Journal of Innovations in Cardiac Rhythm Management最新文献

Multifocal ectopic Purkinje-related premature contractions are a unique electrophysiological finding that can be characteristic of a rare sodium channelopathy. We describe the medical management of this rare channelopathy in a patient who was pregnant.

Catheter ablation of premature ventricular contractions (PVCs) arising from the left ventricular summit (LVS) presents technical challenges due to the regional anatomy and frequent intramural site of origin (SOO). Intracardiac echocardiography (ICE) and the CARTOSOUND^® (Biosense Webster, Diamond Bar, CA, USA) module allow the operator to directly reconstruct and visualize the dimensions and orientation of the LVS live and present it in relation to neighboring structures. We retrospectively reviewed consecutive cases between January 2021 and December 2022 of patients undergoing PVC ablation for a presumed LVS origin. The LVS was reconstructed by creating a three-dimensional representation of the left ventricular septum, using two-dimensional ICE sections. The earliest site in each chamber was tagged on the reconstructed LVS, and the presumed SOO was localized using a geometrical center point from all sites. Ablation was first delivered to the earliest site, except when the presence of coronary branches precluded radiofrequency delivery within the great cardiac vein. Of 20 patients (8 women, 62.4 ± 7.1 years old) with a presumed LVS origin, 12 had PVC recurrence within the monitoring period after the initial ablation for 192.5 ± 37.2 s at the earliest site. Among them, earliest activation was seen at the sinus of Valsalva (SoV), coronary venous system (CVS), and left ventricular endocardium (LVE) in four, six, and two patients, respectively. Using the reconstructed LVS, the anatomically closest site to the SOO was identified in the SoV, CVS, and LVE in four, two, and six cases, respectively. Throughout the study period (14.5 months; range, 9.3-19.7 months), 17 patients (85%) had complete elimination of PVCs as evaluated by 24-h event monitors at the 12-month visit. In 50% of cases, among patients in whom ablation at the earliest signal was unsuccessful, the site of successful ablation did not correlate with the second earliest signal or had no identifiable signal during initial activation mapping. The reconstructed LVS not only guided activation mapping but also identified sites proximal to the center point that had either a late activation signal, a low-amplitude signal, or no signal at all.

Conduction system pacing involving either His bundle pacing (HBP) or left bundle branch pacing (LBBP) is a modality that has been introduced as a safe and effective alternative to right ventricular (RV) pacing to help prevent pacemaker-associated cardiomyopathy. While HBP has been employed in the pediatric and congenital populations, several small studies have shown LBBP to be safe and effective in the pediatric population. We present a patient with congenital atrioventricular block and postoperative ventricular septal defect repair cardiomyopathy with subsequent left ventricular function improvement following a transition from an RV epicardial pacemaker system to an LBBP system. This case report serves as a foundation for a review of the current state of LBBP in pediatrics and congenital heart disease.

Dysfunction of the cardiac autonomic nervous system (CANS) is associated with various cardiac arrhythmias. Subsequently, invasive techniques have successfully targeted the CANS for the treatment of certain arrhythmias, such as sympathetic denervation for ventricular tachycardia storm. Non-invasive strategies capable of modulating the CANS for arrhythmia treatment have begun to gain interest due to their low-risk profile and applicability as an adjuvant therapy. This review provides an evidence-based overview of the currently studied technologies capable of non-invasively modulating CANS for the suppression of atrial fibrillation and ventricular arrhythmias.

Aberrant conduction during orthodromic reciprocating tachycardia (ORT) prolongs the ventriculoatrial conduction time, which can be essential for the maintenance of tachycardia in specific cases. We searched for ORT relying on aberrancy among 220 cases in our center. Three patients showed the phenomenon of aberrancy-dependent ORT. All accessory pathways were located at the lateral regions of the atrioventricular annulus. None of them had a baseline bundle branch block (BBB). Creating a functional BBB was necessary to induce the tachycardias. In two cases, termination of tachycardias was directly associated with resolution of the aberration. In the other case, re-entry required both BBB and slow pathway conduction. We conclude that extra transseptal time caused by aberrancy can be an integral part of the ORT circuit, which explains the infrequent and unsustainable episodes of ORT in certain patients and is useful in understanding the circuit and localizing the pathway.

In this case report, omnipolar mapping, a unique technology, was used to analyze complex atrial arrhythmias in an adult with congenital heart disease. Our patient had surgically corrected tetralogy of Fallot and presented with highly symptomatic atrial arrhythmias. A successful ablation was performed with standard bipolar mapping techniques. However, due to the complex nature of the substrate and arrhythmias in this patient, bipolar arrhythmia maps were difficult to interpret, and ablation lesions were delivered based on inference and "educated guesses." An offline re-analysis with omnipolar technology (OT) research software, days after the procedure was performed, revealed details not seen with traditional mapping and explained why the delivered lesions were effective. The findings of this retrospective analysis are provocative, suggesting that OT may increase the accuracy and efficiency of mapping and ablation of complex arrhythmias. Further investigation using commercially released OT in real time is needed.

Pacemaker implantation in neonates can be challenging due to their small size. Even pulse generators adapted for pediatric patients, such as the Microny device (Abbott, Chicago, IL, USA), are proportionately large in comparison to the size of the smallest newborns. Due to anatomic considerations, such as small vascular and ventricular sizes, leadless pacemakers and transvenous implantation in the youngest neonatal population remain unsuitable. Even so, the desire for leadless devices has prompted the industry to create the smallest pacemakers available. Adapting the smaller Micra™ transcatheter leadless pacing system (Medtronic, Minneapolis, MN, USA) for an epicardial pacing application may be advantageous to the smallest patients. This case illustrates the use of a Micra™ device modified with a header block to serve as the pulse generator in a ventricular epicardial pacing system for a 1-day-old, 2.68-kg patient with complete heart block.

Pacing-induced cardiomyopathy (PICM) is defined as a drop in left ventricular ejection fraction (LVEF) in the setting of chronic, high-burden right ventricular pacing. Cardiac resynchronization therapy (CRT) and conduction system pacing (CSP) have been proposed to manage PICM. Although acute myocardial infarction has been described as a predictor of PICM, there are no guideline recommendations for CRT or CSP in patients with coronary artery disease (CAD) and preserved LVEF. In this report, we present and discuss three cases of PICM in patients with CAD and preserved LVEF.