One-year outcomes of pulmonary vein isolation with a novel cryoballoon: Primary results of the FROZEN AF trial.

INTRODUCTION: Cryoablation therapy for pulmonary vein isolation (PVI) to treat paroxysmal atrial fibrillation (PAF) is well established. A novel 28 mm cryoballoon system designed to operate under low pressure to safely reach a lower nadir temperature and maintain constant balloon size during cooling has not been prospectively studied in a large patient population for safety and efficacy. The FROZEN AF (NCT04133168) trial was an international multicenter, open-label, prospective, single-arm study on the safety and performance of a novel cryoballoon system for treatment of PAF. METHODS AND RESULTS: The study enrolled patients at 44 sites in 10 countries across North America, Europe, and Asia. Subjects were indicated for PVI treatment of PAF and had failed or were intolerant of one or more antiarrhythmic drugs. Procedural outcomes were defined based on the 2017 HRS consensus statement. Follow-up was performed at 7 days, 3, 6, and 12 months. Data are reported as mean ± SD or median (IQR). PVI was performed with a 28 mm cryoballoon in 325 drug refractory PAF patients. Complete PVI was achieved in 95.7% of patients. In cryoablation lesions longer than 60 s, 60.1% of PV isolations required only a single cryoballoon application. Procedure related complications included: phrenic nerve palsy [temporary 4 (1.2%), persistent 0 (0.0%)], cardiac tamponade/perforation 2 (0.6%), and air embolism 1 (0.3%). Freedom from documented atrial arrhythmia recurrence at 12 months was 79.9% (AF 82.7%, AFL 96.5%, AT 98.1%), antiarrhythmic drugs (AAD) were continued or re-initiated in 26.8% of patients after the 3-month blanking period. Additionally, an extension arm enrolled 50 pts for treatment with 28/31 mm variable size cryoballoon. A single temporary PNP occurred in this group, which resolved before discharge. Freedom from documented recurrence at 12 months in these pts was 82.0%. CONCLUSIONS: This novel cryoballoon may facilitate PVI to treat PAF, providing more options to address the variety of anatomies present in patients with PAF. This cryoballoon system proved to be safe and effective for treatment of patients with drug refractory or drug intolerant PAF.

High-power short-duration versus low-power long-duration ablation for pulmonary vein isolation: A substudy of the AWARE randomized controlled trial.

INTRODUCTION: Pulmonary vein isolations (PVI) are being performed using a high-power, short-duration (HPSD) strategy. The purpose of this study was to compare the clinical efficacy and safety outcomes of an HPSD versus low-power, long-duration (LPLD) approach to PVI in patients with paroxysmal atrial fibrillation (AF). METHODS: Patients were grouped according to a HPSD (≥40 W) or LPLD (≤35 W) strategy. The primary endpoint was the 1-year recurrence of any atrial arrhythmia lasting ≥30 s, detected using three 14-day ambulatory continuous ECG monitoring. Procedural and safety endpoints were also evaluated. The primary analysis were regression models incorporating propensity scores yielding adjusted relative risk (RRa ) and mean difference (MDa ) estimates. RESULTS: Of the 398 patients included in the AWARE Trial, 173 (43%) underwent HPSD and 225 (57%) LPLD ablation. The distribution of power was 50 W in 75%, 45 W in 20%, and 40 W in 5% in the HPSD group, and 35 W with 25 W on the posterior wall in the LPLD group. The primary outcome was not statistically significant at 30.1% versus 22.2% in HPSD and LPLD groups with RRa 0.77 (95% confidence interval [CI]) 0.55-1.10; p = .165). The secondary outcome of repeat catheter ablation was not statistically significant at 6.9% and 9.8% (RRa 1.59 [95% CI 0.77-3.30]; p = .208) respectively, nor was the incidence of any ECG documented AF during the blanking period: 1.7% versus 8.0% (RRa 3.95 [95% CI 1.00-15.61; p = .049) in the HPSD versus LPLD group respectively. The total procedure time was significantly shorter in the HPSD group (MDa 97.5 min [95% CI 84.8-110.4)]; p < .0001) with no difference in adjudicated serious adverse events. CONCLUSIONS: An HPSD strategy was associated with significantly shorter procedural times with similar efficacy in terms of clinical arrhythmia recurrence. Importantly, there was no signal for increased harm with a HPSD strategy.

