Cardiac veins: A review of the literature

Clinical anatomy of the coronary venous system and relevance to retrograde cardioplegia and cardiac electrophysiological interventions

Anomalies of coronary venous system, the valve of the coronary sinus (Thebesian valve) and other cardiac malformations may make interventions through the coronary sinus difficult. These variants may pose a challenge in cannulating the coronary sinus for retrograde cardioplegia and for interventions performed through the coronary sinus by cardiac electrophysiologist/interventional cardiologist. Retrograde cardioplegia is an established method of myocardial protection with advantages, indications, and complications. A good knowledge of the anatomy of the coronary sinus and its variants is important in understanding the difficulties encountered while cannulating the coronary sinus for the delivery of retrograde cardioplegia, cardiac resynchronization therapy, treatment of arrhythmias, and percutaneous mitral valve annuloplasty.

Characteristics of Right-Sided Accessory Pathways Associated With Right Cardiac Veins

BACKGROUND

The anatomy of myocardial fibers around the right cardiac veins (RCVs) and their roles in accessory pathways (APs) are rarely reported.

METHODS

Six RCV-APs were identified from 566 patients with right-sided APs. Mapping of retrograde atrial activation was performed using CARTO 3 system under orthodromic tachycardia or right ventricular pacing. Venography of RCVs was acquired at the earliest retrograde atrial activation.

RESULTS

Patients enrolled had a median age of 30 (11-51) years, 5 of them were male. Venography of RCVs could be classified into 3 distinct patterns based on the identified ventricular branches, right marginal vein only (type I; n=3), both right marginal vein and anterior cardiac veins (type II; n=2), and anterior cardiac vein only (type III; n=1). Patients with type I venography had rS QRS pattern in lead V1, negative delta wave in lead III and negative or isoelectric delta wave in lead aVF. However, patients with type II and III venography had QS QRS patterns in lead V1 and variable patterns of delta wave in inferior leads. Earliest retrograde atrial activation was found at a median of 16.75 (14.60-20.00) mm away from the tricuspid annulus, all with A larger than V. At the earliest retrograde atrial activation, far-field ventricular electrogram was found 30 ms later than QRS onset in 1 patient under sinus rhythm. AP conduction was eliminated by mechanical pressure in 2 and by radiofrequency ablation in 4 at the ostium of the veins colocalizing with the earliest retrograde activation of the right atrium. No recurrence was observed during 36 (10-60) months follow-up.

CONCLUSIONS

The RCV-AP is a rare form of right-sided APs characterized by atrial insertions distant from the annulus. ECG-speculated ventricular insertion sites conformed to the location of identified RCVs.

Myocardial Blood Flow Determination From Contrast-Free Magnetic Resonance Imaging Quantification of Coronary Sinus Flow

BACKGROUND

Determination of myocardial blood flow (MBF) with MRI is usually performed with dynamic contrast enhanced imaging (MBFDCE ). MBF can also be determined from coronary sinus blood flow (MBFCS ), which has the advantage of being a noncontrast technique. However, comparative studies of MBFDCE and MBFCS in large cohorts are lacking.

PURPOSE

To compare MBFCS and MBFDCE in a large cohort.

STUDY TYPE

Prospective, sequence-comparison study.

POPULATION

147 patients with type 2 diabetes mellitus (age: 56+/-12 years; 106 male; diabetes duration: 12.9+/-8.1 years), and 25 age-matched controls.

FIELD STRENGTH/SEQUENCES

1.5 Tesla scanner. Saturation recovery sequence for MBFDCE vs. phase-contrast gradient-echo pulse sequence (free-breathing) for MBFCS .

ASSESSMENT

MBFDCE and MBFCS were determined at rest and during coronary dilatation achieved by administration of adenosine at 140 μg/kg/min. Myocardial perfusion reserve (MPR) was calculated as the stress/rest ratio of MBF values. Coronary sinus flow was determined twice in the same imaging session for repeatability assessment.

STATISTICAL TESTS

Agreement between MBFDCE and MBFCS was assessed with Bland and Altman's technique. Repeatability was determined from single-rater random intraclass and repeatability coefficients.

