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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.LAA ligation using the LARIAT suture delivery device: Tips and tricks for a successful procedure
Chronic oral anticoagulation (OAC) has traditionally been considered as the most effective prophylaxis against thromboembolic events in patients with atrial fibrillation (AF). However, as many as 20% of the patients with AF are not candidates for OAC.1,2 Reasons for ineligibility range from intracranial bleeding (the most serious complication) to increased propensity for mechanical injury (the least serious complication). The resumption of OAC in patients who have suffered a life-threatening complication due to OAC is associated with a much higher risk of such events in the future.Safety and feasibility of transseptal puncture for atrial fibrillation ablation in patients with atrial septal defect closure devices
AF 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.Two-incision technique for implantation of the subcutaneous implantable cardioverter-defibrillator
Three incisions in the chest are necessary for implantation of the entirely subcutaneous implantable cardioverter-defibrillator (S-ICD). The superior parasternal incision is a possible risk for infection and a potential source of discomfort. A less invasive alternative technique of implanting the S-ICD electrode—the two-incision technique—avoids the superior parasternal incision.How to perform ventricular tachycardia ablation with a percutaneous left ventricular assist device
A majority of patients with structural heart disease and scar-related ventricular tachycardia (VT) have fast, hemodynamically unstable VT.1 In fact, up to one-fifth of the patients have only unstable VT, which precludes detailed activation and entrainment mapping.2 In addition, even in those with well-tolerated VT, procedural success can be complicated by acute heart failure as a consequence of prolonged episodes of induced VT and intravascular volume expansion; and one consequence of this acute decompensated heart failure is a significant increase in the short-term morbidity and mortality of the procedure.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.How to perform antral pulmonary venous isolation using the cryoballoon
This article describes our current practice, clinical outcomes, and future directions for the use of balloon cryoablation for the treatment of atrial fibrillation.Management of hemopericardium related to percutaneous epicardial access, mapping, and ablation
Percutaneous epicardial access (Figs. 1A and 1B) has gained wide acceptance as an interventional technique to access the pericardial space. Since its initial description1 in targeting epicardial circuits of ventricular tachycardia (VT) in patients with Chagasic cardiomyopathy, percutaneous epicardial access and ablation has come to play an important role in interventional electrophysiology. This technique has been recognized as a vital addition to catheter ablation of certain cardiac arrhythmias and for the delivery of newer investigational devices such as epicardial suture ligation of the left atrial appendage.Recording and interpreting unipolar electrograms to guide catheter ablation
Electrophysiology laboratories commonly use closely spaced bipolar recordings for mapping. However, unipolar recordings have some useful features that can provide additional complimentary information, provided the limitations of these recordings and the particular recording techniques are recognized.Implantable cardioverter-defibrillators in congenital heart disease: 10 programming tips
Advances in cardiac care of the young have given rise to a growing and aging population of patients with congenital heart disease. Despite remarkable improvements in overall survival, sudden cardiac death remains the most common cause of late mortality. As a result, implantable cardioverter-defibrillators (ICDs) are increasingly used in this heterogeneous patient population. Tetralogy of Fallot and transposition of the great arteries are the most prevalent subtypes of congenital heart disease in ICD recipients.Left cardiac sympathetic denervation for the prevention of life-threatening arrhythmias: The surgical supraclavicular approach to cervicothoracic sympathectomy
The progressive understanding of the diseases associated with significant risk for sudden cardiac death has fostered the development of early diagnosis and risk stratification. Thus, instead of starting from either a sudden death victim or a survivor of a cardiac arrest, it has become relatively common for cardiologists to identify individuals at high risk for sudden death, often after an arrhythmic nonlethal cardiac event such as syncope. Besides ischemic heart disease, it has also been recognized that children and young adults can be affected by arrhythmogenic disorders of genetic origin with a high propensity for lethal arrhythmias.How to troubleshoot the electroanatomic map