Atrial fibrillation progression after cryoablation vs. radiofrequency ablation: the CIRCA-DOSE trial.

BACKGROUND AND AIMS: Atrial fibrillation (AF) is a chronic progressive disorder. Persistent forms of AF are associated with increased rates of thromboembolism, heart failure, and death. Catheter ablation modifies the pathogenic mechanism of AF progression. No randomized studies have evaluated the impact of the ablation energy on progression to persistent atrial tachyarrhythmia. METHODS: Three hundred forty-six patients with drug-refractory paroxysmal AF were enrolled and randomly assigned to contact-force-guided RF ablation (CF-RF ablation, 115), 4 min cryoballoon ablation (CRYO-4, 115), or 2 min cryoballoon ablation (CRYO-2, 116). Implantable cardiac monitors placed at study entry were used for follow-up. The main outcome was the first episode of persistent atrial tachyarrhythmia. Secondary outcomes included atrial tachyarrhythmia recurrence and arrhythmia burden on the implantable monitor. RESULTS: At a median of 944.0 (interquartile range [IQR], 612.5-1104) days, 0 of 115 patients (0.0%) randomly assigned to CF-RF, 8 of 115 patients (7.0%) assigned to CRYO-4, and 5 of 116 patients (4.3%) assigned to CRYO-2 experienced an episode of persistent atrial tachyarrhythmia (P = .03). A documented recurrence of any atrial tachyarrhythmia ≥30 s occurred in 56.5%, 53.9%, and 62.9% of those randomized to CF-RF, CRYO-4, and CRYO-2, respectively; P = .65. Compared with that of the pre-ablation monitoring period, AF burden was reduced by a median of 99.5% (IQR 94.0%, 100.0%) with CF-RF, 99.9% (IQR 93.3%-100.0%) with CRYO-4, and 99.1%% (IQR 87.0%-100.0%) with CRYO-2 (P = .38). CONCLUSIONS: Catheter ablation of paroxysmal AF using radiofrequency energy was associated with fewer patients developing persistent AF on follow-up.

Leucocyte-derived micro-RNAs as candidate biomarkers in Brugada syndrome.

AIMS: Risk stratification for sudden cardiac death in patients with Brugada syndrome remains a major challenge. Contemporary risk prediction models have only modest predictive value. The aim of this study was to assess the role of micro-RNAs from peripheral blood as candidate biomarkers in Brugada syndrome. METHODS AND RESULTS: In this prospective study, Brugada patients and unaffected control individuals were enrolled for analysis of leucocyte-derived microRNAs (miRNAs) levels. Expression levels of 798 different circulating miRNAs were analysed on the NanoString® nCounter platform. All results were cross-validated by using a quantitative polymerase chain reaction. Micro-RNA expression levels of Brugada patients were compared with clinical data. A total of 21 definite Brugada patients (38% with a history of ventricular arrhythmia or cardiac arrest) and 30 unaffected control individuals were included in the study. Micro-RNA analysis showed a distinct expression profile in Brugada patients with 42 differentially expressed markers (38 up-regulated, 4 down-regulated miRNAs). The symptom status of Brugada patients was associated with a distinct miRNA signature. Micro-RNAs 145-5p and 585-3p were significantly up-regulated in symptomatic Brugada patients (P = 0.04). Incorporating miRNAs 145-5p and 585-3p into a multivariable model demonstrated significantly increased symptom prediction (area under the curve = 0.96; 95% confidence interval: 0.88-1.00). CONCLUSION: Brugada patients display a distinct miRNA expression profile compared with unaffected control individuals. There is also evidence that certain miRNAs (miR-145-5p and miR-585-3p) are associated with the symptom status of Brugada patients. The results suggest the principal utility of leucocyte-derived miRNAs as prognostic biomarkers for Brugada syndrome.

Novel filamin C (FLNC) variant causes a severe form of familial mixed hypertrophic-restrictive cardiomyopathy.

