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.

Efficacy and safety of supraclavicular and pectoralis nerve blocks as primary peri-procedural analgesia for cardiac electronic device implantation: A pilot study.

BACKGROUND: Cardiac implantable electronic devices (CIEDs) are routinely implanted using intravenous drugs for sedation. However, some patients are poor candidates for intravenous sedation. OBJECTIVE: We present a case series demonstrating the safety and efficacy of a novel, ultrasound-guided nerve block technique that allows for pre-pectoral CIED implantation. The targets are the supraclavicular nerve (SCN) and pectoral nerve (PECS1). METHODS: We enrolled 20 patients who were planned for new CIED implantation. Following US-localization of the SCN and PECS1, local anesthetic (LA) was instilled at least 30-60 min pre-procedure. Successful nerve block was determined if < 5 mL of intraprocedural LA was used, along with lack of sensation with skin and deep tissue pinprick. Optional sedation was offered to patients' pre-procedure if discomfort was reported. RESULTS: Seventeen patients (85%) had a successful periprocedural nerve block, with only three patients exceeding 5 mL of LA. SCN and PECS1 success occurred in 19 (95%) and 18 (90%) patients, respectively. The overall success of nerve block by fulfilling all the criteria was demonstrated in 17 out of 20 patients (85%). Patients who reported no pain (VAS score = 0) were distributed as follows: 13 patients (65%) in the immediate post-procedure interval, 18 patients (90%) at the 1 h post-implant interval, and 14 patients (70%) at the 24 h post- implant interval. The median cumulative VAS score was 0 (IQR = 0 - 1). There were no reported significant adverse effects. CONCLUSION: SCN and PECS1 nerve blocks are safe and effective for patients undergoing CIED implantation to minimize or eliminate the use of intravenous sedation.

Rationale and Design of the Randomized Bayesian Multicenter COME-TAVI Trial in Patients With a New Onset Left Bundle Branch Block.

Patients with new-onset left bundle branch block (LBBB) after transcatheter aortic valve implantation (TAVI) are at risk of developing delayed high-degree atrioventricular block. Management of new-onset LBBB post-TAVI remains controversial. In the Comparison of a Clinical Monitoring Strategy Versus Electrophysiology-Guided Algorithmic Approach in Patients With a New LBBB After TAVI (COME-TAVI) trial, consenting patients with new-onset LBBB that persists on day 2 after TAVI, meeting exclusion/inclusion criteria, are randomized to an electrophysiological study (EPS)-guided approach or 30-day electrocardiographic monitoring. In the EPS-guided approach, patients with a His to ventricle (HV) interval ≥ 65 ms undergo permanent pacemaker implantation. Patients randomized to noninvasive monitoring receive a wearable continuous electrocardiographic recording and transmitting device for 30 days. Follow-up will be performed at 3, 6, and 12 months. The primary endpoint is a composite outcome designed to capture net clinical benefit. The endpoint incorporates major consequences of both strategies in patients with new-onset LBBB after TAVI, as follows: (i) sudden cardiac death; (ii) syncope; (iii) atrioventricular conduction disorder requiring a pacemaker (for a class I or IIa indication); and (iv) complications related to the pacemaker or EPS. The trial incorporates a Bayesian design with a noninformative prior, outcome-adaptive randomization (initially 1:1), and 2 prespecified interim analyses once 25% and 50% of the anticipated number of primary endpoints are reached. The trial is event-driven, with an anticipated upper limit of 452 patients required to reach 77 primary outcome events over 12 months of follow-up. In summary, the aim of this Bayesian multicentre randomized trial is to compare 2 management strategies in patients with new-onset LBBB post-TAVI-an EPS-guided approach vs noninvasive 30-day monitoring. Trial registration number: NCT03303612.

