Fluoroscopic cardiac anatomy for catheter ablation of tachycardia

The understanding of cardiac anatomy is crucial for the interventional arrhythmologist. In spite of the introduction of several nonfluroscopic navigational tools, some of them capable of reconstructing a computer-based surrogate of the endocardial surface of the heart cavities, simple fluoroscopy with or without the aid of angiographic techniques is still the most widely used method to guide mapping and ablation procedures. In some instances, fluoroscopic and angiographic methods have no possible replacement to unravel certain arrhythmologically useful anatomic landmarks. New interpretations of cardiac architecture show the need to challenge some traditional anatomic views, like the concept of septums within the heart. The fluoroscopic anatomy also needs to be reconsidered in the light of the new attitudinally oriented nomenclature. This article presents an overview of the fluoroscopic anatomy of the heart. When pertinent, some anatomical concepts are discussed in more detail like the triangle of Koch, the pyramidal space, and the interatrial groove. In the sections on the atria and on the ventricles, the authors focus on the anatomic information that is relevant for mapping and ablation from a fluoroscopic viewpoint, providing some hints on how best to depict the morphological features from the stance of the interventional arrhythmologist. The Visible Human Slice and Surface Server using data sets from the Visible Human Male and Female Project, has been used to facilitate the understanding of the fluoroscopic anatomy.     

Anatomy of the Left Atrium for Interventional Electrophysiologists

Increasingly, interventional procedures require accessing the left atrium from the inside of the heart as well as from the pericardial space. The right phrenic nerve running along the fibrous pericardium is close to the atrial insertion of the right superior pulmonary vein while the left phrenic nerve passes over the left atrial appendage. Posteriorly, the esophagus descends adjacent to the fibrous pericardium covering the posterior and postero‐inferior walls of the left atrium. The component parts of the left atrium are reviewed with emphasis on the structure of the atrial septum, the left atrial ridge, the mitral isthmus, and the left atrial walls. Although the atrial walls are mainly smooth, pits and crevices are common in the region of the mitral isthmus and the vicinity of the os of the atrial appendage. The muscular rim around the valve of the oval fossa delimits the extent of the true atrial septum. Interatrial muscular connections exist at the septum, along Bachmann's bundle and also at the muscular sleeves of the coronary sinus and pulmonary veins. Anatomical features relevant to interventional electrophysiologists are highlighted. (PACE 2010; 620–627)     

Use of a New Non-Fluoroscopic Three-Dimensional Mapping System in Type I Atrial Flutter Ablation

We studied 40 patients who underwent cavo-tricuspid isthmus ablation for typical counterclockwise atrial flutter with cooled tip catheters between 2001 and 2003. Complete bi-directional isthmus block was created in all patients. A new, three-dimensional (3D), non-fluoroscopic mapping system was used in 20 patients (test group), and conventional fluoroscopy in 20 others (conventional group), using anatomic and electrophysiologic criteria in both groups. We measured the total procedure, ablation procedure, and overall fluoroscopy times, and the total number of radiofrequency (RF) applications delivered in the two groups. The overall fluoroscopy time was shorter in the test group (mean 8.8 minutes, range 2–17 minutes) than the conventional group (29.7 minutes, range 12–57 minutes; P < 0.001). Though the overall procedure time was similar in both groups (92.5 ± 28.6 minutes vs 106.5 ± 20.9 minutes; P = 0.067) the ablation duration (25.1 ± 6.6 minutes versus 43.3 ± 19.6 minutes; P = 0.0051) and the total RF applications (10.6 ± 9.4 versus 16.4 ± 9.4; P = 0.044) were smaller in the test group. The use of a new, 3D non-fluoroscopic mapping system markedly reduced the fluoroscopy exposure during typical atrial flutter ablation. It was also associated with a significant reduction in ablation time and in the number of RF applications. Since atrial flutter ablation is one of the most frequently performed procedures, this system may significantly reduce the overall amount of radiation exposure in high-volume laboratories.     

Reduction of Radiation Exposure in the Cardiac Electrophysiology Laboratory

WITTKAMPF, F.H.M., et al. Reduction of Radiation Exposure in the Cardiac Electrophysiology Laboratory. The purpose of this study was to determine the effects of various protective measures on patient and operator radiation dose levels in catheter ablation procedures. Catheter ablation procedures are associated with significant radiation levels. The patient's skin and operator radiation levels were measured (1) at baseline, (2) after primary beam filtration by 0.3-mm copper sheet and 2-mm aluminium plate and implementation of the LocaLisa system, and (3) after reduction of the left anterior oblique fluoroscopic pulse rate and installation of a lead glass screen. Additionally, a comparative analysis of radiation exposure levels was performed in the seven Dutch catheter ablation centers. Filtration of both primary beams resulted in a more than two-fold reduction in patient skin dose. Together with the LocaLisa system, this resulted in a six-fold reduction in patient and operator dose. As expected, lowering of the left anterior oblique pulse rate from 25 to 12.5 Hz reduced the corresponding patient skin dose with a factor 2 while the leadglass protection caused an extra factor 2 reduction for the operator. Large differences were observed between fluoroscopy systems used for catheter ablation in the Netherlands. Depending on patient body mass and fluoroscopy system, patient skin dose varied between 0.2 and 8.4 Gy/hour. Proper measures may allow for a significant reduction of patient and operator radiation exposure in catheter ablation procedures. The large influence of body mass and equipment on patient's skin dose requires a more direct monitoring of skin dose than total fluoroscopy time.     

