Long-Term Safety and Efficacy of Intraoperative Leadless Pacemaker Implantation During Valve Surgery.

BACKGROUND: Intraoperative implantation of leadless cardiac pacemakers (LCPs) under direct visualization during cardiac surgery is a novel strategy to provide pacing to patients with an elevated risk of postoperative conduction disorders or with a preexisting pacing indication undergoing valve surgery. OBJECTIVES: This study sought to evaluate the long-term safety and efficacy of intraoperative LCP implantation in 100 consecutive patients. METHODS: Retrospective single-center cohort study of consecutive patients (n = 100) who underwent intraoperative LCP implantation during valve surgery. Safety and efficacy were assessed at implantation and follow-up visits. RESULTS: A total of 100 patients (age 68 ± 13 years, 47% female) underwent intraoperative LCP implantation. The surgery involved the tricuspid valve in 99 patients (99%), including tricuspid valve repair in 59 (59%) and tricuspid valve replacement in 40 (40%). Most of the patients (78%) underwent multivalve surgery. The indication for LCP implantation was elevated risk of postoperative atrioventricular block in 54% and preexisting bradyarrhythmias in 46%. LCP implantation was successful in all patients. During a median of 10.6 months (IQR: 2.0-22.7 months) of follow-up, no device-related complications occurred. At 12-month follow-up, the pacing thresholds were acceptable (≤2.0 V at 0.24 milliseconds) in 95% of patients. CONCLUSIONS: Intraoperative LCP implantation under direct visualization is a safe strategy to provide permanent pacing in patients undergoing valve surgery, with a postoperative electrical performance comparable to percutaneously placed LCPs.

Short-term safety and feasibility of a practical approach to combined atrial and ventricular physiological pacing: An initial single-center experience.

Background: Traditional right atrial appendage (RAA) pacing accentuates conduction disturbances as opposed to Bachmann bundle pacing (BBP). Objective: The purpose of this study was to evaluate the feasibility, efficacy, and safety of routine anatomically guided high right atrial septal (HRAS) pacing with activation of Bachmann bundle combined with routine left bundle branch area pacing (LBBAP). Methods: This retrospective single-center study included 96 consecutive patients who underwent 1 of 2 strategies: physiological pacing (PP) (n = 32) with HRAS and LBBAP leads and conventional pacing (CP) (n = 64) with traditional RAA and right ventricular apical leads. Baseline characteristics, sensing, pacing thresholds, and impedances were recorded at implantation and follow-up. Results: The PP and CP cohorts were of similar age (74.2 ± 13.8 years vs 73.9 ± 9.9 years) and sex (28.1% vs 40.6% female). There were no differences in procedural time (95.0 ± 31.4 minutes vs 86.5 ± 33.3 minutes; P = .19) or fluoroscopy time (12.1 ± 4.5 minutes vs 12.3 ± 13.5 minutes; P = .89) between cohorts. After excluding patients who received >2 leads, these parameters became significantly shorter in the CP cohort. The PP cohort exhibited higher atrial pacing thresholds (1.5 ± 1.1 mV vs 0.8 ± 0.3 mV; P <.001) and lower p waves (1.8 ± 0.8 mV vs 3.8 ± 2.3 mV; P <.001) at implantation and at follow-up. In the PP cohort, 72% of implants met criteria for BBP; of the ventricular leads, 94% demonstrated evidence of LBBAP. One lead-related complication occurred in each cohort. Conclusion: Routine placement of leads in the HRAS is a feasible and safe alternative to standard RAA pacing, allowing for BBP in 72% of patients. HRAS pacing can be combined with LBBAP as a routine strategy.

Premature ventricular complexes after catheter ablation for atrial fibrillation: Accounting for regression to the mean.

