Koch's triangle and the atrioventricular node in Ebstein's anomaly: implications for catheter ablation

Coronary artery anatomy in peri-crux cordis area on computed coronary tomography angiography

Background

The peri-crux area is an anatomical structure of the heart. Unfortunately, important information on this area mainly derives from autopsy heart with a small, under-representative sample size, resulting in limited clinical applications. Furthermore, little has been done to standardize the definition of the peri-crux area on coronary computed tomography angiography (CCTA) images or to investigate coronary artery anatomy wherein potential values are attracting experienced inventional cardiologists in terms of the revascularization strategies. The current study aimed to identify the peri-crux cordis area and to observe coronary artery anatomical distributions in this area on CCTA.

Methods

A total of 1,006 consecutive patients undergoing CCTA exams were enrolled. We delineated the peri-crux cordis area based on the posterior interatrial sulcus, posterior interventricular sulcus (PIS), left and right posterior atrioventricular groove on the diaphragmatic surface of the heart. Then we observed the coronary artery distributions in the peri-crux cordis area in different sexes.

Results

We have defined the peri-crux cordis area according to the anatomical landmarks on the diaphragmatic surface of the heart on CCTA images. We have observed 8 coronary artery distributions in the peri-crux cordis area. Right dominance has 4 types (types 1-4); left, 1 type (type 0) and balanced, 3 types (types 5-7). Out of the 1,006 cases, the type 1 is commonest with 834 cases (82.9%). There are no statistically significant differences in terms of coronary dominances and coronary artery distributions in the peri-crux cordis area between sexes (P>0.05).

Conclusions

We have defined the peri-crux cordis area utilizing the anatomical landmarks of the heart on CCTA images, where 8 types of coronary artery distributions have been identified. The current study may provide interventional cardiologists with useful information on recognition of coronary artery dominance, use of collateral channels for revascularization of chronic total occluded lesions, and evaluation of prognosis in patients with coronary artery disease (CAD).

Anatomy of the normal fetal heart: The basis for understanding fetal echocardiography

The rapid changes that have taken place in recent years in relation to techniques used to image the fetal heart have emphasized the need to have a detailed knowledge ofnormal cardiac anatomy. Without such knowledge, it is difficult, if not impossible, to recognize the multiple facets of congenital cardiac disease. From the inception of fetal echocardiographic screening, the importance of basic knowledge of cardiac anatomy has been well recognized. The current machines used for imaging, however, now make it possible potentially to recognize features not appreciated at the start of the specialty. So as to match the advances made in imaging, we have now revisited our understanding of normal cardiac anatomy in the mid-gestational fetus. This was made possible by our dissection of 10 fetal hearts, followed by production of addition histological sections that mimic the standard ultrasound views. The fetuses ranged in gestational age from between 20 and 28 weeks. We then correlated the obtained anatomic images with the corresponding ultrasonic images used in the standard fetal screening scan. We also interrogated the anatomic sections so as to clarify ongoing controversies regarding detailed features of the normal cardiac anatomy. We have been able to show that the views now obtained using current technology reveal many details of anatomy not always appreciated at earlier times. Knowledge of these features should now permit diagnosis of most congenital cardiac malformations. The anatomic-echocardiographic correlations additionally provide a valuable resource for both the understanding and teaching of fetal echocardiography.

Morphometry of the triangle of Koch and position of the coronary sinus opening in cadaveric fetal hearts

AIMS

The aim of the present study was to determine the variations in the position of the coronary sinus (CS) ostium in normal cadaveric fetal (28 weeks or more) hearts and to assess the impact that these variations had on the dimensions of the triangle of Koch (TK).

METHODS

This cross-sectional analytical study was conducted on 28 fetal hearts. The dimensions and area of the TK were calculated by two methods, M1 (anatomical) and M2 (clinical). The position of the CS was defined with respect to the tendon of Todaro. Differences between M1 and M2 were estimated using the paired T test. Pearson's correlation coefficient and the adjusted correlation coefficient were used to estimate the strength of association between measurements made by the methods.

RESULTS

Ten (35.7%) cadavers were male and 18 (64.3%) female. The mean gestational age was 32.4±3.3 weeks. Using M1, the mean dimensions of the triangle in millimeters (mm) were 9.2±2.2, 6.6±1.8, and 6±2.4 respectively for a, b and c. Similarly, the dimensions using M2 were 7±2.1, 4.7±1.5, and 4.8±2.2. The area in mm² was 20.4±10.4 and 11.7±6.7 using M1 and M2 respectively. All measurements were significantly greater with M1. All correlation coefficients were high and significant. The CS ostium and tendon of Todaro maintained a relatively constant positional relationship.

CONCLUSIONS

Significantly higher values were noted in the dimensions of TK using M1. High significant positive correlations were observed in measurements made by the two methods. The CS ostium was relatively constantly placed within the TK.

Anatomical Basis for the Cardiac Interventional Electrophysiologist

The establishment of radiofrequency catheter ablation techniques as the mainstay in the treatment of tachycardia has renewed new interest in cardiac anatomy. The interventional arrhythmologist has drawn attention not only to the gross anatomic details of the heart but also to architectural and histological characteristics of various cardiac regions that are relevant to the development or recurrence of tachyarrhythmias and procedural related complications of catheter ablation. In this review, therefore, we discuss some anatomic landmarks commonly used in catheter ablations including the terminal crest, sinus node region, Koch's triangle, cavotricuspid isthmus, Eustachian ridge and valve, pulmonary venous orifices, venoatrial junctions, and ventricular outflow tracts. We also discuss the anatomical features of important structures in the vicinity of the atria and pulmonary veins, such as the esophagus and phrenic nerves. This paper provides basic anatomic information to improve understanding of the mapping and ablative procedures for cardiac interventional electrophysiologists.

Standardized review of atrial anatomy for cardiac electrophysiologists

Catheter ablation of cardiac arrhythmias has rapidly evolved from a highly experimental procedure to a standard form of therapy for various tachyarrhythmias. The advances in this field have included, first, the development of techniques of catheter ablation that often requires the precise destruction of minute amounts of arrhythmogenic tissues and, second, techniques of resynchronization therapy that require pacing different parts of the ventricles. A detailed prepocedural knowledge of cardiac anatomy can improve the safety of the procedure and its rate success. It helps the electrophysiologist to choose the appropiate region for ablation, shortening the procedural time. The atrial anatomy structures are usually localized before ablation by different imaging techniques such as fluoroscopy, electroanatomic mapping, intracardiac echocardiography or multidetector computed tomography. In this review, we describe the normal anatomy of the atria, highlighting the landmarks of interest to intervencional cardiologist, stressing their relationship to other structures. This article is part of a JCTR special issue on Cardiac Anatomy.