Background By consensus statements, catheter ablation is a recommended treatment for patients with symptomatic drug-refractory paroxysmal atrial fibrillation (AF), as patients try to alleviate the burdensome AF symptoms that reduce the Quality of Life (QoL). Yet, first-line treatment of symptomatic patients via catheter ablation prior to initiation of antiarrhythmic drugs (AADs) is only a reasonable alternative (Class IIa). Clearly, more clinical data is necessary that compares catheter ablation to AAD therapy in treatment naïve patients. Purpose The Cryo-FIRST trial was designed to compare AAD treatment against pulmonary vein isolation (PVI) while using a cryoballoon catheter (Arctic Front Advance; Medtronic, Inc.). This current data analysis examines the QoL endpoints when comparing AADs to cryoballoon ablation in patients with symptomatic treatment naïve paroxysmal AF. Methods This randomized multicenter trial enrolled 220 patients from 18 sites in 9 countries (Europe, Australia, and Latin America) in a prospective open-blinded endpoint study design. Patients had not been administered a class I or III AAD for longer than 48 hours for inclusion into the study. Subjects were randomized (1:1) into a cohort that was administered AAD therapy or a cohort that received PVI via cryoablation. The prespecified QoL endpoint at 12 months was measured using the Atrial Fibrillation Effect on Quality of Life (AFEQT) scores, and QoL recordings were taken at baseline, 1, 3, 6, 9, and 12 months following the index treatment. Results Of the 218 patients randomized (age 52±13 years, 68% male) 86% completed the 12-month follow-up. Crossovers occurred in 9% of subjects (N=20), including: 1 subject in the cryoablation arm and 19 subjects in the AAD arm. At 12 months, 86.5% of the patients in the cryoablation arm and 70.4% of the patients in the AAD arm where without symptoms (EHRA score 1). The mean AFEQT summary score was more favorable in the catheter ablation group compared to the drug therapy group at 12 months (88.9 vs. 78.1 points, respectively). The adjusted difference was 9.9 points (95% CI: 5.5–14.2; P<0.0001). Conclusions Cryoballoon ablation resulted in a significant improvement in QoL at 12 months compared to AAD therapy in treatment naïve patients with first-line symptomatic paroxysmal AF. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Medtronic International Trading Sàrl

Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Medtronic OnBehalf The Cryo-FIRST Investigators Background Cryoballoon ablation (CBA) as a first-line rhythm control strategy is superior to antiarrhythmic drugs (AADs) for preventing atrial arrhythmia recurrence; however, the impact of first-line CBA specifically on atrial fibrillation (AF) recurrence and quality of life (QoL) has not been well characterized. Purpose To compare AF recurrence and QoL following first-line CBA vs. AAD therapy in patients with paroxysmal AF within the CryoFIRST trial (NCT01803438). Methods Patients with recurrent symptomatic paroxysmal AF who had not been administered class I or III AAD therapy for >48 hours were enrolled at 18 sites in 9 countries. Patients were randomized (1:1) to CBA or AAD treatment (Class I or III). Subjects were followed by 7-day Holter at 1, 3, 6, 9, and 12 months. Time-to-first AF recurrence outside of a 90-day blanking period was estimated by Kaplan-Meier analysis.  QoL was evaluated using the Atrial Fibrillation Effect on Quality of Life (AFEQT) and 36-Item Short Form Health Survey (SF-36) v2 questionnaires. Results Of the 218 randomized subjects, 187 (86%) completed the 12-month follow-up. By intention-to-treat (ITT) analysis, freedom from AF after blanking was achieved in 86.6% in the CBA and 74.5% in the AAD group (p = 0.023).  There was no difference in the time-to-first serious adverse event between groups. In total, 84.3% of patients in the CBA vs. 75.0% of patients in the AAD arm had a clinically important improvement (≥5 points) in the AFEQT summary score.  The adjusted mean difference in the AFEQT summary score at 12 months was 9.9 points higher in the CBA group (95% CI: 5.5-14.2; P < 0.001).  All AFEQT subscale scores were more favorable in the CBA vs. AAD group at 12 months.  There were no significant group differences in any of the SF-36 health domain scores at 12 months in the ITT analysis.  In the per-protocol analysis, clinically important and significant group differences in favor of CBA were observed at 12 months for 3 of 8 SF-36 health domain scores (physical functioning, general health and social functioning). Conclusion CBA is superior to AAD for preventing AF recurrence and improving AF-specific QoL in patients with paroxysmal AF. AFEQT Scores at Baseline and 12 MonthsAFEQT Score, Mean ± Standard DeviationCBAAADAdjusted Mean Difference at 12 Months (CBA vs. AAD)p-valueBaseline12 MonthsBaseline12 MonthsDaily Activities65.3 ± 25.887.8 ± 17.161.0 ± 27.976.6 ± 25.48.9 (3.2-14.6)0.002Symptoms59.9 ± 24.888.8 ± 15.658.4 ± 25.280.9 ± 22.27.1 (1.5-12.7)0.014Treatment Concern59.9 ± 23.189.8 ± 14.060.4 ± 24.577.7 ± 22.212.7 (7.9-17.5)<0.001AFEQT, Atrial Fibrillation Effect on Quality of Life questionnaire. CBA, cryoballoon ablation. AAD antiarrhythmic drug.Abstract Figure. Freedom From Atrial Fibrillation

