Publications

Catheter-based ultrasonography is a widely used tool in cardiac electrophysiology practice, and intracardiac echocardiography is supplanting other forms of imaging to become the dominant imaging modality. Given advances in pericardial access, intrapericardial echocardiography can be performed using ultrasound catheters as well. Intrapericardial echocardiography and echocardiography from the coronary sinus, also an epicardial structure, allows interventionalists to obtain unique views from virtually any vantage point, compared with other forms of echocardiography. Both intrapericardial echocardiography and coronary sinus echocardiography are safe and important alternatives that can be used during complex procedures in the electrophysiology laboratory.

Heterogeneity in depolarization and repolarization among regions of cardiac cells has long been recognized as a major factor in cardiac arrhythmogenesis. This fundamental principle has motivated development of noninvasive techniques for quantification of heterogeneity using the surface electrocardiogram (ECG). The initial approaches focused on interval analysis such as interlead QT dispersion and Tpeak -Tend difference. However, because of inherent difficulties in measuring the termination point of the T wave and commonly encountered irregularities in the apex of the T wave, additional techniques have been pursued. The newer methods incorporate assessment of the entire morphology of the T wave and in some cases of the R wave as well. This goal has been accomplished using a number of promising vectorial approaches with the resting 12-lead ECG. An important limitation of vectorcardiographic analyses is that they require exquisite stability of the recordings and are not inherently suitable for use in exercise tolerance testing (ETT) and/or ambulatory ECG monitoring for provocative stress testing or evaluation of the influence of daily activities on cardiac electrical instability. The objectives of the present review are to describe a technique that has been under clinical evaluation for nearly a decade, termed "interlead ECG heterogeneity." Preclinical testing data will be briefly reviewed. We will discuss the main clinical findings with regard to sudden cardiac death risk stratification, heart failure evaluation, and myocardial ischemia detection using standard recording platforms including resting 12-lead ECG, ambulatory ECG monitoring, ETT, and pharmacologic stress testing in conjunction with single-photon emission computed tomography myocardial perfusion imaging.

INTRODUCTION: The objective of this study was to evaluate the safety and efficacy of preprocedural computed tomography (CT) to guide percutaneous epicardial puncture for catheter ablation of ventricular tachycardia.

METHODS AND RESULTS: A preprocedural CT was used to plan the site, angle, and depth of needle insertion during epicardial access in 10 consecutive patients undergoing ventricular tachycardia (VT) ablation. Adjacent structures (right ventricle, diaphragm, liver, colon, internal mammary artery) were visualized and the course of the needle was planned avoiding these structures. During epicardial access, a protractor was used to guide the angle of needle entry into the subxiphoid space. Postprocedural CT was performed to calculate the deviation between the planned and executed access and to assess for any collateral damage. Percutaneous epicardial access was obtained successfully in all the patients using anterior (n = 4) and inferior (n = 6) approaches. The planned site and angle of puncture was more caudal (2.9 ± 0.9 vs. 3.7 ± 0.7 cm, p = .021) and acute (61.7 ± 5.8 vs. 49.0 ± 5.4°, p = .011) for an anterior approach compared to an inferior approach, respectively. Postprocedure CT revealed minimal deviation of the puncture site (5.4 ± 1.0 mm), angle (5.4 ± 1.2°), and length of needle insertion (0.5 ± 0.2 cm). With regard to the site of entry in the pericardial space, there was a deviation of 5.9 ± 1.1, 6.1 ± 1.1, and 5.8 ± 1.4 mm in the x, y, and z dimensions, respectively. In eight patients with minimal deviation between planned and executed access, there was no collateral injury to adjacent viscera or vessels. In two patients with increased deviation of angle and length of needle insertion, there was entry through the diaphragm during inferior access.

CONCLUSIONS: Utilizing pre-procedural CT planning may aid in the success and safety of percutaneous epicardial access during VT ablation.

Lacus, ultrices in ultrices tellus odio nunc urna. Massa aenean sed ipsum praesent enim. Porttitor iaculis augue pulvinar nam feugiat. Aliquam morbi ut ultricies elementum adipiscing purus proin semper. Viverra accumsan tempus, vitae auctor a. Dictumst cras dui sit feugiat. Enim nulla pulvinar urna sit eu placerat.

Nascetur nisi, tortor velit et ipsum commodo. Tempor massa, non suscipit at sagittis morbi eget euismod.

Lacus, ultrices in ultrices tellus odio nunc urna. Massa aenean sed ipsum praesent enim. Porttitor iaculis augue pulvinar nam feugiat. Aliquam morbi ut ultricies elementum adipiscing purus proin semper. Viverra accumsan tempus, vitae auctor a. Dictumst cras dui sit feugiat. Enim nulla pulvinar urna sit eu placerat.

Nascetur nisi, tortor velit et ipsum commodo. Tempor massa, non suscipit at sagittis morbi eget euismod.

Lacus, ultrices in ultrices tellus odio nunc urna. Massa aenean sed ipsum praesent enim. Porttitor iaculis augue pulvinar nam feugiat. Aliquam morbi ut ultricies elementum adipiscing purus proin semper. Viverra accumsan tempus, vitae auctor a. Dictumst cras dui sit feugiat. Enim nulla pulvinar urna sit eu placerat.

Nascetur nisi, tortor velit et ipsum commodo. Tempor massa, non suscipit at sagittis morbi eget euismod.

Since their introduction >2 decades ago, percutaneous catheter-based epicardial mapping and ablation have become widely adopted by cardiac electrophysiologists around the world. Although epicardial mapping has been used for catheter ablation of a wide variety of cardiac arrhythmias, its most common use is for ablation of intramural and subepicardial substrates that give rise to ventricular tachycardia, particularly in patients with nonischemic cardiomyopathy. As such, the subxiphoid percutaneous epicardial approach has emerged as an important adjunct, and, in some cases, is the preferred strategy in this regard. This review discusses the rationale and indications for epicardial catheter mapping and/or ablation. This paper also reviews the prevalence of epicardial arrhythmias and their electrocardiographic criteria. In addition, it examines the anatomy of the pericardium and commonly used epicardial access techniques, as well as the optimal methodologies for epicardial mapping and ablation and the impact of epicardial fat. Finally, this review discusses the potential of the various complications associated with the percutaneous epicardial approach, in addition to patient-specific risk factors, and potential strategies to mitigate the risk of complications.