Aims: The MicraTM transcatheter pacing system (TPS) (Medtronic) is the only leadless pacemaker that promotes atrioventricular (AV) synchrony via accelerometer-based atrial sensing. Data regarding the real-world experience with this novel system are currently lacking. We sought to characterize patients undergoing MicraTM -AV implants, describe percentage AV synchrony achieved, and analyze the causes for suboptimal AV synchrony. Methods: In this retrospective cohort study, electronic medical records from 56 consecutive patients undergoing MicraTM -AV implants at the Mayo Clinic sites in Minnesota, Florida, and Arizona with a minimum follow-up of 3 months were reviewed. Demographic data, comorbidities, echocardiographic data, and clinical outcomes were compared among patients with and without atrial synchronous-ventricular pacing (AsVP) ≥70%. Results: Fifty-six percent of patients achieved AsVP ≥70%. Patients with adequate AsVP had smaller body mass indices, a lower proportion of congestive heart failure and pulmonary hypertension. Echocardiographic parameters and procedural characteristics were similar across the two groups. Active device troubleshooting was associated with higher AsVP. The likely reasons for low AsVP were persistent atrial arrhythmias, small A4-wave amplitude, and inadequate device reprogramming. Importantly, in patients with low AsVP, subjective clinical worsening was not noted during follow-up. Conclusion: With the increasing popularity of leadless PM, it is paramount for device implanting teams to be familiar with common predictors of AV synchrony and troubleshooting with MicraTM -AV devices.
Background: Data regarding ventricular tachycardia (VT) or premature ventricular complex (PVC) ablation following MVS is limited.) CA can be challenging given perivalvular substrate in the setting of mitral annuloplasty or prosthetic valves. Objective: To investigate the characteristics, safety, and outcomes of radiofrequency catheter ablation (CA) in patients with prior mitral valve surgery (MVS) and ventricular arrhythmias (VA). Methods: We identified consecutive patients with prior MVS who underwent CA for VT or PVC between January 2013- December 2018. We investigated the mechanism of arrhythmia, ablation approach, peri-operative complications, and outcomes. Results: In our cohort of 31 patients (77% men, mean age 62.3±10.8 years, left ventricular ejection fraction 39.2±13.9%) with prior MVS underwent CA (16 VT; 15 PVC). Access to the left ventricle was via transseptal approach in 17 patients, and a retrograde aortic approach was used in 13 patients. A combined transseptal and retrograde aortic approach was used in one patient, and a percutaneous epicardial approach was combined with trans-septal approach in 1patient. Heterogenous scar regions were present in 94% of VT patients and scar-related reentry was the dominant mechanism of VT. Clinical VA substrates involved the peri-mitral area in 6 patients with VT and 5 patients with PVC ablation. No procedure-related complications were reported. The overall recurrence-free rate at 1-year was 72.2%; 67% in the VT group and 78% in the PVC group. No arrhythmia-related death was documented on long-term follow-up. Conclusion: CA of VAs can be performed safely and effectively in patients with MVS
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:firstname.lastname@example.org
Background: Left atrial appendage occlusion with the Watchman device is an alternative strategy for stroke risk reduction in patients with non-valvular atrial fibrillation. There are rare case reports of Watchman associated infection. Currently, there is no formal study that evaluated the incidence and outcomes of Watchman-related infections. Methods: All patients who underwent Watchman implantation over a 14 year study period (July 2004 through December 2018) comprised our cohort. Baseline characteristics, procedural data, and post-implantation events were identified. Primary study outcomes included Watchman related infection, other cardiovascular device related infection, bacteremia, and mortality. Results: A total of 181 patients with an average age of 75, and a median CHA2DS2-VASc Score of 4 (interquartile range 2) and a median HAS-BLED Score of 3 (interquartile range 1), were included for analysis. A total of 534.7 patient years of follow up was accrued with an average of 2.9 years per patient. The most common indications for implantation included gastrointestinal bleeding (56 patients; 30.9%) and intracerebral bleeding (51 patients; 28.2%). During follow up, 38 patients (21%) died. Six developed evidence of bacteremia. Only one developed an implantable cardioverter defibrillator (ICD) infection that required complete system extraction. None of the cohort developed Watchman-related device infection during the study period. Conclusion: In a single center study spanning a 14 year period, we report no Watchman-related devices infections. This is despite the presence of patients with bacteremia, as well as an ICD infection requiring extraction. These data suggest that Watchman devices are extremely unlikely to become infected.
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.