RESULTS

Rest and stress flows, including both MBFDCE and MBFCS values, ranged from 33 to 146 mL/min/100 g and 92 to 501 mL/min/100 g, respectively. Intraclass and repeatability coefficients for MBFCS were 0.95 (CI 0.90; 0.95) and 5 mL/min/100 g. In Bland-Altman analysis, mean bias at rest was -1.1 mL/min/100 g (CI -3.1; 0.9) with limits of agreement of -27 and 24.8 mL/min/100 g. Mean bias at stress was 6.3 mL/min/100 g (CI -1.1; 14.1) with limits of agreement of -86.9 and 99.9. Mean bias of MPR was 0.11 (CI: -0.02; 0.23) with limits of agreement of -1.43 and 1.64.

CONCLUSION

MBF may be determined from coronary sinus blood flow, with acceptable bias, but relatively large limits of agreement, against the reference of MBFDCE .

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY STAGE: 2.

Spontaneous Coronary Sinus Thrombosis in a Patient With Pulmonary Embolism and No Prior Cardiac Instrumentation

•Spontaneous CS thrombosis is a rare condition. •High clinical suspicion is needed to diagnose spontaneous CS thrombosis. •Heart instrumentation may cause CS thrombosis.

Venous Ethanol Ablation Approaches for Radiofrequency-Refractory Cardiac Arrhythmias

PURPOSE OF REVIEW

In this review, we summarize the procedural approach and outcomes of venous ethanol infusion in the treatment of ventricular arrhythmias with intramural site of origin.

RECENT FINDINGS

Coronary venous ethanol infusion has emerged as a novel, safe, and effective adjunctive strategy to radiofrequency ablation of drug refractory ventricular arrhythmias with an intramural origin. Radiofrequency catheter ablation is the first-line treatment for drug refractory ventricular arrythmias. Its success is highly dependent on the ability to reach targeted myocardium. Radiofrequency failures are common in patients with ventricular arrhythmias arising from deep intramural substrates, and those whose origin is in close proximity to vital structures such as coronary arteries or the phrenic nerve. Coronary venous ethanol infusion has emerged as a novel technique that circumvents these limitations.

Coronary Sinus Defect, Premature Restriction of Foramen Ovale and Cysto-Colic Peritoneal Band

Background: Unroofed coronary sinus is a congenital cardiac anomaly usually associated with persistent left superior vena cava. Premature restriction or closure of foramen ovale is described in association with hypoplastic left heart syndrome. Abdominal peritoneal bands when present manifest clinically. Case report: A 27 years, gravida 2, presented with intrauterine fetal death at 24 weeks gestation due to fetal congestive cardiac failure, cardiomegaly and hydrops. Perinatal autopsy showed absent coronary sinus with cardiac veins draining directly into the heart. There was no persistent left superior vena cava. The foramen ovale was restricted prematurely. The ductus arteriosus was present and non-restrictive. Abdomen showed a cysto-colic peritoneal band. Conclusion: This is the first report showing a triad of (1) complete absence of coronary sinus without left superior vena cava (type-II); (2) premature restriction of foramen ovale without hypoplastic left heart; and (3) a cysto-colic peritoneal band between the gall bladder and colon.

Retrograde Coronary Venous Ethanol Infusion for Ablation of Refractory Left Ventricular Summit Arrhythmias

Chemical ablation using the transcoronary arterial system has a lengthy but arduous history. Although it has shown to be efficacious in controlling ventricular arrhythmias, safety concerns from cannulation of the coronary arterial system to unwanted ethanol downstream effects have limited transcoronary ethanol ablation (TCEA)'s use. Retrograde coronary venous ethanol ablation (RCVEA) has shown promising results. Although it appears to be in its infancy, RCVEA appears to be the future of chemical ablation in comparison to TCEA due to its increased safety and efficacy. Prospective randomized trial data is needed for this adjunctive treatment to radiofrequency ablation.

Chemical Ablation of Ventricular Tachycardia Using Coronary Arterial and Venous Systems

Radiofrequency catheter ablation (RFCA) is the first-line therapy for treatment of drug refractory ventricular arrhythmias (VAs), however, creating a safe, transmural lesion can be difficult. Ethanol in the arterial system has been used as an adjunctive therapy to RFCA since 1986, but with limited use due to technical and efficacy limitations. Venous ethanol is emerging as powerful alternative.