Variants of filamin C (FLNC) have been identified as rare genetic substrate for hypertrophic cardiomyopathy (HCM). Data on the clinical course of FLNC-related HCM are conflicting with some studies suggesting mild phenotypes whereas other studies have reported more severe outcomes. In this study, we present a novel FLNC variant (Ile1937Asn) that was identified in a large family of French-Canadian descent with excellent segregation data. FLNC-Ile1937Asn is a novel missense variant characterized by full penetrance and poor clinical outcomes. End stage heart failure requiring transplantation occurred in 43% and sudden cardiac death in 29% of affected family members. Other particular features of FLNC-Ile1937Asn include an early disease onset (mean age of 19 years) and the development of a marked atrial myopathy (severe biatrial dilatation with remodeling and multiple complex atrial arrhythmias) that was present in all gene carriers. The FLNC-Ile1937Asn variant is a novel, pathogenic mutation resulting in a severe form of HCM with full disease penetrance. The variant is associated with a high proportion of end-stage heart failure, heart transplantation, and disease-related mortality. Close follow-up and appropriate risk stratification of affected individuals at specialized heart centers is recommended.

Progression of Atrial Fibrillation after Cryoablation or Drug Therapy.

BACKGROUND: Atrial fibrillation is a chronic, progressive disorder, and persistent forms of atrial fibrillation are associated with increased risks of thromboembolism and heart failure. Catheter ablation as initial therapy may modify the pathogenic mechanism of atrial fibrillation and alter progression to persistent atrial fibrillation. METHODS: We report the 3-year follow-up of patients with paroxysmal, untreated atrial fibrillation who were enrolled in a trial in which they had been randomly assigned to undergo initial rhythm-control therapy with cryoballoon ablation or to receive antiarrhythmic drug therapy. All the patients had implantable loop recorders placed at the time of trial entry, and evaluation was conducted by means of downloaded daily recordings and in-person visits every 6 months. Data regarding the first episode of persistent atrial fibrillation (lasting ≥7 days or lasting 48 hours to 7 days but requiring cardioversion for termination), recurrent atrial tachyarrhythmia (defined as atrial fibrillation, flutter, or tachycardia lasting ≥30 seconds), the burden of atrial fibrillation (percentage of time in atrial fibrillation), quality-of-life metrics, health care utilization, and safety were collected. RESULTS: A total of 303 patients were enrolled, with 154 patients assigned to undergo initial rhythm-control therapy with cryoballoon ablation and 149 assigned to receive antiarrhythmic drug therapy. Over 36 months of follow-up, 3 patients (1.9%) in the ablation group had an episode of persistent atrial fibrillation, as compared with 11 patients (7.4%) in the antiarrhythmic drug group (hazard ratio, 0.25; 95% confidence interval [CI], 0.09 to 0.70). Recurrent atrial tachyarrhythmia occurred in 87 patients in the ablation group (56.5%) and in 115 in the antiarrhythmic drug group (77.2%) (hazard ratio, 0.51; 95% CI, 0.38 to 0.67). The median percentage of time in atrial fibrillation was 0.00% (interquartile range, 0.00 to 0.12) in the ablation group and 0.24% (interquartile range, 0.01 to 0.94) in the antiarrhythmic drug group. At 3 years, 8 patients (5.2%) in the ablation group and 25 (16.8%) in the antiarrhythmic drug group had been hospitalized (relative risk, 0.31; 95% CI, 0.14 to 0.66). Serious adverse events occurred in 7 patients (4.5%) in the ablation group and in 15 (10.1%) in the antiarrhythmic drug group. CONCLUSIONS: Initial treatment of paroxysmal atrial fibrillation with catheter cryoballoon ablation was associated with a lower incidence of persistent atrial fibrillation or recurrent atrial tachyarrhythmia over 3 years of follow-up than initial use of antiarrhythmic drugs. (Funded by the Cardiac Arrhythmia Network of Canada and others; EARLY-AF ClinicalTrials.gov number, NCT02825979.).

Leadless Pacemaker Implantation in a Patient With Hypoplasia of the Left Brachiocephalic Vein.

Venous anomalies are typically asymptomatic and may be discovered unexpectedly at the time of implantation of a cardiac implantable electronic device. We report a case of leadless pacemaker implantation in a patient with hypoplasia of the left brachiocephalic vein who had previously undergone multiple interventions for relapsing right-sided breast cancer. The prevalence and etiology of this anatomic variant remain unknown. However, awareness of its existence may prevent complications during left-sided interventions. such as placement of a central venous line or a cardiac implantable electronic device. Alternative diagnostics and implantation strategies are discussed.

