Multidisciplinary approach to long-standing left bundle branch block with dyssynchrony and aortic stenosis: case report

Background

Cardiac resynchronization therapy (CRT) is recommended for patients with symptomatic heart failure in sinus rhythm with left ventricular ejection fraction (LVEF) ≤ 35%, QRS duration ≥ 150 ms, and left bundle branch block (LBBB) morphology. However, when severe left ventricular dysfunction and cardiogenic shock are present, treatment paradigms are often limited to palliative medical therapy or advanced therapies with durable left ventricular assist device or heart transplant as the functional and survival benefit of CRT in these patients remains uncertain.

Case summary

A 77-year-old white man with long-standing LBBB with dyssynchrony, severely reduced LVEF of 4%, and severe bicuspid aortic stenosis (AS) presented with worsening heart failure symptoms. After multidisciplinary heart team evaluation and pre-operative optimization, the patient underwent a surgical aortic valve replacement with simultaneous intraoperative initiation of CRT with pacemaker (CRT-P) and temporary mechanical circulatory support. Echocardiography at 44 days and 201 days post-discharge showed an LVEF of 29% and 40%, respectively.

Discussion

This case demonstrates that reverse remodelling and native heart recovery were successfully achieved in a patient with advanced structural heart disease, presenting with cardiogenic shock, through an early and aggressive approach involving multidisciplinary heart team evaluation, treatment of severe AS with surgical aortic valve replacement, prophylactic intraoperative initiation of temporary mechanical circulatory support, and early initiation of CRT-P.

The Cost-Effectiveness of First-Line Cryoablation vs First-Line Antiarrhythmic Drugs in Canadian Patients With Paroxysmal Atrial Fibrillation

BACKGROUND

The EARLY-AF (NCT02825979), STOP AF First (NCT03118518), and Cryo-FIRST (NCT01803438) randomised controlled trials (RCTs) demonstrated that cryoballoon pulmonary vein isolation reduces atrial fibrillation (AF) recurrence compared with antiarrhythmic drugs (AADs) in patients with symptomatic paroxysmal atrial fibrillation (PAF). The present study developed a cost-effectiveness model (CEM) of first-line cryoablation compared with first-line AADs for PAF, from the Canadian health care payer's perspective.

METHODS

Data from the 3 RCTs were analysed to estimate key CEM parameters. The model structure used a decision tree for the first 12 months and a Markov model with a 3-month cycle length for the remaining lifetime time horizon. Costs were set at 2023 Canadian dollars, health benefits were expressed as quality-adjusted life years (QALYs), and both were discounted 3% annually. Probabilistic sensitivity analysis (PSA) considered parameter uncertainty.

RESULTS

The statistical analysis estimated that first-line cryoablation generates a 47% reduction (P < 0.001) in the rate of AF recurrence, a 73% reduction in the rate of subsequent ablation (P < 0.001), and a 4.3% (P = 0.025) increase in health-related quality of life, compared with first-line AADs. The PSA indicates that an individual treated with first-line cryoablation accrues less costs (-$3,862) and more QALYs (0.19) compared with first-line AADs. Cryoablation is cost-saving in 98.4% of PSA iterations and has a 99.9% probability of being cost-effective at a cost-effectiveness threshold of $50,000 per QALY gained. Cost-effectiveness results were robust to changes in key model parameters.

CONCLUSIONS

First-line cryoballoon ablation is cost-effective when compared with AADs for patients with symptomatic PAF.

Cardioneuroablation for the Treatment of Hypervagotonic Sinus Node Dysfunction

Hypervagotonic sinus node dysfunction (SND) is a form of SND with sinus bradycardia caused by enhanced vagal tone. Indirect proof of hypervagotonia as the mechanism can be inferred from resolution of bradycardia following atropine infusion. In symptomatic patients, pacemaker implantation is recommended. We describe cardioneuroablation as a treatment for hypervagotonic SND.

Economic evaluation of first-line cryoballoon ablation versus antiarrhythmic drug therapy for the treatment of paroxysmal atrial fibrillation from an English National Health Service perspective

INTRODUCTION

Three recent randomised controlled trials have demonstrated that pulmonary vein isolation as an initial rhythm control strategy with cryoablation reduces atrial arrhythmia recurrence in patients with symptomatic paroxysmal atrial fibrillation (PAF) compared with antiarrhythmic drug (AAD) therapy. The aim of this study was to evaluate the cost-effectiveness of first-line cryoablation compared with first-line AADs for treating symptomatic PAF in an English National Health Service (NHS) setting.

METHODS

Individual patient-level data from 703 participants with PAF enrolled into Cryo-FIRST (Catheter Cryoablation Versus Antiarrhythmic Drug as First-Line Therapy of Paroxysmal Atrial Fibrillation), STOP AF First (Cryoballoon Catheter Ablation in an Antiarrhythmic Drug Naive Paroxysmal Atrial Fibrillation) and EARLY-AF (Early Aggressive Invasive Intervention for Atrial Fibrillation) were used to derive the parameters applied in the cost-effectiveness model (CEM). The CEM comprised a hybrid decision tree and Markov structure. The decision tree had a 1-year time horizon and was used to inform the initial health state allocation in the first cycle of the Markov model (40-year time horizon; 3-month cycle length). Health benefits were expressed in quality-adjusted life years (QALYs). Costs and benefits were discounted at 3.5% per year. Model outcomes were generated using probabilistic sensitivity analysis.

RESULTS

The results estimated that cryoablation would yield more QALYs (+0.17) and higher costs (+£641) per patient over a lifetime than AADs. This produced an incremental cost-effectiveness ratio of £3783 per QALY gained. Independent of initial treatment, individuals were expected to receive ~1.2 ablations over a lifetime. There was a 45% relative reduction in time spent in AF health states for those initially treated with cryoablation.

DISCUSSION

AF rhythm control with first-line cryoablation is cost effective compared with first-line AADs in an English NHS setting.

The Added Value of Preprocedural Cardiac Computed Tomography in Planning Left Atrial Appendage Closure With the Watchman FLX Device

•Cardiac computed tomography (CCT) can be used as a useful complementary tool in preprocedural planning of left atrial appendage closure.•CCT planning includes assessing exclusion criteria, device sizing, sheath selection, anticipating challenging anatomies, and transseptal puncture planning.•Procedural 3D intracardiac echocardiography (3D-ICE) is increasingly being used instead of transesophageal echocardiography. In this setting, preprocedural CCT is useful to compensate for 3D ICE's reduced resolution.

An economic evaluation of first-line cryoballoon ablation vs antiarrhythmic drug therapy for the treatment of paroxysmal atrial fibrillation from a U.S. Medicare perspective

Background

Three recent randomized controlled trials have demonstrated that, as an initial rhythm control strategy, first-line cryoballoon ablation (cryoablation) reduces atrial arrhythmia recurrence compared with antiarrhythmic drugs (AADs) in patients with symptomatic paroxysmal atrial fibrillation (PAF).

Objective

The study sought to evaluate the cost-effectiveness of first-line cryoablation compared with first-line AADs for treating symptomatic PAF from a U.S. Medicare payer perspective.

Methods

Individual patient-level data from 703 participants with PAF enrolled into the Cryo-FIRST (NCT01803438), STOP AF First (NCT03118518), and EARLY-AF (NCT02825979) trials were used to derive parameters for the cost-effectiveness model. The cost-effectiveness model used a hybrid decision tree and Markov structure. The decision tree had a 1-year time horizon and was used to inform the initial health state allocation in the first cycle of the Markov model. The Markov model used a 40-year time horizon (3-month cycle length). Health benefits were expressed in quality-adjusted life years (QALYs). Costs and benefits were discounted at 3% per year.

Results

Cryoablation was estimated to yield higher QALYs (+0.17) and higher costs (+$4274) per patient over a 40-year time horizon than AADs. Ultimately, this produced an average incremental cost-effectiveness ratio of $24,637 per QALY gained. Independent of initial treatment, individuals were expected to receive ∼1.2 ablations over a lifetime. There was a 45% relative reduction in time spent in atrial fibrillation health states for those initially treated with cryoablation compared with AADs.

