Title: Activation Pattern During His-Bundle PacingOmar Yasin MD, MS1, Jamie Bush BS2, Vaibhav Vaidya MBBS1, Jason Tri1, Martin van Zyl, MBBCh1, Peilin Xiao PhD3, Jie Han MD, PhD4, Cory Scheuermann3, Samuel J. Asirvatham, MD1,5, Yong-Mei Cha, M.D1Department of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USABoston Scientific Corporation, Washington DC, USAThe Second Affiliated Hospital of Chongqing Medical University, Chongqing ChinaThe First Affiliated Hospital of Zhejiang University, Hangzhou, ChinaDepartment of Pediatrics and Adolescent Medicine, Mayo clinic, Rochester, MN, USAFunding: NoneDisclosures: NoneCorresponding AuthorYong-Mei Cha, MD, FHRSDepartment of Cardiovascular Diseases, Mayo Clinic200 1st ST SWRochester, MN 55901Email:[email protected]

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.

Background: The improved life expectancy observed in patients living with Human Immunodeficiency Virus (HIV) infection has made age-related cardiovascular complications, including arrhythmias, a growing health concern. We describe the temporal trends in frequency of various arrhythmias and assess impact of arrhythmias on hospitalized HIV patients using the Nationwide Inpatient Sample (NIS) Methods and Results: Data on HIV-related hospitalizations from 2005 to 2014 were obtained from the NIS using International Classification of Diseases, 9th Revision (ICD-9) codes. Data was further subclassified into hospitalizations with associated arrhythmias and those without arrhythmia. Baseline demographics and comorbidities were determined. Outcomes including in-hospital mortality, cost of care, and length of stay were extracted. SAS 9.4 (SAS Institute Inc., Cary, North Carolina) was utilized for analysis. A multivariable analysis was performed to identify predictors of arrhythmias among hospitalized HIV patients. Among 2,370,751 HIV-related hospitalizations identified, the overall frequency of any arrhythmia was 3.01%. Atrial fibrillation (AF) was the most frequent arrhythmia (2110 per 100,000). The overall frequency of arrhythmias has increased over time by 108%, primarily due to a 132% increase in AF. Arrhythmias are more frequent among older males, lowest income quartile and non-elective admissions. Patients with arrhythmias had a higher in-hospital mortality rate (9.6%). In-hospital mortality among patients with arrhythmias has decreased over time by 43.8%. The cost of care and length of stay associated with arrhythmia-related hospitalizations were mostly unchanged. Conclusions: Arrhythmias are associated with significant morbidity and mortality in hospitalized HIV patients. AF is the most frequent arrhythmia in hospitalized HIV patients.