Les patients chez qui un bloc de branche gauche (BBG) est récemment apparu à la suite de l'implantation valvulaire aortique par cathéter (IVAC) présentent un risque de bloc auriculoventriculaire de haut degré tardif. La prise en charge d'un BBG récemment apparu après une IVAC demeure controversée. Dans le cadre de l'essai COME-TAVI (Comparison of a ClinicalMonitoring Strategy VersusElectrophysiology-Guided Algorithmic Approach in Patients With a New LBBB AfterTAVI, ou comparaison d'une stratégie de surveillance clinique, par rapport à une approche guidée par étude électrophysiologique et fondée sur un algorithme, chez des patients présentant un BBG d'apparition récente à la suite d'une IVAC), des patients qui présentent un BBG d'apparition récente persistant le 2e jour après une IVAC, qui répondent aux critères d'admissibilité et qui ont donné leur consentement sont répartis aléatoirement pour être suivis à l'aide d'une approche guidée par une étude électrophysiologique (EEP) ou faire l'objet d'une surveillance électrocardiographique d'une durée de 30 jours. Un stimulateur cardiaque est implanté chez les patients du groupe de l'EEP dont l'intervalle HV (temps de conduction dans le tronc du faisceau de His jusqu'aux ventricules) est ≥ 65 ms. Les patients du groupe de surveillance non invasive reçoivent un dispositif portable d'enregistrement et de transmission continue de données électrocardiographiques pour une période de 30 jours. Le suivi sera réalisé aux 3e, 6e et 12e mois. Le critère d'évaluation principal est un paramètre composite conçu afin de saisir le bienfait clinique net. Il comprend les conséquences majeures des deux stratégies chez les patients présentant un BBG d'apparition récente après une IVAC, comme suit : (i) mort subite d'origine cardiaque; (ii) syncope; (iii) trouble de la conduction auriculoventriculaire nécessitant la pose d'un stimulateur cardiaque (pour une indication de classe I ou IIa); et (iv) complications relatives au stimulateur cardiaque ou à l'EEP. L'essai intègre une conception bayésienne avec une répartition aléatoire (dans un rapport initial de 1:1) antérieure non informative adaptée aux résultats et deux analyses intermédiaires définies au préalable lorsque 25 % et 50 % du nombre anticipé des critères d'évaluation principaux seront atteints. L'essai est axé sur les événements, et la limite supérieure anticipée pour atteindre 77 événements relatifs aux critères d'évaluation principaux sur 12 mois de suivi est de 452 patients. En résumé, l'objectif de cet essai bayésien multicentrique à répartition aléatoire est de comparer deux stratégies de prise en charge de patients présentant un BBG d'apparition récente après une IVAC, soit une approche guidée par une EEP, par rapport à une surveillance non invasive de 30 jours. Trial registration number: NCT03303612.

Hemodynamically Tolerated Ventricular Tachycardia With Mildly Impaired Ejection Fraction: Do These Patients Have VT/VF Recurrence and ICD Therapies?

BACKGROUND: Patients with hemodynamically tolerated ventricular tachycardia (VT) and minimally reduced left ventricular ejection fraction (LVEF) remain a group that presents a prognostic and therapeutic dilemma. METHODS: We studied patients from our implanted cardioverter-defibrillator (ICD) database who received ICDs for hemodynamically tolerated VT and mildly reduced LVEF (36%-49%) at time of implant between May 2015 and December 2019. Time to appropriate ICD therapy was assessed. Clinical features associated with recurrent VT/ventricular fibrillation (VF) with ICD therapies were explored using binary logistic regression. RESULTS: Among 2037 ICDs placed between May 2015 and December 2019, 64 subjects met the inclusion criteria. The mean age of the study group was 68 ± 12 years, and 58 (90.6%) subjects were male. Average ejection fraction was 40% ± 4.4 (range 36%-49%). Twenty-two (34%) subjects received antitachycardia pacing (ATP) for VT at 229 ± 265 days after ICD placement. Fifteen (23%) subjects received appropriate ICD shocks 305 ± 321 days after implant. The rate of recurrent VT/VF among the 37 patients with ICD therapy was 195 ± 39 beats per minute (bpm). This was significantly more rapid than initial presenting VT rates before ICD placement (183 ± 27 bpm) (P = 0.048). Multivariate analysis showed no factors independently associated with recurrent VT/VF. CONCLUSIONS: Patients with mildly impaired LV function and hemodynamically tolerated VT receive appropriate ICD therapies over the 3 years following implant. This patient group warrants further investigation, as their recurrent VT/VF rates can be much more rapid, and 23% go on to receive appropriate ICD shocks.

Randomized Ablation-Based Rhythm-Control Versus Rate-Control Trial in Patients With Heart Failure and Atrial Fibrillation: Results from the RAFT-AF trial.

