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The development of cardiac resynchronization therapy (CRT) has been crucial in reducing morbidity and mortality in patients with advanced heart failure. However, a significant proportion of patients who receive CRT fail to derive significant clinical benefits from this therapy. Successful CRT depends on a multitude of factors, including appropriate patient selection, left ventricular lead positioning, and postimplant management. Newer device-based algorithms, multipoint ventricular pacing, and the development of leadless CRT devices constitute important facets of both the present and near-future evolution of this therapy.Optical coherence tomography (OCT) employs near-infrared light to image the microstructure of different tissues. Clinically, it has been used to image the walls of coronary arteries. In research settings, one of the applications for OCT is visualizing endocardial and subendocardial structures. The present experiment sought to determine whether OCT can identify native conduction tissues in adult porcine hearts. During the study, the right atrial endocardial surfaces of excised adult porcine hearts were exposed. Selleckchem Voruciclib The triangle of Koch was imaged with the OCT system and the conduction tissue was identified. The area was then prepared for histologic examination with Masson's trichrome stain. The results of histologic preparations and OCT images were then compared. Ultimately, nine porcine hearts were examined using this methodology. OCT imaging successfully identified subendocardial structures presumed to be the compact atrioventricular node. Histologic images of the preparations delineated the different tissue types and conduction tissue was easily identified. The location of distinctive hyporeflective areas in the OCT images correlated with the location of conduction tissue in the histology images. In light of the findings of this study, it is suggested that atrioventricular nodal tissue can be identified by OCT in freshly dissected unfixed porcine hearts. OCT images distinguished the differentiated conduction tissue in close proximity with the endocardium, myofibers, and fibrous tissue, and the success of this was verified with histology. This technology may be useful for the direct visualization of the native conduction system during procedures in the operating room and electrophysiology laboratory. Further studies with perfused tissue samples and live animal experiments are needed to better assess the efficacy of this novel application.His-bundle pacing (HBP) constitutes an excellent alternative to right ventricular pacing. Recently, several studies have reported on the success and efficacy of HBP in patients with left bundle branch block requiring cardiac resynchronization therapy. Nonetheless, HBP may not always be feasible due to high capture thresholds or disease in the distal His bundle. The present report discusses the utility and feasibility of pacing in the left bundle branch area located distal to the site of conduction block.We report a case of direct His-bundle lead placement at the time of implantable cardioverter-defibrillator insertion and atrioventricular node ablation. The patient was found to have an isolated persistent left superior vena cava, and selective His-bundle pacing was successfully achieved through the use of a steerable sheath and dedicated mapping catheter.Temporary cardiac pacing is commonly used in patients with life-threatening bradycardia and serves as a bridge to implantation of a permanent pacemaker (PPM). For years, passive fixation leads have been used for this purpose, offering the advantage of that they can be placed at bedside. The downside, however, is that patients must remain on telemetry and bed rest until lead removal due to the risk of displacement and failure to capture. Even then, the latter cannot always be prevented. Temporary cardiac pacing with passive fixation leads has also been related to a higher incidence of infection and venous thrombosis, delayed recovery, and increased length of stay. Thus, over the last couple of decades, pacemaker leads with an active fixation mechanism have become increasingly used. This is known as a temporary PPM (TPPM) approach, which carries a very low risk of lead dislodgement and allows patients to ambulate, among other advantages. Here, we performed a review of the literature on the use of TPPMs and theiisk in a patient who is already hemodynamically unstable. When possible, a screw-in-lead pacemaker should be used for temporary pacing.Atrioesophageal fistula (AEF) is an uncommon but devastating complication of catheter ablation for atrial fibrillation. Even with appropriate recognition and treatment, mortality is greater than 30% in most studies. If AEF is suspected, it is essential to avoid endoscopy and to order immediate cross-sectional imaging. If the diagnosis is confirmed, a thoracic surgeon should be promptly notified and must assess the patient urgently. The prognosis for AEF is poor even if it is appropriately recognized and addressed, so prevention must be a high priority. Prevention of AEF should involve the use of low-risk and cost-effective measures during ablation, which may increase safety, efficacy, or both. These strategies may include conscious sedation (as opposed to general anesthesia), low-power ablation, low-flow irrigation, short-duration lesions, esophageal temperature measurement, esophageal deviation, and pharmacologic prophylaxis with proton pump inhibitors or histamine H2 receptor blockers. Multiple new technologies are now becoming available, which may further reduce esophageal injury. Proceduralists should be aware of the available techniques and equipment that may help to reduce the risk of AEF, while simultaneously considering the possibility of unintended consequences.Pacemaker-dependent (PD) patients undergoing implantable cardiac electronic device extraction often must be subjected to temporary pacing interventions. We sought to determine the safety and utility of a leadless pacing system (Micra™; Medtronic, Minneapolis, MN, USA) in patients undergoing system extraction as compared with externalized temporary transvenous right ventricular lead (temp-perm) placement. We performed a retrospective cohort analysis of all patients receiving either permanent Micra™ or temp-perm systems following system extraction from October 2013 to September 2017 at Vanderbilt University Hospital. The Micra™ and temp-perm cohorts included nine and 27 patients meeting the inclusion criteria, respectively. System infection was the most common indication for extraction (67% Micra™, 84% temp-perm), but no patients had active bacteremia at the time of permanent system reimplantation. There was no difference in system type (p = 0.09) or mean lead dwell time extracted (109 versus 81 months; p = 0.93).