Funding Acknowledgements Type of funding sources: None. Introduction Implantable cardioverter defibrillator (ICD) is gold standard therapy for primary and secondary prevention of sudden cardiac death (SCD) and ventricular tachyarrhythmias. While reducing arrhythmic mortality in patients with left ventricular dysfunction of various causes, inherited primary arrhythmia syndromes and after aborted SCD, these devices can have serious adverse effects including inappropriate shocks and device-related infection. Purpose The aim of this study was to create an institutional ICD registry and to examine the major complications after ICD implantation. Methods We analysed the data concerning all newly implanted ICDs in our institution from 2011 to 2017. All patients received periprocedural antibiotic prophylaxis according to relevant guidelines. Follow-up data was collected from hospital electronic medical records. Results Total number of implanted ICDs was 507 (85.4% male, 57.6 ± 14.0 years-old) and mean follow-up was 34.3 ± 23.8 months. Major complications (infection, large haematoma/hemorrhage, lead displacement/dysfunction) occurred in 18 (3.6%) patients. In 9 (1.8%) cases patients were diagnosed with ICD infection (8 surgical wound/pocket infections and 1 confirmed endocarditis of the lead). Device was explanted in 5 cases (1.0%) while the rest were treated only with antibiotic therapy (empirically or according to swab/blood culture results). All of the infections were successfully resolved and no relapses were noted. Eventually, 3 of 5 devices were reimplanted. One death was recorded 5 month after the explanation. Second most common complication was lead displacement/dysfunction which occurred in 5 (1.0%) patients and was successfully repaired in all cases. Large haematoma and/or hemorrhage at the implantation site were present in 5 (0.8%) patients (2 required surgical revision and transfusion while 2 were managed by needle aspiration). Pneumothorax (2 cases, 0.4%) had to be drained in one patient. There was one case of subclavian vein thrombosis which was treated by anticoagulation. Conclusion Despite appropriate antibiotic prophylaxis, the rate of ICD infections in our institution was relatively higher than the one reported in similar registries. The prevalence of other major complications, including lead dysfunction was quite low. Institutional registries could help monitor and plan actions to resolve ICD-related complications to improve patient outcomes.

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Funding Acknowledgements Type of funding sources: None. Background His bundle pacing (HBP) physiologically activates the ventricles by a direct stimulation of the His-Purkinje cardiac conduction system. It was first described in the 1970s, and the initial feasibility studies were reported in the early 2000s. Later on, technological advances led to its widespread adoption and growing evidence base.  Purpose This retrospective study aimed to assess implant success rate, feasibility and safety of the His-bundle lead implantation program in our centre. Methods All patients who underwent His-bundle lead implantation in our centre from the start of the HBP program in November 2018 until November 2020 were analyzed. Data were collected from existing hospital electronic medical records. Results A total of 125 patients (64.8 % male, 65.1 ± 13.9 years) were included in the study. Nearly half of patients (47.2 %) had chronic heart failure and 39.2 % had atrial fibrillation. Indications for pacing included antibradycardia pacing (68.8 %) and cardiac resynchronization therapy (31.2 %). His-bundle lead was successfully implanted in 114 patients (91.2 % acute success), while the rest of the procedures were converted into right ventricle lead placement. 32.8 % of all patients had native narrow QRS complexes. Among patients who received HBP for cardiac resynchronization therapy, QRS duration was reduced from 177.5 ± 26.4 at baseline to 145.8 ± 23.9 after HBP (p < 0.001). However, QRS duration slightly prolonged in the antibradycardia group from 118.8 ± 31.9 at baseline to 130.4 ± 25.3 after HBP (p = 0.011). Seven (8.6 %) patients in the antibradycardia group had late lead disfunction/dislodgement and therefore underwent reoperation with the conventional right ventricle lead placement. Two patients (4.7 %) from the resynchronization group had inappropriate resynchronization response and underwent the conventional coronary sinus lead implantation. Only one patient (0.8 %) had a device-associated infection.  Conclusion Our data suggest that HBP is a feasible strategy of physiological pacing and resynchronization with an acceptable success and low complication rates. Our His-bundle implantation program results are similar to data available in the current literature.