BACKGROUND: Atrial fibrillation (AF) and heart failure (HF) frequently coexist and can be challenging to treat. Pharmacologically based rhythm control of AF has not proven to be superior to rate control. Ablation-based rhythm control was compared with rate control to evaluate if clinical outcomes in patients with HF and AF could be improved. METHODS: This was a multicenter, open-label trial with blinded outcome evaluation using a central adjudication committee. Patients with high-burden paroxysmal (>4 episodes in 6 months) or persistent (duration <3 years) AF, New York Heart Association class II to III HF, and elevated NT-proBNP (N-terminal pro brain natriuretic peptide) were randomly assigned to ablation-based rhythm control or rate control. The primary outcome was a composite of all-cause mortality and all HF events, with a minimum follow-up of 2 years. Secondary outcomes included left ventricular ejection fraction, 6-minute walk test, and NT-proBNP. Quality of life was measured using the Minnesota Living With Heart Failure Questionnaire and the AF Effect on Quality of Life. The primary analysis was time-to-event using Cox proportional hazards modeling. The trial was stopped early because of a determination of apparent futility by the Data Safety Monitoring Committee. RESULTS: From December 1, 2011, to January 20, 2018, 411 patients were randomly assigned to ablation-based rhythm control (n=214) or rate control (n=197). The primary outcome occurred in 50 (23.4%) patients in the ablation-based rhythm-control group and 64 (32.5%) patients in the rate-control group (hazard ratio, 0.71 [95% CI, 0.49-1.03]; P=0.066). Left ventricular ejection fraction increased in the ablation-based group (10.1±1.2% versus 3.8±1.2%, P=0.017), 6-minute walk distance improved (44.9±9.1 m versus 27.5±9.7 m, P=0.025), and NT-proBNP demonstrated a decrease (mean change -77.1% versus -39.2%, P<0.0001). Minnesota Living With Heart Failure Questionnaire demonstrated greater improvement in the ablation-based rhythm-control group (least-squares mean difference of -5.4 [95% CI, -10.5 to -0.3]; P=0.0036), as did the AF Effect on Quality of Life score (least-squares mean difference of 6.2 [95% CI, 1.7-10.7]; P=0.0005). Serious adverse events were observed in 50% of patients in both treatment groups. CONCLUSIONS: In patients with high-burden AF and HF, there was no statistical difference in all-cause mortality or HF events with ablation-based rhythm control versus rate control; however, there was a nonsignificant trend for improved outcomes with ablation-based rhythm control over rate control. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT01420393.

Variability in Reassessment of Left Ventricular Ejection Fraction After Myocardial Infarction in the Acute Myocardial Infarction Quality Assurance Canada Study.

Importance: Persistently depressed left ventricular ejection fraction (LVEF) after myocardial infarction (MI) is associated with adverse prognosis and directs the use of evidence-based treatments to prevent sudden cardiac death and/or progressive heart failure. Objective: To assess adherence with guideline-recommended LVEF reassessment and to study the evolution of LVEF over 6 months of follow-up. Design, Setting, and Participants: This was a multicenter cohort study at Canadian academic and community hospitals with on-site cardiac catheterization services. Patients with type 1 acute MI and LVEF less than or equal to 45% during the index hospitalization were enrolled between January 2018 and August 2019 and were followed-up for 6 months. Data analysis was performed from May 2020 to September 2021. Exposures: Baseline clinical factors, in-hospital care and LVEF, and site-specific features. Main Outcomes and Measures: The main outcomes were receipt of repeat LVEF assessment by 6 months and the presence of a persistent LVEF reduction at 2 thresholds: LVEF less than or equal to 40%, prompting consideration of additional medical therapy for heart failure, or LVEF less than or equal to 35%, prompting referral for implanted cardioverter defibrillator in addition to medical therapy. Results: This study included 501 patients (mean [SD] age, 63.3 [13.0] years; 113 women [22.6%]). Overall, 370 patients (73.4%) presented with STEMI, and 454 (90.6%) had in-hospital revascularization. The median (IQR) baseline LVEF was 40% (34%-43%). Of 458 patients (91.4%) who completed the 6-month follow-up, 303 (66.2%; 95% CI, 61.7%-70.5%) had LVEF reassessment, with a range of 46.7% to 90.0% across sites (χ213 = 19.6; P = .11). Participants from community hospitals were more likely than those from academic hospitals to undergo LVEF reassessment (73.6% vs 63.2%; χ21 = 4.50; P = .03), as were those with worse LVEF at baseline. Follow-up LVEF improved by an absolute median (IQR) of 8% (3%-15%). However, 103 patients (34.1%) met the definitions of clinically relevant LVEF reduction, including 52 patients (17.2%) with LVEF less than or equal to 35% and 51 patients (16.9%) with LVEF of 35.1% to 40.0%. Conclusions and Relevance: In this cohort study, approximately 1 in 3 patients with at least mild LVEF reduction after acute MI did not undergo indicated LVEF reassessment within 6 months, suggesting that programs to improve the quality of post-MI care should include measures to ensure that indicated repeat cardiac imaging is performed. In those with follow-up imaging, clinically relevant persistent LVEF reduction was identified in more than one-third of patients.

