Can EnSite Nav X Accurately Raise Suspicion of Anomalous Systemic Venous Connections?

DOI: 10.19102/icrm.2014.050205

M. SANTIAGO RESTREPO, MD, ABHAY DIVEKAR, MBBS, MD and IAN LAW, MD, FHRS

Division of Pediatric Cardiology, Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, IA, USA

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KEYWORDS. 3D cardiac mapping, anatomical chamber geometry, invasive electrophysiology studies.

The authors report no conflicts of interest for the published content.
Manuscript received October 26, 2013, final version accepted December 1, 2013.

Address correspondence to: Ian H. Law, MD, FHRS 200 Hawkins Drive, 2801 JPP Iowa City, IA 52242.
E-mail: ian-law@uiowa.edu

Introduction

Placement of intracardiac catheters during invasive electrophysiology procedures usually follows a predictable course in structurally normal hearts. EnSite NavX is a new and rapidly evolving technology that allows accurate non-fluoroscopic anatomical and electrical three-dimensional (3D) cardiac mapping^1,2. This technology uses real-time 3D catheter localization and navigation with an externally applied transthoracic electrical field in three orthogonal directions using the principle of triangulation, allowing creation and display of accurate anatomical chamber geometry.

Methods

Two patients underwent invasive electrophysiology studies (EP) for ablation of supraventricular tachycardia. The procedures were performed in the usual fashion with the use of non-fluoroscopic EnSite NavX cardiac mapping technology (St. Jude Medical, Inc. St. Paul, MN) according to institutional protocols. Anatomic variations were suspected and confirmed by traditional methods.

Results

The first patient underwent catheter placement without difficulty. The coronary sinus could not be entered, raising a strong suspicion for atresia of the coronary sinus os, a rare congenital anomaly. Angiography demonstrated atresia of the coronary sinus os and drainage via decompressing cardiac veins to the right atrium and through the persistent left superior vena cava to the innominate vein (Figures 1 and 2).

Figure 1: Three-dimensional geometry of the right atrium. Purple dots delineate the coronary sinus pouch; the red and green dots represent ablations sites.

Figure 2: Angiography showing atresia of the coronary sinus os with drainage via decompressing cardiac veins to the right atrium and a persistent left superior vena cava to the innominate vein.

In the second patient the catheters were easily placed; however, the superior vena cava (SVC) could not be entered and there was an unusually prominent coronary sinus, raising suspicion for congenital absence of the right-sided SVC. Angiography confirmed congenital absence of the right SVC and drainage through a persistent left SVC to the coronary sinus (Figures 3 and 4).

Figure 3: Three-dimensional geometry of the right atrium showing the position of the coronary sinus catheter in a dilated coronary sinus and the high right atrial (HRA) catheter in a blind ending pouch.

Figure 4: Angiography showing absent right superior vena cava (SVC) and a single left SVC draining to the coronary sinus.

Conclusions

Based on these findings, we believe experienced operators should feel confident that the created 3D geometry accurately reflects the underlying anatomy; even complex and rare structural abnormalities can be accurately diagnosed. Hopefully similar technologies can be developed to aid in navigating diagnostic and interventional catheters, thereby decreasing radiation exposure.

References

Tuzcu V. A non-fluoroscopic approach for electrophysiology and catheter ablation procedures using a three-dimensional navigation system. Pacing Clin Electrophysiol 2007; 30:519–525. [CrossRef] [PubMed]
Smith G, Clark JM. Elimination of fluoroscopy use in a pediatric electrophysiology laboratory utilizing three-dimensional mapping. Pacing Clin Electrophysiol 2007; 30:510–518. [CrossRef] [PubMed]