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.

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.

• 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.

BACKGROUND/UNASSIGNED:A lack of explainability in published machine learning (ML) models limits clinicians' understanding of how predictions are made, in turn undermining uptake of the models into clinical practice. OBJECTIVE/UNASSIGNED:The purpose of this study was to develop explainable ML models to predict in-hospital mortality in patients hospitalized for myocardial infarction (MI). METHODS/UNASSIGNED:Adult patients hospitalized for an MI were identified in the National Inpatient Sample between January 1, 2012, and September 30, 2015. The resulting cohort comprised 457,096 patients described by 64 predictor variables relating to demographic/comorbidity characteristics and in-hospital complications. The gradient boosting algorithm eXtreme Gradient Boosting (XGBoost) was used to develop explainable models for in-hospital mortality prediction in the overall cohort and patient subgroups based on MI type and/or sex. RESULTS/UNASSIGNED:The resulting models exhibited an area under the receiver operating characteristic curve (AUC) ranging from 0.876 to 0.942, specificity 82% to 87%, and sensitivity 75% to 87%. All models exhibited high negative predictive value ≥0.974. The SHapley Additive exPlanation (SHAP) framework was applied to explain the models. The top predictor variables of increasing and decreasing mortality were age and undergoing percutaneous coronary intervention, respectively. Other notable findings included a decreased mortality risk associated with certain patient subpopulations with hyperlipidemia and a comparatively greater risk of death among women below age 55 years. CONCLUSION/UNASSIGNED:The literature lacks explainable ML models predicting in-hospital mortality after an MI. In a national registry, explainable ML models performed best in ruling out in-hospital death post-MI, and their explanation illustrated their potential for guiding hypothesis generation and future study design.

PURPOSE/UNASSIGNED:Cardiac radioablation is an emerging therapy for recurrent ventricular tachycardia. Electrophysiology (EP) data, including electroanatomic maps (EAM) and electrocardiographic imaging (ECGI), provide crucial information for defining the arrhythmogenic target volume. The absence of standardized workflows and software tools to integrate the EP maps into a radiation planning system limits their use. This study developed a comprehensive software tool to enable efficient utilization of the mapping for cardiac radioablation treatment planning. METHODS AND MATERIALS/UNASSIGNED:After the scar area is outlined on the mapping surface, the tool extracts and extends the annotated patch into a closed surface and converts it into a structure set associated with the anatomic images. The tool then exports the structure set and the images as The Digital Imaging and Communications in Medicine Standard in Radiotherapy for a radiation treatment planning system to import. Overlapping the scar structure on simulation CT, a transmural target volume is delineated for treatment planning. RESULTS/UNASSIGNED:The tool has been used to transfer Ensite NavX EAM data into the Varian Eclipse treatment planning system in radioablation on 2 patients with ventricular tachycardia. The ECGI data from CardioInsight was retrospectively evaluated using the tool to derive the target volume for a patient with left ventricular assist device, showing volumetric matching with the clinically used target with a Dice coefficient of 0.71. CONCLUSIONS/UNASSIGNED:HeaRTmap smoothly fuses EP information from different mapping systems with simulation CT for accurate definition of radiation target volume. The efficient integration of EP data into treatment planning potentially facilitates the study and adoption of the technique.

• Individual cases of Watchman FLX DAT are scare in literature. • The Watchman FLX has shown lower rates of DAT than the Watchman 2.0. • Thrombus formation is still possible in rare instances with the Watchman FLX.

Objectives: Prior proof-of-concept studies demonstrated that accelerometer-based mechanically delivered AV synchronous (AVS) pacing is feasible using a leadless ventricular pacemaker; however, ambulatory performance and maintenance of AVS over time have not been studied.
Method(s): AccelAV was a prospective single-arm study to characterize AVS in patients implanted with a Micra AV, which uses the device accelerometer to mechanically detect atrial contractions and promote VDD pacing. The primary objective was to characterize resting AVS at 1 month in patients with complete AV block (AVB) and normal sinus function.
Result(s): A total of 152 patients were enrolled and implanted with a leadless pacemaker, including 19 patients from Hong Kong. Among patients with normal sinus function and complete AVB (n = 54), the mean resting AVS was 85.4% at 1 month, while ambulatory AVS was 74.5%. Mean resting and ambulatory AVS were similar among Hong Kong patients (n = 7; 85.6% resting, 72.7% ambulatory, p > 0.8). Among patients (n = 20) with programming optimization, the mean ambulatory AVS was 82.6%, representing a 10.5% improvement (p < 0.001). Quality of life as measured by the EQ-5D-3L improved significantly from pre-implant to 3 months (p = 0.031). There were no upgrades to dual-chamber devices or CRT through 3 months.
Conclusion(s): Accelerometer-based mechanical atrial sensing significantly improves the quality in patients with AVB and normal sinus function and a leadless pacemaker implanted in the right ventricle. Mean resting and ambulatory AVS among Hong Kong patients were similar to the overall cohort with an increase in ambulatory AVS among patients with programming optimization. There were no upgrades to dual-chamber pacemakers