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Chapter 88: Catheter-Ablative Techniques

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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?

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A. Right atrium and left atrium

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B. Atria and ventricles

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C. Right ventricle and left ventricle

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D. Medial and lateral cardiac silhouette

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E. Septal and free wall

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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).

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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?

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A. Entrainment mapping

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B. Substrate mapping

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C. Activation mapping

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D. Pace mapping

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E. Fluoroscopic mapping

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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 ...

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