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STATE-OF-THE-ART REVIEW

Fluoroscopic Anatomy of Left-Sided HeartStructures for Transcatheter InterventionsInsight From Multislice Computed Tomography

Pascal Thériault-Lauzier, PHD,* Ali Andalib, MD,* Giuseppe Martucci, MD,* Darren Mylotte, MD,* Renzo Cecere, MD,yRüediger Lange, MD, PHD,z Didier Tchétché, MD,x Thomas Modine, MD, PHD,k Nicolas van Mieghem, MD,{Stephan Windecker, MD,# Jean Buithieu, MD,* Nicolo Piazza, MD, PHD*z

ABSTRACT

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With the introduction of transcatheter structural heart therapies, cardiologists are increasingly aware of the importance

of understanding anatomical details of left-sided heart structures. Understanding fluoroscopic cardiac anatomy can

facilitate optimal positioning and deployment of prostheses during transcatheter valve repair/replacement, left atrial

appendage occlusion, septal defect closure, and paravalvular leak closure. It is possible to use multislice computed to-

mography to determine optimal fluoroscopic viewing angles for such transcatheter therapies. The purpose of this paper is

to describe how optimal fluoroscopic viewing angles of left-sided heart structures can be obtained using computed

tomography. Two- and 3-chamber views are described and may become standard in the context of transcatheter

structural heart interventions. (J Am Coll Cardiol Intv 2014;7:947–57) © 2014 by the American College of Cardiology

Foundation.

S ince the introduction of transcatheter struc-tural heart therapies, cardiologists havebecome increasingly aware of the importance

of understanding anatomical details of left-sided car-diac structures (1). Many critical anatomical struc-tures comprise several components and are arrangedin a complex tridimensional geometry. Even thoughthese anatomical and functional components havebeen the topic of numerous publications (1,2), littleconsideration has been given to understanding theirconfiguration as appreciated under fluoroscopy (3).Understanding fluoroscopic cardiac anatomy canfacilitate optimal positioning and deployment of

m the *Department of Medicine, Division of Cardiology, McGill Univ

epartment of Surgery, Division of Cardiovascular Surgery, McGill Uni

epartment of Cardiovascular Surgery, German Heart Centre Munich, Mun

gy, Clinique Pasteur, Toulouse, France; kDepartment of Cardiovascular

epartment of Cardiology, Thoraxcentre, Erasmus Medical Centre, Rott

erventional Cardiology, University Hospital, Bern, Switzerland. Dr. Mart

sulting and lecture fees from Medtronic. Dr. Modine receives consultin

sulting fees from Medtronic and Boston Scientific. Dr. Windecker has rece

Jude Medical; and serves on the scientific advisory board of Cardialysis B

s from Medtronic. All other authors have reported that they have no rel

close.

nuscript received March 12, 2014; revised manuscript received May 2, 20

prostheses during transcatheter valve repair/replace-ment, left atrial appendage occlusion, septal defectclosure, and paravalvular leak closure. Commonly,these therapies are conducted using standard fluoro-scopic angulations irrespective of variations in anat-omy. It is possible that patient-specific fluoroscopicviewing angles can improve procedural safety andefficacy.

Multislice computed tomography (MSCT) multi-planar reconstruction of the aortic valvular complexhas enhanced patient selection and proceduralplanning for transcatheter aortic valve replacement(4). For example, MSCT affords physicians the

ersity Health Centre, Montreal, Quebec, Canada;

versity Health Centre, Montreal, Quebec, Canada;

ich, Germany; xDepartment of Interventional Cardi-

Surgery, University Hospital of Lille, Lille, France;

erdam, the Netherlands; and the #Department of

ucci is a proctor for Medtronic. Dr. Lange receives

g fees from Medtronic. Dr. van Mieghem receives

ived institutional research grants from Biotronik and

V. Dr. Piazza is a proctor for and receives consulting

ationships relevant to the contents of this paper to

14, accepted June 4, 2014.

FIGUR

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angles

ABBR EV I A T I ON S

AND ACRONYMS

CAU = caudal

CRA = cranial

LAO = left-anterior oblique

MSCT = multislice computed

tomography

RAO = right-anterior oblique

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opportunity to pre-select optimal x-ray fluo-roscopic viewing angles for deployment ofthe valve prosthesis (5–15). Such angle opti-mization may decrease procedure time, ra-diation exposure, and injected contrast agentvolume (15). It may reduce the risk of acutekidney injury (15) and paravalvular regurgi-tation (14). MSCT can also be used to deter-mine optimal fluoroscopic viewing angles for

transcatheter therapies targeting the mitral valvularcomplex, the left atrial appendage, the pulmonaryveins, and the atrial septum.