Electroanatomical Mapping of the Heart: Basic Concepts and Implications for the Treatment of Cardiac Arrhythmias

The CARTO electroanatomical mapping system represents a paradigm shift in the ability to map the three-dimensional anatomy of the heart and determine the cardiac electrical activity at any given mapped point. The system associates anatomical structure and electrophysiological data and displays the combined information in an easily readable, visual fashion. The system consists of a roving mapping catheter with small magnetic sensors in the tip, a fixed sensor that acts as a reference point, a low magnetic field generating pad, and a data acquisition and display system. When the roving catheter is moved in three-dimensional space, its location in relation to the fixed sensor is monitored by the system, with a resolution of < 1 mm. By gating the acquisition of points in space to the cardiac electrical activity, points that represent both location and electrical activity at that location can be acquired and displayed on a computer screen. After acquiring a number of points, a three-dimensional representation is constructed, and may be displayed from any viewing projection. Clinical applications of the system include defining the mechanisms of arrhythmias, designing ablation strategies, guiding ablations, and improving the safety of mapping and ablation procedures by allowing localization of critical cardiac structures such as the atrioventricular node and His bundle. The system holds the potential to both further our understanding of arrhythmias and increase the safety, efficacy, and efficiency of catheter ablation.     

Fluoroscopic Technique of Subclavian Venous Puncture for Permanent Pacing: A Safer and Easier Approach

Infraclavicular subclavian puncture may be performed with fluoroscopic observation of the needle trajectory. In 92 patients so implanted between July 1985 and May 1987 uneventful venous access was achieved in 90, one was unsuccessful and one patient had subcutaneous emphysema, a complication rate of 2.2%.     

The Construction of Endocardial Balloon Arrays for Cardiac Mapping

The advent of multichannel recording systems has enabled clinical mapping to be performed on a beat-by-beat basis using multi-electrode arrays. Surgical ablation of ventricular arrhythmias generally requires endocardial mapping. Clinical usage has indicated that an inflatable balloon array is the most practical design and can obviate the need for ventriculotomy by a transatrial introduction in the deflated state. Successful experience with the left ventricular balloon led to the development of a right ventricular balloon array suitably configured to extend into the outflow tract. Custom moulds are used to create an appropriate balloon from liquid latex. Nylon cloth is cut from a cardboard pattern to fashion a stretchable sock to envelope the balloon. Electrodes are formed by stitching 2-mm silver beads to the balloon sock in a preconfigured pattern. Teflon-coated 31 G multi-strand stainless-steel wires 130 mm in length connect the electrode beads by solder to the multipin connectors for easy hookup to the amplifier inputs. Tygon tubing 0.53 cm in diameter fitted to the balloon allows inflation and pressure monitoring. This basic design has been successfully implemented for the last 6 years.     

Retrospective Comparison of Ultrasound and Fluoroscopic Image Guidance for Intercostal Steroid Injections

Introduction: Steroid injection around the intercostal nerves is one of the treatment options for intercostal neuralgia. The technique may be performed blindly, under fluoroscopic guidance (FSG) or with the use of ultrasound guidance (USG). This study is a retrospective comparison of image guidance for intercostal steroid injections. Methods: After Institutional Review Board approval, a retrospective review of all patient charts who received intercostal steroid injections from 2005 to 2009 was performed. A total of 39 blocks were performed in that period. Of that 12 were USG blocks and 27 FSG blocks. The preprocedure visual analog scale (VAS) and postprocedure VAS and the duration of pain relief were compared between the 2 techniques. A Mann–Whitney test and Kruskal–Wallis test were performed looking for differences between the techniques. Results: The median change in the VAS for FSG and USG were ?5.000 and ?4.000, respectively, and duration of pain relief with a median difference of 2 weeks (95% confidence interval of ?4, 7). There were 2 occasions of intravascular spread noticed with the FSG although this should not affect the study result as the needle was repositioned and steroid injected only after contrast dye confirmation. Conclusion: With similar change in VAS scores and duration of pain relief between the 2 guidance methods based on this retrospective study, both image guidance techniques may offer similar pain relief.     

