Great cardiac vein variations

Morphometry of the Great Cardiac Vein in Cadaveric Hearts of South Indian Origin

Introduction

In recent years, rapid developments in procedures like cardiac pacing, targeted drug therapy, and trans coronary venous ablation have necessitated a need for a detailed study of cardiac venous anatomy. Because the number, diameter, and course of the coronary veins vary, extensive information on the patient's specific anatomy is required for the best planning of the treatment. With this background, we planned the current research to analyze the anatomy of the great cardiac vein (GCV) in terms of length and diameter, provide a formula for calculating diameter using linear regression analysis and report the frequency of formation of the triangle of Brocq and Mouchet.

Methods

We conducted this cross-sectional study on fifty-two adult human cadaveric hearts of South Indian origin collected during dissection classes for undergraduate medical students. We measured the GCV's length and diameter and applied the linear regression analysis to derive a formula for estimating the diameter of the GCV. We also noted the frequency of formation of the triangle of Brocq and Mouchet and presented it as a percentage.

Results

The mean length and width of the GCV were 67.77 mm and 2.76 mm, respectively. The formula obtained after linear regression analysis for calculating the diameter of the GCV was: the diameter of GCV=0.0089 (length of GCV vein) ± 2.147. The triangle of Brocq and Mouchet with GCV as the base was present in 97% of the hearts.

Conclusion

The length and diameter of the GCV reported in the current study were considerably lesser than the reported findings in the literature. These findings suggest significant variations in the anatomy of the cardiac veins and call for further research on the anatomy of cardiac veins.

Left Ventricular Summit-Concept, Anatomical Structure and Clinical Significance

The left ventricular summit (LVS) is a triangular area located at the most superior portion of the left epicardial ventricular region, surrounded by the two branches of the left coronary artery: the left anterior interventricular artery and the left circumflex artery. The triangle is bounded by the apex, septal and mitral margins and base. This review aims to provide a systematic and comprehensive anatomical description and proper terminology in the LVS region that may facilitate exchanging information among anatomists and electrophysiologists, increasing knowledge of this cardiac region. We postulate that the most dominant septal perforator (not the first septal perforator) should characterize the LVS definition. Abundant epicardial adipose tissue overlying the LVS myocardium may affect arrhythmogenic processes and electrophysiological procedures within the LVS region. The LVS is divided into two clinically significant regions: accessible and inaccessible areas. Rich arterial and venous coronary vasculature and a relatively dense network of cardiac autonomic nerve fibers are present within the LVS boundaries. Although the approach to the LVS may be challenging, it can be executed indirectly using the surrounding structures. Delivery of the proper radiofrequency energy to the arrhythmia source, avoiding coronary artery damage at the same time, may be a challenge. Therefore, coronary angiography or cardiac computed tomography imaging is strongly recommended before any procedure within the LVS region. Further research on LVS morphology and physiology should increase the safety and effectiveness of invasive electrophysiological procedures performed within this region of the human heart.

Coronary venous anatomy and anomalies

Coronary venous anatomy can be divided into the greater cardiac venous system and the lesser cardiac venous system. With protocol optimization, including appropriate contrast bolus timing, coronary veins can be depicted with excellent detail on CT. Knowledge of variant coronary venous anatomy can sometimes play a role in pre-procedural planning. Analysis of the coronary venous anatomy on CT can detect coronary venous anomalies that cause right to left shunts with risk of stroke, left to right shunts, and arrhythmias.

Anomalous great cardiac vein draining into the right atrium combined with a single left coronary artery

In contrast to the coronary arterial system, little attention has been paid to the coronary venous system in previous literature. We report a rare case of a combined anomaly of the coronary artery and the great cardiac vein (GCV). In this patient, the right coronary artery (RCA) arose from the left coronary artery, and the GCV drained directly into the right atrium. The anomalous RCA and GCV ran parallel courses along the anterior side of the right ventricular outflow tract. We briefly review the clinical significance and the role of cardiac computed tomography in this anomaly.