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.

Prevalence and outcome of early recurrence of atrial tachyarrhythmias in the Cryoballoon vs Irrigated Radiofrequency Catheter Ablation (CIRCA-DOSE) study.

BACKGROUND: Early recurrence of atrial tachyarrhythmia (ERAT) is common after pulmonary vein isolation (PVI) and has been associated with an increased risk of late atrial fibrillation (AF) recurrence. OBJECTIVE: The purpose of this study was to determine the incidence and outcomes of patients experiencing ERAT after PVI using advanced-generation ablation technologies. METHODS: This is a prespecified substudy of the CIRCA-DOSE (Cryoballoon vs Irrigated Radiofrequency Catheter Ablation: Double-Short vs Standard Exposure Duration) trial, a prospective, randomized, multicenter study comparing PVI with contact force-guided radiofrequency ablation to secondary-generation cryoballoon ablation for paroxysmal AF. All study patients received an implantable cardiac monitor to allow continuous rhythm monitoring. ERAT was defined as any recurrent atrial tachyarrhythmia within the first 90 days after AF ablation. RESULTS: ERAT occurred in 61% of the 346 patients at a median of 12 days (range 1-90 days) after ablation. ERAF was a significant predictor of late recurrence (60.1% with ER vs 25.9% without ER; P <.001) and symptomatic atrial tachyarrhythmia (31.6% with ERAF vs 6.7% without ERAF; P <.001). Receiver operating curve analyses revealed a strong correlation between ERAT timing and burden and late recurrence. Multivariate analysis identified ER timing (hazard ratio [HR] 2.90; 95% confidence interval [CI] 1.41-5.95; P = .004) and burden (HR 1.05 per 1% ER burden; 95% CI 1.04-1.07; P <.001) as strong independent predictors of late recurrence. Incidence rate, timing, burden, and prognostic significance of ER did not differ between the study groups. CONCLUSION: ERAT remains common after PVI despite use of advanced-generation ablation technologies. Early AF recurrence beyond 3 weeks after ablation is associated with increased risk of late recurrence.

Enrichment of loss-of-function and copy number variants in ventricular cardiomyopathy genes in 'lone' atrial fibrillation.

AIMS: Atrial fibrillation (AF) is a complex heritable disease whose genetic underpinnings remain largely unexplained, though recent work has suggested that the arrhythmia may develop secondary to an underlying atrial cardiomyopathy. We sought to evaluate for enrichment of loss-of-function (LOF) and copy number variants (CNVs) in genes implicated in ventricular cardiomyopathy in 'lone' AF. METHODS AND RESULTS: Whole-exome sequencing was performed in 255 early onset 'lone' AF cases, defined as arrhythmia onset prior to 60 years of age in the absence of known clinical risk factors. Subsequent evaluations were restricted to 195 cases of European genetic ancestry, as defined by principal component analysis, and focused on a pre-defined set of 43 genes previously implicated in ventricular cardiomyopathy. Bioinformatic analysis identified 6 LOF variants (3.1%), including 3 within the TTN gene, among cases in comparison with 4 of 503 (0.80%) controls [odds ratio: 3.96; 95% confidence interval (CI): 1.11-14.2; P = 0.033]. Further, two AF cases possessed a novel heterozygous 8521 base pair TTN deletion, confirmed with Sanger sequencing and breakpoint validation, which was absent from 4958 controls (P = 0.0014). Subsequent cascade screening in two families revealed evidence of co-segregation of a LOF variant with 'lone' AF. CONCLUSION: 'Lone' AF cases are enriched in rare LOF variants from cardiomyopathy genes, findings primarily driven by TTN, and a novel TTN deletion, providing additional evidence to implicate atrial cardiomyopathy as an AF genetic sub-phenotype. Our results also highlight that AF may develop in the context of these variants in the absence of a discernable ventricular cardiomyopathy.

Bidirectional Ventricular Tachycardia in a Patient With Fulminant Myocarditis Secondary to Cardiac Sarcoidosis Mimicking Giant Cell Myocarditis.