Conclusion

Initial rhythm control with first-line cryoballoon ablation is highly cost-effective compared with first-line AADs from a U.S. Medicare payer perspective.

Pacing-Related Differences After SAPIEN-3 TAVI: Clinical and Echocardiographic Correlates

Data regarding the impact of pacing on outcomes after transcatheter aortic valve implantation (TAVI) is evolving especially with regards to pre-existing permanent pacemaker (PPM). We examined the impact of new and previous PPM on the clinical and hemodynamic outcomes after SAPIEN-3 TAVI. We included all consecutive patients who underwent transfemoral TAVI using SAPIEN-3 valve from 2015 to 2018 at our institution. Among 1,028 patients, 10.2% required a new PPM within 30 days, whereas 14% had a pre-existing PPM. The presence of either previous or new PPM had no impact on the 3-year mortality (log-rank p = 0.6) or 1-year major adverse cardiac and cerebrovascular events (log-rank p = 0.65). New PPM was associated with lower left ventricular (LV) ejection fraction (LVEF) at both 30 days (54.4 ± 11.3% vs 58.4 ± 10.1%, p = 0.001) and 1 year (54.2 ± 12% vs 59.1 ± 9.9%, p = 0.009) than no PPM. Similarly, previous PPM was associated with worse LVEF at 30 days (53.6 ± 12.3%, p <0.001) and 1 year (55.5 ± 12.1%, p = 0.006) than no PPM. Interestingly, new PPM was associated with lower 1-year mean gradient (11.4 ± 3.8 vs 12.6 ± 5.6 mm Hg, p = 0.04) and peak gradient (21.3 ± 6.5 vs 24.1 ± 10.4 mm Hg, p = 0.01), despite no baseline differences. Previous PPM was also associated with lower 1-year mean gradient (10.3 ± 4.4 mm Hg, p = 0.001) and peak gradient (19.4 ± 8 mm Hg, p <0.001) and higher Doppler velocity index (0.51 ± 0.12 vs 0.47 ± 0.13, p = 0.039). Moreover, 1-year LV end-systolic volume index was higher with new (23.2 ± 16.1 vs 20 ± 10.8 ml/m², p = 0.038) and previous PPM (24.5 ± 19.7, p = 0.038) than no PPM. Previous PPM was associated with higher moderate-to-severe tricuspid regurgitation (35.3% vs 17.7%, p <0.001). There were no differences regarding the rest of the studied echocardiographic outcomes at 1 year. In conclusion, new and previous PPM did not affect 3-year mortality or 1-year major adverse cardiac and cerebrovascular events; however, they were associated with worse LVEF, higher 1-year LV end-systolic volume index, and lower mean and peak gradients on follow-up than no PPM.

Two-Year Outcomes With a Next-Generation Left Atrial Appendage Device: Final Results of the PINNACLE FLX Trial

Background The PINNACLE FLX (Protection Against Embolism for Non-valvular AF [Atrial Fibrillation] Patients: Investigational Device Evaluation of the Watchman FLX LAA [Left Atrial Appendage] Closure Technology) trial evaluated the safety and efficacy of a next-generation left atrial appendage closure device (WATCHMAN FLX; Boston Scientific, Marlborough, MA). At 1 year, the study met the primary end points of safety and anatomical efficacy/appendage closure. This final report of the PINNACLE FLX trial includes the prespecified secondary end point of ischemic stroke or systemic embolism at 2 years, also making it the first report of 2-year outcomes with this next-generation left atrial appendage closure device. Methods and Results Patients with nonvalvular atrial fibrillation with CHA₂DS₂-VASc score ≥2 (men) or ≥3 (women), with an appropriate rationale for left atrial appendage closure, were enrolled to receive the left atrial appendage closure device at 29 US centers. Adverse events were assessed by an independent clinical events committee, and imaging was assessed by independent core laboratories. Among 395 implanted patients (36% women; mean age, 74 years; CHA₂DS₂-VASc, 4.2±1.5), the secondary efficacy end point of 2-year ischemic stroke or systemic embolism was met, with an absolute rate of 3.4% (annualized rate, 1.7%) and an upper 1-sided 95% confidence bound of 5.3%, which was superior to the 8.7% performance goal. Two-year rates of adverse events were as follows: 9.3% all-cause mortality, 5.5% cardiovascular death, 3.4% all stroke, and 10.1% major bleeding (Bleeding Academic Research Consortium 3 or 5). There were no additional systemic embolisms, device embolizations, pericardial effusions, or symptomatic device-related thrombi after 1 year. Conclusions The secondary end point of 2-year stroke or systemic embolism was met at 3.4%. In these final results of the PINNACLE FLX trial, the next-generation WATCHMAN FLX device demonstrated favorable safety and efficacy outcomes.

Junctional Tachycardia

Junctional tachycardia (JT) is typically considered to have an automatic mechanism originating from the distal atrioventricular node. When there is 1:1 retrograde conduction via the fast pathway, JT would resemble the typical form of atrioventricular nodal re-entrant tachycardia (AVNRT). Atrial pacing maneuvers have been proposed to exclude AVNRT and suggest a diagnosis of JT. However, after excluding AVNRT, one should consider the possibility of an infra-atrial narrow QRS re-entrant tachycardia, which can exhibit features that resemble AVNRT as well as JT. Pacing maneuvers and mapping techniques should be performed to assess for infra-atrial re-entrant tachycardia before concluding that JT is the mechanism of a narrow QRS tachycardia. Distinguishing JT from typical AVNRT or infra-atrial re-entrant tachycardia has notable implications regarding the approach to ablation of the tachycardia. Ultimately, a contemporary review of the evidence on JT raises some questions as to the mechanism and source of what has traditionally been considered JT.

Clinical and echocardiographic outcomes with new-onset left bundle branch block after SAPIEN-3 transcatheter aortic valve replacement

BACKGROUND

New-onset left bundle branch block (LBBB) can develop after transcatheter aortic valve replacement (TAVR) resulting in worse outcomes.

AIMS

Describe clinical and echocardiographic outcomes with new-onset LBBB after TAVR.

METHODS

We included consecutive patients who underwent transfemoral-TAVR with SAPIEN-3 (S3) valve between April 2015 and December 2018. Exclusion criteria included pre-existing LBBB, right BBB, left anterior hemiblock, left posterior hemiblock, wide QRS ≥ 120ms, prior permanent pacemaker (PPM), and nontransfemoral access.

RESULTS

Among 612 patients, 11.4% developed new-onset LBBB upon discharge. The length of stay was longer with new-onset LBBB compared with no LBBB [3 (2-5) days versus 2 (1-3) days; p < 0.001]. New-onset LBBB was associated with higher rates of 30-day PPM requirement (18.6% vs. 5.4%; p < 0.001) and 1-year heart failure hospitalizations (10.7% vs. 4.4%; p = 0.033). There was no difference in 3-year mortality between both groups (30.9% vs. 30.6%; p = 0.829). Further, new-onset LBBB was associated with lower left ventricular ejection fraction (LVEF) at both 30 days (55.9 ± 11.4% vs. 59.3 ± 9%; p = 0.026) and 1 year (55 ± 12% vs. 60.1 ± 8.9%; p = 0.002). These changes were still present when we stratified patients according to baseline LVEF (≥50% or <50%). New-onset LBBBs were associated with a higher 1-year LV end-diastolic volume index (51.4 ± 18.6 vs. 46.4 ± 15.1 ml/m² ; p = 0.036), and LV end-systolic volume index (23.2 ± 14.1 vs. 18.9 ± 9.7 ml/m² ; p = 0.009). Compared with resolved new-onset LBBB, persistent new-onset LBBB was associated with worse LVEF and higher PPM at 1 year.

CONCLUSIONS

New-onset LBBB after S3 TAVR was associated with higher PPM requirement, worse LVEF, higher LV volumes, and increased heart failure hospitalizations, with no difference in mortality.

Predictors and outcome of electrical storm-induced cardiogenic shock

AIM

Limited information is available about the short- and long-term outcomes in electrical storm (ES)-induced cardiogenic shock (CS) and its predictors.