INTRODUCTION: Prior studies have indicated that the frequency of premature ventricular complexes (PVC) increases after catheter ablation for atrial fibrillation (AF). However, these studies have primarily focused on patients whose PVC burden increased rather than including the full spectrum of outcomes. METHODS AND RESULTS: We performed a single-center retrospective cohort study of consecutive patients who underwent first-time AF ablation from 1/2018 to 12/2022 for paroxysmal or persistent AF and had both preablation and postablation rhythm monitoring within 6 months of the procedure. Patients were excluded if they had prior AF or PVC ablation or were prescribed a class I or III antiarrhythmic medication. Among 2945 patients who underwent AF ablation during the study period, 130 patients underwent first-time AF ablation and received both pre and post ambulatory monitoring. The median PVC burden before ablation was <1%. Most patients (63%) had no change in PVC burden after AF ablation compared with preablation, and patients who had an increase in PVC burden were offset by those with reductions in PVCs. A paired analysis pre- and post-AF ablation showed no significant change in PVC burden (p = .495). CONCLUSION: Although an elevated PVC burden after AF ablation may be seen clinically, the majority of patients have no change in burden. Studies that suggest an increase in PVC burden after AF ablation may suffer from incomplete sample selection and thus omit the important effect of regression to the mean.

Ventricular Tachycardia Ablation Through a Recanalized Surgically Plicated Left Ventricular Apical Aneurysm.

Left ventricular apical aneurysms are associated with scar-related ventricular tachycardia (VT) in hypertrophic cardiomyopathy patients. We present a patient with apical hypertrophic cardiomyopathy who underwent combined epicardial and endocardial VT ablation of a left ventricular apical aneurysm, necessitating repeat endocardial VT ablation through a recanalized surgical plication.

Nitroglycerin to Ameliorate Coronary Artery Spasm During Focal Pulsed-Field Ablation for Atrial Fibrillation.

BACKGROUND: In treating atrial fibrillation, pulsed-field ablation (PFA) has comparable efficacy to conventional thermal ablation, but with important safety advantages: no esophageal injury or pulmonary vein stenosis, and rare phrenic nerve injury. However, when PFA is delivered in proximity to coronary arteries using a pentaspline catheter, which generates a broad electrical field, severe vasospasm can be provoked. OBJECTIVES: The authors sought to study the vasospastic potential of a focal PFA catheter with a narrower electrical field and develop a preventive strategy with nitroglycerin. METHODS: During atrial fibrillation ablation, a focal PFA catheter was used for cavotricuspid isthmus ablation. Angiography of the right coronary artery (some with fractional flow reserve measurement) was performed before, during, and after PFA. Beyond no nitroglycerin (n = 5), and a few testing strategies (n = 8), 2 primary nitroglycerin administration strategies were studied: 1) multiple boluses (3-2 mg every 2 min) into the right atrium (n = 10), and 2) a bolus (3 mg) into the right atrium with continuous peripheral intravenous infusion (1 mg/min; n = 10). RESULTS: Without nitroglycerin, cavotricuspid isthmus ablation provoked moderate-severe vasospasm in 4 of 5 (80%) patients (fractional flow reserve 0.71 ± 0.08). With repetitive nitroglycerin boluses, severe spasm did not occur, and mild-moderate vasospasm occurred in only 2 of 10 (20%). Using the bolus + infusion strategy, severe and mild-moderate spasm occurred in 1 and 3 of 10 patients (aggregate 40%). No patient had ST-segment changes. CONCLUSIONS: Ablation of the cavotricuspid isthmus using a focal PFA catheter routinely provokes right coronary vasospasm. Pretreatment with high doses of parenteral nitroglycerin prevents severe spasm.

Severity of Ischemic Stroke After Left Atrial Appendage Closure vs Nonwarfarin Oral Anticoagulants.

