Vaidya, Vaibhav R.

AbstractIntroductionThe need for transparency in financial relationships in the healthcare system, has culminated in Open Payments database, managed by the Center for Medicare and Medicaid Services (CMS). Since its inception in 2013, the trend in such payments to physicians practicing cardiac electrophysiology was not examined.Methods and ResultsPayment information reported to CMS from January 2013 to December 2018 was obtained from the publicly available Open Payments data set using the online query tool. The data were analyzed by an individual provider and by state. An in‐depth analysis of payments in the year 2018 payments was performed. From 2014 to 2018, there was an 18% increase in the total number of payments reported from 88 877 payments in 2014 to 105 000 in 2018. Despite the increase in the total number of payments reported, the average payment steadily decreased over time, resulting in an overall reduction in the total amount of payments from 2014 to 2018 ($34.9 million to $28.2 million). Payments to the top 5% of individual recipients have also decreased over this time. In 2018, 2888 unique providers received reportable payments, a total of 105 000 payments, with a median payment amount of $1378 (interquartile range: $165–$5781). The majority of these payments were for food and beverage (82%) and travel/lodging (10%). The top five payers include Boston Scientific, Medtronic Vascular, Abbott Laboratories, Janssen Pharmaceuticals, and Biotronik.ConclusionAmong cardiac electrophysiologists, there is increased reporting of payments in the Open Payments program over time, with a notable decrease in the payment amount.

Abstract Aims Current electrophysiology signal recording and mapping systems have limited dynamic range (DR) and bandwidth, which causes loss of valuable information during acquisition of cardiac signals. We evaluated a novel advanced signal processing platform with the objective to obtain and assess additional information of clinical importance. Methods and results Over 10 canines, we compared intracardiac recordings within all cardiac chambers, in various rhythms, in pacing and during radiofrequency (RF) ablation across two platforms; a conventional system and the PURE EP™ [(PEP); Bio Sig Technologies, Inc., Los Angeles, CA, USA]. Recording cardiac signals with varying amplitudes were consistently and reproducibly observed, without loss of detail or introduction of artefact. Further the amplitude of current of injury (COI) on the unipolar signals correlated with the instantaneous contact force (CF) recorded on the sensing catheter in all the animals (r2 = 0.94 in ventricle). The maximum change in the unipolar COI correlated with the change in local electrogram amplitude during non-irrigated RF ablation (r2 = 0.61 in atrium). Reduction in artefact attributable to pacing (20 sites) and noise during ablation (48 sites) was present on the PEP system. Within the PEP system, simultaneous display of identical signals, filtered differently, aided the visualization of discrete conduction tissue signals. Conclusion Compared to current system, the PEP system provided incremental information including identifying conduction tissue signals, estimates of CF and a surrogate for lesion formation. This novel signal processing platform with increased DR and minimal front-end filtering may be useful in clinical practice.

Abstract Introduction: Therapies for substrate-related arrhythmias include ablation or drugs targeted at altering conductive properties or disruption of slow zones in heterogeneous myocardium. Conductive compounds such as carbon nanotubes may provide a novel personalizable therapy for arrhythmia treatment by allowing tissue homogenization. Methods: A nanocellulose-carbon nanotube conductive hydrogel was developed to have conduction properties similar to normal myocardium. Ex vivo perfused canine hearts were studied. Electroanatomic activation mapping of the epicardial surface was performed at baseline, after radiofrequency ablation, and after uniform needle injections of the conductive hydrogel through the injured tissue. Gross histology was used to assess distribution of conductive hydrogel in the tissue. Results: The conductive hydrogel viscosity was optimized to decrease with increasing shear rate to allow expression through a syringe. The DC conductivity under aqueous conduction was 4.3·10-1 S/cm. In 4 canine hearts, when compared to the homogeneous baseline conduction, isochronal maps demonstrated sequential myocardial activation with a shift in direction of activation to surround the edges of the ablated region. After injection of conductive hydrogel, isochrones demonstrated conduction through the ablated tissue with activation similar to baseline in all 4 hearts. Gross specimen examination demonstrated retention of the hydrogel within the tissue. Conclusions: This proof-of-concept study demonstrates that conductive hydrogel can be injected into acutely disrupted myocardium to restore conduction. Future experiments should focus on evaluating long-term retention and biocompatibility of the hydrogel through in vivo experimentation.

Abstract Background Choosing the appropriate animal model for development of novel technologies requires an understanding of anatomy and physiology of these different models. There are little data about the characteristics of different animal models for the study of technologies used for epicardial ablation. We aimed to compare the incidence of ventricular arrhythmias during epicardial radiofrequency ablation between swine and canine models using novel epicardial ablation catheters. Methods We conducted a retrospective study using data obtained from epicardial ablation experiments performed on swine ( Sus Scrofa ) and canine ( Canis familiaris ) models. We compared the incidence of ventricular arrhythmias during ablation between swine and canine using multivariate regression analysis. Six swine and six canine animals underwent successful epicardial radiofrequency ablation. A total of 103 ablation applications were recorded. Results Ventricular arrhythmias requiring cardioversion occurred in 13.11% of radiofrequency ablation applications in swine and 9.75% in canine (relative risk: 117.6%, 95% confidence interval [CI]: 83.97‐164.69, animal‐based odds ratio [OR]: .55, 95% CI: .23‐61.33; P = .184). When adjusting for application position, duration of ablation and power, the odds of developing potentially lethal ventricular arrhythmia in swine increased significantly compared to canine (OR: 3.60, 95% CI: 1.35‐9.55; P = .010). Conclusions The swine myocardium is more susceptible to developing ventricular arrhythmias compared to canine model during epicardial ablation. This issue should be carefully considered in future studies.