METHODS AND RESULTS

This is a retrospective, single-centre cohort study of consecutive patients with ES admitted to the Cardiac Intensive Care Unit between 2015 and 2020. The proportion of ES patients who developed CS was adjudicated, and clinical predictors of in-hospital ventricular arrhythmia (VA)-related mortality and 1-year all-cause mortality were investigated. Of the 214 patients with ES, 33.6% developed CS. Left-ventricular ejection fraction, admission lactate, absence of an implantable cardioverter defibrillator, and admission central venous pressure were independently associated with development of CS (P < 0.03 for all). Based on these variables, a FLIC score was developed (https://riskcalc.org/FLICscore/) to predict ES-induced CS [area under the curve (AUC) = 0.949, with AUC = 0.954 in a validation cohort, both P < 0.001]. Patients who developed CS had a 11.3-fold [95% confidence interval (CI) 2.7-12.8] increased odds for in-hospital VA-related mortality and 9.4-fold (95% CI 4.0-22.4) increased odds for in-hospital all-cause mortality. A FLIC score above 0.62 was associated with a 6.2- and 5.8-fold increased odds for respectively similar endpoints. Patients with ES-induced CS received more treatment modalities to manage the ES (4.5 ± 1.8 vs. 2.3 ± 1.2, P < 0.001) and had longer length of stay [14 (8-27) vs. 8 (5-13), P < 0.001] than patients without CS. Interestingly, if patients with ES-induced CS survived to discharge, their outcomes were similar to those without CS at 1 year.

CONCLUSION

Cardiogenic shock in ES is a frequent and potentially life-threatening complication with high short-term mortality. A novel risk score could identify patient at risk, generating a potential for early risk-based interventions.

Role of Cardiac Contractility Modulation in Heart Failure With a Higher Ejection Fraction

Cardiac contractility modulation (also known as CCM) is a novel device therapy that delivers nonexcitatory electric stimulation to cardiac myocytes during the absolute refractory period, and it has been shown to improve functional status and clinical outcomes in patients with heart failure (HF) with reduced ejection fraction (HFrEF). CCM therapy is currently recommended for a subset of patients with advanced HFrEF who are not candidates for cardiac resynchronization therapy. A growing body of evidence demonstrates the benefit of CCM therapy in patients with HFrEF and with ejection fraction at the upper end of the spectrum and in patients with HF and with mildly reduced ejection fraction (HFmrEF). Experimental studies have also observed reversal of pathological biomolecular intracellular changes with CCM therapy in HF with preserved ejection fraction (HFpEF), indicating the potential for clinically meaningful benefits of CCM therapy in these patients. In this review, we sought to discuss the basis of CCM therapy and its potential for management of patients with HF with higher ejection fractions.

Decreased device related thrombus and enhanced neo-endocardial tissue maturation with a new generation left atrial appendage closure (LAAC) device. An anticoagulation and antiplatelet free canin study

Introduction

Device related thrombus (DRT) has been reported in up to 7% of patients post LAAC even while on anticoagulation. Clinical predictors of DRT are poorly understood and may be related to patient, procedural and device factors. A next generation WATCHMAN LAAC device (NG) is identical in shape and geometry to the current WATCHMAN FLX device (CW) but has a device coating designed to make it hemocompatible and less thrombogenic.

Objective

To evaluate the incidence and burden of WM surface thrombus formation as detected longitudinally by TEE and at necropsy in a canine model implanted with the NG device.

Methods

The study included 12 canine (6 implanted with CW and 6 implanted with NG) that underwent serial TEE follow up at 14, 28 and 45 days to evaluate surface thrombus on WM face. This was a challenged canine model designed to induce thrombus with no anticoagulation or antiplatelet use throughout the study. D-dimer levels were measured at 7 days and 45 days and compared to baseline measurements.

Results

All devices were successfully implanted. TEE follow up at 14 days showed noticeably reduced thrombus burden on the NG device compared to CW (fig.1) with even further diminution by 28 days in the NG (6/6) as compared to only in 1/6 in the CW group (fig.2). After 45 days in-life, the post-fixation trim en-face images show a smooth, glistening neoendocardial covering (absence of acute thrombus material) in all (6/6) NG compared to only 2/6 in the CW (fig.3). The CW had 3/6 devices with exuberant, bulging calcified thrombus mass one of which was considered to be a mobile DRT. D Dimer levels at 7 and 45 days were significantly lower relative to baseline in the NG compared to CW.

Conclusion

The NG device compared to the CW device was associated with markedly less thrombus formation at 14 days and no thrombus formation at 28 days post implant on no anticoagulant and no antiplatelet therapy along with a more mature uniform tissue coverage at 45 days. The WATCHMAN FLX Pro device coating is a promising step to reduce DRT even without the use of anticoagulation and antiplatelets and merits further investigation in human studies.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Boston Scientific

Direct Oral Anticoagulants Versus Warfarin in Patients With Atrial Fibrillation and Valve Replacement or Repair

Background

We sought to examine outcomes of direct oral anticoagulants (DOACs) versus warfarin in atrial fibrillation with valve repair/replacement.

Methods and Results

Two atrial fibrillation cohorts from Medicare were identified from 2015 to 2019. They comprised patients who underwent surgical or transcatheter mitral valve repair (MV repair cohort) and surgical aortic or mitral bioprosthetic or transcatheter aortic valve replacement (bioprosthetic cohort). Each cohort was divided into warfarin and DOACs (apixaban, rivaroxaban, and dabigatran) groups. Study outcomes included mortality, stroke, and major bleeding. Inverse probability weighting was used for adjustment between the 2 groups in each cohort. The MV repair cohort included 1178 patients. After a median of 468 days, DOACs were associated with lower risk of mortality (hazard ratio [HR], 0.67 [95% CI, 0.55–0.82], P<0.001), ischemic stroke (HR, 0.72 [95% CI, 0.52–1.00], P=0.05) and bleeding (HR, 0.79 [95% CI, 0.63–0.99], P=0.04) compared with warfarin. The bioprosthetic cohort included 8089 patients. After a median follow‐up of 413 days, DOACs were associated with similar risk of mortality (adjusted HR, 0.93 [95% CI, 0.86–1.01], P=0.08), higher risk of ischemic stroke (adjusted HR, 1.27 [95% CI, 1.13–1.43], P<0.001), and lower risk of bleeding (adjusted HR, 0.86 [95% CI, 0.80–0.93], P<0.001) compared with warfarin.

Conclusions

In patients with atrial fibrillation, DOACs are associated with similar mortality, lower bleeding, but higher stroke with bioprosthetic valve replacement and lower risk of all 3 outcomes with MV repair compared with warfarin.

Short-Term Outcomes Following Left Atrial Appendage Closure in the Very Elderly: A Population-Based Analysis

Background

Data on percutaneous left atrial appendage closure (LAAC) outcomes in the very elderly with atrial fibrillation are limited. We aimed to investigate the clinical characteristics and short‐term outcomes of patients 80 years or older following percutaneous LAAC in a large nationwide database.

Methods and Results

Using the Nationwide Readmissions Database, we identified patients who underwent percutaneous LAAC between January 2016 and December 2018. Patients were categorized based on age (≥80 and <80 years old). The primary outcome was in‐hospital mortality. Secondary outcomes were in‐hospital end points including periprocedural complications, 30‐day outcomes, and all‐cause 30‐day readmissions. A propensity score–matched model (1:1) was used to adjust for baseline characteristics among the study groups. A total of 13 208 patients were included in this study (43% women, median age in years [interquartile range] 79.5 [73–84]) and matched one‐to‐one (6604 and 6604 patients were ≥80 and <80 years old, respectively). In‐hospital mortality was not statistically different between the study groups and occurred in 21 patients ≥80 years old (0.32%) and in 14 patients <80 years old (0.21%); P=0.236. Rates of in‐hospital stroke/transient ischemic attack were higher in patients ≥80 years old compared with those <80 years old (1.22% versus 0.77%; P=0.009). In‐hospital bleeding requiring transfusion, vascular complications, systemic embolization, and pericardial effusion/tamponade requiring pericardiocentesis or surgical intervention occurred more frequently in patients ≥80 years old. Furthermore, the elderly group was more likely to be readmitted within 30 days compared with those <80 years old (9.91% versus 8.4%; P=0.004); however, rates of 30‐day complications were not statistically different between the study groups.

