Hands On
Performing transcatheter left atrial appendage closure: Techniques and challenges
The left atrial appendage (LAA) has been demonstrated to be the major source of thromboemboli in patients with atrial fibrillation.1 The rationale of LAA closure is based on eliminating LAA continuity with the left atrium (LA), thereby reducing stroke risk. Indeed, left atrial appendage occlusion (LAAO) procedures play an important role in anticoagulation-intolerant patients who are at risk for atrial fibrillation–related stroke. Based on the PROTECT AF (Watchman Left Atrial Appendage System for Embolic PROTECTion in Patients With Atrial Fibrillation)2 and PREVAIL (Prospective Randomized Evaluation of the WATCHMAN LAA Closure Device in Patients With Atrial Fibrillation [AF] Versus Long Term Warfarin Therapy)3 studies, the Food and Drug Administration (FDA) approved use of the Watchman (Boston Scientific, Marlborough, MA) device in 2015, with an updated generation of device subsequently ratified in 2020 following the PINNACLE-FLX (Protection Against Embolism for Nonvalvular AF Patients: Investigational Device Evaluation of the Watchman FLX LAA Closure Technology) study.How to perform an epicardial ventricular tachycardia ablation: A contemporary and practical approach
Catheter ablation is increasingly used for the treatment of cardiac arrhythmias. In the 1990s, in order to treat ventricular arrhythmias resulting from chagasic cardiomyopathy, Sosa et al1 developed a technique to enter the pericardium percutaneously in the absence of a pericardial effusion. Since then, “dry” epicardial access has become a regular part of complex catheter ablation. In this review, we concentrate on the technical aspects of performing epicardial ablation for ventricular tachycardia (VT), including the management of potential complications.How to perform ethanol ablation of the vein of Marshall for treatment of atrial fibrillation
The arrhythmogenicity of the vein of Marshall (VoM) in atrial fibrillation (AF) has been known for more than 20 years.1 A recent randomized trial showed a reduced odds ratio (0.63; 95% confidence interval 0.41–0.97; P = .04) for the primary outcome of AF or atrial tachycardia (AT) recurrence in patients with persistent AF by adding VoM ethanol infusion (VoM-Et) to the standard ablation approach.2 The VoM is involved in 30% of ATs after AF ablation, and VoM ablation significantly improves the freedom from recurrent arrhythmia.Left atrial appendage occlusion using intracardiac echocardiography
Left atrial appendage (LAA) closure (LAAC) has emerged as an alternative prevention strategy for patients with nonvalvular atrial fibrillation and contraindications to long-term anticoagulation.1 In randomized trials studying the Watchman device (Boston Scientific, St. Paul, MN), implantation was performed under transesophageal echocardiography (TEE) guidance.1 The use of TEE often mandates the presence of general anesthesia and an additional cardiologist or anesthesiologist to perform TEE. This uses greater health care resources and adds additional complexity to the procedure.How to use intracardiac echocardiography to guide catheter ablation of outflow tract ventricular arrhythmias
The 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.When bigger is better: Novel use of a 27 F leadless pacemaker delivery sheath for femoral lead extractions
As the implantation rate of cardiac implantable electronic devices has continued to increase, lead extractions for clinical indications such as infection, lead failure, and lead recall have also increased.1 A femoral approach to transvenous lead extractions is needed when removing previously cut and abandoned leads, leads that disrupt during a superior extraction attempt and in some cases involving central venous obstruction.2A beginner's guide to permanent left bundle branch pacing
Studies have demonstrated the feasibility and clinical benefits of permanent His-bundle pacing (HBP).1 However, concerns regarding higher pacing thresholds, lower R-wave amplitudes, and the potential to develop distal conduction block have limited the clinical application of HBP in certain subgroups.1,2Mitral isthmus ablation: A hierarchical approach guided by electroanatomic correlation
Mitral isthmus ablation is an established technique used to treat perimitral atrial flutter. The classic approach involves creating an ablation line connecting the left inferior pulmonary vein (LIPV) to the lateral mitral annulus.1 Its feasibility was first prospectively studied by Jais et al,1 who reported a high rate of bidirectional block. However, subsequent studies by the same group, as well as others, have been less promising.2 This is important because failure to achieve bidirectional block with ablation has been shown to be proarrhythmic.Retrograde venous ethanol ablation for ventricular tachycardia