BACKGROUND: Strokes after left atrial appendage closure (LAAC) prophylaxis are generally less severe than those after warfarin prophylaxis-thought to be secondary to more hemorrhagic strokes with warfarin. Hemorrhagic strokes are similarly infrequent with direct oral anticoagulant (DOAC) prophylaxis, so the primary subtype after either LAAC or DOAC prophylaxis is ischemic stroke (IS). OBJECTIVES: The purpose of this study was to compare the severity of IS using the modified Rankin Scale in atrial fibrillation patients receiving prophylaxis with DOACs vs LAAC. METHODS: A retrospective analysis was performed of consecutive patients undergoing LAAC at 8 centers who developed an IS (ISLAAC) compared with contemporaneous consecutive patients who developed IS during treatment with DOACs (ISDOAC). The primary outcome was disabling/fatal stroke (modified Rankin Scale 3-5) at discharge and 3 months later. RESULTS: Compared with ISDOAC patients (n = 322), ISLAAC patients (n = 125) were older (age 77.2 ± 13.4 years vs 73.1 ± 11.9 years; P = 0.002), with higher HAS-BLED scores (3.0 vs 2.0; P = 0.004) and more frequent prior bleeding events (54.4% vs 23.6%; P < 0.001), but similar CHA2DS2-VASc scores (5.0 vs 5.0; P = 0.28). Strokes were less frequently disabling/fatal with ISLAAC than ISDOAC at both hospital discharge (38.3% vs 70.3%; P < 0.001) and 3 months later (33.3% vs 56.2%; P < 0.001). Differences in stroke severity persisted after propensity score matching. By multivariate regression analysis, ISLAAC was independently associated with fewer disabling/fatal strokes at discharge (OR: 0.22; 95% CI: 0.13-0.39; P < 0.001) and 3 months (OR: 0.25; 95% CI: 0.12-0.50; P < 0.001), and fewer deaths at 3 months (OR: 0.28; 95% CI: 0.12-0.64; P < 0.001). CONCLUSIONS: Ischemic strokes in patients with atrial fibrillation are less often disabling or fatal with LAAC than DOAC prophylaxis.

Coronary Artery Spasm During Pulsed Field vs Radiofrequency Catheter Ablation of the Mitral Isthmus.

Importance: In treating atrial fibrillation, pulsed field ablation (PFA) is a novel energy modality with comparable efficacy to conventional thermal ablation, such as radiofrequency ablation (RFA), but with the benefit of some preferentiality to myocardial tissue ablation. Studies have demonstrated important safety advantages, including the absence of esophageal injury or pulmonary vein stenosis and only rare phrenic nerve injury. However, there is emerging evidence of coronary artery vasospasm provoked by PFA. Objective: To compare the incidence and severity of left circumflex arterial vasospasm between PFA and RFA during adjacent ablation along the mitral isthmus. Design, Setting, and Participants: This prospective cohort study enrolled consecutive adult patients receiving first-ever PFA or RFA of the mitral isthmus during catheter ablation of atrial fibrillation in 2022 with acute follow-up at a single referral European center. Exposure: A posterolateral mitral isthmus line was created using either a multielectrode pentaspline PFA catheter (endocardial ablation) or a saline-irrigated RFA catheter. Simultaneous diagnostic coronary angiography was performed before, during, and after catheter ablation. Nitroglycerin was planned for spasm persisting beyond 20 minutes or for significant electrocardiographic changes. Main Outcomes and Measures: The frequency and severity of left circumflex arterial vasospasm was assessed and monitored, as were time to remission and any need for nitroglycerin administration. Results: Of 26 included patients, 19 (73%) were male, and the mean (SD) age was 65.5 (9.3) years. Patients underwent either PFA (n = 17) or RFA (n = 9) along the mitral isthmus. Coronary spasm was observed in 7 of 17 patients (41.2%) undergoing PFA: in 7 of 9 (77.8%) when the mitral isthmus ablation line was situated superiorly and in 0 of 8 when situated inferiorly. Conversely, coronary spasm did not occur in any of the 9 patients undergoing RFA. Of 5 patients in whom crossover PFA was performed after RFA failed to achieve conduction block, coronary spasm occurred in 3 (60%). Most instances of spasm (9 of 10 [90%]) were subclinical, with 2 (20%) requiring nitroglycerin administration. The median (range) time to resolution of spasm was 5 (5-25) minutes. Conclusion and Relevance: When creating a mitral isthmus ablation line during catheter ablation of atrial fibrillation, adjacent left circumflex arterial vasospasm frequently occurred with PFA and not RFA but was typically subclinical.

Ultrastructural insights from myocardial ablation lesions from microsecond pulsed field vs radiofrequency energy.