Conclusions

In a large nationwide database, patients ≥80 years old undergoing percutaneous LAAC were found to have similar in‐hospital mortality but an increased risk of periprocedural complications and 30‐day readmission compared with younger patients. Our data suggest that LAAC should be considered on a case‐by‐case basis in the very elderly, taking into consideration the risks and benefits of this intervention. Further studies are needed to assess long‐term LAAC outcomes in this high‐risk population.

Effect of MRI-Guided Fibrosis Ablation vs Conventional Catheter Ablation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation: The DECAAF II Randomized Clinical Trial

Importance

Ablation of persistent atrial fibrillation (AF) remains a challenge. Left atrial fibrosis plays an important role in the pathophysiology of AF and has been associated with poor procedural outcomes.

Objective

To investigate the efficacy and adverse events of targeting atrial fibrosis detected on magnetic resonance imaging (MRI) in reducing atrial arrhythmia recurrence in persistent AF.

Design, Setting, and Participants

The Efficacy of Delayed Enhancement-MRI-Guided Fibrosis Ablation vs Conventional Catheter Ablation of Atrial Fibrillation trial was an investigator-initiated, multicenter, randomized clinical trial involving 44 academic and nonacademic centers in 10 countries. A total of 843 patients with symptomatic or asymptomatic persistent AF and undergoing AF ablation were enrolled from July 2016 to January 2020, with follow-up through February 19, 2021.

Interventions

Patients with persistent AF were randomly assigned to pulmonary vein isolation (PVI) plus MRI-guided atrial fibrosis ablation (421 patients) or PVI alone (422 patients). Delayed-enhancement MRI was performed in both groups before the ablation procedure to assess baseline atrial fibrosis and at 3 months postablation to assess for ablation scar.

Main Outcomes and Measures

The primary end point was time to first atrial arrhythmia recurrence after a 90-day blanking period postablation. The primary safety composite outcome was defined by the occurrence of 1 or more of the following events within 30 days postablation: stroke, PV stenosis, bleeding, heart failure, or death.

Results

Among 843 patients who were randomized (mean age 62.7 years; 178 [21.1%] women), 815 (96.9%) completed the 90-day blanking period and contributed to the efficacy analyses. There was no significant difference in atrial arrhythmia recurrence between groups (fibrosis-guided ablation plus PVI patients, 175 [43.0%] vs PVI-only patients, 188 [46.1%]; hazard ratio [HR], 0.95 [95% CI, 0.77-1.17]; P = .63). Patients in the fibrosis-guided ablation plus PVI group experienced a higher rate of safety outcomes (9 [2.2%] vs 0 in PVI group; P = .001). Six patients (1.5%) in the fibrosis-guided ablation plus PVI group had an ischemic stroke compared with none in PVI-only group. Two deaths occurred in the fibrosis-guided ablation plus PVI group, and the first one was possibly related to the procedure.

Conclusions and Relevance

Among patients with persistent AF, MRI-guided fibrosis ablation plus PVI, compared with PVI catheter ablation only, resulted in no significant difference in atrial arrhythmia recurrence. Findings do not support the use of MRI-guided fibrosis ablation for the treatment of persistent AF.

Trial Registration

ClinicalTrials.gov Identifier: NCT02529319.

Case report. Thrombus formation on left atrial appendage clip: surgical exclusion and anticoagulation do not obviate transesophageal echocardiography prior to cardioversion

Background

The cornerstone treatment for atrial fibrillation (Afib) is based on the prevention of cardioembolism with the use oral anticoagulants, which inherently increase the risk of bleeding. An alternative for these patients corresponds to left atrial appendage (LAA) exclusion/closure techniques such as Atriclip.

Cases summary

Patient 1: Seventy-two-year-old female who presented with decompensated heart failure, non ST elevation myocardial infarct, and paroxysmal Afib. She underwent coronary artery bypass graft, MAZE procedure, mitral valve repair, and Atriclip (40 mm). Recurrence of Afib postoperatively led to a precardioversion transesophageal echocardiogram (TEE) which demonstrated a LAA pouch thrombus. Patient 2: Sixty-seven-year-old male who underwent electively mitral and tricuspid valve repairs, MAZE procedure, and Atriclip (35 mm). He had recurrent atrial flutter/Afib postoperatively. He received apixaban in addition to rate control medications, and he was readmitted for precardioversion TEE which also demonstrated a LAA pouch thrombus.

Discussion

Atriclip is a stapler exclusion device via epicardial approach which has shown excellent exclusion rates in contemporary data. One of the pitfalls of this technique is the possibility of leaving a LAA remnant stump or pouch that is highly thrombogenic. The optimal timing for stopping anticoagulation and the need for precardioversion echocardiography remain uncertain.

A Case Series of Very Slow Atrioventricular Nodal Reentrant Tachycardia Resembling Junctional Tachycardia

Introduction

The surface electrocardiography of typical atrioventricular nodal reentrant tachycardia (AVNRT) shows simultaneous ventricular‐atrial (RP) activation with pseudo R′ in V1 and typical heart rates ranging from 150 to 220/min. Slower rates are suspicious for junctional tachycardia (JT). However, occasionally we encounter typical AVNRT with slow ventricular rates. We describe a series of typical AVNRT cases with heart rates under 110/min.

Methods

A total of 1972 patients with AVNRT who underwent slow pathway ablation were analyzed. Typical AVNRT was diagnosed when; (1) evidence of dual atrioventricular nodal conduction, (2) tachycardia initiation by atrial drive train with atrial‐His‐atrial response, (3) short septal ventriculoatrial time, and (4) ventricular‐atrial‐ventricular (V‐A‐V) response to ventricular overdrive (VOD) pacing with corrected post pacing interval‐tachycardia cycle length (cPPI‐TCL) > 110 ms. JT was excluded by either termination or advancement of tachycardia by atrial extrastimuli (AES) or atrial overdrive (AOD) pacing.

Results

We found 11 patients (age 20−78 years old, six female) who met the above‐mentioned criteria. The TCL ranged from 560 to 782 ms. Except for one patient showing tachycardia termination, all patients demonstrated a V‐A‐V response and cPPI‐TCL over 110 ms with VOD. AES or AOD pacing successfully excluded JT by either advancing the tachycardia in 10 patients or by tachycardia termination in one patient. Slow pathway was successfully ablated, and tachycardia was not inducible in all patients.

Conclusions

This case series describes patients with typical AVNRT with slow ventricular rate (less than 110/min) who may mimic JT. We emphasize the importance of using pacing maneuvers to exclude JT.

Efficacy and Safety of Catheter Ablation vs Antiarrhythmic Drugs as Initial Therapy for Management of Symptomatic Paroxysmal Atrial Fibrillation: A Meta-Analysis

BACKGROUND

Catheter ablation is an effective treatment for atrial fibrillation (AF), primarily performed in patients who fail antiarrhythmic drugs. Whether early catheter ablation, as first-line therapy, is associated with improved clinical outcomes remains unclear.

METHODS

Electronic databases (PubMed, Scopus, Embase) were searched until March 28th, 2021. Randomized controlled trials (RCTs) compared catheter ablation vs antiarrhythmic drug therapy as first-line therapy were included. The primary outcome of interest was the first documented recurrence of any atrial tachyarrhythmia (symptomatic or asymptomatic; AF, atrial flutter, and atrial tachycardia). Secondary outcomes included symptomatic atrial tachyarrhythmia (AF, atrial flutter, and atrial tachycardia) and serious adverse events. Unadjusted risk ratios (RR) were calculated from dichotomous data using Mantel Haenszel (M-H) random-effects with statistical significance considered if the confidence interval (CI) excludes one and p < 0.05.