Differentiating between sarcoidosis and giant cell myocarditis (GCM) based on clinical presentation is difficult. We present the case of a 57-year-old woman who was initially diagnosed with GCM based on endomyocardial biopsy. The patient was refractory to standard management for GCM and went on to develop bidirectional ventricular tachycardia, a finding suggestive of sarcoidosis. Unfortunately, the patient eventually needed cardiac transplantation. The explanted heart demonstrated cardiac sarcoidosis. Bidirectional ventricular tachycardia has not been demonstrated in GCM, and its presence may help in distinguishing between GCM and cardiac sarcoidosis.

La distinction entre la sarcoïdose et la myocardite à cellules géantes (MCG) fondée sur le tableau clinique est difficile. Nous présentons le cas d'une femme de 57 ans qui avait initialement reçu un diagnostic de MCG à la suite de la biopsie endomyocardique. Comme la MCG diagnostiquée chez la patiente était réfractaire à la prise en charge thérapeutique habituelle, elle a continué à souffrir de tachycardie ventriculaire bidirectionnelle, un signe évocateur de sarcoïdose. Malheureusement, la patiente a finalement eu besoin d'une transplantation cardiaque. Le cœur explanté a démontré une sarcoïdose cardiaque. Bien que la tachycardie ventriculaire bidirectionnelle n'ait pas été démontrée lors de MCG, sa présence peut aider à distinguer la MCG de la sarcoïdose cardiaque.

Differences in Healthcare Use Between Patients With Persistent and Paroxysmal Atrial Fibrillation Undergoing Catheter-Based Atrial Fibrillation Ablation: A Population-Based Cohort Study From Ontario, Canada.

Background Patients with persistent atrial fibrillation (AF) undergoing catheter-based AF ablation have lower success rates than those with paroxysmal AF. We compared healthcare use and clinical outcomes between patients according to their AF subtypes. Methods and Results Consecutive patients undergoing AF ablation were prospectively identified from a population-based registry in Ontario, Canada. Via linkage with administrative databases, we performed a retrospective analysis comparing the following outcomes between patients with persistent and paroxysmal AF: healthcare use (defined as AF-related hospitalizations/emergency room visits), periprocedural complications, and mortality. Multivariable Poisson modeling was performed to compare the rates of AF-related and all-cause hospitalizations/emergency room visits in the year before versus after ablation. Between April 2012 and March 2016, there were 3768 consecutive patients who underwent first-time AF ablation, of whom 1040 (27.6%) had persistent AF. The mean follow-up was 1329 days. Patients with persistent AF had higher risk of AF-related hospitalization/emergency room visits (hazard ratio [HR], 1.21; 95% CI, 1.09-1.34), mortality (HR, 1.74; 95% CI, 1.15-2.63), and periprocedural complications (odds ratio, 1.36; 95% CI, 1.02-1.75) than those with paroxysmal AF. In the overall cohort, there was a 48% reduction in the rate of AF-related hospitalization/emergency room visits in the year after versus before ablation (rate ratio [RR], 0.52; 95% CI, 0.48-0.56). This reduction was observed for patients with paroxysmal (RR, 0.45; 95% CI, 0.41-0.50) and persistent (RR, 0.74; 95% CI, 0.63-0.87) AF. Conclusions Although patients with persistent AF had higher risk of adverse outcomes than those with paroxysmal AF, ablation was associated with a favorable reduction in downstream AF-related healthcare use, irrespective of AF type.

Para-Hisian Pacing During Sinus Rhythm: Establishing Threshold Values to Distinguish Nodal From Septal Pathway Conduction.

