A narrow complex tachycardia with a short HV interval: What is the mechanism?

The case was a 15-year-old male with a history of paroxysmal supraventricular tachycardia refractory to medical therapy and prior catheter. A repeat electrophysiology study and catheter ablation were applied. Baseline AH and HV intervals were 100 and 55 ms during normal sinus rhythm (NSR), respectively.

Spatial analysis and characteristics of persistent late potentials after ablation of scar-related VT substrate: Implications for late potential elimination as a procedural endpoint with high-resolution mapping.

Background: Late potential (LP) elimination has been proposed as a surrogate endpoint for scar-related ventricular tachycardia (VT) ablation procedures. The characteristics, distribution, and predictors of persistent late potentials (pLPs) after ablation have not been studied.

Objective: The purpose of this study was to characterize the spatial distribution and features of pLP after catheter ablation of VT substrate with high-resolution mapping.

In vivo safety and pulmonary vein isolation performance of a new cryoballoon for the treatment of atrial fibrillation.

Background: Cryoablation to achieve pulmonary vein (PV) isolation has become one of the standard approaches for atrial fibrillation (AF) ablation. The Arctic Front series cryoballoon and Achieve circular mapping catheter (Medtronic) inherently possess design defects that have been associated with unfavorite clinical outcomes. Lately, a new cryoablation system (Nordica Cryoablation System, Synaptic Medical) was developed with improved design of the cryoballoon and circular mapping catheter to address the inadequacies of current cryoablation technology.

Sympathetic toggled paroxysmal atrial fibrillation and recurrent premature atrial contractions in ambulatory patients.

Background: Autonomic nerve activity is important in the mechanisms of paroxysmal atrial fibrillation (PAF).

Objective: The purpose of this study was to test the hypothesis that a single burst of skin sympathetic nerve activity (SKNA) can toggle on and off PAF or premature atrial contraction (PAC) clusters.

Methods: Simultaneous recording of SKNA and electrocardiogram (neuECG) recording was performed over 7 days in patients with PAF.

False Tendons in the Left Ventricle: Implications for Successful Ablation of Left Posterior Fascicular Tachycardias.

Background: The anatomical substrate for left posterior fascicular ventricular tachycardia (LPF-VT) is still unclear.

Objectives: The purpose of this study is to describe the endocavitary substrate of the re-entrant loop of LPF-VT.

Methods: A total of 26 consecutive patients with LPF-VT underwent an electrophysiology study and radiofrequency ablation.

Catheter ablation of idiopathic left fascicular ventricular tachycardia: Implications of false tendons for mapping and ablation.

Introduction: The anatomical substrate for idiopathic left ventricular tachycardia (ILVT) remains speculative. Purkinje networks surrounding false tendons (FTs) might be involved in the reentrant circuit of ILVT. The objective was to evaluate the anatomical and electrophysiological features of false tendons FTs in relation to ILVT.

Atrial fibrillation mechanisms before and after pulmonary vein isolation characterized by noncontact charge density mapping.

Background: The interaction of the pulmonary vein (PV) and putative nonpulmonary triggers of atrial fibrillation (AF) remains unclear and has yet to translate into patient-tailored ablation strategies.

Objective: 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.

Methods: Forty patients during AF ablation underwent mapping using a noncontact catheter (AcQMap, Acutus Medical, Inc.

Biological substrate modification suppresses ventricular arrhythmias in a porcine model of chronic ischaemic cardiomyopathy.

Aims: Cardiomyopathy patients are prone to ventricular arrhythmias (VA) and sudden cardiac death. Current therapies to prevent VA include radiofrequency ablation to destroy slowly conducting pathways of viable myocardium which support re-entry. Here, we tested the reverse concept, namely that boosting local tissue viability in zones of slow conduction might eliminate slow conduction and suppress VA in ischaemic cardiomyopathy.

Administration of Adenosine Triphosphate Provides Additional Value Over Programmed Electrophysiologic Study in Confirmation of Successful Ablation of Atrioventricular Accessory Pathways.

To study the benefit of adenosine triphosphate (ATP) in evaluating ablation endpoints of accessory pathways (AP) and subsequent long-term prognosis. We reviewed consecutive patients with supraventricular tachycardias due to APs that underwent radiofrequency catheter ablation (RFCA) from January 2016 to September 2018 in our center. The patients were divided into two groups: the ATP group (who had passed both the ATP test and PES after ablation as the endpoint) and the non-ATP group (who had passed PES only after ablation as the endpoint).

Novel aggregated multiposition noncontact mapping of atrial tachycardia in humans: From computational modeling to clinical validation.

Background: A novel aggregated multiposition noncontact mapping (AMP-NCM) algorithm is proposed to diagnose cardiac arrhythmias.

Objective: The purpose of this study was to computationally determine an accuracy threshold and to compare the accuracy and clinical utility of AMP-NCM to gold standard contact mapping.

Methods: In a cellular automata model, the number of catheter positions and chamber coverage were varied to establish accuracy requirements for clinically relevant AMP-NCM.

Delayed repolarization and ventricular tachycardia in patients with heart failure and preserved ejection fraction.