RESULTS

A total of six RCTs with 1212 patients (Ablation n = 609; Antiarrhythmic n = 603) were included. Follow- up period ranged from 1-2 years. Patients who underwent ablation were less likely to experience any recurrent atrial tachyarrhythmia when compared to patients receiving antiarrhythmic drugs (RR 0.63; 95% CI 0.55-0.73; p < 0.00001). Symptomatic atrial tachyarrhythmia was also lower in the ablation arm (RR 0.53; 95% CI 0.32-0.87; p = 0.01). No statistically significant differences were noted for overall any type of adverse events (RR 0.93; 95% CI 0.68-1.27; p = 0.64) and cardiovascular adverse events (RR 0.90; 95% CI 0.56-1.44; p = 0.65) respectively.

CONCLUSIONS

Catheter ablation, as first-line therapy, was associated with a significantly lower rate of tachyarrhythmia recurrence compared to conventional antiarrhythmic drugs, with a similar adverse effect risk profile. These findings support a catheter ablation strategy as first-line therapy among patients with symptomatic paroxysmal atrial fibrillation.

Impact of High-Power Short-Duration Radiofrequency Ablation on Esophageal Temperature Dynamic

BACKGROUND

High-power short-duration (HP-SD) radiofrequency ablation (RFA) has been proposed as a method for producing rapid and effective lesions for pulmonary vein isolation. The underlying hypothesis assumes an increased resistive heating phase and decreased conductive heating phase, potentially reducing the risk for esophageal thermal injury. The objective of this study was to compare the esophageal temperature dynamic profile between HP-SD and moderate-power moderate-duration (MP-MD) RFA ablation strategies.

METHODS

In patients undergoing pulmonary vein isolation, RFA juxtaposed to the esophagus was delivered in an alternate sequence of HP-SD (50 W, 8-10 s) and MP-MD (25 W, 15-20 s) between adjacent applications (distance, ≤4 mm). Esophageal temperature was recorded using a multisensor probe (CIRCA S-CATH). Temperature data included magnitude of temperature rise, maximal temperature, time to maximal temperature, and time return to baseline. In swine, a similar experimental design compared the effect of HP-SD and MP-MD on patterns of esophageal injury.

RESULTS

In 20 patients (68.9±5.8 years old; 60% persistent atrial fibrillation), 55 paired HP-SD and MP-MD applications were analyzed. The esophageal temperature dynamic profile was similar between HP-SD and MP-MD ablation strategies. Specifically, the magnitude of temperature rise (2.1 °C [1.4-3] versus 2.0 °C [1.5-3]; P=0.22), maximal temperature (38.4 °C [37.8-39.3] versus 38.5 °C [37.9-39.4]; P=0.17), time to maximal temperature (24.9±7.5 versus 26.3±6.8 s; P=0.1), and time of temperature to return to baseline (110±23.2 versus 111±25.1 s; P=0.86) were similar between HP-SD and MP-MD ablation strategies. In 6 swine, esophageal injury was qualitatively similar between HP-SD and MP-MD strategies.

CONCLUSIONS

Esophageal temperature dynamics are similar between HP-SD and MP-MD RFA strategies and result in comparable esophageal tissue injury. Therefore, when using a HP-SD RFA strategy, the shorter application duration should not prompt shorter intervals between applications.

Effect of DrOnedarone on atrial fibrosis progression and atrial fibrillation recurrence postablation: Design of the EDORA randomized clinical trial

Background

Atrial fibrillation (AF) recurrence after catheter ablation is associated with worse outcomes and quality of life. Left atrial (LA) structural remodeling provides the essential substrate for AF perpetuation. Baseline extent and the progression of LA fibrosis after ablation are strong predictors of postprocedural AF recurrence. Dronedarone is an antiarrhythmic drug proven to efficiently maintain sinus rhythm.

Objective

We sought to investigate the effect of the antiarrhythmic drug Dronedarone in decreasing LA fibrosis progression and AF recurrence after ablation of AF patients.

Methods

EDORA (NCT04704050) is a multicenter, prospective, randomized controlled clinical trial. Patients with persistent or paroxysmal AF undergoing AF ablation will be randomized into Dronedarone versus placebo/standard of care. The co‐primary outcomes are the recurrence of atrial arrhythmias (AA) within 13 months of follow‐up after ablation and the progression of left atrial fibrosis postablation. All patients will receive a late‐gadolinium enhancement magnetic resonance imaging at baseline, 3‐ and 12‐month follow‐up for the quantification of LA fibrosis and ablation‐related scarring. AA recurrence and burden will be assessed using a 30‐day ECG patch every 3 months with daily ECG recordings in between. Quality of life improvement is assessed using the AFEQT and AFSS questionnaires.

Conclusion

EDORA will be the first trial to assess the progression of LA structural remodeling after ablation and its association with Dronedarone treatment and ablation success in a randomized controlled fashion. The trial will provide insight into the pathophysiology of AF recurrence after ablation and may provide potential therapeutic targets to optimize procedural outcomes.

Impact of pacing-related differences on clinical and echocardiographic outcomes after TAVR with SAPIEN-3 valve

Background

Data regarding the impact of pacing on outcomes after transcatheter aortic valve replacement (TAVR) is evolving especially with regards to pre-existing PPM. We examined the impact of new and prior PPM on clinical and hemodynamic outcomes after SAPIEN-3 (S3) TAVR.

Methods

Consecutive patients who underwent transfemoral-TAVR using S3 valve between April 2015 and December 2018 at our Clinic were included.

Results

Among 1028 patients, 10.2% required new PPM within 30 days, while 14% had pre-existing PPM. The presence of either prior or new PPM had no impact on 3-year mortality (log-rank p=0.6), or 1-year major adverse cardiac and cerebrovascular event (MACCE) (log-rank p=0.65). New PPM was associated with lower left ventricular ejection fraction (LVEF) at both 30 days (54.4±11.3% vs. 58.4±10.1%; p=0.001), and 1 year (54.2±12% vs. 59.1±9.9%; p=0.009) compared to no PPM. Similarly, prior PPM was associated with worse LVEF at 30 days (53.6±12.3%; p&lt;0.001) and 1 year (55.5±12.1%; p=0.006) compared to no PPM. Interestingly, new PPM was associated with lower 1-year mean gradient (11.4±3.8 vs. 12.6±5.6 mmHg; p=0.04), and peak gradient (21.3±6.5 vs. 24.1±10.4 mmHg; p=0.01) despite no baseline differences. Prior PPM was also associated with lower 1-year mean gradient (10.3±4.4 mmHg; p=0.001), and peak gradient (19.4±8 mmHg; p&lt;0.001), and higher doppler velocity index (0.51±0.12 vs. 0.47±0.13; p=0.039). Moreover, 1-year LV end-systolic volume (LVESVi) was higher with new (23.2±16.1 vs. 20±10.8 ml/m2; p=0.038), and prior PPM (24.5±19.7; p=0.038) compared to no PPM. Prior PPM was associated with higher moderate-to-severe tricuspid regurgitation (35.3% vs. 17.7%; p&lt;0.001). There were no differences with regards to the rest of the studied echocardiographic outcomes at 1 year.

Conclusion

In this S3 cohort, new and prior PPM did not affect 3-year mortality or 1-year MACCE, however they were associated with worse LVEF, higher LVESVi and lower mean and peak gradients on follow-up compared to no PPM.

Funding Acknowledgement

Type of funding sources: None. Figure 1. All-cause Survival

Racial and Sex Disparities in Anticoagulation After Electrical Cardioversion for Atrial Fibrillation and Flutter

Background Anticoagulation is indicated for 4 weeks after cardioversion in patients with atrial fibrillation/flutter. We sought to examine whether there is evidence of sex or racial disparity in anticoagulant prescription following cardioversion, and whether postcardioversion anticoagulation affects outcomes. Methods and Results We identified a representative sample of Medicare patients who underwent elective electric cardioversion in an outpatient setting from 2015 to 2017. We identified patients who had an anticoagulant prescription for 3 months after the cardioversion date. Multivariable logistic regression was used to assess factors associated with a prescription of an anticoagulant after cardioversion. Cox regression analysis was used to test association of anticoagulation with a composite end point of 90-day mortality, ischemic stroke, or arterial embolism. The final study cohort included 7860 patients. Overall, 5510 patients (70.1%) received any anticoagulation following cardioversion, while 2350 (29.9%) did not. Patients who did not receive anticoagulation were younger, with a lower burden of most comorbidities. Patients were less likely to receive anticoagulation if they had dementia or atrial flutter, while patients with valvular heart disease, obesity, heart failure, peripheral vascular or coronary disease, or hypertension were more likely to receive anticoagulation. Female sex (adjusted odds ratio, 0.84; 95% CI, 0.75-0.92; P<0.001), Black and Hispanic race (adjusted odds ratio, 0.50; 95% CI, 0.38-0.65; and odds ratio, 0.56; 95% CI, 0.41-0.75, respectively; P<0.001) were independently associated with lower probability of anticoagulant prescription. Postcardioversion anticoagulation was associated with lower risk of the composite end point (adjusted hazard ratio, 0.38; 95% CI, 0.27-0.52; P<0.001). Conclusions Racial and sex disparities exist in anticoagulant prescription after outpatient elective cardioversion for atrial fibrillation.