BACKGROUND: Ultrastructural findings immediately after pulsed field ablation (PFA) of the myocardium have not been described. OBJECTIVES: The purpose of this study was to elucidate ultrastructural characteristics and differences between microsecond PFA at the 1- and 4-hour timepoints after pulse delivery and to compare them to irrigated radiofrequency ablation (RFA) lesions. METHODS: Healthy swine underwent endocardial PFA or RFA followed by necropsy. Discrete microsecond PFA and irrigated RFA lesions were created in the ventricles with a lattice tip ablation catheter. Lesions were delivered in a manner so as to allow sampling to occur 1 and 4 hours after ablation. All lesions were located at necropsy, and samples were carefully obtained from within the lesion core, lesion periphery, and adjacent healthy myocardium. Transmission electron microscopic assessment was performed after fixation using paraformaldehyde and glutaraldehyde. RESULTS: One hour after microsecond PFA delivery, myocytes were noted to be significantly and uniformly disrupted. Clustered, misaligned, swollen mitochondria coupled with degenerating nuclei and condensed chromatin were visualized. These findings progressed over the subsequent few hours with worsening edema. Similar changes were seen with RFA but reduced in severity. However, there was prominent extravasation of red blood cells with occlusion of capillaries that was not seen in PFA. At the lesion periphery, an abrupt change in the degree of myocyte damage was observed with PFA but not RFA. CONCLUSION: Transmission electron microscopy demonstrates evidence of widespread destruction of myocytes as early as an hour after PFA and corroborates known histologic features such as sparing of vessels and sharp lesion margins.

Electrographic flow mapping of persistent atrial fibrillation: intra- and inter-procedure reproducibility in the absence of 'ground truth'.

AIMS: Validating mapping systems that identify atrial fibrillation (AF) sources (focal/rotational activity) is confounded by the absence of ground truth. A key concern of prior mapping technologies is spatiotemporal instability, manifesting as poor map reproducibility. Electrographic flow (EGF) employs a novel algorithm that visualizes atrial electrical wavefront propagation to identify putative AF sources. We analysed both intra- (3 min) and inter- (>3 months) procedure EGF map reproducibility. METHODS AND RESULTS: In 23 persistent AF patients, after pulmonary vein isolation (PVI), EGF maps were generated from 3 serial 1 min recordings using a 64-electrode basket mapping catheter (triplets) at right and left atrial locations. Source prevalence from map triplets was compared between recordings. Per protocol, 12 patients returned for 3-month remapping (1 non-inducible): index procedure post-PVI EGF maps were compared with initial EGF remapping at 3-month redo. Intra-procedure reproducibility: analysing 224 map triplets (111 right atrium, 113 left atrium) revealed a high degree of map consistency with minimal min-to-min shifts: 97 triplets (43%), exact match of leading sources on all 3 maps; 95 triplets (42%), leading source within 1 electrode space on 2 of 3 maps; and 32 triplets (14%), chaotic leading source pattern. Average deviation in source prevalence over 60 s was low (6.4%). Inter-procedure reproducibility: spatiotemporal stability of EGF mapping >3 months was seen in 16 of 18 (89%) sources mapped in 12 patients with (re)inducible AF. CONCLUSION: Electrographic flow mapping generates reproducible intra- and inter-procedural maps, providing rationale for randomized clinical trials targeting these putative AF sources.

Paroxysmal atrial fibrillation ablation with a novel temperature-controlled CF-sensing catheter: Q-FFICIENCY clinical and healthcare utilization benefits.

INTRODUCTION: The prospective, nonrandomized, multicenter Q-FFICIENCY study demonstrated the safety and 12-month efficacy of paroxysmal atrial fibrillation (AF) ablation with the novel QDOT MICRO temperature-controlled, contact force-sensing, radiofrequency (RF) catheter. Participants underwent pulmonary vein isolation with very high-power short-duration (vHPSD) mode (90 W, ≤4 s) alone or combined with conventional-power temperature-controlled (CPTC) mode (25-50 W). This study aimed to assess quality-of-life (QOL) and healthcare utilization (HCU) benefits experienced by Q-FFICIENCY study participants. METHODS: Besides evaluating procedural efficiency, QOL and HCU were assessed through 12 months postablation via Atrial Fibrillation Effect on Quality-of-Life Tool (AFEQT) score, antiarrhythmic drug (AAD) use, and incidence of cardioversion and cardiovascular hospitalization. RESULTS: Of 191 participants enrolled, 166 were ablated with the new catheter. Compared to baseline, statistically significant, clinically meaningful improvements in composite and subcategories of AFEQT scores were observed at 3 months and sustained through 12 months (12-month increase, 29.3-44.2 points). Class I/III AAD use decreased from 97.6% (162/166) at baseline to 19.6% (31/158) during Months 6-12, representing a significant 79.9% reduction. The cardioversion rate significantly declined by 93.9% from 31.3% (12 months preablation) to 1.9% (evaluation period). One-year Kaplan-Meier estimates of freedom from all-cause and cardiovascular hospitalization were 80.9% (95% confidence interval [CI], 74.8%-86.9%) and 88.8% (95% CI, 84.0%-93.7%), respectively. CONCLUSIONS: Paroxysmal AF ablation with the novel temperature-controlled RF catheter in vHPSD mode, alone or with CPTC mode, led to clinically meaningful improvement in QOL and significant reduction in AAD use, cardioversion, and cardiovascular hospitalization.