OBJECTIVES: This study sought to identify minimum threshold values below which conduction over the atrioventricular (AV) node would be unexpected. BACKGROUND: Para-Hisian pacing is used to evaluate for the presence of a septal accessory pathway (AP); however, threshold values to differentiate nodal from AP conduction are unknown. METHODS: The authors performed high- and low-output para-Hisian pacing during sinus rhythm to capture the His and para-Hisian ventricular myocardium (H+V) and para-Hisian ventricular myocardium (V) alone, respectively. The change in stimulation (stim)-to-atrial electrogram interval after loss of His bundle capture in patients with (AP+) and without (AP-) a septal AP was evaluated. Stim-to-proximal coronary sinus (PCS) and stim-to-high right atrium (HRA) intervals were measured and within-patient differences (△) for V and H+V capture were calculated. RESULTS: A total of 23 AP+ and 45 AP- patients were evaluated. The difference in stimulus to earliest atrial signal in the high right atrial catheter seen with the loss of His bundle capture (△-stim-HRA) (21 ms; interquartile range [IQR]: 3 to 43 ms vs. 64 ms; IQR: 56 to 73 ms; p < 0.001) and difference in stimulus to earliest atrial signal in the proximal coronary sinus catheter seen with the loss of His Bundle capture (△-stim-PCS) (11 ms; IQR: 0 to 30 ms vs. 61 ms; IQR: 52 to 72 ms; p < 0.001) were shorter in AP+ patients. The shortest △-stim-PCS and △-stim-HRA in AP- patients were 37 ms and 32 ms, respectively, whereas the longest corresponding intervals in AP+ patients were 51 ms and 75 ms, respectively. CONCLUSIONS: A △-stim-PCS <37 ms or △-stim-HRA <32 ms confirmed the presence of a septal AP, whereas a value >51 ms for △-stim-PCS or >75 ms for △-stim-HRA excluded it. Alternatively, the minimum △-stim-PCS with loss of His capture compatible with AV nodal conduction in isolation was 37 ms, and a △-stim-PCS >51 ms effectively ruled out the presence of a septal AP.

A simple maneuver to determine if septal accessory pathway ablation requires a left atrial approach.

INTRODUCTION: Septal accessory pathway (AP) ablation can be challenging due to the complex anatomy of the septal region. The decision to access the left atrium (LA) is often made after failure of ablation from the right. We sought to establish whether the difference between ventriculo-atrial (VA) time during right ventricular (RV) apical pacing versus the VA during tachycardia would help establish the successful site for ablation of septal APs. METHODS: Intracardiac electrograms of patients with orthodromic reciprocating tachycardia (ORT) using a septal AP with successful catheter ablation were reviewed. The ∆VA was the difference between the VA interval during RV apical pacing and the VA interval during ORT. The difference in the VA interval during right ventricular entrainment and ORT (StimA-VA) was also measured. RESULTS: The median ∆VA time was significantly less in patients with a septal AP ablated on the right side compared with patients with a septal AP ablated on the left side (12 ± 19 vs. 56 ± 10 ms, p < .001). The StimA-VA was significantly different between the two groups (22 ± 14 vs. 53 ± 9 ms, p < .001). The ∆VA and StimA-VA were always ≤ 40 ms in patients with non-decremental septal APs ablated from the right side and always greater than 40 ms in those with septal APs ablated from the left. CONCLUSION: ΔVA and StimA-VA values identified with RV apical pacing in the setting of ORT involving a septal AP predict when left atrial access will be necessary for successful ablation.

Quality of Life and Health Care Utilization in the CIRCA-DOSE Study.

OBJECTIVES: This study evaluated the impact of contact force-guided radiofrequency ablation versus cryoballoon ablation on quality of life and health care utilization. BACKGROUND: Traditional outcome parameters, such as arrhythmia-free survival, are insufficient to evaluate the clinical impact of atrial fibrillation (AF), as it fails to the capture patient- and health system-level differences in treatment approaches. METHODS: The CIRCA-DOSE (Cryoballoon Vs. Contact-Force Atrial Fibrillation Ablation) study randomly assigned 346 patients with drug-refractory paroxysmal AF to contact force-guided radiofrequency or cryoballoon ablation. Health-related quality-of-life (HRQOL) was assessed at baseline, and at 6 and 12 months post-ablation using a disease-specific and generic HRQOL instruments. Health care utilization (hospitalization, emergency department visits, and cardioversion) and antiarrhythmic drug use for the 12 months preceding ablation was compared with the 12 months following ablation. RESULTS: Disease-specific and generic HRQOL was moderately to severely impaired at baseline and improved significantly at 6 and 12 months of follow-up (median improvement in AFEQT [Atrial Fibrillation Effect on QualiTy of Life] score 32.4 [interquartile range: 17.7 to 48.9]). When compared with the 12 months pre-ablation, the proportion and absolute number of cardioversions decreased significantly (41.1% vs. 10.1% of patients, 137 vs. 35 events; p < 0.0001). Similar significant reductions in emergency department visits (66.7% vs. 25.1% of patients, 224 vs. 87 events; p < 0.0001), and hospitalizations (25.5% vs. 14.5% of patients, 86 vs. 50 events; p < 0.001) were observed. There were no significant differences between randomized groups. CONCLUSIONS: In this multicenter randomized trial, catheter ablation with advanced-generation technologies resulted in a significant improvement in HRQOL and a significant reduction in health care utilization in the year following AF ablation. (Cryoballoon vs. Irrigated Radiofrequency Catheter Ablation [CIRCA-DOSE]; NCT01913522).