Incidence, Predictors, and Implications of Permanent Pacemaker Requirement After Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) is a safe and feasible alternative to surgery in patients with symptomatic severe aortic stenosis regardless of the surgical risk. Conduction abnormalities requiring permanent pacemaker (PPM) implantation remain a common finding after TAVR due to the close proximity of the atrioventricular conduction system to the aortic root. High-grade atrioventricular block and new onset left bundle branch block (LBBB) are the most commonly reported conduction abnormalities after TAVR. The overall rate of PPM implantation after TAVR varies and is related to pre-procedural and intraprocedural factors. The available literature regarding the impact of conduction abnormalities and PPM requirement on morbidity and mortality is still conflicting. Pre-procedural conduction abnormalities such as right bundle branch block and LBBB have been linked with increased PPM implantation and mortality after TAVR. When screening patients for TAVR, heart teams should be aware of various anatomical and pathophysiological conditions that make patients more susceptible to increased risk of conduction abnormalities and PPM requirement after the procedure. This is particularly important as TAVR has been recently approved for patients with low surgical risk. The purpose of this review is to discuss the incidence, predictors, impact, and management of the various conduction abnormalities requiring PPM implantation in patients undergoing TAVR.

Impact of baseline conduction abnormalities on outcomes after transcatheter aortic valve replacement with SAPIEN-3

BACKGROUND

Baseline conduction abnormalities are known risk factors for permanent pacemaker (PPM) implantation after transcatheter aortic valve replacement (TAVR). We sought to determine the impact of baseline right bundle branch block (RBBB), left bundle branch block (LBBB), left anterior hemiblock (LAHB), first-degree atrioventricular block (AVB) and atrial fibrillation/flutter (AF) on TAVR outcomes.

METHODS

Consecutive patients who underwent transfemoral TAVR with SAPIEN-3 (S3) were included. We excluded patients with prior PPM, nontransfemoral access or valve-in-valve.

RESULTS

Among 886 patients, baseline RBBB was seen in 15.9%, LBBB in 6.3%, LAHB in 6.2%, first-degree AVB in 26.3% and AF in 37.5%. The rate of 30-day PPM was 10.1%. Baseline RBBB (OR 4.005; 95% CI 2.386-6.723; p < .001) and first-degree AVB (OR 1.847; 95% CI 1.133-3.009; p = .014) were independent predictors of 30 day PPM. LAHB also resulted in higher PPM rates but only in unadjusted analysis (21.8% vs. 9.4%; p = .003). Baseline LBBB and AF were associated with lower left ventricular ejection fraction (LVEF) at both baseline and 1 year after TAVR. However, Δ LVEF over time were noted to be similar with baseline LBBB (1.8% vs. 1.4%; p = .809) and AF (1.1% vs. 1.7%; p = .458). Moreover, baseline AF was also associated with higher stroke/transient ischemic attack (TIA) at 1 year (4.4% vs. 1.8%; p = .019), 1-year major adverse cardiac and cerebrovascular events (MACCE) (19.5% vs. 13.3%; p = .012) and 2 year mortality (23.5% vs. 15.2%; p = .016). None of the other baseline conduction defects affected long-term mortality or MACCE.

CONCLUSION

In our S3 TAVR population, baseline RBBB and first-degree AVB predicted higher PPM risk. Prior LBBB and AF were associated with lower LVEF at both baseline and 1 year. Lastly, preexisting AF was associated with higher rates of mortality, stroke/TIA, and MACCE.

Atrial fibrillation ablation in patients with transthyretin cardiac amyloidosis

AIMS

Atrial fibrillation (AF) occurs in as many as 70% of patients with transthyretin cardiac amyloidosis (ATTR CA). The aim of our study was to investigate the impact of AF ablation on freedom from recurrent arrhythmia, hospitalization for AF or heart failure (HF), and mortality.

METHODS AND RESULTS

This was a retrospective observational cohort study of 72 patients with ATTR CA and AF, of whom 24 underwent AF ablation and were matched in a 2:1 manner based on age, gender, ATTR CA stage, New York Heart Association functional class, ejection fraction, and date of AF diagnosis with 48 patients with ATTR CA and AF undergoing medical management. During a mean follow-up of 39 ± 26 months, 10 (42%) patients remained free of recurrent arrhythmia following ablation. Ablation was significantly more effective in those with Stage I or II ATTR CA, with 9/14 (64%) patients with Stage I or II ATTR CA remaining free of recurrent arrhythmia compared to only 1/10 (10%) patients with Stage III disease (P = 0.005). Death occurred in 7 (29%) patients in the ablation group compared to 36 (75%) in the non-ablation arm (P = 0.01). Rates of ischaemic stroke were similar in both groups. Ablation was associated with a significant reduction in the frequency of hospitalization for HF/arrhythmia (1.7 ± 2.4 hospitalizations vs. 4 ± 3.5, P = 0.005). On Cox proportional hazards analyses, ablation was associated with improved survival (hazard ratio 0.38, 95% confidence intervals 0.17-0.86; P = 0.02).

CONCLUSION

Atrial fibrillation ablation is associated with reduced mortality in ATTR CA and is most effective when performed earlier during the disease process.

Atrial fibrillation catheter ablation complications in obese and diabetic patients: Insights from the US Nationwide Inpatient Sample 2005-2013

BACKGROUND

Obesity and diabetes are risk factors for atrial fibrillation (AF) incidence and recurrence after catheter ablation. However, their impact on post-ablation complications in real-world practice is unknown.

OBJECTIVES

We examine annual trends in AF ablations and procedural outcomes in obese and diabetic patients in the US and whether obesity and diabetes are independently associated with adverse outcomes.

METHODS

Using the Nationwide Inpatient Sample (2005-2013), we identified obese and diabetic patients admitted for AF ablation. Common complications were identified using ICD-9-CM codes. The primary outcome included the composite of any in-hospital complication or death. Annual trends of the primary outcome, length-of-stay (LOS) and total-inflation adjusted hospital charges were examined. Multivariate analyses studied the association of obesity and diabetes with outcomes.

RESULTS

An estimated 106 462 AF ablations were performed in the US from 2005 to 2013. Annual trends revealed a gradual increase in ablations performed in obese and diabetic patients and in complication rates. The overall rate of the primary outcome in obese was 11.7% versus 8.2% in non-obese and 10.7% in diabetic versus 8.2% in non-diabetic patients (p < .001).

CONCLUSIONS

Obesity was independently associated with increased complications (adjusted OR, 95% CI:1.39, 1.20-1.62), longer LOS (1.36, 1.23-1.49), and higher charges (1.16, 1.12-1.19). Diabetes was only associated with longer LOS (1.27, 1.16-1.38). Obesity, but not diabetes, in patients undergoing AF ablation is an independent risk factor for immediate post-ablation complications and higher costs. Future studies should investigate whether weight loss prior to ablation reduces complications and costs.

Primary Outcome Evaluation of a Next-Generation Left Atrial Appendage Closure Device: Results From the PINNACLE FLX Trial

BACKGROUND

Left atrial appendage (LAA) occlusion provides an alternative to oral anticoagulation for thromboembolic risk reduction in patients with nonvalvular atrial fibrillation. Since regulatory approval in 2015, the WATCHMAN device has been the only LAA closure device available for clinical use in the United States. The PINNACLE FLX study (Protection Against Embolism for Nonvalvular AF Patients: Investigational Device Evaluation of the Watchman FLX LAA Closure Technology) evaluated the safety and effectiveness of the next-generation WATCHMAN FLX LAA closure device in patients with nonvalvular atrial fibrillation in whom oral anticoagulation is indicated, but who have an appropriate rationale to seek a nonpharmaceutical alternative.