A Novel ECG-Based Deep Learning Algorithm to Predict Cardiomyopathy in Patients With Premature Ventricular Complexes.

BACKGROUND: Premature ventricular complexes (PVCs) are prevalent and, although often benign, they may lead to PVC-induced cardiomyopathy. We created a deep-learning algorithm to predict left ventricular ejection fraction (LVEF) reduction in patients with PVCs from a 12-lead electrocardiogram (ECG). OBJECTIVES: This study aims to assess a deep-learning model to predict cardiomyopathy among patients with PVCs. METHODS: We used electronic medical records from 5 hospitals and identified ECGs from adults with documented PVCs. Internal training and testing were performed at one hospital. External validation was performed with the others. The primary outcome was first diagnosis of LVEF ≤40% within 6 months. The dataset included 383,514 ECGs, of which 14,241 remained for analysis. We analyzed area under the receiver operating curves and explainability plots for representative patients, algorithm prediction, PVC burden, and demographics in a multivariable Cox model to assess independent predictors for cardiomyopathy. RESULTS: Among the 14,241-patient cohort (age 67.6 ± 14.8 years; female 43.8%; White 29.5%, Black 8.6%, Hispanic 6.5%, Asian 2.2%), 22.9% experienced reductions in LVEF to ≤40% within 6 months. The model predicted reductions in LVEF to ≤40% with area under the receiver operating curve of 0.79 (95% CI: 0.77-0.81). The gradient weighted class activation map explainability framework highlighted the sinus rhythm QRS complex-ST segment. In patients who underwent successful PVC ablation there was a post-ablation improvement in LVEF with resolution of cardiomyopathy in most (89%) patients. CONCLUSIONS: Deep-learning on the 12-lead ECG alone can accurately predict new-onset cardiomyopathy in patients with PVCs independent of PVC burden. Model prediction performed well across sex and race, relying on the QRS complex/ST-segment in sinus rhythm, not PVC morphology.

Interatrial Block Association With Adverse Cardiovascular Outcomes in Patients Without a History of Atrial Fibrillation.

BACKGROUND: Interatrial block (IAB) is associated with thromboembolism and atrial arrhythmias. However, prior studies included small patient cohorts so it remains unclear whether IAB predicts adverse outcomes particularly in context of atrial fibrillation (AF)/atrial flutter (AFL). OBJECTIVES: This study sought to determine whether IAB portends increased stroke risk in a large cohort in the presence or absence of AFAF/AFL. METHODS: We performed a 5-center retrospective analysis of 4,837,989 electrocardiograms (ECGs) from 1,228,291 patients. IAB was defined as P-wave duration ≥120 ms in leads II, III, or aVF. Measurements were extracted as .XML files. After excluding patients with prior AF/AFL, 1,825,958 ECGs from 458,994 patients remained. Outcomes were analyzed using restricted mean survival time analysis and restricted mean time lost. RESULTS: There were 86,317 patients with IAB and 355,032 patients without IAB. IAB prevalence in the cohort was 19.6% and was most common in Black (26.1%), White (20.9%), and Hispanic (18.5%) patients and least prevalent in Native Americans (9.2%). IAB was independently associated with increased stroke probability (restricted mean time lost ratio coefficient [RMTLRC]: 1.43; 95% CI: 1.35-1.51; tau = 1,895), mortality (RMTLRC: 1.14; 95% CI: 1.07-1.21; tau = 1,924), heart failure (RMTLRC: 1.94; 95% CI: 1.83-2.04; tau = 1,921), systemic thromboembolism (RMTLRC: 1.62; 95% CI: 1.53-1.71; tau = 1,897), and incident AF/AFL (RMTLRC: 1.16; 95% CI: 1.10-1.22; tau = 1,888). IAB was not associated with stroke in patients with pre-existing AF/AFL. CONCLUSIONS: IAB is independently associated with stroke in patients with no history of AF/AFL even after adjustment for incident AF/AFL and CHA2DS2-VASc score. Patients are at increased risk of stroke even when AF/AFL is not identified.