Les anomalies veineuses sont généralement asymptomatiques et peuvent être découvertes de façon inattendue au moment de l'implantation d'un dispositif cardiaque électronique. Nous présentons un cas d'implantation d'un stimulateur cardiaque sans sonde chez une patiente atteinte d'hypoplasie de la veine brachiocéphalique gauche qui avait déjà subi de nombreuses interventions en raison de la rechute d'un cancer du sein du côté droit. On ignore la prévalence et l'étiologie de cette variante anatomique. Toutefois, la sensibilisation à son existence peut permettre de prévenir les complications durant les interventions du côté gauche telles que la pose d'un cathéter veineux central ou l'implantation d'un dispositif cardiaque électronique. Les autres diagnostics et stratégies d'implantation font l'objet de discussions.

Safety of Cefazolin Test Dose in Patients With Penicillin Allergy Just Prior to Cardiac Device Implantation: A Single-Centre Experience.

Background: Cephalosporins are the cornerstone of cardiac device infection prophylaxis. Owing to fears of cross-reactivity, penicillin-allergic patients are exposed to potentially more-toxic drugs, with decreased efficacy. We evaluated the safety of a cefazolin test dose (CTD) in self-reported penicillin-allergic patients. Methods: In this single-centre study, we evaluated consecutive patients with chart documentation of penicillin allergy undergoing cardiac device implantation, over a 2-year period. A CTD was performed if no cephalosporin allergy or severe anaphylactic reaction to penicillin had been documented. Patients were given 2 doses of 100 mg IV cefazolin, and if no allergic reaction occurred after 5 minutes, the full dose (1800 mg) was administered in the electrophysiology laboratory just before the implantation procedure. Results: A total of 2200 patients were included. The frequency of reported penicillin allergy was 9.3% (n = 204). In 80% of cases, the type of allergic reaction was not reported in medical notes or was unknown by the patient. A CTD was performed in 67.6% of patients with a penicillin allergy (n = 138). A total of 5 adverse events occurred (3.6% of patients [95% confidence interval, 1.1%-6.1%]) - 4 skin rashes and 1 tongue edema. These 5 patients became asymptomatic after antihistaminic and corticosteroid IV treatment. Even if the test dose was negative, 79% of patients also were administered vancomycin before the procedure, as it requires a 1-hour infusion prior to the CTD in the implantation procedure room. Conclusion: A CTD in most penicillin-allergic patients appears to be safe and allows its use per recommended guidelines.

Contexte: Les céphalosporines sont la pierre angulaire de la prophylaxie des infections des dispositifs cardiaques. En raison du risque appréhendé de réactivité croisée, les patients allergiques à la pénicilline se trouvent exposés à des médicaments potentiellement plus toxiques, qui s'avèrent aussi moins efficaces. Nous avons évalué l'innocuité d'une dose d'essai de céfazoline chez des patients qui s'étaient dits allergiques à la pénicilline. Méthodologie: Dans cette étude monocentrique, nous avons suivi pendant deux ans des patients consécutifs dont le dossier médical faisait état d'une allergie à la pénicilline et chez qui un dispositif cardiaque devait être implanté. Une dose d'essai de céfazoline a été administrée aux patients sans antécédents documentés d'allergie aux céphalosporines ou de réaction anaphylactique sévère à la pénicilline. Deux doses de 100 mg de céfazoline ont été administrées par voie intraveineuse. En l'absence de réaction allergique après cinq minutes, les patients recevaient la dose complète (1 800 mg) au laboratoire d'électrophysiologie juste avant l'implantation du dispositif cardiaque. Résultats: Au total, 2 200 patients ont été inscrits à l'étude. Le taux de signalement de l'allergie à la pénicilline était de 9,3 % (n = 204). Dans 80 % des cas, le type de réaction allergique n'a pas été précisé dans les notes médicales ou était inconnu du patient. Une dose d'essai de céfazoline a été administrée à 67,6 % des patients allergiques à la pénicilline (n = 138). Au total, cinq événements indésirables se sont produits (3,6 % des patients [intervalle de confiance à 95 % : 1,1-6,1 %]) ­ quatre éruptions cutanées et un œdème de la langue. Les cinq patients touchés par ces événements sont devenus asymptomatiques après avoir reçu un antihistaminique et un corticostéroïde par voie intraveineuse. Même en l'absence de réaction allergique à la dose d'essai, 79 % des patients ont reçu de la vancomycine avant l'intervention, cet agent devant être administré par perfusion durant une heure avant la dose d'essai de céfazoline dans la salle d'intervention. Conclusion: Chez la plupart des patients allergiques à la pénicilline, une dose d'essai de céfazoline semble sans danger et permet d'avoir recours à ce médicament conformément aux lignes directrices.