Therefore, the purpose of this paper is to describehow optimal fluoroscopic viewing angles of left-sidedheart structures can be obtained using computed to-mography (CT). We describe 2- and 3-chamber viewsthat may become standard in the context of left-sidedstructural heart interventions.

ATTITUDINAL DESCRIPTION OF ANATOMY

In our discussion, structures will be termed accordingto their attitudinally correct anatomical position (16).

E 1 Geometry of the Optimal Projection Curve

ctor joining the x-ray source and the center point of the detector is d

B) The angular system (cranial [CRA]/caudal [CAU] and right anterio

ribed. (C) All vectors vd perpendicular to vector vs are optimal view

of all vectors vd for a particular structure of interest. (D) The optim

This implies that the subject is facing the observer andstanding upright. Thus, structures closer to theobserver are described as being anterior and thoserelatively farther away within the body are posterior.Components lying closer to the head are superior(i.e., cranial [CRA]) and those toward the feet are saidto be inferior (i.e., caudal [CAU]). Structures to theleft-hand side of the observer are right-sided andthose to the observer’s right are left-sided. Discussingheart structures in their attitudinal position is in per-fect agreement with nomenclatures used for CT andx-ray fluoroscopic imaging; this is not necessarily truewith echocardiography. The fluoroscopic screen por-trays the thorax in an upright orientation despite thepatient being in a supine position. Superior and infe-rior structures are appreciated in the upper and lowerhalves of the screen. The direction of fluoroscopicprojections is described based on 2 conventional an-gles, CRA/CAU and left anterior oblique (LAO)/rightanterior oblique (RAO) (Figures 1A and 1B). In theanteroposterior viewing angle (CRA/CAU 0�, LAO/RAO0�), right- and left-sided structures are found on theleft and right sides of the screen, respectively.

esignated vd, and the vector pointing along a structure of interest is vs.

r oblique [RAO]/left anterior oblique [LAO] angles) used influoroscopy

ing angles. The optimal projection curve is the plot of the fluoroscopic

al projection curve is shown for different cardiac structures.

FIGURE 2 Aortic Valve Sinuses

Multislice computed tomography (MSCT) double-oblique reslices are shown parallel to the aortic annulus at the level of the aortic sinus (A), just

above the aortic annulus (B), and at the annulus (C). The eye symbols describe the position of the x-ray detector in the corresponding

fluoroscopic view: blue corresponds to F and red to G. (D) The MSCT reslice is in the same orientation as the fluoroscopic view in F and shows

the right coronary aortic sinus (RCAS) between the noncoronary aortic sinus (NCAS) and left coronary aortic sinus (LCAS). (E) The MSCT reslice

is in the same orientation as the fluoroscopic view in G and shows the NCAS between RCAS and LCAS. The fluoroscopic angulations are indicated

in the figures. AR ¼ anterior-right; IL ¼ inferior-left; IR ¼ inferior-right; LA ¼ left-anterior; PL ¼ posterior-left; RP ¼ right-posterior; SL ¼superior-left; SR ¼ superior-right; other abbreviations as in Figure 1.

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FLUOROSCOPIC ANATOMY USING MSCT

Fluoroscopy is used to guide the vast majority oftranscatheter cardiac procedures. Inherently, it is a2-dimensional imaging modality that requires theuser to select a viewing angle that provides accurateinformation on device positioning. For a particularstructure, an optimal viewing angle should minimizepositioning errors due to parallax. The goal of manytranscatheter procedures—such as valve implanta-tions, left-atrial appendage occlusions, septal defectclosures, and paravalvular leak occlusions—is toimplant a quasicylindrical device inside a highlyvariable anatomical structure. The fluoroscopic pro-jection that minimizes parallax during deploymentis such that the source-to-detector direction isorthogonal to the axis of symmetry of the anatomicalfeature of interest (Figure 1C). Based on this criterion,it is possible to determine an optimal CRA/CAU anglefor any given LAO/RAO angle. The plot of theoptimal combinations is called the optimal projection

curve (7,8,10–12,15). MSCT is a 3-dimensional imag-ing modality that is not affected by parallax. MSCTimages can be used to define the direction of struc-tures and produce an optimal projection curve(Figure 1D).

