Dual-Chamber Leadless Pacemaker Implant Procedure Outcomes: Insights from the AVEIR DR i2i Study.

Background: Initial results were recently reported for the AVEIR DR i2i study which involved the percutaneous implantation of a novel dual-chamber leadless pacemaker (LP) system, with right atrial (RA) and ventricular (RV) LPs delivering atrioventricular synchronous pacing.

Objective: Evaluate procedural outcomes and learning curve for de novo implantation of the dual-chamber LP (AVEIR DR™, Abbott).

Methods: Implant procedure metrics collected during the study were analyzed, including procedural complications within 30 days post-implant.

Integration of 3D nuclear imaging in 3D mapping system for ventricular tachycardia ablation in patients with implanted devices: Perfusion/voltage retrospective assessment of scar location.

Background: The identification of low-voltage proarrhythmic areas for catheter ablation of scar-mediated ventricular tachycardia (VT) remains challenging. Integration of myocardial perfusion imaging (single-photon emission computed tomography/computed tomography; SPECT/CT) and electroanatomical mapping (EAM) may improve delineation of the arrhythmogenic substrate.

Objective: To assess the feasibility of SPECT/CT image integration with voltage maps using the EnSite Precision system (Abbott) in patients undergoing scar-mediated VT ablation.

Electroanatomical Navigation to Minimize Contrast Medium or X-Rays During Stenting: Insights From an Experimental Model.

Stents can be effectively implemented with no x-rays or contrast medium. Modified stents were successfully implanted in 9 of 11 attempted targets (82%) (7 carotid and 4 coronary arteries) using an impedance-sensitive navigation system and optical coherence tomography. Electroanatomical navigation systems can be used to assist interventionalists in performing arterial stenting while minimizing x-ray and contrast use, thereby potentially enhancing safety for both patients and catheterization laboratory staff members.

Peripheral Interventions Radiation Exposure Reduction Using a Sensor-Based Navigation System: A Proof-of-Concept Study.

Background: Intravascular catheter positioning is done with radiography imaging. Increasing evidence indicates excessive ionizing radiation exposure for patients and physicians during catheterization procedures, making solutions to reduce radiation exposure a priority. This study evaluated the feasibility and impact of using sensor-based magnetic navigation on (i) fluoroscopy time and (ii) positioning accuracy and safety of a peripheral angioplasty balloon catheter.

Simultaneous epicardial and noncontact endocardial mapping of the canine right atrium: simulation and experiment.

Epicardial high-density electrical mapping is a well-established experimental instrument to monitor in vivo the activity of the atria in response to modulations of the autonomic nervous system in sinus rhythm. In regions that are not accessible by epicardial mapping, noncontact endocardial mapping performed through a balloon catheter may provide a more comprehensive description of atrial activity. We developed a computer model of the canine right atrium to compare epicardial and noncontact endocardial mapping.

Engineering and therapeutic application of single-chain bivalent TGF-β family traps.

Deregulation of TGF-β superfamily signaling is a causative factor in many diseases. Here we describe a protein engineering strategy for the generation of single-chain bivalent receptor traps for TGF-β superfamily ligands. Traps were assembled using the intrinsically disordered regions flanking the structured binding domain of each receptor as "native linkers" between two binding domains.

Alpha-adrenoceptor blockade modifies neurally induced atrial arrhythmias.

Our objective was to determine whether neuronally induced atrial arrhythmias can be modified by alpha-adrenergic receptor blockade. In 30 anesthetized dogs, trains of five electrical stimuli (1 mA; 1 ms) were delivered immediately after the P wave of the ECG to mediastinal nerves associated with the superior vena cava. Regional atrial electrical events were monitored with 191 atrial unipolar electrodes.

Cervical vagosympathetic and mediastinal nerves activation effects on atrial arrhythmia formation.

In anesthetized dogs both epi-and endocardial atrial activation maps and corresponding isointegral repolarization maps were created before and during right or left mediastinal nerve (RMN and LMN) and cervical vagus nerve (CVN) stimulation. Right mediastinal nerve stimulation typically caused sinus slowing, atrial tachycardia (AT), followed by atrial fibrillation (AF). Activation maps during AT showed epicardial breakthroughs from the right atrial free wall or Bachmann's bundle.

Origin and pharmacological response of atrial tachyarrhythmias induced by activation of mediastinal nerves in canines.

We sought to determine the sites of origin of atrial tachyarrhythmias induced by activating mediastinal nerves, as well as the response of such arrhythmias to autonomic modulation. Under general anaesthesia, atrioventricular block was induced after thoracotomy in 19 canines. Brief trains of 5 electrical stimuli were delivered to right-sided mediastinal nerves during the atrial refractory period.