[Technical innovations and limitation in cardiac electrotherapy]

Coronary sinus (CS) lead positioning is one of the main determinants of cardiac resynchronization therapy (CRT). The implantation of the CS lead is faced with several technical difficulties that may prevent the achievement of a stable position and good performance of the CS lead without phrenic nerve stimulation (PNS). New developments in catheter and lead technology to overcome these difficulties are presented.

A full 3-D reconstruction of the entire porcine coronary vasculature

We have previously reconstructed the entire coronary arterial tree of the porcine heart down to the first segment of capillaries. Here, we extend the vascular model through the capillary bed and the entire coronary venous system. The reconstruction was based on comprehensive morphometric data previously measured in the porcine heart. The reconstruction was formulated as a large-scale optimization process, subject to both global constraints relating to the location of the larger veins and to local constraints of measured morphological features. The venous network was partitioned into epicardial, transmural, and perfusion functional subnetworks. The epicardial portion was generated by a simulated annealing search for the optimal coverage of the area perfused by the arterial epicardial vessels. The epicardial subnetwork and coronary arterial capillary network served as boundary conditions for the reconstruction of the in-between transmural and perfusion networks, which were generated to optimize vascular homogeneity. Five sets of full coronary trees, which spanned the entire network down to the capillary level, were reconstructed. The total number of reconstructed venous segments was 17,148,946 ± 1,049,498 (n = 5), which spanned the coronary sinus (order -12) to the first segment of the venous capillary (order 0v). Combined with the reconstructed arterial network, the number of vessel segments for the entire coronary network added up to 27,307,376 ± 1,155,359 (n = 5). The reconstructed full coronary vascular network agreed with the gross anatomy of coronary networks in terms of structure, location of major vessels, and measured morphometric statistics of native coronary networks. This is the first full model of the entire coronary vasculature, which can serve as a foundation for realistic large-scale coronary flow analysis.

[Optimal electrode placement. What to consider during implantation of a biventricular pacemaker?]

Since the introduction of transvenous left ventricular lead systems nearly a decade ago, resynchronization therapy has gained widespread acceptance and has become a growing field in heart failure therapy. Due to the increasing numbers of implanting centers and physicians, the need for adequate education is increasing. This article describes and illustrates the anatomical background, the technical opportunities and pitfalls, which have to be overcome, to achieve an implanting success rate of 95% to 98%, as can be achieved by well-trained physicians under optimal conditions.

Aneurysm of the great cardiac vein

Anatomical variations in the cardiac veins have the potential to cause iatrogenic injuries during cardiac surgical procedures or cardiac resynchronization therapy. We present a case of an 86-year-old man, which presented with a great cardiac vein aneurysm. The great cardiac vein arose near the apex of the interventricular sulcus to the right of the anterior interventricular branch (AIB) of the left coronary artery and crossed the AIB anteriorly to the left. The great cardiac vein aneurysm appeared to be due to a possible distal constriction of the great cardiac vein by a small muscular branch of the circumflex branch and a possible proximal constriction by the left marginal artery. Cardiologists who interpret imaging of the cardiac veins and cardiac surgeons who operate close to the great cardiac vein should be aware of such a variation.

The Coronary Venous Anatomy

The coronary sinus is the gateway for left ventricular (LV) epicardial lead placement for cardiac resynchronization therapy. The implanting electrophysiologist is usually challenged by a high degree of variability in the coronary venous anatomy, making it important to have a more consistent and uniform segmental approach to describe the coronary venous tree and its branches. Classifying the coronary sinus branches and tributaries by the segment of their location rather than by conventional anatomic names (i.e., middle cardiac vein, great cardiac vein, and so on), would provide more relevant anatomic and functional information at the time of LV lead placement. This would enable the implanting physician to proactively correlate the venous anatomy with the segmental wall motion abnormalities or dyssynchrony, as defined by echocardiography and other imaging modalities. The current viewpoint calls for a more systematic segmental approach for describing the coronary venous anatomy.