Radiofrequency 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.Cosmetic aspects of device implantation
The cosmetic aspects of device implantation imply achieving an aesthetically pleasing surgical result. It involves concealing the cardiac implantable electronic device, avoiding unsightly scars, device bulges, and protrusion (Figure 1). Cosmetic device implantation is indicated for the extremely thin patient at risk of erosion and the young patient concerned with body image. These techniques are also important in the pediatric population, patients with burn injury, and patients after mastectomy.How to perform left atrial appendage electrical isolation using radiofrequency ablation
Although 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.Approach to permanent His bundle pacing in challenging implants
Right ventricular apical pacing has been the cornerstone of bradycardia pacing for decades. It is well established that right ventricular pacing leads to ventricular dyssynchrony, reduced left ventricular function, and heart failure.1,2 Since the initial description of permanent His bundle pacing (HBP) by Deshmukh et al in 2000,3 several investigators have demonstrated the clinical utility of HBP in patients with atrioventricular (AV) nodal block, infranodal AV block, and bundle branch block.4–7 Increasing interest in HBP has been hampered in part by challenges and limitations associated with a limited implantation tool set.How to map and ablate parahisian ventricular arrhythmias
Ventricular 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.Implantation of the subcutaneous implantable cardioverter–defibrillator with truncal plane blocks
Operative anesthetic requirements and perioperative discomfort are barriers to wide adoption of the subcutaneous implantable cardioverter–defibrillator (SICD) system. The SICD implant procedure involves incision and dissection in the richly innervated midaxillary line of the chest wall for placement of the pulse generator and tunneling in subcutaneous tissue for implantation of the defibrillator lead.1 Intraoperative local anesthetic wound infiltration is routine and provides moderate analgesia, but the effects are short-lasting, and complete coverage of the affected areas is difficult.Evaluation of shortness of breath after atrial fibrillation ablation—Is there a stiff left atrium?
Ablation has emerged as the most effective therapy for atrial fibrillation (AF), with the primary goal to improve symptoms. However, there is a subset of patients who develop limiting symptoms after successful ablation despite reestablishment of sinus rhythm. There is now recognition of “stiff left atrial (LA) syndrome” related to adverse consequences of ablation itself on LA hemodynamics, as described by Gibson and others.1,2 Although relatively uncommon (1.4% incidence in the Gibson series), this syndrome is important to diagnose, as it can cause severe unexplained dyspnea.Transcatheter/leadless pacing
Entirely self-contained cardiac pacing systems for direct implantation within the heart via deflectable catheter are now available for use in humans. Worldwide, there have been more 7000 implants of the “transcatheter” or “leadless” pacemaker.∗ The concept of these pacing systems is far from new; Spickler et al.1 were able to achieve cardiac pacing in animals using a capsular nuclear-powered system in 1970. However, only recently has technology enabled sufficient miniaturization to make transcatheter pacing feasible.When and how to target atrial fibrillation sources outside the pulmonary veins: A practical approach
Pulmonary 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.How to perform transconduit and transbaffle puncture in patients who have previously undergone the Fontan or Mustard operation
The incidence of arrhythmia is high in patients who have undergone a surgical procedure for complex congenital heart disease.1 Catheter ablation is a good therapeutic option to achieve a cure for tachyarrhythmia or a decrease in tachycardia burden. However, there are considerable limitations for a catheter approach to the heart in patients who have undergone a lateral tunnel or extracardiac conduit Fontan operation or an atrial switch operation (eg, Senning operation or Mustard operation).2 In these patients, a transconduit or transbaffle puncture is needed for electrophysiological procedures.How to map and ablate papillary muscle ventricular arrhythmias
The papillary muscles (PMs) are a source of ventricular arrhythmias (VAs) in both structurally normal and abnormal hearts. Presentation includes isolated premature ventricular contractions (PVCs), nonsustained ventricular tachycardia (VT), and sustained recurrent VT. In addition, PVCs arising from the PMs may play a role as triggers of ventricular fibrillation (VF).1,2 Because of their highly variable and complex anatomy and independent motion during the cardiac cycle, catheter ablation is challenging, with lower procedural success and higher recurrence rates compared with other locations.Fluoroless catheter ablation of atrial fibrillation