In addition to parallax errors, optimal viewangles should also minimize the overlap of anatomicstructures, a problem that also stems from the2-dimensional nature of fluoroscopy. In the contextof transcatheter interventions, some cardiac struc-tures must be distinguished in order to accuratelyimplant devices. The overlap of a highly attenuatinganatomical structure with the region of implantationmay reduce the contrast-to-noise ratio and com-promise visualization. Therefore, it is crucial to un-derstand which fluoroscopic angulations providemaximal separation between structures of interest.This understanding can be obtained from MSCTangiography, which depicts cardiac structures withrelatively high soft-tissue contrast, as well as hightemporal and spatial resolution.

FIGURE 3 Aortic Annulus

(A) The MSCT double-oblique reslice is at the level of the aortic annulus. The 2 eye symbols describe the position of the x-ray detector

in the corresponding fluoroscopic view: blue corresponds to B and red to E. (B) The MSCT reslice is in the same orientation as the

fluoroscopic view in C and shows the maximal annulus diameter (DMAX) in plane. (D) The MSCT reslice is in the same orientation as the view

in E and shows the minimal annulus diameter (DMIN) in plane. The fluoroscopic angulations are indicated in the figures. Abbreviations as

in Figures 1 and 2.

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Fluoroscopy and MSCT share a common imagecontrast mechanism: x-ray attenuation. Conse-quently, it is possible to use MSCT volumetric data tosimulate fluoroscopic images. A ray-casting methodbased on this principle was used to generate thefluoroscopic images presented in this paper. Todemonstrate how MSCT may provide optimal fluo-roscopic viewing angles for left-sided heart struc-tures, we used an MSCT scan from a 66-year-oldmale patient with moderate functional mitralregurgitation. It is important to note that fluoro-scopic angulations are dependent on the specificorientation of the heart within the thorax, a param-eter that may vary considerably between patients(7,8,10–12,15). Although we describe general angula-tions, exact angulations may be determined for aspecific patient prior to an intervention. Measure-ment of fluoroscopic angulation from MSCT data canbe done with visualization software packages thatoffer double-oblique multiplanar reconstruction; theexact CRA/CAU and RAO/LAO angulations for aparticular structure can be obtained by analyzing theoblique sagittal and oblique transverse views,respectively.

AORTIC ROOT, VALVE, AND

LEFT VENTRICULAR OUTFLOW TRACT

The aortic root extends from the basal attachmentpoints of the aortic valve leaflets to their superiorattachment at the level of the sinotubular junction(17). The 3 leaflets form the limits of the right, left,and noncoronary aortic sinuses. Optimal fluoroscopicviews of the aortic root can be selected such that theview is perpendicular to the plane of the aorticannulus (Figures 2A to 2C). During transcatheter aorticvalve replacements, physicians often select a viewthat shows the right coronary sinus between thenoncoronary and left coronary sinuses (Figures 2Dand 2F). In the current patient, this view is obtainedusing a mild LAO and mild CAU angulation. Alterna-tively, a view with the noncoronary or left coronarysinus in the central position can also be obtained(Figures 2E and 2G). In this case, an LAO and CRAangulation is selected.

The aortic valve annulus is defined as the planarring of tissue that unites the most proximal point ofeach leaflet attachment line. The annulus is rarelycircular (18). Rather, it has a long and a short axis that

FIGURE 4 Mitral Valve Leaflets

(A) The MSCT double-oblique reslice is parallel to the mitral annulus best-fit plane and intersects the leaflets of the valve. The 2 eye symbols

describe the position of the x-ray detector in the corresponding fluoroscopic view: blue corresponds to C and red to F. (B) The MSCT reslice is in

the same orientation as the fluoroscopic view in C, which shows the aortic (A) and mural (P) leaflets without overlap. This view results in an

overlap of the 3 segments (1,2,3). The MSCT reslices show the mural (D) and aortic (E) leaflets, respectively. D and E are in the same orientation

as the fluoroscopic view in F, which shows the leaflet segments (1,2,3) without overlap, but results in an overlap of the A and P leaflets. The

fluoroscopic angulations are indicated in the figures. Abbreviations as in Figures 1 and 2.

