Faculty Bibliography

BACKGROUND:Left bundle branch area pacing (LBBAP) has swiftly emerged as a safe and effective alternative to right ventricular (RV) pacing. Limited data exists on the use of retractable-helix, stylet-driven leads (SDL) for LBBAP. OBJECTIVE:The objective is to prospectively evaluate performance and safety of the Solia S stylet-driven pacing lead in a rigorously controlled multi-center trial to support U.S. market application. METHODS:A multi-center, prospective, non-randomized trial enrolled patients with standard pacing indications. Implant procedural and lead data, including threshold, sensing, impedance, and capture type were collected through 3-months. Primary endpoints were freedom from LBBAP lead-related serious complications through 3-months and LBBAP implant success according to pre-specified criteria. A blinded Clinical Events Committee (CEC) adjudicated all potential endpoint complications. RESULTS:A total of 186 patients were included from 14 US sites. LBBAP implants were successful in 95.7% (178/186; 95% CI: 91.7%, 98.1%; p< 0.0001 for comparison to performance goal of 88%). Through the 3-month follow-up, 3 patients experienced a serious LBBAP complication, all lead dislodgements, resulting in a LBBAP lead-related complication-free rate of 98.3%. A total of 13 patients (7.8%) experienced any system-related or procedure-related complication. Mean threshold was 0.89V at 0.4ms, sensing was 10.8mV, and impedance was 608 ohms. CONCLUSION/CONCLUSIONS:The short-term results from this prospective trial demonstrate both high implant success and freedom from LBBAP lead-related complications utilizing this stylet driven retractable helix lead. This trial supports the safety, use, and effectiveness of SDL for performing contemporary physiologic pacing.

BACKGROUND:The ADVENT randomized trial revealed no significant difference in 1-year freedom from atrial arrhythmias (AA) between thermal (RF/Cryo) and pulsed field ablation (PFA). However, recent studies indicate that the post-ablation AA burden is a better predictor of clinical outcomes than the dichotomous endpoint of 30-second AA recurrence. OBJECTIVES/OBJECTIVE:To determine i) the impact of post-ablation AA burden on outcomes, and ii) the effect of ablation modality on AA burden. METHODS:In ADVENT, symptomatic drug-refractory paroxysmal AF (PAF) patients underwent PFA or thermal ablation. Post-ablation transtelephonic ECG monitor (TTM) recordings were collected weekly or for symptoms, and 72-hour Holters were at 6- and 12-months. AA burden was calculated from percentage AA on Holters and TTMs. Quality-of-life assessments were at baseline and 12-months. RESULTS:From 593 randomized patients (299 PFA, 294 thermal), using aggregate PFA/thermal data, an AA burden exceeding 0.1% was associated with a significantly reduced quality-of-life and an increase in clinical interventions: redo ablation, cardioversion and hospitalization. There were more patients with residual AA burden <0.1% with PFA than thermal ablation (OR 1.5, 95%CI: 1.0, 2.3; p=0.04). Evaluation of outcomes by baseline demographics revealed that patients with prior failed Class I/III AADs had less residual AA burden after PFA compared to thermal ablation (OR 2.5, 95%CI: 1.4, 4.3; p=0.002); patients receiving only Class II/IV AADs pre-ablation had no difference in AA burden between ablation groups. CONCLUSION/CONCLUSIONS:Compared to thermal ablation, PFA more often resulted in an AA burden less than the clinically-significant threshold of 0.1% burden.

BACKGROUND:Prediction of drug-induced long QT syndrome (diLQTS) is of critical importance given its association with torsades de pointes. There is no reliable method for the outpatient prediction of diLQTS. OBJECTIVES/OBJECTIVE:This study sought to evaluate the use of a convolutional neural network (CNN) applied to electrocardiograms (ECGs) to predict diLQTS in an outpatient population. METHODS:We identified all adult outpatients newly prescribed a QT-prolonging medication between January 1, 2003, and March 31, 2022, who had a 12-lead sinus ECG in the preceding 6 months. Using risk factor data and the ECG signal as inputs, the CNN QTNet was implemented in TensorFlow to predict diLQTS. RESULTS:Models were evaluated in a held-out test dataset of 44,386 patients (57% female) with a median age of 62 years. Compared with 3 other models relying on risk factors or ECG signal or baseline QTc alone, QTNet achieved the best (P < 0.001) performance with a mean area under the curve of 0.802 (95% CI: 0.786-0.818). In a survival analysis, QTNet also had the highest inverse probability of censorship-weighted area under the receiver-operating characteristic curve at day 2 (0.875; 95% CI: 0.848-0.904) and up to 6 months. In a subgroup analysis, QTNet performed best among males and patients ≤50 years or with baseline QTc <450 ms. In an external validation cohort of solely suburban outpatient practices, QTNet similarly maintained the highest predictive performance. CONCLUSIONS:An ECG-based CNN can accurately predict diLQTS in the outpatient setting while maintaining its predictive performance over time. In the outpatient setting, our model could identify higher-risk individuals who would benefit from closer monitoring.

