Intracardiac echocardiography-guided transcatheter closure of secundum atrial septal defect
A new efficient device selection method
Mario Zanchetta, MD*,*,
Eustaquio Onorato, MD ,
Gianluca Rigatelli, MD*,
Luigi Pedon, MD*,
Marco Zennaro, MD*,
Antonio Carrozza, MD* and
Pietro Maiolino, MD*
* Department of Cardiovascular Disease, Cittadella General Hospital, Via Riva Ospedale, Padua, Italy
Division of Cardiology, Humanitas Gavazzeni, Bergamo, Italy
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Figure 1 Geometry of an ellipse. In our example here, the ellipse is longer in the horizontal direction: this length is called the major axis and the up-and-down width is called the minor axis. Two distinct fixed points can be identified on the major axis, called foci and marked F and F', the sum of whose distances from each point on the ellipse is constant. The distance across the ellipse at the focal point is called the latus rectum. The semi-major axis is labeled a, the semi-minor axis b, the half-focal distance c, and the semi-latus rectum p.
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Figure 2 Conceptual circle that best fits an ellipse. An ellipse (red line) can be constructed by drawing two concentric circles (black lines): the radius of the inscribed circle defines the semi-minor axis (b), whereas the radius of the circumscribed circle defines the semi-major axis (a). From c and p values, the radius (r) of the circle that intersects the ellipse in its semi-latus rectum (blue line) can be computed.
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Figure 3 Transverse section on the aortic valve plane (A), and longitudinal section on the four-chamber plane (B) in a patient with secundum atrial septal defect (ASD). The major and minor axes of the fossa ovalis can be accurately evaluated by intracardiac echocardiography (ICE): a = 9.8 mm and b = 9.3 mm. The r value is computed as follows: c = 9.82 – 9.32 = 3.090 mm, p = 
= 8.825 mm, r = 3.0902 + 8.8252 = 9.35 mm, where c is the foci half-distance, p is the semi-latus rectum distance, and r is the estimated radius of the ICE-derived Amplatzer Septal Occluder (ASO). In this case, we implanted a 19-mm ASO. AoD = descending aorta; LA = left atrium; MV = mitral valve; RA = right atrium; RUPV = right upper pulmonary vein; TV = tricuspid valve.
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Figure 4 Longitudinal section on the four-chamber plane of an implanted ASO. Note how both disks are clearly visible, thanks to the optimal echogenicity and the characteristic "multiple ray" pattern of the prosthesis. The released device acquires a flat shape and covers the entire fossa ovalis. Abbreviations as in Figure 1.
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