3D IMAGING TO GUIDE ABLATIONS

Case presented by:

BRIAN D. POWELL, MD AND DOUGLAS L. PACKER, MD

A 57-year-old female presented with paroxysmal atrial fibrillation (AF). She reported palpitations, fatigue, and dyspnea occurring twice a week and lasting between 30 minutes and 12 hours. Symptoms continued in spite of treatment with propafenone. She has a past history of hypertension and mild left atrial enlargement. She has elected to undergo pulmonary vein (PV) isolation ablation.

Question No. 1: Compared to performing an AF ablation guided by standard fluoroscopy alone, the addition of three-dimensional (3D) imaging has been shown to have which of the following benefits?

A.Increased achievement of PV entrance block.

B.Decreased recurrence of AF at 1-year follow-up.

C.Decreased radiation exposure to the patient.

D.Decreased procedure cost.

Discussion

Various imaging modalities have been used to guide ablation procedures. Technology has rapidly progressed from two-dimensional (2D) fluoroscopic imaging to several different forms of 3D mapping systems using magnetic and impedance sensors, as well as automated imaging components derived from computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound and rotational angiography. These have provided greater anatomic detail for accurate ablation. However, ablation outcomes rely not only on image-guided proper lesion location, but also adequate catheter contact, power, duration of energy delivery and overall ablation strategy.

CT and MRI provide detailed 3D geometries of the chambers of the heart. Carto^® (Biosense Webster Inc., Diamond Bar, CA) and EnSite NavX^™ (St. Jude Medical Inc., St. Paul, MN) mapping systems have the capability for integration of 3D CT and MRI images with electroanatomic maps. More recently, 3D rotational angiography can be used as an alternative to CT or MRI for image integration. Image registration is typically done by matching distinct landmarks or fiducial points on the electroanatomic map with the CT (or MRI) image. The registration process can be optimized by manual adjustment, or using a more global surface registration algorithm. The integrated image has an average accuracy of 1 to 3 mm. However, individual points can be inaccurate by more than 10 to 15 mm.¹

Stay updated, free articles. Join our Telegram channel

Join