METHODS

This was a prospective, nonrandomized, multicenter US Food and Drug Administration study. The primary safety end point was the occurrence of one of the following events within 7 days after the procedure or by hospital discharge, whichever was later: death, ischemic stroke, systemic embolism, or device- or procedure-related events requiring cardiac surgery. The primary effectiveness end point was the incidence of effective LAA closure (peri-device flow ≤5 mm), as assessed by the echocardiography core laboratory at 12-month follow-up.

RESULTS

A total of 400 patients were enrolled. The mean age was 73.8±8.6 years and the mean CHA₂DS₂-VASc score was 4.2±1.5. The incidence of the primary safety end point was 0.5% with a 1-sided 95% upper CI of 1.6%, meeting the performance goal of 4.2% (P<0.0001). The incidence of the primary effectiveness end point was 100%, with a 1-sided 95% lower CI of 99.1%, again meeting the performance goal of 97.0% (P<0.0001). Device-related thrombus was reported in 7 patients, no patients experienced pericardial effusion requiring open cardiac surgery, and there were no device embolizations.

CONCLUSIONS

LAA closure with this next-generation LAA closure device was associated with a low incidence of adverse events and a high incidence of anatomic closure. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02702271.

Efficacy of LGE-MRI-guided fibrosis ablation versus conventional catheter ablation of atrial fibrillation: The DECAAF II trial: Study design

INTRODUCTION

Success rates of catheter ablation in persistent atrial fibrillation (AF) remain suboptimal. A better and more targeted ablation strategy is urgently needed to optimize outcomes of AF treatment. We sought to assess the safety and efficacy of targeting atrial fibrosis during ablation of persistent AF patients in improving procedural outcomes.

METHODS

The DECAAF II trial (ClinicalTrials. gov identifier number NCT02529319) is a prospective, randomized, multicenter trial of patients with persistent AF. Patients with persistent AF undergoing a first-time ablation procedure were randomized in a 1:1 fashion to receive conventional pulmonary vein isolation (PVI) ablation (Group 1) or PVI + fibrosis-guided ablation (Group 2). Left atrial fibrosis and ablation induced scarring were defined by late gadolinium enhancement magnetic resonance imaging at baseline and at 3-12 months postablation, respectively. The primary endpoint is the recurrence of atrial arrhythmia postablation, including atrial fibrillation, atrial flutter, or atrial tachycardia after the 90-day postablation blanking period. Patients were followed for a period of 12-18 months with a smartphone ECG Device (ECG Check Device, Cardiac Designs Inc.). With an anticipated enrollment of 900 patients, this study has an 80% power to detect a 26% reduction in the hazard ratio of the primary endpoint.

RESULTS AND CONCLUSION

The DECAAF II trial is the first prospective, randomized, multicenter trial of patients with persistent AF using imaging defined atrial fibrosis as a treatment target. The trial will help define an optimal approach to catheter ablation of persistent AF, further our understanding of influencers of ablation lesion formation, and refine selection criteria for ablation based on atrial myopathy burden.

Incidental Thoracic Aortic Dilation on Chest Computed Tomography in Patients With Atrial Fibrillation

Patients with atrial fibrillation (AF) have risk factors that predispose to thoracic aneurysmal disease (TAD) and atherosclerosis. In this study in patients with AF, we assessed the occurrence of incidental TAD and assessed if a validated predictive score used to predict AF, the CHARGE-AF score, was associated with greater aortic dimensions. We also assessed the prevalence of coronary calcification. We conducted a cross-sectional study of 1,000 consecutive patients with AF undergoing chest multidetector CT during evaluation for pulmonary vein isolation. A dilated aortic root or ascending aorta (AA, dimension/ body surface area >2.05 cm/m²) were found in 195 (20%). A total of 12 (1%) had significant aortic aneurysmal enlargement of > 5.0 cm. Advancing age, a bicuspid aortic valve, hypertension, and male gender were associated with increased aortic dimensions. Aortic root dimensions increased linearly (p < 0.001) and ascending aortic dimensions increased nonlinearly across CHARGE-AF deciles (p < 0.001). Nearly two-thirds (63%) had coronary calcification, 38% of whom were not on lipid-lowering therapy. In conclusion, in patients with AF undergoing gated chest CT, 1 in 5 had previously undetected TAD, with a small proportion having significantly aneurysmal dimensions approaching surgical thresholds. Risk factors previously established to increase the propensity to develop AF are also associated with increased TAD. These findings raise the need to consider a surveillance strategy for TAD in patients with AF, particularly in those with other risk factors for aortic disease. A high prevalence of coronary calcium was also detected, representing an opportunity to optimize statin therapy in patients with AF.

Exercise Ventricular Rates, Cardiopulmonary Exercise Performance, and Mortality in Patients With Heart Failure With Atrial Fibrillation

BACKGROUND

In heart failure (HF) with sinus rhythm, resting and exercise heart rates correlate with exercise capacity and mortality. However, in HF with atrial fibrillation (AF), this correlation is unknown. Our aim is to investigate the association of resting and exercise ventricular rates (VRs) with exercise capacity and mortality in HF with AF.

METHODS

We identified 903 patients with HF and AF referred for cardiopulmonary stress testing. AF was defined as history of AF and AF during cardiopulmonary stress testing. We constructed multivariable models to evaluate the association of resting VR, peak exercise VR, VR reserve (peak VR-resting VR), and chronotropic index with (1) peak oxygen consumption (PVO₂) ≤18 mL/kg per minute, (2) continuous PVO₂, and (3) 10-year all-cause mortality.

RESULTS

Median (25th-75th percentile) age was 60 (52-67) years, left ventricular ejection fraction was 25 (15-50)%, and 76.1% were males. Patients with lower (quartile 1) compared with higher (quartile 4) peak VR, VR reserve, and chronotropic index were more likely to have PVO₂ ≤18 mL/kg per min (adjusted odds ratio [95% CI]: 14.92 [8.07-27.58], 24.60 [12.36-48.98], and 22.31 [11.24-44.27], respectively), and higher all-cause mortality (adjusted hazard ratio [95% CI]: 2.56 [1.62-4.04], 2.29 [1.47-3.59], and 2.30 [1.51-3.49], respectively). For every 10 beats per minute increase in VR reserve, PVO₂ increased by 1.05 mL/kg per minute (B-coefficient [95% CI]: 1.05 [0.94-1.15]) and mortality decreased by 12% (adjusted hazard ratio [95% CI]: 0.88 [0.83-0.94]). Resting VR was associated with PVO₂ (B-coefficient [95% CI]: -0.46 [-0.70 to -0.23]) but not mortality (adjusted hazard ratio [95% CI]: 0.97 [0.88-1.06]).

CONCLUSIONS

In patients with HF and AF, higher resting VR and lower peak exercise VR, VR reserve, and chronotropic index were all associated with worse peak exercise capacity, but only lower exercise VR parameters were associated with higher mortality. Dedicated studies are needed to gauge whether modulating exercise VR enhances exercise performance and outcomes.

Circular Multielectrode Pulsed Field Ablation Catheter Lasso Pulsed Field Ablation: Lesion Characteristics, Durability, and Effect on Neighboring Structures

BACKGROUND

Pulsed field ablation (PFA) is a nonthermal energy with potential safety advantages over radiofrequency ablation. This study investigated a novel PFA system-a circular multielectrode catheter (PFA lasso) and a multichannel generator designed to work with Carto 3 mapping system.

METHODS

A 7.5F bidirectional circular catheter with 10 electrodes and variable expansion was designed for PFA (biphasic, 1800 Volts). This study included a total of 16 swine used to investigate the following 3 experimental aims: Aim 1 examined the feasibility to create a right atrial ablation line of block from the superior vena cava to the inferior vena cava. Aim 2 examined the effect of PFA on lesion maturation including durability after a 30-day survival period. Aim 3 examined the effect of high-intensity PFA (10 applications) on esophageal and phrenic nerve tissue in comparison to normal intensity radiofrequency ablation (1-2 applications). Histopathologic analysis of all cardiac, esophageal, and phrenic nerve tissue was performed.