Worldwide Experience With an Irrigated Needle Catheter for Ablation of Refractory Ventricular Arrhythmias: Final Report.

BACKGROUND: We previously reported feasibility of irrigated needle ablation (INA) with a retractable 27-G end-hole needle catheter to treat nonendocardial ventricular arrhythmia substrate, an important cause of ablation failure. OBJECTIVES: The purpose of this study was to report outcomes and complications in our entire INA-treated population. METHODS: Patients with recurrent sustained monomorphic ventricular tachycardia (VT) or high-density premature ventricular contractions (PVCs) despite radiofrequency ablation were prospectively enrolled at 4 centers. Endpoints included a 70% decrease in VT frequency or PVC burden decrease to <5,000/24 h at 6 months. RESULTS: INA was performed in 111 patients (median: 2 failed prior ablations, 71% nonischemic heart disease, and left ventricular ejection fraction 36% ± 14%). INA acutely abolished targeted PVCs in 33 of 37 patients (89%), and PVCs were reduced to <5,000/day in 29 patients (78%). During 6-month follow-up, freedom from hospitalization was observed in 50 of 72 patients with VT (69%), and improvement or abolition of VT occurred in 47%. All patients received multiple INA applications, with more in the VT group than in the PVC group (median: 12 [IQR: 7-19] vs 7 [5-15]; P < 0.01). After INA, additional endocardial standard radiofrequency ablation was required in 23% of patients. Adverse events included 4 pericardial effusions (3.5%), 3 cases of (anticipated) atrioventricular block (2.6%), and 3 heart failure exacerbations (2.6%). During 6-month follow-up, 5 deaths occurred; none were procedure-related. CONCLUSIONS: INA achieves improved arrhythmia control in 78% of patients with PVCs and avoids hospitalization in 69% of patients with VT refractory to standard ablation at 6-month follow-up. Procedural risks are acceptable. (Intramural Needle Ablation for Ablation of Recurrent Ventricular Tachycardia, NCT01791543; Intramural Needle Ablation for the Treatment of Refractory Ventricular Arrhythmias, NCT03204981).

Arrhythmic Mitral Valve Prolapse With Only Mild or Moderate Mitral Regurgitation: Characterization of Myocardial Substrate.

BACKGROUND: Sustained ventricular tachycardia and sudden cardiac death due to degenerative mitral valve prolapse (MVP) can occur in the absence of severe mitral regurgitation (MR). A significant percentage of patients with MVP-related sudden death do not have any evidence of replacement fibrosis, suggesting other unrecognized proarrhythmic factors may place these patients at risk. OBJECTIVES: This study aims to characterize myocardial fibrosis/inflammation and ventricular arrhythmia complexity in patients with MVP and only mild or moderate MR. METHODS: Prospective observational study of patients with MVP and only mild or moderate MR underwent ventricular arrhythmia characterization and hybrid positron emission tomography (PET)/magnetic resonance imaging (MRI). Coregistered hybrid 18F-fluorodeoxyglucose (18F-FDG)-PET and MRI late gadolinium enhancement images were assessed and categorized. Recruitment occurred in the cardiac electrophysiology clinic. RESULTS: In 12 patients with degenerative MVP with only mild or moderate MR, of which a majority had complex ventricular ectopy (n = 10, 83%), focal (or focal-on-diffuse) uptake of 18F-FDG (PET-positive) was detected in 83% (n = 10) of patients. Three-quarters of the patients (n = 9, 75%) had FDG uptake that coexisted with areas of late gadolinium enhancement (PET/MRI-positive). Abnormal T1, T2 and extracellular volume (ECV) values were observed in 58% (n = 7), 25% (n = 3), and 16% (n = 2), respectively. CONCLUSIONS: Most patients with degenerative MVP, ventricular ectopy, and mild or moderate MR show myocardial inflammation that is concordant with myocardial scar. Further study is needed to determine whether these findings contribute to the observation that most MVP-related sudden deaths occur in patients with less than severe MR.