Anatomy and physiology of the pharynx

Radiographic evaluation of the passage of a bolus from the mouth through the pharynx into the esophagus is based upon identification of specific anatomical landmarks and the integrated motion accomplished by the oral and pharyngeal muscles during swallowing. Twenty-six muscles and 6 cranial nerves must be coordinated to enable the safe performance of the complex physiological task of transporting liquids and firm food from the mouth into the esophagus. The following discussion and illustrations of pharyngeal anatomy and physiology are pertinent to an understanding of normal swallowing function.     

Hip: Anatomy and US technique

Ultrasound (US) has always had a relatively limited role in the evaluation of the hip due to the deep location of this joint. However, many hip diseases are well detectable at US, but before approaching such a study it is necessary to be thoroughly familiar with the normal anatomy and related US images. The study technique is particularly important as optimization of various parameters is required, such as probe frequency, focalization, positioning of the probe, etc. Also the patient’s position is important, as it varies according to the area requiring examination. For the study of the anterior structures, the patient should be in the supine position; for the medial structures, the leg should be abducted and rotated outward with the knee flexed; for the lateral structures, the patient should be in the controlateral decubitus position; for the posterior structures the patient must be in the prone position. US study of the hip includes assessment of the soft tissues, tendons, ligaments and muscles, and also of the bone structures, joint space and serous bursae. The purpose of this article is to review the normal anatomy of the hip as well as the US anatomy of this joint.     

Trans-myocardial bipolar electrogram: A strategy for mapping and determining efficacy of bipolar ablation of deep foci

Mapping and ablation of intramural ventricular tachycardia (VT) remain a challenge. We developed a trans-myocardial electrogram recording across distal tips of two separate ablation catheters placed on contralateral sides of the myocardium to record a trans-myocardial bipole and a novel pacing electrode configuration. This trans-myocardial bipole was applied during bipolar ablation in a patient with septal VT. Local activation in this trans-myocardial bipole was similar to the earliest activation recorded from detailed activation maps from both sides of the septum. Pacing from this trans-myocardial bipole resulted in a perfect morphology match. After bipolar ablation, the trans-myocardial bipolar voltage decreased by 82%, and pacing threshold increased by 800%. These findings correlated with VT noninducibility.     

A Nonfluoroscopic Technique for Coronary Arteries Three‐Dimensional Mapping during Epicardial Ventricular Tachycardia Ablation

When performing epicardial ablation of ventricular tachycardia (VT), caution must be taken not to damage the coronary arteries. We report a case in which a new, nonfluoroscopic technique for incorporating an accurate, real‐time reconstruction of the main coronary vessels into a three‐dimensional electroanatomic map was used for epicardial VT ablation.     

正常阴囊及其内容物的超声应用解剖

器官和组织的病理解剖是超声诊断疾病的客观基础。了解阴囊、睾丸、附睾的正常解剖特征和血管分布特点，是超声诊断这类器官疾病的必要条件。文中指出，睾丸大小形态、血管分布、动脉血流速度和阻力指数、附睾的大小、形态以及阴囊壁厚度等等都是诊断和鉴别诊断的主要线索，同时以大量的图片辅助说明。此外还阐述了应用彩色多普勒超声检查阴囊时如何提高仪器灵敏度，尽可能发现更细微、更全面的病变信息的技术要领。     

Evidence for an Intramural Origin of Idiopathic Premature Ventricular Contractions Successfully Ablated within the Great Cardiac Vein

A 37‐year‐old woman with idiopathic premature ventricular contractions (PVCs), exhibiting a right bundle branch block and inferior axis QRS morphology, underwent electrophysiological testing. The earliest ventricular activation with an isolated prepotential was observed within the great cardiac vein during the PVCs. Pacing from this site with an output of 10 mA produced an excellent pace map, whereas that with an output of 2 mA produced a wider QRS with notches in the early phase. A radiofrequency application delivered at this site eliminated the PVCs. These findings suggested that the PVC origin might have been intramural rather than epicardial. (PACE 2011; 34:e112–e114)     

Interventional and surgical treatment of cardiac arrhythmias in adults with congenital heart disease

Arrhythmias are a major cause of morbidity, mortality and hospital admission in adults with congenital heart disease (CHD). The etiology of arrhythmias in this population is often multifactorial and includes electrical disturbances as part of the underlying defect, surgical intervention or hemodynamic abnormalities. Despite the numerous existing arrhythmia management tools including drug therapy, pacing and ablation, management of arrhythmias in adults with CHD remains difficult and challenging. Owing to improvement in mapping and ablation techniques, ablation and arrhythmia surgery are being performed more frequently in adults with CHD. However, there is little information on the long-term results of these treatment strategies. The purpose of this article is therefore to review the available data on nonpharmacological treatment of cardiac arrhythmias in adult patients with CHD and to give an overview of the available data on the early and late outcomes of these treatment strategies.