RESULTS

Acute line of block was achieved in 12/12 swine (100%) and required a total PFA time of 14 seconds (interquartile range [IQR], 9-24.5) per line. Ablation line durability after 28±3 days was maintained in 11/12 (91.7%) swine. PFA resulted in transmural lesions in 179/183 (97.8%) sections and a median lesion width of 14.2 mm. High-intensity PFA (9 [IQR, 8-14] application) had no effect on the esophagus while standard intensity radiofrequency ablation (1.5 [IQR, 1-2] applications) resulted in deep esophageal tissue injury involving the muscularis propria and adventitia layers. High-intensity PFA (16 [IQR, 10-28] applications) has no effect on phrenic nerve function and structure while standard dose radiofrequency ablation (1.5 [IQR, 1-2] applications) resulted in acute phrenic nerve paralysis.

CONCLUSIONS

In this preclinical model, a multielectrode circular catheter and multichannel generator produced durable atrial lesions with lower vulnerability to esophageal or phrenic nerve damage.

Clinical Characteristics and Outcomes of Non-ICU Hospitalization for COVID-19 in a Nonepicenter, Centrally Monitored Healthcare System

BACKGROUND

The clinical characteristics and outcomes associated with non-intensive care unit (non-ICU) hospitalizations for coronavirus disease 2019 (COVID-19) outside disease epicenters remain poorly characterized.

METHODS

Systematic analysis of all non-ICU patient hospitalizations for COVID-19 completing discharge between March 13 and May 1, 2020, in a large US health care system utilizing off-site central monitoring. Variables of interest were examined in relation to a composite event rate of death, ICU transfer, or increased oxygen requirement to high-flow nasal cannula, noninvasive ventilation, or mechanical ventilation.

RESULTS

Among 350 patients (age, 64 ± 16 years; 55% male), most (73%) required 3 L/min or less of supplemental oxygen during admission. Telemetry was widely utilized (79%) yet arrhythmias were uncommon (14%) and were predominantly (90%) among patients with abnormal troponin levels or known cardiovascular disease. Ventricular tachycardia was rare (5%), nonsustained, and not associated with hydroxychloroquine/azithromycin treatment. Adverse events occurred in 62 patients (18%), including 22 deaths (6%), 48 ICU transfers (14%), and 49 patients with increased oxygen requirement (14%) and were independently associated with elevated C-reactive protein (odds ratio, 1.09 per 1 mg/dL; 95% CI, 1.01-1.18; P = .04) and lactate dehydrogenase (OR, 1.006 per 1U/L; 95% CI, 1.001-1.012; P = .03) in multivariable analysis.

CONCLUSION

Among non-critically ill patients hospitalized within a nonepicenter health care system, overall survival was 94% with the development of more severe illness or death independently associated with higher levels of C-reactive protein and lactate dehydrogenase on admission. Clinical decompensation was largely respiratory-related, while serious cardiac arrhythmias were rare, which suggests that telemetry can be prioritized for high-risk patients.

Risk stratification using late gadolinium enhancement on cardiac magnetic resonance imaging in patients with hypertrophic cardiomyopathy: A systematic review and meta-analysis

Background The role of late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (c-MRI) for predicting outcomes of patients with hypertrophic cardiomyopathy (HCM) has been debated. Methods We searched PubMed and Embase and various published bibliographies for prospective studies published in English between January 1990 and February 2019. Two investigators screened 2646 abstracts and full-text articles for inclusion and relevant outcomes. We then performed a systematic review and meta-analysis to calculate pooled odds ratios for LGE on c-MRI and a pooled sensitivity and specificity analysis. Results Our systematic review included 8 prospective studies and 3808 patients. LGE positivity was associated with higher odds of the endpoint of sudden cardiac death (SCD;OR 1.69, 95%CI 1.03-2.78), aborted SCD or appropriate implantable cardioverter- defibrillator (ICD) discharge (OR 3.27 [1.75-6.10]), SCD or aborted SCD or appropriate ICD discharge (OR 2.32 [1.56-3.43]), and all-cause mortality (OR 2.10 [CI 1.00-4.41]). The pooled sensitivity and specificity of positive LGE on c-MRI for SCD were 65% and 42%, respectively; for aborted SCD or appropriate ICD discharge, 79% and 39%; for SCD or aborted SCD or appropriate ICD discharge, 74% and 39%; and for all-cause mortality, 78% and 39%. Conclusion In patients with HCM, LGE on c-MRI is a strong predictor of arrhythmic outcomes including SCD, aborted SCD, and appropriate ICD therapy. These data support the routine use of LGE on c-MRI as a marker of SCD risk in this population.

Analysis of cardiac motion without respiratory motion for cardiac stereotactic body radiation therapy

Purpose/objective(s)

To study the heart motion using cardiac gated computed tomographies (CGCT) to provide guidance on treatment planning margins during cardiac stereotactic body radiation therapy (SBRT).

Materials/methods

Ten patients were selected for this study, who received CGCT scans that were acquired with intravenous contrast under a voluntary breath‐hold using a dual source CT scanner. For each patient, CGCT images were reconstructed in multiple phases (10%–90%) of the cardiac cycle and the left ventricle (LV), right ventricle (RV), ascending aorta (AAo), ostia of the right coronary artery (O‐RCA), left coronary artery (O‐LCA), and left anterior descending artery (LAD) were contoured at each phase. For these contours, the centroid displacements from their corresponding average positions were measured at each phase in the superior–inferior (SI), medial–lateral (ML), and anterior–posterior (AP). The average volumes as well as the maximum to minimum ratios were analyzed for the LV and RV.

Results

For the six contoured substructures, more than 90% of the measured displacements were <5 mm. For these patients, the average volumes ranged from 191.25 to 429.51 cc for LV and from 91.76 to 286.88 cc for RV. For each patient, the ratios of maximum to minimum volumes within a cardiac cycle ranged from 1.15 to 1.54 for LV and from 1.34 to 1.84 for RV.

Conclusion

Based on this study, cardiac motion is variable depending on the specific substructure of the heart but is mostly within 5 mm. Depending on the location (central or peripheral) of the treatment target and treatment purposes, the treatment planning margins for targets and risk volumes should be adjusted accordingly. In the future, we will further assess heart motion and its dosimetric impact.

Proarrhythmic effects from competitive atrial pacing and potential programming solutions

BACKGROUND

Programmed long AV delays and intrinsic long first degree AV block may increase risk for competitive atrial pacing (CAP) in devices without CAP avoidance algorithms.

METHODS

Patients identified with CAP-induced mode switch episodes were followed clinically from September 2013 to August 2019. Attempts to avoid CAP included shortening of postventricular atrial refractory period (PVARP) or postventricular atrial blanking period (PVAB), or change to AAI or DDI modes. After observing associations with sensor-driven pacing, rate response was inactivated in a subset.

RESULTS

Among 23 patients identified with CAP (22 St Jude Medical [Abbott]; one Boston Scientific Corporation devices), atrial fibrillation (AF) was induced in 12 (52%), lasting 10 seconds to 28 hours and 32 minutes. In one patient with an ICD CAP-induced AF with rapid ventricular rates that triggered a shock, inducing ventricular fibrillation, syncope, and another shock. Changing AV delays and shortening of PVARP failed to resolve CAP. After noting that all had CAP during sensor-driven pacing, rate response was inactivated in seven, resolving further device-induced AF in the three of seven that had prior CAP-induced AF. In two patients with intact AV conduction, AAI(R) pacing resolved further documentation of CAP.

CONCLUSIONS

CAP predominantly occurs during sensor-driven atrial pacing that competes with intrinsic atrial events falling in PVARP. Inactivation of the activity sensor or change to atrial-based pacing modes (AAI/R) appears to effectively prevent induction of device-induced atrial proarrhythmia. Ultimately, a corrective algorithm is needed to avoid CAP-induced proarrhythmia.