SGLT2 inhibitors reduce sudden cardiac death risk in heart failure: Meta-analysis of randomized clinical trials.

INTRODUCTION: Multiple randomized controlled trials have demonstrated sodium-glucose cotransporter-2 inhibitors (SGLT2i) decrease the composite endpoint of cardiovascular death or heart failure hospitalizations in all heart failure patients. It is uncertain whether SGLT2i impacts the risk of sudden cardiac death in patients with heart failure. METHODS: A comprehensive search was performed to identify relevant data published before August 28, 2022. Trials were included if: (1) all patients had clinical heart failure (2) SGLT2i and placebo were compared (3) all patients received conventional medical therapy and (4) reported outcomes of interest (sudden cardiac death [SCD], ventricular arrhythmias, atrial arrhythmias). RESULTS: SCD was reported in seven of the eleven trials meeting selection criteria: 10 796 patients received SGLT2i and 10 796 received placebo. SGLT2i therapy was associated with a significant reduction in the risk of SCD (risk ratios [RR]: 0.68; 95% confidence intervals [CI]: 0.48-0.95; p = .03; I2 = 0%). Absent dedicated rhythm monitoring, there were no significant differences in the incidence of sustained ventricular arrhythmias not associated with SCD (RR: 1.03; 95% CI: 0.83-1.29; p = .77; I2 = 0%) or atrial arrhythmias (RR: 0.91; 95% CI: 0.77-1.09; p = .31; I2 = 29%) between patients receiving an SGLT2i versus placebo. CONCLUSION: SGLT2i therapy is associated with a reduced risk of SCD in patients with heart failure receiving contemporary medical therapy. Prospective trials are needed to determine the long-term impact of SGLT2i therapy on atrial and ventricular arrhythmias.

Very High-Power Short-Duration, Temperature-Controlled Radiofrequency Ablation in Paroxysmal Atrial Fibrillation: The Prospective Multicenter Q-FFICIENCY Trial.

BACKGROUND: QDOT MICRO (QDM) is a novel contact force-sensing catheter optimized for temperature-controlled radiofrequency (RF) ablation. The very high-power short-duration (vHPSD) algorithm modulates power, maintaining target temperature during 90 W ablations for ≤4 seconds. OBJECTIVES: This study aims to evaluate safety and 12-month effectiveness of the QDM catheter in paroxysmal atrial fibrillation (AF) ablation using the vHPSD mode combined with conventional-power temperature-controlled (CPTC) mode. METHODS: In this prospective, multicenter, nonrandomized study, patients with drug-refractory, symptomatic paroxysmal AF underwent pulmonary vein (PV) isolation with QDM catheter with vHPSD as primary ablation mode, with optional use of the CPTC mode (25 to 50 W) for PV touch-up or non-PV ablation. The primary safety endpoint was incidence of primary adverse events within ≤7 days of ablation. The primary effectiveness endpoint was freedom from documented atrial tachyarrhythmia recurrence and acute procedural, repeat ablation, and antiarrhythmic drug failure. RESULTS: Of 191 enrolled participants, 166 had the catheter inserted, received RF ablation, and met eligibility criteria. Median procedural, RF application for ablating PVs, and fluoroscopy times were 132.0, 8.0, and 9.1 minutes, respectively. The primary adverse event rate was 3.6%. Imaging conducted in a subset of participants (n = 40) at 3 months did not show moderate or severe PV stenosis. The Kaplan-Meier estimated 12-month rate for primary effectiveness success was 76.7%; freedom from atrial tachyarrhythmia recurrence was 82.1%; clinical success (freedom from symptomatic recurrence) was 86.0%; and freedom from repeat ablation was 92.1%. CONCLUSIONS: Temperature-controlled paroxysmal AF ablation with the novel QDM catheter in vHPSD mode (90 W, ≤4 seconds), alone or with CPTC mode (25 to 50 W), is highly efficient and effective without compromising safety. (Evaluation of QDOT MICRO Catheter for Pulmonary Vein Isolation in Subjects With Paroxysmal Atrial Fibrillation [Q-FFICIENCY]; NCT03775512).