Experience of Combined Procedure during Percutaneous LAA Closure.

INTRODUCTION: Percutaneous left atrial appendage closure (LAAC) is an alternative to oral anticoagulants (OAC) in patients with non-valvular atrial fibrillation (AF) and contraindication to long-term OAC. Combined strategy with percutaneous LAAC at the same time of other cardiac structural or electrophysiological procedures has emerged as an alternative to a staged strategy. AIM: To describe our experience with combined LAAC procedures using Watchman™ devices. METHODS: All patients with combined LAAC procedures using Watchman™ (WN) devices performed from 2016 to 2021 were included. The primary safety endpoint was a composite of periprocedural complications and adverse events during the follow-up. The primary efficacy endpoint included strokes, systemic embolisms, major bleeding and cardiovascular death. RESULTS: From 2016, among 160 patients who underwent LAAC using WN devices, 19 underwent a combined strategy: 7 transcatheter edge-to-edge mitral valve repair (TEMVR) (37%), 6 typical atrial flutter ablation (31%), 2 leadless pacemaker (LP) implantation (10%) and 4 AF ablation (22%). The WN device was successfully implanted in 98% and 100% of cases for single and combined LAAC procedures, respectively (p = 0.63). Median follow-up was 13 months (IQR 25/75 3/24). Device-related complications occurred in 6 out of 141 patients (4%) who underwent single LAAC and in no (0/19) patient in the combined LAAC procedure (p = ns). The procedural-related complications did not differ significantly between groups (5% vs. 10%, respectively, in the single and combined group, p = 0.1). CONCLUSION: Combined procedure using the Watchman™ devices and one other structural or electrophysiological procedure appears safe and effective. Larger series are needed to confirm these results.

Randomized trial of conventional versus radiofrequency needle transseptal puncture for cryoballoon ablation: the CRYO-LATS trial.

BACKGROUND: Transseptal puncture to achieve left atrial access is necessary for many cardiac procedures, including atrial fibrillation ablation. More recently, there has been an increasing need for left atrial access using large caliber sheaths, which increases risk of perforation associated with the initial advancement into the left atrium. We compared the effectiveness of a radiofrequency needle-based transseptal system versus conventional needle for transseptal access. METHODS: This prospective controlled trial randomized 161 patients with symptomatic paroxysmal atrial fibrillation undergoing cryoballoon pulmonary vein isolation to transseptal access with a commercially available transseptal system (radiofrequency needle plus stiff pigtail wire; RF + Pigtail group) versus conventional transseptal access (standard group). The primary outcome was time required for left atrial access. Secondary outcomes included failure of the assigned transseptal system, radiation exposure, and complications. RESULTS: The median transseptal puncture time was significantly shorter using the radiofrequency needle plus stiff pigtail wire transseptal system compared with conventional transseptal (840 ± 323 vs. 956 ± 407 s, P = 0.0489). Compared to conventional transseptal puncture, fewer transseptal attempts were required (1.0 ± 0.5 RF applications vs. 1.3 ± 0.8 mechanical punctures, P = 0.0123) and the fluoroscopy time was significantly shorter (72.0 [IQR 48.0, 129.0] vs. 93.0 [IQR 60.0, 171.0] s, P = 0.0490) with the radiofrequency needle plus stiff pigtail wire transseptal system. Failure to achieve transseptal LA access with the assigned system was rarely observed (1.3% vs. 5.7%, P = 0.2192). There were no procedural complications observed with either system. CONCLUSIONS: The use of a radiofrequency needle plus stiff pigtail wire resulted in shorter time to left atrial access and reduced fluoroscopy time compared to left atrial access using conventional transseptal equipment. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT03199703.

