Hands On
Ablation above the semilunar valves: When, why, and how? Part II
In this two-part series on arrhythmias occurring above the semilunar valve, we discuss the relevant underlying anatomy and the technique for mapping and ablation above the aortic and pulmonic valve. In part I, we focused on ventricular arrhythmias, and in this paper (part II), we discuss the anatomy and present knowledge of the substrate mapped and ablated above the aortic valve for atrial tachycardia in certain unusual accessory pathways. The background anatomy of the aortic valve has been discussed in part I of this series, to which the reader is referred.How to prevent, recognize, and manage complications of lead extraction. Part III: Procedural factors
The major risks of percutaneous lead extraction include cardiac perforation (1%–4%), emergency cardiac surgery (1%–2%), and death (0.4%–0.8%). However, risk to an individual varies in accordance with a number of factors (Table 1), and informed consent must be tailored to the specific patient. Indicators of very high risk (Table 2) define relative contraindications to the procedure; patients without other options should be referred to experienced centers capable of managing these special cases. Surgical backup should be secured prior to every extraction.How to avoid inappropriate shocks
Implantable cardioverter-defibrillator (ICD) usage has increased dramatically over the past decade. In part this is due to improved patient survival after myocardial infarction, but principally this is due to the increased number of implants for primary prevention. While the salutary effects of ICD therapy in this population of patients are generally accepted, complications from ICD implantation have become a common and pressing issue. First among these complications, both in terms of frequency and impact on quality of life, is inappropriate ICD therapy.Ablation using irrigated radiofrequency: A hands-on guide
The advent of irrigated radiofrequency (RF) catheters has led to the common misconception that irrigation somehow makes ablation both safer and more effective. In fact, this is not true. Irrigation (or any other means of cooling the catheter tip) results in the ability to deliver greater energy and as such can lead to steam pops, collateral damage, and thrombus formation. It is important to recognize that irrigation allows greater energy delivery; it does not mandate it. The operator must determine the appropriate power settings, irrigant flow rates, and lesion duration for each ablation site.Novel ablative approach for atrial fibrillation to decrease risk of esophageal injury
Percutaneous atrial fibrillation (AF) ablation using catheter-delivered radiofrequency energy continues to improve in safety and effectiveness. Nonetheless, the potential risk of esophageal injury often limits the ability to fully ablate the posterior portion of the left atrium to achieve optimal procedural success without complications. We present a comprehensive approach that addresses this challenge. Our ablative strategies include (1) identifying the esophagus to minimize ablative energy, when possible, in the proximity of the esophagus, (2) maximize the ability of the esophagus to remove heat and to heal from potential thermal injury, and (3) optimizing energy delivery to avoid deep tissue injury while maintaining procedural efficacy.How to prevent, recognize, and manage complications of lead extraction. Part II: Avoiding lead extraction—Noninfectious issues
The first part of this review examined the infectious indications for lead extraction. This part discusses noninfectious indications for lead extraction and strategies for reducing the incidence of such indications.How to prevent, recognize, and manage complications of lead extraction. Part I: Avoiding lead extraction—Infectious issues
As the number of implanted devices continues to grow, so does the need for extraction of chronic endocardial leads. Extraction carries with it considerable risk of morbidity and mortality (both intraprocedure and postprocedure), even in experienced hands. Although the evolution of technology directed at this approach has facilitated the successful removal of leads, no evidence indicates that this technology has lessened the incidence or nature of adverse events. Risks associated with lead extraction include vascular and cardiac perforation, tricuspid valve injury, various arrhythmias, sepsis, pulmonary embolism, bleeding, stroke, and myocardial infarction.Percutaneous extraction of coronary sinus vein and branch leads
Extraction of cardiac leads and electrodes will continue to be a statistical necessity as electrode implant numbers and durations increase. Improved implant success and expanded indications in heart failure patients for left ventricular (LV) pacing electrodes via the coronary sinus (CS) and its branches have resulted in unique interactions among the leads, venous system, and epicardial heart that are not typically seen with traditional endocardial right heart cardiac electrodes. LV lead placement, as well as the myocardium’s response to it, requires continual evaluation to better understand the limitations that may be encountered during extraction of LV leads, especially as the mean duration of implant reaches beyond 1 year.European perspective on lead extraction: Part II
If manual extraction is not successful, a locking stylet is used after the inner lumen is reamed using another stylet to remove debris. Use of a locking stylet with a very flexible tip is essential so that a tortuous lead can be negotiated. Equally important is locking the stylet as close as possible to the lead tip and not allowing the stylet to slip during the procedure. The risk of severing the sometimes fragile interpolar section of encapsulated bipolar leads is high if a positive lock close to the lead tip cannot be achieved.A European perspective on lead extraction: Part I
The need for lead extraction has increased exponentially in the last decade due to greatly increased “total lead exposure time.” The increased total lead exposure time is the result of new indications for device treatment, device therapy involving more leads per patient, and longer average patient life. Improved general lead reliability noted over recent years may have decreased slightly the need for extraction; however, this effect is more than countered by recent advisories, recalls, and increased complication rates, probably related to many new centers offering device treatment.How to treat and identify device infections
