The first article is “Impact of Atrial Fibrillation Ablation on Activity Minutes in Patients With Cardiac Implantable Electronic Devices”. The authors used the Medtronic CareLink® database to identify patients who had a CIED with AF detection and accelerometer capabilities. Of 4297 eligible patients who underwent AF ablation, 409 (9.5%) were included in the analysis. After ablation, the relative AF burden decreased by 75.1%. There was no change in activity minutes per day after ablation in the entire cohort. The authors conclude that there were no clinically significant changes in activity minutes per day in patients with CIEDs after ablation for AF.

The next article is “Incidence of new onset atrial fibrillation after transcatheter PFO closure using 15 years of Ontario administrative health data”. Of 1533 patients, 96 (6.26%) developed new-onset AF following PFO closure, over an average follow-up time of 8.2 years. Age >60 years and diabetes were statistically significant, independent predictors of AF according to the Cox model. The authors conclude that the incidence of new-onset AF after PFO closure was relatively low. Having diabetes and age >60 years were the most important factors associated with new-onset AF in this population.

Up next is “Atrial Fibrillation Mechanisms Before and After Pulmonary Vein Isolation Characterized by Non-Contact Charge Density Mapping”. The purpose of this study was to use noncontact mapping to detail the global conduction patterns in paroxysmal and persistent AF and how they are modified during PV ablation. Forty patients during AF ablation underwent mapping using a noncontact catheter before and after PV isolation (PVI). Propagation history maps were analyzed postprocedure for each patient to categorize conduction patterns into focal, organized reentrant, and disorganized patterns. The authors found that Persistent AF was different from paroxysmal AF in demonstrating a higher region number and higher prevalence of disorganized-Patterns but a lower region number and lower prevalence of organized-Patterns and focal-Patterns.

Coming up is “Effect of continuous positive airway pressure therapy on recurrence of atrial fibrillation after pulmonary vein isolation in patients with obstructive sleep apnea: A randomized controlled trial”. The authors randomized patients with paroxysmal AF and an apnea-hypopnea index (AHI) ≥15 events/hour to treatment with CPAP or standard care. PVI was performed in 83 patients. Thirty-seven patients were randomized to CPAP treatment and 46 patients to standard care. The AHI was reduced from 26.7 events/hour to 1.7 events/hour in the CPAP group, but AF burden after ablation was not different between group. The authors conclude that in patients with paroxysmal AF and OSA, treatment with CPAP did not further reduce the risk of AF recurrence after ablation. PVI considerably reduced the burden of AF in OSA patients, without any difference between groups.

Up next is “Permanent pacemaker implantation after valve and arrhythmia surgery in patients with pre-operative atrial fibrillation”. The purpose of this study was to evaluate the prevalence and long-term survival of postoperative PPM implantation in patients with preoperative AF who underwent valve surgery. Results show that PPM implantation after surgery was necessary in only 2.5% of patients. Tricuspid intervention, cardiopulmonary bypass time, and endocarditis were shown to be risk factors for PPM. Over long-term follow-up, PPM was not associated with increased mortality. Surgical ablation was not associated with PPM implantation. In addition, surgical ablation improved survival regardless of PPM status.

The next article is “Serum exosomal long noncoding RNAs as a diagnostic biomarker for atrial fibrillation”. The authors first screened and identified 26 differentially expressed Exosomal long noncoding RNAs in serum exosomes from patients with persistent AF compared with controls. They then performed validation studies to find exosomal long noncoding RNAs were consistently upregulated in the serum of patients with persistent AF compared with controls. The authors conclude that serum-derived exosomal long noncoding RNAs LOC107986997 could serve as a potential diagnostic biomarker for AF.

Up next is “The Secretome of Atrial Epicardial Adipose Tissue Facilitates Reentrant Arrhythmias by Myocardial Remodeling”. The authors collected atrial epicardial adipose tissue and subcutaneous adipose tissue from patients with and without AF. The secretome was collected after a 24-hour incubation of the adipose tissue explants. They then cultured neonatal rat ventricular myocytes with epicardial adipose tissue, subcutaneous adipose tissue secretome, and cardiomyocytes conditioned medium for 72 hours. They found a change of potassium current that depolarized resting membrane of cardiomyocytes, along with decreased expression of connexin43. Cardiomyocytes incubated with epicardial adipose tissue showed reduced conduction velocity and increased conduction heterogeneity. The authors conclude that epicardial adipose tissue slows conduction, depolarizes the resting potential, alters electrical cell-cell coupling, and facilitates reentrant arrhythmias.

In addition to the atrial fibrillation-focused articles, we also published the following regular articles. The first one is titled “Intramyocardial mapping of ventricular premature depolarizations via septal venous perforators: Differentiating the superior intraseptal region from left ventricular summit origins”. The purpose of this study was to differentiate between ventricular premature depolarizations (VPDs) with a basal superior intraseptal site of origin and those originating from the epicardial superior intraseptal using septal intramyocardial mapping. The superior intraseptal site mapping was successful in 44 of 47 cases (93.6%). The authors found that a significant proportion (45.5%) of VPDs that appear to arise from the left ventricular summit actually have a superior intraseptal site origin. A significant minority (11.3%) of these can be ablated from the endocardium by targeting from an anatomic vantage point closest to the earliest intraseptal activation site.

The next article is “Left Bundle Branch Area Pacing in Patients with Atrioventricular Conduction Disease: A Prospective Multicenter Study”. Patients with AV conduction disease referred for pacemaker implantation were included. LBBAP was successful in 340 of 364 patients (93%). Procedural success rates did not differ between indications or between patients with narrow vs wide QRS. Mean LBBAP threshold was 0.77 ± 0.34 V at 0.4 ms at implant and remained stable during follow-up. There were 4 (1.2%) acute LBBAP lead dislodgments. The authors conclude that LBBAP is safe and feasible with high success rates for patients with AV conduction disease. In contrast to His bundle pacing, LBBAP success rates remain high over the entire spectrum of AV conduction disease, and lead parameters remain stable during follow-up.

Up next is “Effects of β-blockers on ventricular repolarization documented by 24-hour electrocardiography in long QT syndrome type 2”. The authors studied 25 patients with type 2 long QT syndrome. β-Blocker therapy decreased the maximal T2/T1-wave amplitude ratio. Under medication, abrupt maximal TPE intervals were shorter at heart rates of ≥75 beats/min and maximal QT intervals were shorter at a heart rate of 100 beats/min. The authors conclude that β-Blockers stabilize ventricular repolarization in LQT2 by reducing electrocardiographic early afterdepolarizations and by reducing abrupt prolongation of electrocardiographic dispersion of repolarization and ventricular repolarization duration at elevated heart rates. The effect of β-blockers on pause-induced electrocardiographic early afterdepolarizations is weak. The findings provide an electrocardiographic explanation for the protective effects of β-blockers against exercise-induced cardiac events in LQT2

Up next is “Factors Associated with Remote Monitoring Adherence for Cardiovascular Implantable Electronic Devices”. The authors linked remote monitoring data from the Veterans Affairs National Cardiac Device Surveillance Program to clinical data. In 52,574 patients, the average remote monitoring adherence was 71.9%. Black or African American patients had a lower odds of complete remote monitoring adherence while Hispanic or Latino patients had a lower odds of complete remote monitoring adherence than non-Hispanic or Latino patients. Dementia, depression, and posttraumatic stress disorder were associated with lower odds of remote monitoring adherence. The authors conclude that there are significant disparities in RM adherence by race, ethnicity, and neuropsychiatric comorbidities.