determine the corrected odds ratio for 3-year mortality. Finally, Kaplan-Meier survival analysis was performed. Results Low volume centers treated different patients than high volume centers. They implant more primary prevention (66.5 vs. 61.6%), more often patients with ischemic cardiomyopathy (49.8 vs 47.9%), less often arrhythmogenic heart disease (13.2 vs 16.6%) and patients with more co-morbidities and from communities with lower average income. High volume centers used more cardiac resynchronization therapy (26.8 vs 22.5%) despite no difference in QRS width. 1 and 3-y mortality were significantly higher in the low volume centers, respectively 5.6 vs. 4.4% and 16 vs. 11.1%. This was also confirmed in Kaplan Meier survival analysis. In multivariate logistic regression underlying heart disease, income, age, EF, NYHA class, CRT, indication and most comorbidities were significantly associated with mortality, but center volume remained an independent risk factor for 3-y mortality (OR = 0.749 (0.702–0.937), p Conclusion Patients treated in low and high-volume centers in Belgium are different. However, there remained an association between volume and mortality of centers when controlling for these differences. Further research to elucidate if this association is due to statistical limitations of our analysis, referral bias or differences in quality of care is necessary. Funding Acknowledgement Type of funding source: None

Indications for pacemakers in young children are rare. In our university hospitals, on average 8 patients/year received a pacemaker in this age group between 2001 and 2015 for a drainage area of 4 million people. In 28% this is for congenital heart block and in 69% for bradycardia after surgical repair of congenital structural heart disease. Despite the extensive range of patient information about pacemakers, we felt a need for targeted material for young patients, who have an indication for a pacemaker, and their family. We wanted to provide this information to this specific group in a creative, accessible and clear way, taking into account their way of thinking. In addition, we also wanted to involve the near and wider environment of the child (family, school, sports club, etc.), and to provide them with tools to better deal with the medical situation. For the little children we created a stop-motion story in which sinus node disease (SND) and AV block (AVB) are represented by a character: Bob Sparkle (Bob Prikkel in Dutch for SND) and Boris Sparkle (Boris Prikkel for AVB). Bob and Boris get into trouble and are rescued by Pacemaker, the third character in the films. This story is preceded by an informative part for parents and older children in which the normal functioning and conduction system of the heart is explained. Based on the films, we designed customized information brochures for +12 and −12 year-old children. The brochure for +12 includes the same information as the adult version, but in more comprehensible language. The figures Bob and Boris were added throughout this brochure as a sort of common thread. For the −12 group we designed 2 reading books in which the story of Bob / Boris is told. The −12 booklets can be included in a cover along with the +12 brochure, so that the parents can estimate for themselves what is most suitable for their child. We conducted a survey on how this information was received by patients and their relatives.61 families were contacted by e-mail to fill in a questionnaire using a 5-point Likert Scale. The survey assessed the following three items: graphic design, intelligibility and aid in coping with illness. Currently we have received answers from 12 patients or their relatives. Overall, there was a positive reception of the different informative tools (agree or strongly agree: booklets: 92.6%; brochure: 77.2%; films: 81.3%). Funding Acknowledgement Type of funding source: None

Background High-density mapping (HDM) has been found to precisely identify the practical isthmus of scar-related atrial tachycardia (AT) circuits. Since practical isthmuses have been found to be shorter than the usual anatomical isthmuses targeted ablation has been proposed. However, outcome data are sparse. Here we describe HDM-guided catheter ablation by targeting the practical isthmus in patients with scar-related ATs. Methods and results In 250 consecutive patients with scar-related ATs HDM-guided catheter ablation with the support of a 64-electrode mini-basket catheter has been performed. Most patients underwent a prior catheter ablation (98%) while 13% had a prior cardiac valve surgery and 6% an underlying congenital heart disease. A total of 355 ATs occurred in the index procedure, of which 64% had a macro-, 26% a micro-reentry and 10% a focal mechanism. The ATs had a mean cycle length of 304±4.3 ms and in 237 patients (95%) an acute termination into sinus rhythm was achieved. They were mainly located in the left atrium (72%) but also in the right atrium (25%), bi-atrially (5%) or in the CS (3%) (see figure). Targeting the practical isthmus revealed arrhythmia freedom in 53% of patients after a single procedure during a mid-term follow-up (median 489 days, range 95–1407 days). Freedom from any arrhythmia could be achieved in 74% of patients after multiple procedures and in 93% of patients after multiple procedures and optimal clinical therapy, including pharmaceutical or electrical cardioversion. Conclusions HDM-guided catheter ablation of the practical isthmus in patients with scar-related ATs leads to a high acute success rate. Nevertheless, multiple procedures are necessary in a relevant number of patients resulting in a low recurrence rate. Funding Acknowledgement Type of funding source: None

Introduction Procedural failure after MitraClip (MC) therapy has a decisive prognostic influence and Re-treatment after acute procedure failure (APF) remains complex due to the generally high-risk patients. The aim of this work is to analyze the mid-term outcome between the surgical and the percutaneous interventional treatment routes according to APF from our High Volume Center. Methods Retrospective analysis of patients (pts.) consecutively treated with MC in the period from 9/2009 - 5/2019 with residual mitral regurgitation (rMR) that is still higher in the case of symptomatic APF (NYHA 3–4). Outcome analysis in primary (PMR) and secondary MR (SMR) with subsequent percutaneous (group Reclip) vs. surgical treatment (group surgery). Results Of a total of 824 pts., 63 (73±10 years, 20 women [31,7%]) showed APF (MR>2) peri / postinterventionally. Mitraclip reintervention was performed in 36 pts. (26 SMR, 10 PMR), while 27 (13 SMR, 14 PMR) underwent surgery. Mitral valve replacement (MVR) was surgically performed on 21 pts. (11 PMR, 10 SMR), while reconstruction (MVrec) was performed on n=6 (3 PMR, 3 SMR). The mechanism of the rMR in the surgery group, n=14 (51.9%) was a pure sail injury (LT) or a partial clip detachment (PCD) or a combination of both, n=9 (33.3%) a severe rMI, n=3 (11.1%) device endocarditis and n=1 (3.7%) a technical device problem. In the reclip group n=15 (41.7%) showed an LT and / or a PCD and n=21 (58.3%) a severe rMR. Thirty-day mortality was 13.9% (n=5 deaths) in the ReClip-group (n=4 SMR, n=1 PMR) an 18.5% in the surgical group (n=5 deaths; all SMR patients). In the midterm FU over 18 months (Figure 1), the surgically treated patients with SMR showed a significantly higher mortality rate than in patients with PMR (p=0.002). In the Reclip intervention group, no significant difference between treated PMR and SMR patients can be objectified (p=0.995). The comparison between surgery / reclip in the PMR group shows no significance, whereas a trend (p=0.148) in favor of the reclip can be distinguished between surgery / reclip in SMR in the outcome. Conclusion Surgically treated patients after AFP with an SMR as index etiology show a very poor short and medium-term survival both in comparison to the PMR patients and to the two reclip groups. With the combination of AFP and SMR, the reclip treatment can be regarded as the primary treatment option despite the lack of statistical significance compared to surgery. In return, surgery combined with AFP and PMR offers a viable alternative and can be favored over the reclip procedure in younger patients. Kaplan-Meier plot of the 4 intervention groups Funding Acknowledgement Type of funding source: None