Crista Terminalis, Musculi Pectinati, and Taenia Sagittalis: Anatomical Observations and Applied Significance

Abstract

Background. The complex architecture of the right atrium, crista terminalis (CT), and the musculi pectinati (MP) poses enormous challenges in electrophysiology and cardiac conduction. Few studies have been undertaken to substantiate the gross features of MP, in relation to the CT, but there is still scarcity of data regarding this. We tried to reinvestigate the gross arrangement of muscle bundles in the right atrium. Methods. Utilizing 151 human hearts and orientation of MP and its variations and relationship to the CT were investigated along with taenia sagittalis (TS). Patterns of MP were grouped in 6 categories and TS under three groups. Result. A plethora of variations were observed. Analysis of all the specimen revealed that 68 samples (45%) were of type 1 category and 27 (18%) fell into type 2 category. Prominent muscular columns were reported in 12 samples (8%). 83 samples (55%) presented with a single trunk of TS. Multiple trunks of TS were reported in 38 samples (25%). Conclusion. Samples with type 6 MP and type B/type C TS, which have a more complex arrangement of fibers, have a tendency to be damaged during cardiac catheterization. Nonetheless, the area as a whole is extremely significant considering the pragmatic application during various cardiac interventions.

Two‐ and three‐dimensional transthoracic echocardiographic assessment of superior vena cava, crista terminalis, and right atrial appendage using the right parasternal approach

“…9 3DTTE also provides the capability of computing RAA volumes which procedures. 13,14 The 3DTTE measurements of SVC, CT, and RAA were significantly larger than 2DTTE in both groups possibly reflecting greater accuracy since 2D echocardiography even when using multiplane 2DTEE has been previously shown to underestimate the size of cardiac defects and masses. 18 We also studied the above parameters in patients who were nor- 12,19 and by computed tomography (CT) analysis of silicon molds of RAA specimens, 20 but these were performed on nonbeating flaccid hearts and hence cannot be directly compared with in vivo measurements.…”

“…The type of TS was also determined: A (no TS), B (one TS), or C (two or more TS) 13,14. The volume of RAA was calculated off line from the 3D datasets using 4D Cardio-View 3.0 (TomTec Imaging Systems, Munich, Germany).The ejection fraction (EF) of RAA was assessed using the formula: EF = (Maximum RAA volume − minimum RAA volume) × 100/ maximum RAA volume.…”

“…SVC AP CI = (Max AP diameter − Min AP diameter)*100/Max AP diameter. A large number of trabeculations and multiple TS in RAA have been correlated with an increased risk of thrombus formation, atrial arrhythmias as well as perforation during ablation procedures 13,14. SVC Area CI = (Max SVC area − Min SVC area)*100/Max SVC area.…”

“…Larger CT measurements with arborization in its lower part are more frequently noted in patients with atrial flutter 16. Also, a large majority of focal RA tachycardia in otherwise normal individuals arise along the CT 14. Although the full extent of CT was visualized in only a few patients by 3DTTE, it is possible that echocardiographic F I G U R E 3 Two-dimensional transthoracic echocardiography.…”

Morphological pattern of Crista terminalis, Musculi pectinati and Taenia sagittalis with applied significance

“…Practically the most common ways of treating atrial flutter is the use of radiofrequency catheter ablation. It is during this ablation procedure the morphology of MP is pertinent as it carries risk of iatrogenic myocardial injury especially in Type 6 MP, Type B TS and Type C TS (SIDDIQUI, DAIMI, GANDHI et al, 2013).…”