Sudden death is the most common mode of mortality in patients with heart failure and preserved ejection fraction (HFpEF). Ventricular arrhythmias (VA) have been suspected as the etiology but the supporting evidence in patients with HFpEF is scarce. We sought to investigate VA prevalence, and to determine if VA are associated with prolonged repolarization, in patients with HFpEF.

A study of differential circRNA and lncRNA expressions in COVID-19-infected peripheral blood.

To conquer the worldwide outbreak of COVID-19 virus, a large number of studies have been carried out on COVID-19 infection, transmission and treatment. However, few studies have been conducted from the perspectives of circRNA and lncRNA, which are known to be involved in regulating many life activities, such as immune tolerance and immune escapes, and hence may provide invaluable information in the emerging COVID-19 infection and recurrence. Moreover, exosomes has been reported to play an important role in COVID-19 recurrence, and thus may interact with the expression of circRNA and lncRNA.

Cardiac arrhythmias in hospitalized patients with COVID-19: A prospective observational study in the western United States.

Arrhythmias have been reported frequently in COVID-19 patients, but the incidence and nature have not been well characterized. Patients admitted with COVID-19 and monitored by telemetry were prospectively enrolled in the study. Baseline characteristics, hospital course, treatment and complications were collected from the patients' medical records.

Identification of miRNAs encoded by Autographa californica nucleopolyhedrovirus.

Two Autographa californica nucleopolyhedrovirus (AcMNPV) encoded miRNAs, AcMNPV-miR-1 and AcMNPV-miR-3, have been reported by us in 2013 and 2019, respectively. Here, we present an integrated investigation of AcMNPV-encoded miRNAs, which include the above two miRNAs and three additional newly identified miRNAs. Six candidate miRNAs were predicted through small RNA deep sequencing and bioinformatics, of which, five were validated.

Catheter ablation for atrial tachycardias: How to interpret the unclear activation map?

Background: Post-ablation atrial tachycardias (ATs) are characterized by low-voltage signals that challenge current mapping methods. In this study, we analyzed common mistakes during activation mapping and delineated a mapping strategy for correct interpretation of tachycardia mechanisms in patients with challenging underlying substrate.

Methods And Results: Thirty-one patients referred for AT ablation were selected for the study.

Electrophysiological manifestations of rare supra-ventricular tachycardias with concealed nodo-ventricular fibers.

Purpose: To clarify the electrophysiological mechanism of supra-ventricular tachycardias (SVT) with concealed nodo-ventricular (NV) fibers.

Methods: We studied the intra-cardiac electrograms during electrophysiological study (EPS) of three cases of SVT which concerned concealed NV fibers. Electrophysiological maneuvers including right ventricular apex entrainments, RS2 stimuli, adenosine triphosphate injection and so on were done for differential diagnosis before ablation.

Purkinje Fibers in Canine False Tendons: New Anatomical and Electrophysiological Findings.

Introduction: Purkinje system and false tendons (FTs) are related to ventricular arrhythmia, but the association between Purkinje fibers and FTs is not clear. This study investigated the associations of anatomical and electrophysiological characteristics between Purkinje fibers and FTs.

Methods And Results: We optimized the protocol of Lugol's iodine solution staining of Purkinje fibers to study the anatomical structure and originated a novel electrophysiological mapping method, named the direct visual mapping (DVM) method, to study the electrophysiological characteristics.

Esophageal contraction during cryoablation: A possible protective mechanism.

Background: Contraction of the esophagus was observed during cryoablation for paroxysmal atrial fibrillation (PAF). The purpose of this study is to investigate the mechanism of esophageal contraction and the correlation between the contraction and esophageal thermal lesions.

Methods: This prospective study enrolled 64 patients with PAF undergoing second-generation cryoballoon (CB2) ablation for pulmonary vein isolation (PVI).

RESCUE-AF in Patients Undergoing Atrial Fibrillation Ablation: The RESCUE-AF Trial.

Background: Although contact force (CF)–sensing catheters improve procedural effectiveness and safety of atrial fibrillation ablation, recent reports documented a higher incidence of atrioesophageal fistula formation relative to ablation with non–CF-sensing catheters.The present study was to assess whether restricting CF to <20 g reduced risk for esophageal injury (EI) in patients with atrial fibrillation undergoing circumferential pulmonary vein isolation.

Methods: This prospective, single-center, randomized study enrolled 89 consecutive patients (mean age, 57.

Inability to capture with increasing current strength: Is this near-field or far-field?

We present a case of wide-complex tachycardia in which the clinical electrophysiological diagnosis was considered to be bundle branch re-entry ventricular tachycardia. A series of ventricular entrainment attempts were performed from the left and right ventricular septum to confirm the diagnosis. Entrainment pacing with a general current output (10 mA) was performed from the right ventricular septum with manifest fusion and a post-pacing interval similar to tachycardia cycle length.

Zero-fluoroscopy approach for ablation of supraventricular tachycardia using the Ensite NavX system: a multicenter experience.

Background: Three-dimensional electroanatomic mapping systems have demonstrated a significant reduction in radiation exposure during radiofrequency catheter ablation procedures. We aimed to investigate the safety, feasibility and efficacy of a completely zero-fluoroscopy approach for catheter ablation of supraventricular tachycardia using the Ensite NavX navigation system compared with a conventional fluoroscopy approach.

Methods: A multicenter prospective non-randomized registry study was performed in seven centers from January 2013 to February 2018.