Chapter 88: Catheter-Ablative Techniques
During the introduction of diagnostic catheters into the coronary sinus, right ventricle, and His regions, a right anterior oblique (RAO) fluoroscopy view is used. Which of the following cardiac structures can be differentiated with an RAO view?
A. Right atrium and left atrium
C. Right ventricle and left ventricle
D. Medial and lateral cardiac silhouette
The answer is B. (Hurst’s The Heart, 14th Edition, Chap. 88) Fluoroscopy provides a two-dimensional projection of the cardiac anatomy and catheter orientation, yet it is operator dependent, using either a single plane of view or two orthogonal views to create a three-dimensional location of catheters. The right anterior oblique (RAO) and the left anterior oblique (LAO) are common views. The RAO is a profile view of the heart. This differentiates the atrial and the ventricular components (option B); however, there is overlap of the left- and right-sided structures. The LAO view is an end-on view from the apex to base with foreshortening of the long axis of the heart. The LAO projection facilitates differentiating the left from the right side chambers (options A and C), the left and right heart borders (option D), and the septal from the free wall aspect within a chamber (option E).
A 65-year-old woman is undergoing an electrophysiology study and ablation for atrial tachycardia. During the tachycardia, a map of the right atrium is created through the annotation of the local activation time (electrogram) compared to a fixed reference point (eg, the proximal coronary sinus catheter). What is this type of mapping called?
The answer is C. (Hurst’s The Heart, 14th Edition, Chap. 88) Cardiac mapping is performed with the acquisition of data during an arrhythmia; it can be achieved in a point-by-point manner or by the use of multielectrode mapping of multiple points simultaneously.1 In activation mapping (option C), the local activation time (electrogram) can be annotated compared to a fiducial reference point (surface electrocardiogram [ECG] or fixed intracardiac electrode). Compilation of the activation times at all sites within a chamber depicts the spread of the activation wavefront. Macroreentrant arrhythmias occur as a result of continuous repetitive activation around a reentry circuit, and they are usually amenable to continuous resetting by pacing at a slightly faster mechanism and location of the ...