The incidence of device-related infections depends directly on the definition employed. The lack of precision is also compounded by the latency between the initiation and manifestation of the infection. It is not rare for there to be some erythema at the incision site during the first week of healing, and it is not clear that this represents infection. Less frequent, but still common, there can be a small, superficial stitch abscess, which will respond to local measures. When the diagnosis of device system infection is made, it should be made on the basis of pocket cellulitis, erosion, abscess, persistent bacteremia, or endocarditis with or without vegetation on the lead.Lead extraction
Lead extraction has grown from a “niche” procedure practiced by a select few individuals to a fairly widely disseminated technique. With the apparent increase in device infections, occluded veins and the need for device “upgrades,” more physicians are attempting to extract chronically implanted pacing and implantable cardioverter-defibrillator (ICD) leads. Unfortunately, obtaining training for this procedure is difficult outside of a training program at a center with a physician experienced in lead extraction.Lead extraction using the femoral vein
Lead extraction using the femoral vein is an alternate approach for lead removal. It has often been dubbed “the inferior approach.” This is because today it is often reserved for use only after a failed primary approach via the implant vein. In reality it is the most versatile approach for lead removal. Prior to the advent of powered sheaths, it was frequently used as a primary approach. It is also the only approach, and the procedure of choice, for removal of broken or cut leads with free ends.How to select patients for lead extraction
The techniques and tools for percutaneous removal of transvenous leads have undergone substantial development over the past several decades. Although the use of locking stylets and powered sheaths to free leads from encapsulated scar tissue has improved the success rate, the procedure still carries a significant risk of morbidity and mortality even in the hands of experienced operators. The threshold for lead extraction continues to evolve. The initial use of the procedure was limited to patients with life-threatening infections because of limited tools, lower success rates and high complication rates.How to perform linear lesions
Atrial 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.Pacing maneuvers for nonpulmonary vein sources: Part II
Superior vena caval (SVC) potentials are similar to pulmonary vein (PV) potentials. The concepts of multiple far-field electrograms and the use of perivenous pacing and specific site and simultaneous pacing described above are equally applicable to understanding the complex electrograms found within the SVC (Figure 1). Specific sites that require pacing to determine the components of a complex electrogram found in the SVC include the right atrium (RA), azygos vein, anomalous PVs draining into the SVC, and right upper PV; in some cases, an anomalous superior branch of the right inferior PV may be required.Pulmonary vein–related maneuvers: Part I
With the rapid evolution of atrial fibrillation ablation procedures, electrophysiologists have necessarily strived for simple and anatomic-based approaches. In all except the most straightforward procedures, however, questions regarding the significance of various potentials recorded on mapping and ablation catheters arise.1,2 Other articles in this series have described in detail the various approaches to atrial fibrillation ablation. In this article, the anatomic and electrophysiologic bases for pacing maneuvers used with a variety of ablation approaches are reviewed.How to determine and assess endpoints for left atrial ablation
Studies 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.How to recognize, manage, and prevent complications during atrial fibrillation ablation
Seminal observations by Haissaguerre et al1 demonstrating initiation of atrial fibrillation (AF) by pulmonary vein (PV) depolarizations led to the development of percutaneous catheter-based endocardial AF ablation procedure. Since its original description, the AF ablation procedure has evolved considerably. Currently, the most accepted ablation strategy involves creating circumferential radiofrequency (RF) ablation lesions around PV ostia (either individually or encircling wide areas around the left-sided and right-sided veins) with or without additional atrial lesions.How to use intracardiac echocardiography for atrial fibrillation ablation procedures
Intracardiac echocardiography (ICE) has been an important tool in the development of advanced catheter ablation procedures. ICE technology now allows complete echocardiographic interrogation of all four heart chambers from the right atrium. A list of the uses for ICE in ablation procedures is given in Table 1.How and when to ablate the ligament of Marshall
The ligament of Marshall is an epicardial vestigial fold that marks the location of the embryologic left superior vena cava. It contains the nerve, vein (vein of Marshall), and muscle tracts.1,2 The proximal portions of the muscle tracts connect directly to the coronary sinus myocardial sleeves. The distal portions of the muscle tracts extend upward into the pulmonary vein region. Figure 1 shows a postmortem human heart with the ligament of Marshall located between the left atrial (LA) appendage and left pulmonary vein.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 do circular mapping catheter-guided pulmonary vein antrum isolation: The Cleveland Clinic approach
Atrial fibrillation (AF) is one of the 20th-century epidemics. Over the past 2 decades, significant advances have been made in the treatment of AF, the last being percutaneous ablation. Haissaguerre et al1 showed that AF triggers often originate from the thoracic veins. The goal of present-day AF ablation is to electrically “disconnect” the pulmonary veins (PVs) from the rest of the left atrium (LA) by ablating around the origin of the veins.2 At present, at least two techniques are used for AF ablation.How to perform electrogram-guided atrial fibrillation ablation
Over the past decade, several mapping studies of human atrial fibrillation (AF) have made the following important observations: (1) Atrial electrograms during sustained atrial fibrillation have three distinct patterns: single potential, double potential, and complex fractionated potential(s) (CFAEs).1–3 (2) The distribution of these atrial electrograms during AF localizes to specific atrial sites, and these electrograms exhibit remarkable temporal and spatial stability.1,2 (3) The CFAE areas represent AF substrate sites and are important targets for AF ablation.