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can be appreciated using MSCT (19). Under fluoros-copy, the aortic annulus’s apparent diameter variesdepending on the view angle (Figure 3A). In the cur-rent patient, a mild LAO projection with minimalCRA/CAU angulation provides a view of the maximumdiameter (Figures 3B and 3D), whereas an extremeRAO and CAU view shows the minimum diameter(Figures 3C and 3E).

MITRAL VALVE

The mitral valve has 2 major leaflets commonlydescribed as being anterior and posterior. Relative tothe anatomical axes of the body, however, the leafletsare in an anterosuperior and posteroinferior orienta-tion. For simplicity, we describe these leaflets asaortic and mural, respectively. The Carpentier clas-sification recognizes 3 scallops in the mural leaflet(P1 to P3) and 3 corresponding segments in the aorticleaflet (A1 to A3) (20). A1P1 and A3P3 segments arelocated superoposterior and inferoanterior, respec-tively, with respect to A2P2 (Figure 4A). Emergingtranscatheter interventions require the positioning

of the delivery catheter in a precise position relativeto each leaflet and each segment. Understanding theleaflet configuration under fluoroscopy may easethis process. In the patient studied, an extreme RAOand CAU view can be used to maximally separate themural and aortic leaflets of the mitral valve(Figures 4B and 4C). In this view, however, the aorticsegments A1,2,3 overlap one another; such an overlapalso exists for mural segments P1,2,3. To separate theleaflet segment (1,2,3), we use an RAO and CRA pro-jection. In this view, mural and aortic leaflets overlapsuch that A1 overlaps P1, A2 overlaps P2, and A3

overlaps P3 (Figures 4D to 4F).The fibrous ring of the mitral valve annulus ex-

tends from the right and left trigones and encirclesthe mural leaflet of the mitral valve. The area offibrous continuity between trigones is commonlyreferred to as the aortic-mitral curtain (Figure 5A).Some designs of transcatheter mitral valve replace-ment devices are not axially symmetric and must bepositioned at a particular angle relative to themitral commissure. In the patient studied, the inter-commissural diameter of the mitral annulus, which

FIGURE 5 Mitral Valve Annulus

(A) The MSCT double-oblique reslice in is parallel to the mitral annulus best-fit plane. The 2 eye symbols describe the position of the x-ray

detector in the corresponding fluoroscopic view: red corresponds to C and blue to E. (B) The MSCT reslice is in the same orientation as the

fluoroscopic view in C, which shows the intercommissural diameter (DCC) of the mitral valve annulus and the right and left trigones maximally

separated. The MSCT reslice in B is in the same orientation as the view in C, which shows the aortomural diameter (DAM) of the annulus,

overlapping right (RTr) and left (LTr) trigones, and the aortic-mitral curtain (AMC) fully separated from the root of the aorta. The fluoroscopic

angulations are indicated in the figures. Abbreviations as in Figures 1 and 2.

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is often the maximum diameter of the annulus, canbe appreciated using a mild RAO and CRA angu-lation (Figure 5B). This angulation is analogous to anechocardiographic 2-chamber view. Also in the pa-tient studied, an extreme RAO and CAU viewshows the aortomural diameter of the mitralannulus—often considered to be the minimumdiameter of the annulus (Figure 5C). This view isanalogous to a 3-chamber echocardiographic view.The aortic-mitral curtain is observed perpendicularlyand clearly separated from the left atrium and theaortic root. This view may be of particular interest tothose implanting transcatheter mitral valve bio-prostheses. Indeed, it can be used to assess theinteraction of the prosthesis with the left ventricularoutflow tract and could potentially reveal anobstruction or a deformation of the aortic-mitralcurtain.

PAPILLARY MUSCLES

Two papillary muscle divisions arise adjacent toeach other within the left ventricular cavity. Using

attitudinal description, it is illogical to describe thesedivisions as being either posteromedial or antero-lateral (16); in the vast majority of cases, the papillarymuscles lie in the posterior one-half of the left ven-tricular cavity and are relatively inferoanterior andposterosuperior to each other (Figure 6A).