OBJECTIVES/OBJECTIVE:We investigated characteristics of left atrial conduction in patients with HCM, paroxysmal AF and normal bipolar voltage. BACKGROUND:Patients with hypertrophic cardiomyopathy (HCM) exhibit abnormal cardiac tissue arrangement. The incidence of atrial fibrillation (AF) is increased fourfold in patients with HCM and confers a fourfold increased risk of death. Catheter ablation is less effective in HCM, with twofold increased risk of AF recurrence. The mechanisms of AF perpetuation in HCM are poorly understood. METHODS:We analyzed 20 patients with HCM and 20 controls presenting for radiofrequency ablation of paroxysmal AF normal left atrial voltage(> 0.5 mV). Intracardiac electrograms were extracted from the CARTO mapping system and analyzed using Matlab/Python code interfacing with Core OpenEP software. Conduction velocity maps were calculated using local activation time gradients. RESULTS: = 0.13, p = 0.03). CONCLUSIONS:Atrial conduction velocity is significantly reduced in patients with HCM and paroxysmal AF, possibly contributing to arrhythmia persistence after catheter ablation.

INTRODUCTION/UNASSIGNED:Excessive dialytic potassium (K) and acid removal are risk factors for arrhythmias; however, treatment-to-treatment dialysate modification is rarely performed. We conducted a multicenter, pilot randomized study to test the safety, feasibility, and efficacy of 4 point-of-care (POC) chemistry-guided protocols to adjust dialysate K and bicarbonate (HCO3) in outpatient hemodialysis (HD) clinics. METHODS/UNASSIGNED:Participants received implantable cardiac loop monitors and crossed over to four 4-week periods with adjustment of dialysate K or HCO3 at each treatment according to pre-HD POC values: (i) K-removal minimization, (ii) K-removal maximization, (iii) Acidosis avoidance, and (iv) Alkalosis avoidance. The primary end point was percentage of treatments adhering to the intervention algorithm. Secondary endpoints included pre-HD K and HCO variability, adverse events, and rates of clinically significant arrhythmias (CSAs). RESULTS/UNASSIGNED:Nineteen subjects were enrolled in the study. HD staff completed POC testing and correctly adjusted the dialysate in 604 of 708 (85%) of available HD treatments. There was 1 K ≤3, 29 HCO3 <20 and 2 HCO3 >32 mEq/l and no serious adverse events related to study interventions. Although there were no significant differences between POC results and conventional laboratory measures drawn concurrently, intertreatment K and HCO3 variability was high. There were 45 CSA events; most were transient atrial fibrillation (AF), with numerically fewer events during the alkalosis avoidance period (8) and K-removal maximization period (3) compared to other intervention periods (17). There were no significant differences in CSA duration among interventions. CONCLUSION/UNASSIGNED:Algorithm-guided K/HCO3 adjustment based on POC testing is feasible. The variability of intertreatment K and HCO3 suggests that a POC-laboratory-guided algorithm could markedly alter dialysate-serum chemistry gradients. Definitive end point-powered trials should be considered.

• Precise LAA anatomy must be established for LAA occlusion device selection. • We have developed the TUPLE maneuver, an acronym for “tilt up and turn left”. • The TUPLE maneuver facilitates LAA device selection and intraprocedural guidance.

BACKGROUND:With the growing use of implantable cardiac devices, the need for transvenous lead extraction has increased, which translates to increased procedural volumes. Sex differences in lead extraction outcomes are not well studied. OBJECTIVE:The present study aims at evaluating the impact of sex on outcomes of lead extraction. METHODS:We identified 71,754 patients who presented between 2016 and 2019 and underwent transvenous lead extraction. Their clinical data were retrospectively accrued from the National Readmission Database (NRD) using the corresponding diagnosis codes. We compared clinical outcomes between male and female patients. Odds ratios (ORs) for the primary and secondary outcomes were calculated, and multivariable regression analysis was utilized to adjust for confounding variables. RESULTS:Compared to male patients, female patients had higher in-hospital complications including pneumothorax (OR 1.26, 95% CI (1.07-1.4), P < 0.01), hemopericardium (OR 1.39, 95% CI (1.02-1.88), P = 0.036), injury to superior vena cava and innominate vein requiring repair (OR 1.88, 95% CI (1.14-3.1), P = 0.014; OR 3.4, 95% CI (1.8-6.5), P < 0.01), need for blood transfusion (OR 1.28, 95% CI (1.18-1.38), P < 0.01), and pericardiocentesis (OR 1.6, 95% CI (1.3-2), P < 0.01). Thirty-day readmission was also significantly higher in female patients (OR 1.09, 95% CI (1.02-1.17), P < 0.01). There was no significant difference regarding in-hospital mortality (OR 0.99, 95% CI (0.87-1.14), P = 0.95). CONCLUSION/CONCLUSIONS:In female patients, lead extraction is associated with worse clinical outcomes and higher 30-day readmission rate.

• LAA membranes are exceedingly rare with variable morphologies. • Thromboembolic risk with LAA membranes remains unknown. • Use of 3D TEE transillumination may assist in visualization and understanding.