Impact of Left Common Pulmonary Veins in the Contact-Force vs. Cryoballoon Atrial Fibrillation Ablation (CIRCA-DOSE) Study.

BACKGROUND: Concerns remain regarding the effectiveness of PVI using the fixed diameter non-compliant cryoballoon in the presence of a left common pulmonary vein (LCPV). We sought to evaluate the effectiveness of PVI performed by contact-force guided radiofrequency (CF-RF) versus second-generation cryoballoon-based ablation in patients with LCPV. METHODS AND RESULTS: We enrolled 346 patients with paroxysmal AF and randomized them to CF-RF or cryoballoon ablation. PV anatomy was not assessed prior to enrolment, and there were no exclusions based on PV anatomy. All patients received an implantable cardiac monitor. LCPV was observed in 13.6% of patients (47/346). Left atrial time and fluoroscopy time did not differ between those with and without LCPV (P=0.58 and P=0.06, respectively). Freedom from any atrial tachyarrhythmia at one year was observed in 46.8% with LCPV and 54.5% without LCPV (P=0.06). In those with LCPV the freedom from any atrial tachyarrhythmia did not differ between those randomized to CF-RF or cryoballoon ablation (HR for recurrence 1.19, 95% CI 0.53-2.65, P=0.69). In those with LCPV the AF burden was reduced to a similar extent with CF-RF and cryoballoon ablation (99.7% vs. 99.5%, respectively; P=0.97). CONCLUSIONS: In this randomized clinical trial, the presence of a LCPV was associated with a trend towards higher rates of arrhythmia recurrence following PVI. No significant difference in arrhythmia recurrence was observed between patients with LCPV randomized to cryoballoon ablation or contact-force guided RF ablation, suggesting that either ablation modality is suitable in this population. (Cryoballoon vs. Irrigated Radiofrequency Catheter Ablation [CIRCA-DOSE], NCT01913522) This article is protected by copyright. All rights reserved.

Association of Atrial Fibrillation Episode Duration With Arrhythmia Recurrence Following Ablation: A Secondary Analysis of a Randomized Clinical Trial.

Importance: Contemporary guidelines recommend that atrial fibrillation (AF) be classified based on episode duration, with these categories forming the basis of therapeutic recommendations. While pragmatic, these classifications are not based on pathophysiologic processes and may not reflect clinical outcomes. Objective: To evaluate the association of baseline AF episode duration with post-AF ablation arrhythmia outcomes. Design, Setting, and Participants: The current study is a secondary analysis of a prospective, parallel-group, multicenter, single-masked randomized clinical trial (the 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 AF referred for first catheter ablation were enrolled. All patients received an implantable cardiac monitor at least 30 days before ablation. Data analysis was performed in September 2019. Exposure: Before ablation, patients were classified based on their longest AF episode. Ablation consisted of circumferential pulmonary vein isolation using standard techniques. Main Outcomes and Measures: Time to first recurrence of symptomatic or asymptomatic atrial tachyarrhythmia (AF, atrial flutter, or atrial tachycardia) following ablation and AF burden (percentage of time in AF) on preablation and postablation continuous rhythm monitoring. Results: The study included 346 patients (mean [SD] age, 59 [10] years; 231 [67.7%] men). Overall, 263 patients (76.0%) had AF episode duration of less than 24 hours; 25 (7.2%), 24 to 48 hours; 40 (11.7%), 2 to 7 days; and 18 (5.2%), more than 7 days. Documented recurrence of any atrial tachyarrhythmia following ablation was significantly lower in patients with baseline AF episode duration of less than 24 continuous hours compared with those with longer AF episodes (24 hours vs 24-48 hours: hazard ratio [HR], 0.41; 95% CI, 0.21-0.80; P = .009; 24 hours vs 2-7 days: HR, 0.25; 95% CI, 0.14-0.45; P < .001; 24 hours vs >7 days: HR, 0.23; 95% CI, 0.09-0.55; P < .001). Patients with preablation AF episodes limited to less than 24 continuous hours had a significantly lower median (interquartile range) postablation AF burden (0% [0%-0.1%]) compared with those with AF preablation episodes lasting 2-7 days (0.1% [0%-1.0%]; P = .003) and those with AF preablation episodes lasting more than 7 days (1.0% [0%-5.4%]; P = .008). There was no significant difference in arrhythmia recurrence or AF burden between the 3 groups with a baseline AF episode duration of longer than 24 hours. Conclusions and Relevance: In this study, patients with AF episodes limited to less than 24 continuous hours had a significantly lower incidence of arrhythmia recurrence following AF ablation. This suggests that current guidelines for classification of AF may not reflect clinical outcomes. Trial Registration: ClinicalTrials.gov Identifier: NCT01913522.