Study of coronary sinus anatomy during levophase of coronary angiography

BACKGROUND

Coronary sinus (CS) imaging has recently gained importance due to increasing need for mapping and ablation of electrophysiological arrhythmias and left ventricular (LV) pacing during cardiac resynchronization therapy (CRT). Retrograde venogram is the current standard for imaging CS and its tributaries.

AIM

To evaluate CS anatomy during levophase of routine coronary angiography to aid LV lead implantation during CRT.

METHODS

In this prospective observational study, 164 patients undergoing routine coronary angiography for various indications (Chronic stable angina-44.5%, acute coronary syndrome- 39.5%, Dilated cardiomyopathy-11%, atypical chest pain-5%) were included. Venous phase (levophase) of left coronary injection was recorded in left anterior oblique - cranial and right anterior oblique -cranial views. Visibility of coronary veins, width and shape of CS ostium, angulations of proximal CS with body of CS were noted. Presence, size, take-off angle and tortuosity of posterolateral vein (PLV), anterior interventricular veins (AIV) and middle cardiac vein (MCV) were also noted.

RESULTS

During levophase, visibility grade (Muhlenbruch grade) for coronary veins was 3 in 74% and 2 in 26% of cases. Visibility of CS did not correlate with body mass index. The diameter of CS ostium was < 10 mm, 10-15 mm and > 15 mm in 48%, 42% and 10% of patients respectively. Proximal CS was tubular in 136 (83%) patients and funnel-shaped in 28 (17%) patients. Sharp take-off angulation between ostium and body of CS was seen in 16 (10%) patients. Two or more PLV were present in 8 patients while PLV was absent in 52 (32%) patients. Angle of take-off of PLV with body of CS was favourable (0°-45°) in 65 (40%) patients. The angle was 45°-90° in 36 patients and difficult take-off angle (> 90°) was seen in 8 patients. Length of PLV reached distal third of myocardium in 84 cases and middle third in 11 cases. There was no tortuosity in 79 cases, a single bend in 29 cases and more than 2 bends in 4 cases. Thirty nine (24%) patients had other veins supplying posterior/Lateral wall of LV. There was a single vein supplying lateral/posterior wall in 31 (19%) patients. Diameter of MCV and AIV was significantly larger in patients with absent PLV as compared to patients with a PLV.

CONCLUSION

Levophase study of left coronary injection is effective in visualization of the CS in almost all patients undergoing coronary angiography and may be an effective alternative to retrograde venogram in patients with LV dysfunction or LBBB.

Double Reducer implantation in the coronary venous system for treatment of refractory angina: a case report

Background

The coronary sinus (CS) Reducer can be considered for the treatment of refractory angina in patients unsuitable for coronary revascularization, but its effect can be influenced by the significant heterogeneity in the anatomy of the cardiac venous system.

Case summary

We report the case of a 70-year-old woman with recurrent episodes of rest angina refractory to optimal medical therapy [Canadian Cardiovascular Society (CCS) Class IV] and inducible ischaemia in a large myocardial territory. Given the diffuse and peripheral nature of the coronary disease, the patient was considered ineligible for percutaneous or surgical revascularization and she was regarded as a good candidate for a CS occluder. Since coronary venous angiography showed the middle cardiac vein (MCV) to be at least as relevant as the CS, successful implantation of two devices, one in the CS and the second in the MCV, was performed. At 6-month follow-up, the patient reported a significant improvement in angina, resulting in a reduction of the CCS class from Grades IV to III.

Discussion

In patients affected by refractory angina and regarded as good candidates for Reducer implantation, a thorough comprehension of the cardiac venous pathway drainage is of pivotal importance to guarantee the therapeutic success of the procedure. In this patient, since the CS and the MCV seemed to contribute equally to coronary venous drainage, Reducer implantation in both vessels allowed to obtain a significant improvement of symptoms. The clinical effectiveness of this strategy needs to be validated in randomized clinical trials.