The exact number, positioning, morphology, andthickness of papillary muscles can vary considerably(21). They are considered to be potential obstaclesto the deployment of transcatheter devices that pro-trude into the left ventricle such as mitral valveprostheses or ventricular septal defect closure de-vices. Therefore, it is important to understand theirconfiguration as observed under fluoroscopy. In thesubject studied, the papillary muscle divisions can bemaximally separated in a mild CRA projection withor without mild left or right angulation (Figures 6Band 6C) (2-chamber view). An extreme RAO and CAUprojection creates an overlap between the papillarymuscles (Figures 6D to 6F) (3-chamber view). Themural attachment of the papillary muscles is dia-metrically opposed to the anteriorly located leftventricular outflow tract.

FIGURE 6 Papillary Muscles

(A) The MSCT double-oblique reslice cuts through the longitudinal axis of the left ventricle. The 2 eye symbols describe the position of the

x-ray detector in the corresponding fluoroscopic view: red corresponds to C and blue to F. (B) The MSCT reslice is in the same orientation as the

fluoroscopic view in C, which shows a maximal separation between the superoposterior papillary muscles (SPPM) and the inferoanterior

papillary muscles (IAPM). The MSCT reslices show the SPPM (D) and IAPM (E), respectively. D and E are in the same orientation as the

fluoroscopic view in F, which shows an overlap between the SPPM and the IAPM. The fluoroscopic angulations are indicated in the figures.

Abbreviations as in Figures 1 and 2.

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LEFT ATRIAL APPENDAGE

The left atrial appendage is a contractile extension ofthe left atrium that lies in its anterior, superior, andleft aspect. It varies considerably in shape and size, aswell as in the number of lobes formed within itslumen (22). The orifice of the left atrial appendage isoval (Figure 7A) and opens in the left atrium adjacentto and at an oblique angle with the mitral valveannulus (23). Transcatheter left atrial appendageclosure devices are deployed in the orifice of theappendage to prevent thrombus formation in patientswith atrial fibrillation. Some physicians size thesedevices based on fluoroscopic images acquired instandard angulations such as CRA 25� and RAO 25�. Inthe subject studied, the orifice of the appendage isappreciated en face in a highly LAO and CRA fluoro-scopic projection (Figures 7B and 7C). The minimumdiameter of the appendage orifice is appreciated in anRAO and mild cranial fluoroscopic view (Figures 7Dto 7F). This angulation can also be used to visualizethe ridge of tissue that separates the left atrialappendage orifice from the left superior pulmonaryvein ostium. The long diameter of the appendage

orifice can be appreciated in an LAO and CAU pro-jection (Figures 7G to 7I). This angulation results in anoverlap of the proximal segment of the left superiorpulmonary vein with the left atrial appendage.

ATRIAL SEPTUM

The atrial septum is a tissue partition betweenthe right and left atria. In a majority of patients, theperiphery of the septum is constantly thick andbecomes thin toward its center at the fossa ovalis,the embryologic remnant of the foramen ovale(24). In normal individuals, the septum is orientedobliquely with the right atrium lying anterior, right,and inferior to the left atrium (25) (Figure 8A). Theaortic root lies left and anterior to the atrial septum.In many procedures, a transseptal puncture is used togain access to the left atrium from the right atrium.An RAO view shows the septum with minimal overlapwith the aortic root. Having said this, a standardCRA/CAU 0� RAO 30� view is often used to confirmthat the puncture needle is positioned over theseptum and not the aortic root. In the subject studied,CRA/CAU 0� RAO 35� achieves minimal overlap

FIGURE 7 Left Atrial Appendage

(A and B) The MSCT double-oblique reslices are in the same orientation as the fluoroscopic view in C, which shows the left atrial

appendage (LAA) orifice en face and its proximity to the left superior pulmonary vein (LSPV). (D and E) The MSCT reslices are in the same

orientation as the view in F, which shows DMIN and maximally separates the appendage and the LSPV. (G and H) The MSCT reslices

are in the same orientation as the view in I, which shows DMAX and an overlap between the LAA and the LSPV. The eye symbols describe

the position of the x-ray detector in the corresponding fluoroscopic view: blue corresponds to C, red to F, and green to I. The fluoroscopic

angulations are indicated in the figures. IPR ¼ inferior-posterior-right; LA ¼ left atrium; SAL ¼ superior-anterior-left; other abbreviations

as in Figures 1 to 3.