Evolution of Devices to Prevent Sudden Cardiac Death: Contemporary Clinical Impacts.

Implantable cardioverter defibrillators (ICDs) are recommended for primary and secondary prevention of sudden cardiac death and were first implanted more than 40 years ago. The addition of cardiac resynchronization improved outcomes in the heart failure population and is now an important part of optimized therapy for this population. In this review, we will address patient selection, risk stratification, and outcomes after ICD placement and technological improvements. Gender disparities in referral and outcomes will be discussed. Far from early technologies with limited pacing capabilities and no antitachycardia pacing (ATP), we have now moved to complex devices with the addition of ATP/ATP during charging, cardiac resynchronization therapy, remote monitoring, and improved battery longevity. The requirement for defibrillation testing at time of implantation has changed and in most implants are not required as part of new clinical guidelines. As the components most likely to fail are the leads, and many complications arise from the intravascular components, extravascular ICDs were developed, the subcutaneous ICD is now an option for many patients, and substernal devices are under clinical trials. Because shocks are associated with worse outcomes, optimized ICD programming is now recommended, with the benefit of reducing appropriate and inappropriate shocks with a decrease in mortality and no increase in the syncopal events. All these improvements will have a positive effect on patient outcomes and quality of life, and new technologies will be developed in the future.

Percutaneous left atrial appendage closure in patients with primary hemostasis disorders and atrial fibrillation.

BACKGROUND OR PURPOSE: We report our single-center experience with percutaneous left atrial appendage closure (LAAC) in patients with non-valvular atrial fibrillation (NVAF) and primary hemostasis disorders (HD). METHODS: Consecutive patients with primary HD who underwent a percutaneous LAAC were included. Baseline characteristics, procedural data, and clinical outcomes were prospectively collected and compared with the overall LAAC cohort without HD. RESULTS: Since 2013, among 229 LAAC, 17 patients (7%) had a primary HD: thrombocytopenia (n = 5), myelodysplastic syndrome (n = 6), von Willebrand syndrome (n = 4), type A hemophilia (n = 1), and dysfibrinogenemia (n = 1). The HD population's age ranged from 61 to 87 years, and the median CHA2DS2VASc was 5. Periprocedural plasmatic management was required in 47% of patients. The immediate LAAC implantation success rate was 100%. Patients received a direct oral anticoagulant (DOA) (n = 9), dual antiplatelet (n = 6), aspirin (n = 1), or no therapy (n = 1) during the first six postoperative weeks, followed with single antiplatelet (n = 16) or no therapy (n = 1) during lifelong. After 20 months, the technical success rate and procedural success rate were 100% and 94%. Zero device-/procedure-related complication and only one life-threatening bleeding occurred. Compared to patients without HD (n = 212), a baseline history of bleeding was less frequent (53% vs 91%, p < 0.001), and more patients received a perioperative blood transfusion (47% vs 4%, p < 0.001) in the HD group. The efficacy and safety outcomes did not differ between HD and non-HD cohorts. CONCLUSIONS: Percutaneous LAAC in primary HD carriers appeared as safe and as effective as in overall LAAC population for stroke and bleeding prevention at midterm follow-up. Percutaneous left atrial appendage closure in patients with atrial fibrillation and primary hemostasis disorders. The percutaneous LAAC in primary hemostasis disorders and AF carriers requires a multidisciplinary approach. Cardiologist, anesthesiologist, and hematologist discussion is a cornerstone to assess anticoagulant contraindication, LAAC feasibility, periprocedural management, and follow-up (high). This multidisciplinary care is illustrated by the case of a 61-year-old male with hemophilia type A and recurrent hemarthrosis. Pre-LAAC assessment confirmed procedural indication and cactus LAA anatomy (left). After plasmatic management with factor VIII infusion, a WATCHMAN™ no. 21 was successfully implanted (middle). During follow-up, without antithrombotic regime, no ischemic or hemorrhagic complication occurred (right). LAA, left atrial appendage; LAAC, left atrial appendage closure; TEE, transesophageal echocardiography. Percutaneous LAAC in primary HD carriers appeared as safe and as effective as in overall LAAC population for stroke and bleeding prevention at midterm follow-up.

DREAM-ICD-II Study.