Glycemic Control in Coronary Artery Bypass Graft Surgery: A Different Perspective

Background

Hyperglycemia during coronary artery bypass graft surgery (CABG) strongly predicts intra- and post-operative adverse consequences.

Objectives

This study aimed to evaluate the quality of glycemic management during CABG in an academic center regarding peripheral blood and coronary sinus values.

Methods

This prospective descriptive study encompassed 55 eligible patients undergoing on-pump CABG surgery in 2020. Peripheral blood glucose (BG) was measured four times, before anesthesia induction (T0), before cardiopulmonary bypass pump (CPB) (T1), during CPB (T2), at the end of CPB (T3), and at the end of surgery (T4). The surgeon also took a sample of the coronary sinus BG.

Results

The BG variations from T0 to T4 were statistically significant (P < 0.0001). The higher values detected in the ASA class III compared to ASA classes II were statistically significant at T1 (P = 0.01) and T2 (P = 0.025): patients with the higher BMI showed the higher levels of BG. In this regard, the differences were significant at T0 (P = 0.0001), T2 (P = 0.004), and T3 (P = 0.015). Regarding coronary sinus, the mean BG was 222.18 ± 75.74 mg/dL. It was also observed that the ASA class III (P = 0.001), longer duration of CPB (P = 0.021), higher IV fluid volume administrated during surgery (P = 0.023), higher BMI (P = 0.0001), and less urine volume at the end of surgery (P = 0.049) were significantly associated with the higher BG of the coronary sinus.

Conclusions

The existing glycemic management protocols on the CABG patients were acceptable in our hospital. However, the BG level of the coronary sinus was higher than the peripheral one.

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.

Venous anatomy of the left ventricular summit: Therapeutic implications for ethanol infusion

BACKGROUND

Venous ethanol ablation (VEA) is effective for treatment of left ventricular (LV) summit (LVS) arrhythmias. The LVS venous anatomy is poorly understood and has inconsistent nomenclature.

OBJECTIVE

The purpose of this study was to delineate the LVS venous anatomy by selective venography and 3-dimensional (3D) mapping during VEA and by venous-phase coronary computed tomographic angiography (vCTA).

METHODS

We analyzed (1) LVS venograms and 3D maps of 53 patients undergoing VEA; and (2) 3D reconstructions of 52 vCTAs, tracing LVS veins.

RESULTS

Angiography identified the following LVS veins: (1) LV annular branch of the great cardiac vein (GCV) (19/53); (2) septal (rightward) branches of the anterior ventricular vein (AIV) (53/53); and (3) diagonal branches of the AIV (51/53). Collateral connections between LVS veins and outflow, conus, and retroaortic veins were common. VEA was delivered to target arrhythmias in 38 of 53 septal, 6 of 53 annular, and 2 of 53 diagonal veins. vCTA identified LVS veins (range 1-5) in a similar distribution. GCV-AIV transition could either form an angle close to the left main artery bifurcation (n = 16; 88° ± 13°) or cut diagonally (n = 36; 133°±12°) (P ≤.001). Twenty-one patients had LV annular vein. In 28 patients only septal LVS veins were visualized in vCTA, in 2 patients only diagonal veins and in 22 patients both septal and diagonal veins were seen. In 39 patients the LVS veins reached the outflow tracts and their vicinity.

CONCLUSION

We provide a systematic atlas and nomenclature of LVS veins related to arrhythmogenic substrates. vCTA can be useful for noninvasive evaluation of LVS veins before ethanol ablation.

Anomalies of the Coronary Sinus and Its Tributaries: Evaluation on Multidetector Computed Tomography Angiography

Imaging of the coronary sinus and its tributaries has gained increasing significance consequent to the development of an array of electrophysiological and interventional procedures using the cardiac venous system, including ablation for arrhythmias, left ventricular pacing, and in the administration of retrograde cardioplegia. Knowledge of the normal anatomy and the possible anomalies and their clinical significance is imperative to circumvent possible complications. A number of coronary sinus (CS) anomalies, both symptomatic and asymptomatic, have been observed with the widespread use of noninvasive cross-sectional imaging for the imaging of the heart. However, it should be kept in mind that even clinically occult lesions of the CS can cause disastrous complications in specific interventions. Hence, a thorough knowledge of the expected anatomy and the possible anomalies involving the CS along with their clinical significance is imperative for the reporting radiologists and the concerned physicians. In this review, we briefly describe the relevant anatomy and embryology and describe the gamut of anomalies pertaining to the CS and its draining veins on multidetector computed tomography angiography along with their clinical importance.