Although 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 syndrome
Brugada 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.How to map and ablate left ventricular summit arrhythmias
Catheter ablation of idiopathic ventricular arrhythmias (VAs) is highly successful, with overall cure rates >90%, and is accepted as a first-line therapy by current guidelines.1 However, despite the advances in mapping and ablation techniques, there is a percentage of patients in whom successful ablation cannot be achieved because of anatomic limitations. In this regard, one of the most challenging clinical problems that electrophysiologists may face in the laboratory is the approach to VAs arising from the summit of the left ventricle (LV).Novel approach to intraprocedural cardiac tamponade: Dual-site drainage with continuous suction
Pericardial effusion and cardiac tamponade is an infrequent complication of invasive electrophysiologic procedures, with an estimated risk of 1%–3%.1–3 The most common procedures with increased risk for myocardial perforation are complex ablation during endocardial mapping and/or ablation, transseptal access, and lead placement for device therapy. Although early recognition with supportive management and immediate drainage with pericardiocentesis are necessary to prevent acute hemodynamic instability, the threshold for recommending surgical correction compared to conservative management is not well established.How to perform permanent His bundle pacing in routine clinical practice
Over the years, various sites of ventricular pacing have been evaluated in clinical trials. Earlier trials established the detrimental effects of right ventricular (RV) apical pacing, including increased risk of atrial fibrillation, heart failure (HF), and mortality. Alternate RV pacing sites have yielded mixed results.1 Biventricular (BiV) pacing in advanced HF and electrical dyssynchrony reduced HF hospitalizations and mortality. Recently, 2 trials evaluated the clinical utility of BiV pacing in the setting of heart block and demonstrated equivocal results.Enhanced cardiac device management utilizing the random EGM: A neglected feature of remote monitoring
Remote monitoring (RM) of cardiac implantable devices is rapidly becoming the standard of care for implantable cardiac device follow-up.Nodo- and fasciculoventricular pathways: Electrophysiological features and a proposed diagnostic algorithm for preexcitation variants
Fasciculoventricular and nodoventricular pathways (FVP and NVP) are uncommon preexcitation variants that can be misleading during electrophysiology studies (EPSs), and differentiating them could be challenging.1–3 In this article, we describe 2 representative cases and then we present various electrophysiological features and phenomenon encountered in patients with these particular accessory pathways (APs).Pulmonary vein signal interpretation during cryoballoon ablation for atrial fibrillation
The 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.Prevention of phrenic nerve injury during interventional electrophysiologic procedures
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The advent of innovative, potent ablative technologies and the adoption of endo–epicardial approaches to treat various arrhythmias have engendered a need for developing strategies to prevent collateral damage to critical structures such as the phrenic nerve (PN) and the esophagus during percutaneous electrophysiologic interventions. Here we detail phrenic nerve injury (PNI) prevention strategies during atrial fibrillation (AF), atrial tachycardia (AT), and ventricular tachycardia (VT) ablation. PNI is more common on the right side because of the anatomic course of the nerve and the greater preponderance of AF and AT ablations.Safety and prevention of complications during percutaneous epicardial access for the ablation of cardiac arrhythmias
Since its introduction, percutaneous epicardial access is increasingly being performed to facilitate catheter ablation of ventricular tachycardias (VTs) with epicardial circuits, difficult cases of idiopathic VTs, focal atrial tachycardia, and accessory pathways that cannot be successfully targeted endocardially.1 A thorough understanding of the clinical anatomy and potential complications is vital in order to perform a safe procedure.2 In this article, we present the clinical anatomy related to epicardial access, the technique of performing a subxiphoid epicardial puncture, and various measures to prevent complications.A straightforward, reliable technique for retaining vascular access during lead replacement
