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Mapping strategies that enhance understanding and therapy for atrial fibrillation (AF) remain essential. The paced electrogram feature analysis (PEFA) technique has previously identified slow conduction zones within the ventricle critical for ventricular fibrillation (VF) or ventricular tachycardia. This prospective, exploratory cohort study aimed to determine if PEFA identifies similar slow conduction zones in the left atrium (LA) of patients with AF compared to controls.The study compared patients with paroxysmal AF undergoing catheter ablation with a control group of non-AF patients undergoing left-side electrophysiological procedures. Four electrogram (EGM) characteristics were assessed in the LA at various locations: EGM duration (ms), last deflection (ms), voltage (mV), and latency (ms). Normal values were established from the control cohort and used to calculate the percentage of abnormal EGM features in AF patients. The study included 24 AF patients and 8 controls. AF patients exhibited a higher proportion of abnormal EGM values compared to controls: last deflection 17.2%, latency 16.4%, voltage 8.5%, and EGM duration 9.8%. Normal values determined from the analysis were: 201.5 ms for last deflection, 84.3 ms for EGM duration, 77.7 ms for latency, and 0.26 mV for voltage. This study employed PEFA in the LA to identify previously undescribed metrics of atrial myopathy associated with AF. PEFA represents a potential method for characterizing the AF substrate by targeting abnormal atrial responses to closely coupled stimulation. [ABSTRACT FROM AUTHOR]

Remote magnetic navigation (RMN) presents a promising approach for catheter ablation in complex arrhythmias. This study aims to offer additional insights into the feasibility, safety, and efficacy of RMN for catheter ablation of epicardial atrial and ventricular arrhythmias in patients without structural heart disease. We present a case series of three patients (39-year-old female, 28-year-old female, and 17-year-old male) referred to our institute for epicardial ablation following unsuccessful endocardial procedures. The first patient exhibited approximately 40,000 monomorphic premature ventricular complexes (PVCs) in a 24-hour Holter recording, while the second patient experienced incessant left ventricular tachycardia (VT). In both cases, the QRS morphology indicated an epicardial origin of the arrhythmia. The third patient suffered from incessant atrial tachycardia (AT) originating from the distal portion of the vein of Marshall (VOM). Epicardial 3D electroanatomic mapping and ablation with RMN were performed with ease and minimal fluoroscopy usage. Coronary angiogram visualization on the RMN screen provided real-time information on the catheter tip's position relative to the coronary arteries. In all cases, the earliest signals were recorded epicardially, and unipolar recordings displayed sharp negative deflections at the sites of successful ablation. In the first patient, pace mapping was superior in the epicardium compared to the endocardium, and PVCs were eradicated by epicardial ablation. In the second patient, epicardial ablation immediately terminated the VT. In the third patient, epicardial ablation at the site exhibiting a distinct VOM potential promptly terminated the AT. No perioperative complications were observed, and all patients remained asymptomatic and free of arrhythmias during long-term follow-up. Our findings suggest that RMN is a feasible, effective, and safe approach for epicardial ablation of left ventricular outflow tract PVCs and VT, as well as atrial tachycardia originating from the VOM. [ABSTRACT FROM AUTHOR]

We investigated whether posterior left atrial (LA) box isolation (BOXI) improved the rhythm outcome of catheter ablation in persistent atrial fibrillation (AF) when compared with complex fractionated atrial electrograms (CFAE) ablation. A total of 183 patients with persistent AF who underwent catheter ablation were recruited from the AF ablation registry database at Mie University Hospital; 68 patients underwent CFAE ablation, and 115 patients underwent BOXI. All patients underwent clinical review and 24-hour ambulatory ECG monitoring to detect asymptomatic arrhythmias at 1, 3, 6, and 12 months post-initial ablation. Patients in the BOXI group had a significantly higher freedom from AF rate than those in the CFAE group (81.5% vs 63.9%, p=0.014), with a similar trend in propensity score-matched patients (p=0.003). The BOXI procedure emerged as the only independent prognostic factor for freedom from AF recurrence. BOXI led to greater reduction in left atrial diameter from baseline to 3-6 months post-catheter ablation compared to CFAE ablation. Thus, BOXI may offer superiority over CFAE ablation in maintaining sinus rhythm in patients with persistent AF, in addition to pulmonary vein isolation. [ABSTRACT FROM AUTHOR]