Preclinical assessment of the feasibility, safety and lesion durability of a novel 'single-shot' pulsed field ablation catheter for pulmonary vein isolation.

AIMS: Single-shot pulmonary vein isolation can improve procedural efficiency. To assess the capability of a novel, expandable lattice-shaped catheter to rapidly isolate thoracic veins using pulsed field ablation (PFA) in healthy swine. METHODS AND RESULTS: The study catheter (SpherePVI; Affera Inc) was used to isolate thoracic veins in two cohorts of swine survived for 1 and 5 weeks. In Experiment 1, an initial dose (PULSE2) was used to isolate the superior vena cava (SVC) and the right superior pulmonary vein (RSPV) in six swine and the SVC only in two swine. In Experiment 2, a final dose (PULSE3) was used for SVC, RSPV, and left superior pulmonary vein (LSPV) in five swine. Baseline and follow-up maps, ostial diameters, and phrenic nerve were assessed. Pulsed field ablation was delivered atop the oesophagus in three swine. All tissues were submitted for pathology. In Experiment 1, all 14/14 veins were isolated acutely with durable isolation demonstrated in 6/6 RSPVs and 6/8 SVC. Both reconnections occurred when only one application/vein was used. Fifty-two and 32 sections from the RSPVs and SVC revealed transmural lesions in 100% with a mean depth of 4.0 ± 2.0 mm. In Experiment 2, 15/15 veins were isolated acutely with 14/15 veins (5/5 SVC, 5/5 RSPV, and 4/5 LSPV) durably isolated. Right superior pulmonary vein (31) and SVC (34) sections had 100% transmural, circumferential ablation with minimal inflammation. Viable vessels and nerves were noted without evidence of venous stenosis, phrenic palsy, or oesophageal injury. CONCLUSION: This novel expandable lattice PFA catheter can achieve durable isolation with transmurality and safety.

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.

Electrophysiology, Pathology, and Imaging of Pulsed Field Ablation of Scarred and Healthy Ventricles in Swine.

BACKGROUND: Pulsed field ablation (PFA) has recently been shown to penetrate ischemic scar, but details on its efficacy, risk of arrhythmias, and imaging insights are lacking. In a porcine model of myocardial scar, we studied the ability of ventricular PFA to penetrate scarred tissue, induce ventricular arrhythmias, and assess the influence of QRS gating during pulse delivery. METHODS: Of a total of 6 swine, 5 underwent coronary occlusion and 1 underwent radiofrequency ablation to create infarct scar and iatrogenic scar models, respectively. Two additional swine served as healthy controls. An 8 Fr focal PFA catheter was used to deliver bipolar, biphasic PFA (2.0 kV) lesions guided by electroanatomical mapping, fluoroscopy, and intracardiac echocardiography over both scarred and healthy myocardium. Swine underwent magnetic resonance imaging 2-7 days post-PFA. RESULTS: PFA successfully penetrated scar without significant difference in lesion depth between lesion at the infarct border (5.9±1.0 mm, n=41) and healthy myocardium (5.7±1.3 mm, n=26; P=0.53). PFA penetration of both infarct and iatrogenic radiofrequency abalation scar was observed in all examined sections. Sustained ventricular arrhythmias requiring defibrillation occurred in 4 of 187 (2.1%) ungated applications, whereas no ventricular arrhythmias occurred during gated PFA applications (0 of 64 [0%]). Dark-blood late-gadolinium-enhanced sequences allowed for improved endocardial border detection as well as lesion boundaries compared with conventional bright-blood late-gadolinium-enhanced sequences. CONCLUSIONS: PFA penetrates infarct and iatrogenic scar successfully to create deep lesions. Gated delivery eliminates the occurrence of ventricular arrhythmias observed with ungated porcine PFA. Optimized magnetic resonance imaging sequences can be helpful in detecting lesion boundaries.