During the removal or replacement of device leads, it is often desirable to retain vascular access, which removes any risk of complications from venous cannulation techniques. In this article, I describe a rapid, safe, and flexible technique for the replacement of a nonadherent device lead while preserving vascular access.Catheter ablation of atrial fibrillation originating from extrapulmonary vein areas: Taipei approach
The pulmonary veins (PVs) are a dominant source of ectopic activity initiating atrial fibrillation (AF).1,2 We and others have demonstrated that extra-PV ectopic activity could initiate AF, and elimination of ectopic activity can cure this specific group of patients with AF.3-6 The Bordeaux group demonstrated that extensive ablation of extra-PV areas after isolation of all four PVs can convert chronic AF to focal or macroreentrant atrial tachycardias, and further elimination of these atrial tachycardias could maintain sinus rhythm in approximately 90% of patients with chronic AF.How to perform ablation of the parasympathetic ganglia of the left atrium
Catheter ablation of atrial fibrillation (AF) has generally consisted of eliminating pulmonary vein (PV) triggers initiating AF1 or modifying the adjacent atrial substrate to isolate the PVs.2 Mapping and ablation of complex fractionated atrial electrograms, thought to be responsible for maintaining AF, also have been reported.3 However, all of these strategies likely are associated with varying degrees of denervation, as suggested by experimental,4 clinical, and systematic analysis of the effects of modification of autonomic tone on the outcome of AF ablation.How to manage the patient with a high defibrillation threshold
Defibrillation threshold (DFT) testing is an integral part of implantable cardioverter-defibrillator (ICD) placement and follow-up. Unfortunately, the DFT can vary widely from day to day, influenced by many factors including electrolytes, sympathetic tone, antiarrhythmic drugs, and other medications. For this reason, a 10-J safety margin between the lowest successful defibrillation energy during testing and the maximal device output has been widely adapted as standard practice.1How to perform noncontact mapping
The anatomic and electrophysiologic complexity of arrhythmias subject to evaluation and catheter-based therapy has increased over the past several years. Use of advanced mapping systems, capable of three-dimensional rendering of cardiac chambers and superimposition of electrical information, are not designed to replace conventional mapping techniques but to be used as an adjunctive tool in the analysis and treatment of complex arrhythmias. EnSite 3000 (Endocardial Solutions, Minneapolis, MN) was the first component of the EnSite mapping system capable of advanced electroanatomic evaluation through novel catheter design and capabilities.How to manage patients with inappropriate sinus tachycardia
The objective of this review is to provide an overview of current understanding of inappropriate sinus tachycardia, with a brief discussion on diagnosis, mechanisms, and therapy. I propose a broad and multidisciplinary management approach for the majority of patients with inappropriate sinus tachycardia.Locating focal atrial tachycardias from P-wave morphology
Atrial tachycardia (AT) foci tend to cluster at characteristic anatomic locations that can be gleaned from careful analysis of the P wave.Para-Hisian pacing: Useful clinical technique to differentiate retrograde conduction between accessory atrioventricular pathways and atrioventricular nodal pathways
Para-Hisian pacing is a useful tool to differentiate between retrograde conduction over an accessory pathway and retrograde conduction over the fast or slow atrioventricular (AV) nodal pathways.1–3 Para-Hisian pacing uses right ventricular (RV) pacing close to the His bundle or proximal right bundle branch (RBB). As the position of the ventricular pacing catheter changes subtly during respiration (or by changing pacing output), the pacing stimulus changes capture among (1) basal anteroseptal RV plus His bundle or proximal RBB (His bundle-RBB capture); (2) capture of basal anteroseptal RV alone; and (3) His bundle-RBB capture alone.Determining inferior vena cava-tricuspid isthmus block after typical atrial flutter ablation
In typical atrial flutter, circular activation around the tricuspid ring is possible because the terminal crest prevents short-circuiting on the posterior wall, and the myocardium between the inferior vena cava (IVC) and the lower rim of the tricuspid ring is the obligatory pathway to close the circuit in the low right atrium (RA) (Figure 1). This IVC-tricuspid ring isthmus (cavotricuspid isthmus) has become the preferred target for ablation because it is the narrowest point of the circuit, it is easily accessible, and it is located far from the AV junction.