Relationship between quality of life and burden of recurrent atrial fibrillation following ablation: CAPCOST multicentre cohort study.

AIMS: Atrial fibrillation (AF) significantly impairs patients' quality of life (QOL). We performed this study to investigate the effect of AF-ablation success and atrial fibrillation burden (AFB) on QOL measures. METHODS AND RESULTS: Overall, 230 patients with paroxysmal AF refractory to antiarrhythmic drugs were enrolled and underwent ablation in a multicentre, prospective cohort. Electrocardiogram, 48-h Holter, Canadian Cardiovascular Society Severity of Atrial Fibrillation (CCS-SAF), short form-12 (SF-12), and Atrial Fibrillation Effect on Quality of life (AFEQT) scales were used to assess patients. Atrial fibrillation burden was defined as total duration of AF during the month prior to each visit (h/month). The change in AFB was calculated as the difference between the month prior to the 12-month post-ablation and the baseline pre-ablation. The Minimal Clinically Important Difference (MCID) was considered as a 19-point change for AFEQT and 3-5-point change for SF-12 scores. There was significant rise in the AFEQT and SF12 and decrease in CCS-SAF score post-AF ablation; however, the magnitude of these changes was greater in patients without AF recurrence (P < 0.05). The QOL score that best differentiated patients with and without recurrence was AFEQT, while, CCS-SAF was the most specific score. Patients with AFB decrease >19 h/month had significantly greater change in QOL scores. Atrial fibrillation burden < 24 h/month at 12-months post-ablation was associated with significant changes in QOL and CCS-SAF when adjusting for baseline scores and other covariates. These changes were consistent with the MCID of these measures. CONCLUSION: Patients experience significant improvements in QOL post-ablation, which correlate with a decrease in AFB despite ongoing brief recurrences of AF. CLINICAL TRIAL REGISTRATION: NCT01562912. https://www.clinicaltrials.gov/ct2/show/NCT01562912? term=capcost&rank=1.

Canada-wide mixed methods analysis evaluating the reasons for inappropriate emergency department presentation in patients with a history of atrial fibrillation: the multicentre AF-ED trial.

OBJECTIVES: The primary objective of this study was to ascertain the reasons for emergency department (ED) attendance among patients with a history of atrial fibrillation (AF). DESIGN: Appropriate ED attendance was defined by the requirement for an electrical or chemical cardioversion and/or an attendance resulting in hospitalisation or administration of intravenous medications for ventricular rate control. Quantitative and qualitative responses were recorded and analysed using descriptive statistics and content analysis, respectively. Random effects logistic regression was performed to estimate the OR of inappropriate ED attendance based on clinically relevant patient characteristics. PARTICIPANTS: Participants ≥18 years with a documented history of AF were approached in one of eight centres partaking in the study across Canada (Ontario, Nova Scotia, Alberta and British Columbia). RESULTS: Of the 356 patients enrolled (67±13, 45% female), the majority (271/356, 76%) had inappropriate reasons for presentation and did not require urgent ED treatment. Approximately 50% of patients(172/356, 48%) were driven to the ED due to symptoms, while the remainder presented on the basis of general fear or anxiety (67/356, 19%) or prior medical advice (117/356, 33%). Random effects logistic regression analysis showed that patients with a history of congestive heart failure were significantly more likely to seek urgent care for appropriate reasons (p=0.03). Likewise, symptom-related concerns for ED presentation were significantly less likely to result in inappropriate visitation (p=0.02). When patients were surveyed on alternatives to ED care, the highest proportion of responses among both groups was in favour of specialised rapid assessment outpatient clinics (186/356, 52%). Qualitative content analysis confirmed these results. CONCLUSIONS: Improved education focused on symptom management and alleviating disease-related anxiety as well as the institution of rapid access arrhythmias clinics may reduce the need for unnecessary healthcare utilisation in the ED and subsequent hospitalisation. TRIAL REGISTRATION NUMBER: NCT03127085.