Perioperative Assessment of the Hemodynamic Ventriculoarterial Junction of the Aortic Root by Three-Dimensional Echocardiography.

Improved strategies in aortic valve-preserving operations appreciate the dynamic, three-dimensional complexity of the aortic root and its valve. This depends not only on detailed four-dimensional imaging of the planar dimensions of the aortic root but also on quantitative assessment of the valvar leaflets and their competency. The zones of apposition and resulting hemodynamic ventriculoarterial junction formed in diastole determine valvar competency. Current understanding and assessment of this junction is limited, often relying on intraoperative direct surgical inspection. However, this direct inspection itself is limited by evaluation in a nonhemodynamic state with limited field of view. In this review, we discuss the anatomy of the aortic root, including its hemodynamic junction. We review current echocardiographic approaches toward interrogating the incompetent aortic valve for presurgical planning. Furthermore, we introduce and standardize a complementary approach to assessing this hemodynamic ventriculoarterial junction by three-dimensional echocardiography to further personalize presurgical planning for aortic valve surgery.

Quantitative assessment of the fast pathway in atrioventricular nodal reentrant tachycardia.

BACKGROUND: Mathematical modelling has allowed calculation of the length of the slow and fast pathways in typical atrioventricular nodal reentrant tachycardia (AVNRT). The length of the slow pathway has been correlated with the measured length of the right inferior extension in human histologic specimens, but no histology data exist about the fast pathway. METHODS: In preparations of cadaveric human hearts, the AV node was identified, and the site of the fast pathway was projected according to both existing evidence and results of our electroanatomic mapping. This permitted measurement of the length of the fast pathway as a limb of the tachycardia circuit. RESULTS: Measurements of the length of the projected area of the fast pathway on histology specimens were performed in 8 hearts. The estimated length of the fast pathway was 39.6 ± 5.8 mm (range: 30.4-45.9 mm). These numbers are comparable to those produced by mathematical calculations of the length of the fast pathway. CONCLUSIONS: Typical AVNRT uses a circuit from the AV node to the septal isthmus of an average size of 5-6 cm, confined within the pyramid of Koch.

Understanding the Aortic Root Using Computed Tomographic Assessment: A Potential Pathway to Improved Customized Surgical Repair.

There is continued interest in surgical repair of both the congenitally malformed aortic valve, and the valve with acquired dysfunction. Aortic valvar repair based on a geometric approach has demonstrated improved durability and outcomes. Such an approach requires a thorough comprehension of the complex 3-dimensional anatomy of both the normal and congenitally malformed aortic root. In this review, we provide an understanding of this anatomy based on the features that can accurately be revealed by contrast-enhanced computed tomographic imaging. We highlight the complimentary role that such imaging, with multiplanar reformatting and 3-dimensional reconstructions, can play in selection of patients, and subsequent presurgical planning for valvar repair. The technique compliments other established techniques for perioperative imaging, with echocardiography maintaining its central role in assessment, and enhances direct surgical evaluation. This additive morphological and functional information holds the potential for improving selection of patients, surgical planning, subsequent surgical repair, and hopefully the subsequent outcomes.

Tripartite Assessment of Right Ventricular Systolic Function in Persistent Pulmonary Hypertension of the Newborn.

Non-invasive evaluation of right ventricular (RV) systolic function in neonates with pulmonary hypertension (PH) with traditional metrics including RV fractional area change (FAC) and tricuspid annular systolic plane excursion (TAPSE) has improved outcomes. Apical three-chamber (3C) RV-FAC, a novel tripartite assessment of the RV, has recently been described in healthy infants. We assess the utility of 3C RV-FAC and biplane RV-FAC in delayed transitioning and neonatal PH. Echocardiograms for 22 normal infants and 22 infants with PH were retrospectively analyzed for RV systolic function indices including four chamber (4C), 3C, and biplane RV-FAC, TAPSE, Tei index, and RV systolic excursion velocity (S'). 4C, 3C, and biplane RV-FAC correlated with PH severity and was decreased in neonates with PH compared to normal neonates (biplane RV-FAC 31.7 ± 13.4% vs. 41 .9 ± 4.7%, p = 0.002). TAPSE was significantly decreased in neonates with PH, but did not correlate with PH severity. Other RV systolic function metrics were not significantly different between normal neonates and neonates with PH. 3C RV-FAC and biplane RV-FAC are lower in neonates with PH. 3C and biplane RV-FAC may allow for improved assessment of global RV systolic dysfunction in newborns with delayed transitioning or PH compared to the commonly used regional methods.

Assessment of the anatomical variation to be found in the normal tricuspid valve.

The normal tricuspid valve is tri-leaflet, supported by tendinous cords, which are themselves supported by papillary muscles. There can be marked variation in the anatomy of the normal tricuspid valve, which must be understood to differentiate it from pathological malformations. The tricuspid valve of 100 normal heart specimens was examined. The three leaflets of the tricuspid valve, along with the papillary muscles supporting the zones of apposition were identified, and details of the anatomy recorded and analyzed. All three leaflets were identified in all 100 hearts. The septal leaflet had tendinous cord attachments in 93 specimens to the ventricular septum. The medial papillary muscle had a single head in the majority of specimens, supporting the zone of apposition with the antero-superior leaflet in 97 specimens. The anterior papillary muscle attached to the mid-portion of the antero-superior leaflet in 62 specimens, and supplied the zone of apposition between the antero-superior and inferior leaflets in 81 specimens. There were rough zone cord attachments to the antero-superior leaflets in all specimens. The inferior leaflet had basal cord attachments in 87 specimens, with attachments to multiple small muscular heads in 37 specimens. The inferior papillary muscle was well formed in only 58 specimens. Although certain features are relatively constant, multiple variations in the normal tricuspid valve have been identified. Knowledge of these normal variations is necessary in understanding the function of this complex valve apparatus, along with the potential for pathology.