Multispline catheters were recently introduced and have led to significant improvements in electrogram acquisition and analysis. Omnipolar mapping is now able to be performed with these multispline catheters. Omnipolar mapping has the advantages of mapping a focal segment without needing the entire chamber of interest to be mapped, does not need a stable reference and is cycle length independent. This article will review the mechanism of omnipolar mapping and show how this technology can be used for multiple arrythmias. [ABSTRACT FROM AUTHOR]

Background: Despite rapid improvement in 3-demensional (3D) mapping technology, fluoroscopy-guided radiofrequency ablation remains the standard of practice in ventricular tachycardia (VT) and premature ventricular contraction (PVC) ablations. This study aimed to demonstrate the safety and efficacy of fluoroless VT/PVC ablation compared with conventional fluoroscopy-guided ablation in a real-world clinical setting. Methods: This was a nonrandomized, single-arm, retrospective study. The primary outcome was the termination of VT/PVC, as determined by noninducible VT/PVC postablation on and off isoproterenol. Safety outcomes included early onset adverse events. Results: Procedural data for 37 fluoroless cases and 39 fluoroscopy-guided cases were included in the analysis. Mean procedure time was significantly lower in the fluoroless group (P = 0.029). Fluoroscopy time was significantly lower in the fluoroless group (P <0.001). Acute success rate and recurrence were not significantly different between both groups (P = 0.675 and P = 0.453, respectively). Complication rates were low and similar between both groups (P = 0.999). Conclusions: Fluoroless VT/PVC ablation with CARTO 3D mapping system guidance showed acceptable procedure time, success in ablation, and adverse event rates. Fluoroscopy and procedure times were better than conventional fluoroscopy-guided VT/PVC ablation. [ABSTRACT FROM AUTHOR]

Myocarditis is a complex inflammatory disease with both acute and chronic stages that have varying presentations of ventricular arrhythmias both upon presentation, as well as during the disease course. The continued expansion of knowledge regarding the arrhythmogenesis of myocarditis has allowed us to understand that ventricular arrhythmias can often occur in spite of resolution of myocardial inflammation, as well as be one of the most severe predictors of worse clinical outcomes. [ABSTRACT FROM AUTHOR]

Premature ventricular complexes (PVCs) are common in the general population, usually a symptomatic, and deemed to be benign in structurally normal hearts. The spectrum of "benign" outflow tract PVCs ranges from single PVCs to recurrent non-sustained ventricular tachycardia (NSVT). Short-coupled right ventricular outflow tract (RVOT) PVCs may trigger polymorphic ventricular tachycardia (VT) in some patients and can be high risk. In many patients, PVCs can be more frequent and cause symptoms of palpitations, shortness of breath, dizziness, and heart failure. In the presence of underlying heart disease, they may indicate an increase drisk of adverse cardiovascular outcomes. A high PVC burden may lead to ventricular dysfunction and worsen underlying cardiomyopathy.PVCs may also be a marker of underlying pathophysiologic processes such as myocarditis and other acquired and inherited infiltrative cardiomyopathies. In this unique case report, we describe the use of a novel non-contact mapping array for mapping RVOT PVCs. [ABSTRACT FROM AUTHOR]