BACKGROUND: Regulatory authorities of most industrialized countries recommend 6 months of private driving restriction after implantation of a secondary prevention implantable cardioverter-defibrillator (ICD). These driving restrictions result in significant inconvenience and social implications. This study aimed to assess the incidence rate of appropriate device therapies in contemporary recipients of a secondary prevention ICD. METHODS: This retrospective study at 3 Canadian tertiary care centers enrolled consecutive patients with new secondary prevention ICD implants between 2016 and 2020. RESULTS: For a median of 760 days (324, 1190 days), 721 patients were followed up. The risk of recurrent ventricular arrhythmia was highest during the first 3 months after device insertion (34.4%) and decreased over time (10.6% between 3 and 6 months, 11.7% between 6 and 12 months). The corresponding incidence rate per 100 patient-days was 0.48 (95% CI, 0.35-0.64) at 90 days, 0.28 (95% CI, 0.17-0.45) at 180 days, and 0.21 (95% CI, 0.13-0.33) between 181 and 365 days after ICD insertion (P<0.001). The cumulative incidence of arrhythmic syncope resulting in sudden cardiac incapacitation was 1.8% within the first 90 days and subsequently dropped to 0.4% between 91 and 180 days (P<0.001) after ICD insertion. CONCLUSIONS: The incidence rate of appropriate therapies resulting in sudden cardiac incapacitation in contemporary recipients of a secondary prevention ICD is much lower than previously reported and declines significantly after the first 3 months. Lowering driving restrictions to 3 months after the index cardiac event seems safe, and revision of existing guidelines should be considered in countries still adhering to a 6-month period. Existing restrictions for private driving after implantation of a secondary prevention ICD should be reconsidered.

Association of Atrial Fibrillation Burden With Health-Related Quality of Life After Atrial Fibrillation Ablation: Substudy of the Cryoballoon vs Contact-Force Atrial Fibrillation Ablation (CIRCA-DOSE) Randomized Clinical Trial.

Importance: Patients with atrial fibrillation (AF) have impaired health-related quality of life primarily owing to symptoms related to AF episodes; however, quality of life can be influenced by AF therapies, AF complications, the frequency of follow-up visits and hospitalizations, illness perceptions, and patient factors, such as anxiety or depression. Objective: To determine the association between change in AF burden and quality of life in the year following ablation. Design, Setting, and Participants: The current study is a secondary analysis of a prospective, parallel-group, multicenter, single-masked randomized clinical trial (Cryoballoon vs Irrigated Radiofrequency Catheter Ablation: Double Short vs Standard Exposure Duration [CIRCA-DOSE] study), which took place at 8 Canadian centers. Between September 2014 and July 2017, 346 patients older than 18 years with symptomatic, primarily low-burden AF refractory to antiarrhythmic therapy referred for first catheter ablation were enrolled. All patients received an implantable cardiac monitor at least 30 days before ablation and were followed up with up to December 2018. Data were analyzed from April 2020 to June 2021. Interventions: Patients were randomized 1:1:1 to contact force-guided radiofrequency ablation, 4-minute cryoballoon ablation, or 2-minute cryoballoon ablation. The exposure in the present analysis is the absolute difference in AF burden prior to ablation and 12 months following ablation, as evaluated by the Atrial Fibrillation Effect on Quality of Life (AFEQT) Score. Main Outcomes and Measures: Absolute difference in quality of life from baseline to 12 months postablation. Results: Of 346 included patients, 231 (66.7%) were male, and the median (interquartile range) age was 60 (52-66) years. A total of 328 patients (94.8%) had paroxysmal AF. The median (interquartile range) preablation AF burden was 2.0% (0.1-11.9), and the AF burden decreased to 0% at 12 months postablation. At 12 months, a 1-point improvement in AFEQT score was observed for every absolute reduction in daily AF burden of 15.8 minutes (95% CI, 7.2-24.4; P < .001), or every 0.63% (95% CI, 0.30-0.95; P < .001) reduction in relative AF burden from baseline. Conclusions and Relevance: In patients with primarily low-burden paroxysmal AF, the reduction in AF burden following ablation may be associated with a clinically meaningful improvement in quality of life. Trial Registration: ClinicalTrials.gov Identifier: NCT01913522.