How to use intracardiac echocardiography to guide catheter ablation of outflow tract ventricular arrhythmiasThe anatomy of the ventricular outflow tracts and semilunar valves as it pertains to catheter ablation of outflow tract ventricular arrhythmias (OTVAs) has been described.1 Assessment of semilunar valve and regional anatomy by fluoroscopy and angiography has limitations. Coronary arteries may be subject to damage from catheter ablation near the semilunar valves due to their proximity to sites of origin of OTVAs. Detailed intracardiac echocardiographic (ICE) views of the semilunar valves may be useful to understand the anatomy, catheter location, and coronary artery proximity and variations.
Retrograde venous ethanol ablation for ventricular tachycardiaRadiofrequency catheter ablation (RFCA) has been considered the first-line therapy for treatment of drug-refractory ventricular arrhythmias (VAs).1 The success of catheter ablation depends on our ability to reach the anatomic location of the ventricular tachycardia (VT) substrate. VTs arising from deep intramural regions2 or in close proximity to coronary vessels3 can have limited RFCA success. Transarterial coronary ethanol ablation has been used as an alternative treatment option and is reasonably successful in treating RFCA-refractory VTs.
How to perform left atrial appendage electrical isolation using radiofrequency ablationAlthough pulmonary vein (PV) isolation (PVI) has been considered an effective treatment for paroxysmal atrial fibrillation (AF), non-paroxysmal AF is a complex arrhythmia for which no ablation strategy has been demonstrated to be effective and widely accepted. As such, a success rate of ∼55% in these patients with AF (Substrate and Trigger Ablation for Reduction of Atrial Fibrillation Trial Part II [Star AF II trial]) is not acceptable in our opinion and efforts should be made to seek for alternative strategies.
How to map and ablate parahisian ventricular arrhythmiasVentricular tachycardia (VT) and premature ventricular contractions (PVCs) originating in the vicinity of the His-bundle region represent 3%–9% of all idiopathic ventricular arrhythmias (VAs).1,2 In addition, patients with cardiomyopathies and scar-related VT may exhibit septal arrhythmogenic substrate involving the parahisian region.3 Catheter ablation of these arrhythmias poses particular challenges because of the risk of inadvertent atrioventricular (AV) block, and a systematic approach is important to improve outcomes and minimize complications.
When and how to target atrial fibrillation sources outside the pulmonary veins: A practical approachPulmonary vein (PV) isolation is an effective procedure in patients with paroxysmal atrial fibrillation (AF). For most patients with persistent AF and a subset of patients with paroxysmal AF, however, PV isolation may not be sufficient. Patients with the persistent form are more often beleaguered with comorbidities, which result in a greater degree of structural alterations that contribute to the maintenance of AF. In addition, the atrial activation rate during AF is higher (as evidenced by a shorter AF cycle length) in patients with persistent AF, consistent with a greater degree of electrical remodeling.
Fluoroless catheter ablation of atrial fibrillationAlthough the concept of performing fluoroless catheter ablation of atrial fibrillation (AF) was introduced several years ago, it has yet to gain wide adoption.1,2 Despite its well-documented advantages, there are several impediments, including concern that a fluoroless approach will add time to the procedure and may require a second operator. However, perhaps the greatest obstacle is that many electrophysiologists are trained to rely on fluoroscopic imaging and are therefore reluctant to trust intracardiac echocardiography (ICE) as their primary visual modality for tracking catheter movement and manipulation.
Epicardial substrate ablation for Brugada syndromeBrugada syndrome (BrS), characterized by the presence of coved-type ST-segment elevation followed by T-wave inversion in the right precordial electrocardiogram (ECG) leads in patients who have no structural heart disease but have a high risk of sudden cardiac death from ventricular fibrillation (VF), has captivated arrhythmia scholars and electrophysiologists for more than 2 decades. As a result, major progresses have been made toward a better understanding of the syndrome with respect to its genetic basis, underlying pathophysiology, and risk stratification.
Pulmonary vein signal interpretation during cryoballoon ablation for atrial fibrillationThe recognition that paroxysmal atrial fibrillation (AF) is predominantly triggered by ectopic beats arising from the vicinity of pulmonary veins (PVs) has spurred the establishment of percutaneous procedures specifically designed to electrically sequestrate the arrhythmogenic PV from the vulnerable left atrium (LA) substrate.1 Recently, the procedure has evolved with the development of purpose-built pulmonary vein isolation (PVI) tools, such as the cryoballoon catheter. This article discusses the anatomic and electrophysiologic bases for the interpretation of pulmonary vein potentials (PVPs) using a small-caliber circular mapping catheter (CMC) and provides an expanded discussion on the pacing maneuvers relevant to cryoballoon-based PVI procedures.
Safety and feasibility of transseptal puncture for atrial fibrillation ablation in patients with atrial septal defect closure devicesAF is often found in association with an ASD.1–4 There are an increasing number of patients undergoing transcatheter closure of an ASD who subsequently develop AF in clinical practice.2–4 Catheter ablation has emerged as an effective treatment strategy for drug-refractory symptomatic AF.5 While transseptal access to the left atrium (LA) is a prerequisite for AF ablation, it may prove difficult in the presence of an ASD closure device.6,7 Anticipating technical difficulties and potential complications may discourage operators from considering catheter ablation of AF in this particular patient population.
How to perform and interpret rotational angiography in the electrophysiology laboratorySophisticated imaging methods have been growing in popularity since the introduction of curative ablation procedures for atrial fibrillation (AF). This trend is predicated on the need for a precise anatomic guidance within the complex left atrial (LA) anatomy and less reliance on electrocardiographic characteristics of the substrate. Traditional two-dimensional imaging methods such as fluoroscopy would not satisfy the needs of a complex catheter navigation inside three-dimensional (3D) anatomic structures that may not be confined to the radiographic cardiac silhouette (e.g., pulmonary veins [PVs]).
Catheter ablation in transposition of the great arteries with Mustard or Senning bafflesComplete transposition of the great arteries (D-TGA) accounts for 5% to 7% of congenital heart defects. Although the arterial switch procedure has now replaced atrial redirection as the surgical procedure of choice, most adults today with D-TGA have had Mustard or Senning baffles. These surgeries involve extensive atrial reconstruction and predispose to sinus node dysfunction and atrial tachyarrhythmias.1,2 By 20 years after surgery, the prevalence of atrial tachyarrhythmias is approximately 25%, continues to increase with time, and is similar among patients with Mustard or Senning baffles.
How to perform linear lesionsAtrial fibrillation (AF) is a particularly complex arrhythmia because the mechanisms leading to fibrillation are not fully understood. Accordingly, ablation strategies have evolved largely on an empirical basis. The creation of linear lesions is a fundamental strategy that is indispensable to an electrophysiology laboratory performing ablation for treatment of this arrhythmia.
How to determine and assess endpoints for left atrial ablationStudies have demonstrated that myocardium surrounding pulmonary vein (PV) ostia plays an important role in the initiation and perpetuation of atrial fibrillation (AF).1,2 This important finding has led to the development of segmental PV ostial isolation, circumferential ablation, and isolation around the PVs using circular linear lesions guided by three-dimensional (3D) electroanatomic mapping. Substrate modification using limited linear ablation also has been demonstrated to improve the clinical outcome after PV isolation in patients with AF inducibility.