An electroanatomical mapping system is a useful tool for complex arrhythmia ablation. The system reconstructs the precise 3-dimensional chamber of interest with electrical and anatomical information. There are several technical aspects that physicians should be aware of to maximize its efficacy. This review provides relevant information on troubleshooting of the mapping system.How to perform and interpret rotational angiography in the electrophysiology laboratory
Sophisticated 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]).How to implant a defibrillation coil in the azygous vein
Implantable cardioverter-defibrillator (ICD) defibrillation testing may reveal failure to achieve a satisfactory safety margin (conventionally, ≥10 J below the maximum energy of the generator) for defibrillation. Options for modification of the defibrillation threshold include repositioning of the ventricular lead, use (or removal) of a defibrillation coil in the superior vena cava (SVC), reversal of shock polarity, and modifying the shock waveform (not available in all devices). Additional defibrillator coils can be added to the subcutaneous space, the subclavian vein, or the coronary sinus.How to diagnose and treat cardiac tamponade in the electrophysiology laboratory
As certain as death and taxes occur, complications will occur when invasive procedures are performed. Pericardial effusion, with or without tamponade, is a well-documented complication even in the most experienced centers.1,2 As a result, electrophysiologists should know how to recognize and manage this complication over the course of their careers. In most situations, the outcome is excellent if the complication is recognized and managed expeditiously; however, delay in diagnosis and treatment can lead to catastrophic results.CRT delivery systems based on guide support for LV lead placement
Despite improvements in LV pacing leads, their placement continues to be limited by the coronary venous anatomy. Frequently, the angioplasty wire does not provide adequate support to advance the LV lead into the vein. However, a guiding catheter preshaped to fit into the ostium of the target can easily provide the required support.1,2 Many implanting physicians are reluctant to adopt preshaped guides for direct LV lead delivery because of lack of familiarity with the approach to open lumen catheter manipulation and contrast injection.How to use balloons as anchors to facilitate cannulation of the coronary sinus left ventricular lead placement and to regain lost coronary sinus or target vein access
Coronary venous anatomy can make successful implantation of a cardiac resynchronization therapy device difficult or impossible. Venogram and coronary balloons can be used as anchors to facilitate initial coronary sinus (CS) cannulation and left ventricular lead placement and to recover lost CS and target vein access.Catheter ablation in tetralogy of Fallot
Tetralogy of Fallot is the most common form of cyanotic heart disease, accounting for approximately 10% of congenital heart defects. Corrective surgery involves atrial and/or ventricular incisions and patches that, when combined with altered hemodynamics, predispose to the late onset of arrhythmias.1,2 In a multicenter cohort followed up for 35 years after corrective surgery, sustained atrial and ventricular tachyarrhythmias occurred in 10% and 12% of patients, respectively.1 Macroreentrant right atrial tachycardia is the most common atrial arrhythmia.Catheter ablation in transposition of the great arteries with Mustard or Senning baffles
Complete 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 magnetic resonance imaging on patients with implantable cardiac arrhythmia devices
Magnetic resonance imaging (MRI) offers unrivaled soft tissue resolution and multiplanar imaging capabilities. Cardiac MRI is capable of accurate characterization of cardiac function and is uniquely capable of identifying scar fibrosis and fat deposition, thus making it an ideal imaging modality for the evaluation of patients presenting with arrhythmia. In addition, the absence of x-ray radiation makes MRI suitable for follow-up of chronic disease and for imaging in young patients and women of childbearing age.How to identify the location of an accessory pathway by the 12-lead ECG
Radiofrequency catheter ablation has become the treatment of choice for patients with symptomatic Wolff-Parkinson-White syndrome (WPW). The QRS complex morphology present on the 12-lead electrocardiogram (ECG) in WPW patients depends on the location of the accessory pathway(s) (AP) and the degree of fusion over the normal atrioventricular (AV) conduction. Accordingly, it is determined by the site of ventricular insertion of the accessory pathway, AV node conduction time, and atrial conduction.Ablation above the semilunar valves: When, why, and how? Part I
In this two-part series, we discuss the anatomical basis for arrhythmias arising above the semilunar valves. In this part (part I), we describe the relevant anatomy and technique for mapping and ablation of ventricular arrhythmias arising above either the pulmonic or the aortic valve. After an initial discussion of the underlying anatomy and characteristics of the substrate targeted for ablation above the semilunar valve, an approach for safe and effective ablation of supravalvar ventricular arrhythmias is presented.