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(Figures 8G to 8I). An RAO and CAU angulation isselected to view the septum en face (Figures 8Band 8C). A puncture needle would point toward theimage in this angulation. In an LAO view (Figures 8Dto 8F), the septum is seen perpendicularly but over-laps the aortic root. In this view angle, the curvatureof a puncture needle would appear maximal becauseit would point directly to the right of the image.

DISCUSSION

The spatial configuration of cardiac anatomy asdepicted using fluoroscopy is difficult to understand.In effect, physicians often rely on pattern recognitionrather than tridimensional mental visualization

when performing image-guided interventions. Fluo-roscopic cardiac anatomy has been previouslydescribed in the context of electrophysiological in-terventions (26–28). This paper also describes fluo-roscopic cardiac anatomy, but it focuses on anatomyrelevant for structural heart interventions. This topichas not previously been covered in a systematicfashion.

As noted throughout the paper, several fluoro-scopic views may be particularly relevant for trans-catheter therapies. Among the different projectionsdescribed, 2 angulations are particularly noteworthy:1) the extreme RAO and CAU view, which we call3-chamber view; and 2) the mild RAO and CRA view,which we refer to as 2-chamber view. Figure 9

FIGURE 8 Atrial Septum

(A) The MSCT axial slice simultaneously cuts through the left ventricle (LV), left atrium (LA), right ventricle (RV), and right atrium (RA). It also

shows a cut through the atrial septum (AS). (B) The MSCT double oblique slice is in the same orientation as the fluoroscopic view in C and shows

the AS en face. (D, E, G, H) The MSCT slices show the relationship of the AS with the ascending aorta (Ao), superior vena cava (SVC), and the

inferior vena cava (IVC). (F) The view is in the same orientation as D and E and shows the overlap of the Ao and the SVC. (I) The view is in the

same orientation as G and H and shows that AS is posterior with respect to the aortic root (AR). The eye symbols describe the position of the

x-ray detector in the corresponding fluoroscopic view: blue corresponds to C, red to F, and green to I. The fluoroscopic angulations are

indicated in the figures. C/C ¼ cranial/caudal; other abbreviations as in Figures 1 and 2.

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summarizes the anatomical structures that can bevisualized in these 2 fluoroscopic views. We believethat these 2 angulations may become a standardin the context of left-sided structural heart in-terventions, and in particular, transcatheter mitralvalve therapies.STUDY LIMITATIONS. In particular, a single MSCTscan in diastole was used, which explains why onlyapproximate angulations were described. Normalanatomical variations as well as pathological statescan have a strong influence on optimal viewing angles.In particular, ventricular hypertrophy, ventricular oratrial dilation, pulmonary hyperinflation, pulmonaryobstructive disease, obesity, and changes associated

with aging are among potential factors influencingfluoroscopic angulations. Furthermore, the use of apre-operative MSCT scan may not accurately reflectthe spatial position of anatomical structures once inthe catheterization laboratory. Respiratory motionmay affect the orientation of the heart. The patient’sarm position also differs between the 2 procedures;the arms are generally placed overhead duringMSCT scanning, whereas they are placed along thebody during the intervention. New technology suchas intraoperative C-arm cone-beam CT, also knownas rotational angiography, might alleviate theselimitations. Furthermore, tridimensional renderingsmay be overlaid over planar fluoroscopic images to

FIGURE 9 Standard Viewing Angles

Summary of anatomic structures as visualized under fluoroscopy in 2-chamber view (A) and 3-chamber view (B). Abbreviations as in Figure 4.

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visualize the anatomy of structures targeted by trans-catheter therapies. In the future, the conceptof CT-based fluoroscopic viewing angles can be appliedto images obtained using these new technologies.

CONCLUSIONS

Herein we present a review of the fluoroscopic anat-omy of left-sided heart structures relevant for trans-catheter therapies. Optimal fluoroscopic angulations,which minimize parallax or overlap with other

clinically relevant structures, were described for theaortic valve, the mitral valve, papillary muscles, andthe atrial septum.

REPRINT REQUESTS AND CORRESPONDENCE: Dr.Nicolo Piazza, Division of Cardiology, Departmentof Medicine, McGill University Health Centre, TheRoyal Victoria Hospital, 687 Pine Avenue West, Mon-treal, Quebec H3A 1A1, Canada. E-mail: nicolopiazza@mac.com.

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KEY WORDS cardiac imaging, fluoroscopicanatomy, interventional imaging, multislicecomputed tomography, transcatheter cardiacintervention