Visualization of elusive structures using intracardiac echocardiography: insights from electrophysiology

Abstract

Electrophysiological mapping and ablation techniques are increasingly used to diagnose and treat many types of supraventricular and ventricular tachycardias. These procedures require an intimate knowledge of intracardiac anatomy and their use has led to a renewed interest in visualization of specific structures. This has required collaborative efforts from imaging as well as electrophysiology experts. Classical imaging techniques may be unable to visualize structures involved in arrhythmia mechanisms and therapy. Novel methods, such as intracardiac echocardiography and three-dimensional echocardiography, have been refined and these technological improvements have opened new perspectives for more effective and accurate imaging during electrophysiology procedures. Concurrently, visualization of these structures noticeably improved our ability to identify intracardiac structures. The aim of this review is to provide electrophysiologists with an overview of recent insights into the structure of the heart obtained with intracardiac echocardiography and to indicate to the echo-specialist which structures are potentially important for the electrophysiologist.

Figure 1

Typical appearance of the interatrial septum with the fossa ovalis recorded by a mechanical intracardiac echo-transducer providing horizontal cross-sectional images.

Figure 2

Three-dimensional echocardiographic "en face" view of the ostium of coronary sinus.

Figure 3

The Thebesian valve guarding the ostium of the coronary sinus. The image was obtained with a 9 MHz rotating mechanical transducer. The Eustachian ridge is very prominent in this patient.

Figure 4

Eustachian valve recorded by a phased array steerable intracardiac ultrasound transducer.

Figure 5

The tendon of Todaro reconstructed form a three-dimensional data-set.

Figure 6

Image showing the bottom of Koch's triangle with an ablation lesion in the area of slow pathway as visualized by echo-contrast infusion.

Figure 7

The crista terminalis.

Figure 8

Image of the cavo-tricuspid isthmus in a patient who underwent ablation of typical atrial flutter.

Figure 9

Visualization of the pulmonary veins from the right atrium using a 5 MHz phased array intracardiac echocardiography transducer.

Figure 10

LV outflow tract visualized using a 9 Mhz rotating transducer place at the level of the tip of Koch's triangle.