Background: Reentrant ventricular arrhythmias are a major cause of sudden death in patients with structural heart disease. Current treatments focus on electrically homogenizing regions of scar contributing to ventricular arrhythmia with ablation or altering conductive properties using antiarrhythmic drugs. The high conductivity of carbon nanotubes may allow restoration of conduction in regions where impaired electrical conduction results in functional abnormalities. We propose a new concept for arrhythmia treatment using a stretchable, flexible biopatch with conductive properties to attempt to restore conduction across regions in which activation is disrupted. Methods: Carbon nanotube patches composed of nanofibrillated cellulose/single-walled carbon nanotube ink 3-dimensionally printed in conductive patterns onto bacterial nanocellulose were developed and evaluated for conductivity, flexibility, and mechanical properties. The patches were applied on 6 canines to epicardium before and after surgical disruption. Electroanatomic mapping was performed on normal epicardium, then repeated over surgically disrupted epicardium, and then finally with the patch applied passively. Results: We developed a 3-dimensional printable carbon nanotube ink complexed on bacterial nanocellulose that was (1) expressable through 3-dimensional printer nozzles, (2) electrically conductive, (3) flexible, and (4) stretchable. Six canines underwent thoracotomy, and, during epicardial ventricular pacing, mapping was performed. We demonstrated disruption of conduction after surgical incision in all 6 canines based on activation mapping. The patch resulted in restored conduction based on mapping and assessment of conduction direction and velocities in all canines. Conclusions: We have demonstrated 3-dimensional custom-printed electrically conductive carbon nanotube patches can be surgically manipulated to improve cardiac conduction when passively applied to surgically disrupted epicardial myocardium in canines.

AbstractBackgroundLeadless cardiac pacing (LCP) has emerged as a new modality for permanent pacing. We sought to describe comparative outcomes between LCP and transvenous pacemakers.MethodsPatients receiving LCP (Micra [Medtronic, Minneapolis, MN, USA] and Nanostim [St. Jude Medical/Abbott Laboratories, Chicago, IL, USA]) between 2014 and 2017 at the Mayo Clinic Heart Rhythm Enterprise practice (Rochester, MN, USA; Jacksonville, FL, USA; and Scottsdale, AZ, USA) were identified. We identified 1:1 age‐ and sex‐matched controls receiving single‐chamber transvenous ventricular pacemakers (TVP). Statistical analyses were performed with JMP 13.0.0 (SAS, Institute Cary, NC, USA).ResultsNinety patients underwent LCP implantation (73 Micra and 17 Nanostim) with a median follow‐up duration of 62 (interquartile range 28‐169) days. Both groups had 100% successful device implant rates. There were no differences in procedure‐related major (0% vs 1%) or minor complications (8% vs 3%) in the LCP versus TVP groups (P > 0.05). Excluding Nanostim patients, there was a lower rate of device‐related revision or extraction in the Micra versus TVP groups (0% vs 5%, P = 0.028). Device endocarditis was more common in the TVP group (0% vs 3%, P = 0.04). Estimated longevity was greater for the LCP group (median 12.0 vs 10.0 years, P < 0.0001). An increase in severity of tricuspid valve regurgitation (TR) by ≥2 grades occurred in none of the LCP patients, and in 19% of the TVP patients (P = 0.017).ConclusionThere are no significant differences in procedural complications among patients receiving LCP versus TVP. The Micra group had lower rates of device‐related revision/extraction compared to the TVP group. Patients with leadless pacemaker were less likely to develop endocarditis or worsening TR.

Background Current thermal ablation methods for atrial fibrillation, including radiofrequency and cryoablation, have a suboptimal success rate. To avoid pulmonary vein (PV) stenosis, ablation is performed outside of the PV, despite the importance of triggers inside the vein. We previously reported on the acute effects of a novel direct current electroporation approach with a balloon catheter to create lesions inside the PVs in addition to the antrum. In this study, we aimed to determine whether the effects created by this nonthermal ablation method were associated with irreversible lesions and whether PV stenosis or other adverse effects occurred after a survival period. Methods and Results Initial and survival studies were performed in 5 canines. At the initial study, the balloon catheter was inflated to contact the antrum and interior of the PV. Direct current energy was delivered between 2 electrodes on the catheter in ECG‐gated 100 μs pulses. A total of 10 PVs were treated demonstrating significant acute local electrogram diminution (mean amplitude decrease of 61.2±19.8%). After the survival period (mean 27 days), computed tomography imaging showed no PV stenosis. On histologic evaluation, transmural, although not circumferential, lesions were seen in each treated vein. No PV stenosis or esophageal injury was present. Conclusions Irreversible, transmural lesions can be created inside the PV without evidence of stenosis after a 27‐day survival period using this balloon‐based direct current ablation approach. These early data show promise for an ablation approach that could directly treat PV triggers in addition to traditional PV antrum ablation.