Background: The long-term results of endocardial and percutaneous epicardial catheter ablation of ventricular tachycardia (VT) in patients with structural heart disease are disappointing. Arrhythmia recurrence after ablation, and VTs with an epicardial substrate remain a clinical challenge. The purpose of this manuscript is to elaborate on feasibility and potential advantages of a surgical hybrid ablation (i.e., combined endocardial and surgical epicardial ablation) based on our initial experience consisting of five cases. Methods: Endocardial electro-anatomical voltage and activation maps were created (Carto, Biosense Webster, California, USA), and endocardial radiofrequency applications were applied at exit sites, low voltage areas and isthmi. Next, after surgical access, epicardial voltage and activation maps were produced in combination with visual assessment of the epicardial substrate. Epicardial low voltage areas, isthmi and exit sites were identified and ablated using radiofrequency energy. Results: After the procedure, VT was non-inducible in 80% of the cases (4/5, in one case no induction was performed). No peri-procedural complications occurred. After a mean follow-up of 18 months, one patient remained in sinus rhythm without, and 2 with use of antiarrhythmic drugs. One patient needed a redo procedure after 21 months, and in one patient the amiodarone dose was raised because of 2 sustained VTs. After this additional treatment, both kept sinus rhythm. Conclusions: Hybrid VT ablation is a safe and effective patient tailored procedure that comprises the major advantage of combining direct anatomical visualization and enhanced catheter stability with high-density 3D mapping. As a consequence, this procedure should be considered as a valid treatment option in complex VT management. [ABSTRACT FROM AUTHOR]

Introduction: Failure to differentiate supraventricular from ventricular arrhythmias is the most frequent cause of inappropriate implantable cardioverter-defibrillator (ICD) therapies. We hypothesized that the postpacing interval (PPI) after overdrive right ventricular pacing may differentiate ventricular (VT) from supraventricular tachycardia (SVT) such as sinus tachycardia, atrial flutter and atrial tachycardia. This hypothesis is based on the entrainment maneuver. Reentrant tachycardia circuit for VTs would haveshorter distance to RV apex than SVTs have, and the conduction time between a ventricular pacing site and the tachycardia origin is expected to be shorter in VTs than in SVTs. Methods: 220episodes from 38 patients with single chamber ICDs that RV overdrive pacing could not terminate or change the tachycardia cycle length (TCL) were retrospectively reviewed. Episodes were classified as VTs (n=115) and SVTs (n=105). TCLs, PPIs and PPI-TCL were compared between groups. Results: The cycle length of VTs was shorter than SVTs (320.6±30.3 vs 366.5±40 ms, p=0.001). PPI and PPI-TCL of VTs were shorter than SVTs (504.7±128.3 vs 689.2±121.8 ms, p=0.001, 184±103 vs 322.6±106.6 ms, p=0.001; respectively). ROC curve analysis demonstrated a 525 ms cut-off value for PPI has 89% sensitivity and 57.4% specificity to predict inappropriate ICD therapies due to SVTs (AUC:0.852). Similarly, A PPI-TCL <195 ms favored VT as a diagnosis rather than SVT with a 90% sensitivity, and 51% specificity (AUC:0.838). Conclusions: Analyzing of PPI during overdrive pacing from RV apex may discriminate supraventricular from ventricular tachycardia. This criterion may have a potential role in implantable devices that use a single ventricular lead. [ABSTRACT FROM AUTHOR]

Premature ventricular complexes (PVCs) and ventricular tachycardia (VT) in patients with structurally normal hearts originate from the right ventricular outflow tract (RVOT) in the majority of cases. In the last few decades catheter ablation of these arrhythmias has been proven to be effective. RVOT VT/PVCs may cause disabling symptoms or arrhythmia induced cardiomyopathy. However, the PVC burden at which catheter ablation should be recommended is still controversial. What adds to the controversy is why some patients with only a low number of PVCs can be highly symptomatic and may even develop arrhythmia induced cardiomyopathy, whilst others may have a higher PVC/VT burden and remain asymptomatic and do not develop cardiomyopathy for a long period of time. Therefore, although catheter ablation of RVOT PVCs has high success and low complication rates, the time point of when ablation should be recommended is currently still under debate. This review discusses the treatment strategies and prognosis for RVOT tachycardias and focuses on the question of which arrhythmia burden is appropriate to offer RF ablation. [ABSTRACT FROM AUTHOR]