Cardiac MRI demonstrates compressibility in healthy myocardium but not in myocardium with reduced ejection fraction

BACKGROUND

The professional guidelines assume that the myocardial volume in systole (MVs) is equal to that in diastole (MVd), despite some limited evidence that points to the contrary. The aim of this manuscript is to determine whether this is true in healthy myocardium using gold standard cardiac MRI, as well as transthoracic echocardiography (TTE). The secondary aim is to determine whether there are similar MV changes in patients with heart failure with reduced ejection fraction (HFrEF).

METHOD

A prospectively derived cohort at Mayo Clinic of 115 adult subjects (mean age 42.8 years, 58% female) with no cardiac risk factors was identified. Cardiac MRI was obtained on all 115 patients, 51 of whom also consented to a TTE. MRI from a retrospectively derived cohort of 50 HFrEF patients was also collected. MVs and MVd was calculated using standard approaches with inclusion of the papillary muscles.

RESULTS

In the healthy population, MRI demonstrated MVs/MVd = 0.87 (SD 0.04) and TTE demonstrated MVs/MVd = 0.79 (SD 0.07), suggesting compressibility (p < 0.0001). In the 51 healthy patients who received both imaging modalities, MVs/MVd was 8.0% higher in MRI than TTE (p < 0.0001), but both modalities had MVs/MVd < 1 (p < 0.0001). A Bland-Altman plot demonstrated that as the mean MVs/MVd increases, the difference in MVs/MVd MRI-TTE declines (r = -0.53, p < 0.0001). However, in HFrEF populations, MVs/MVd = 1.01 (0.03), suggesting myocardial incompressibility.

CONCLUSION

Contrary to currently accepted standards, healthy myocardium is compressible but HFrEF myocardium is incompressible. The ratio MVs/MVd merits further study in an expanded normal cohort and in disease states.

Coronary Sinus Phlebography in Cardiac Resynchronization Therapy Patients: Identifying and Solving Demanding Cases

Cardiac resynchronization therapy (CRT) improves symptoms and reduces morbidity and mortality in select heart failure patients but remains challenging to deploy widely because of difficult or unsuccessful coronary sinus (CS) access in up to 10% to 15% of patients. This report describes the radiological and anatomical aspects for improving CS catheterization and left ventricular (LV) lead positioning, focusing on the radioscopic and anatomical aspects, based on phlebography, to identify demanding cases in patients with dilated cardiomyopathy referred for CRT implantation. Anatomical and radiological aspects were explored in the anteroposterior, 30° left anterior oblique, and 30° right anterior oblique (RAO) views. In total, 117 phlebographies were performed in 39 consecutive procedures (one reintervention). Access to the CS was successful 37 times (94.9%). The most difficult cases were complicated by issues related to the altered spatial orientation of the CS ostium toward the tricuspid annular plane (TAP), which was best perceived in the 30° RAO projection and occurred in 37% of patients. One of two catheterization failures that occurred was caused by anomalous coronary venous drainage into the left atrium. Final LV lead positioning was successful in 36 (92.3%) of 39 procedures. More severe heart failure and worse LV ejection fraction did not translate into greater difficulty in LV lead implantation. As such, understanding anatomical and radiological relationships is the key to successful LV lead positioning. RAO projection can be particularly useful in the assessment of demanding CRT implant cases, especially when the CS ostium pointed to the TAP.

MDCT of unique drainage of the anterior interventricular coronary vein into the left atrium: two case reports

Pre-procedural CT mapping of the coronary venous system is advised by the current guidelines before many interventional procedures. The published literature for variants of the coronary venous system is scarce. The variant of anterior interventricular vein (AIV) drainage into the left atrium is extremely rare. In this paper, we present multidetector CT findings of two cases of anomalous drainage of the anterior interventricular vein into the left atrium.

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.

Localization of Left Ventricular Lead Electrodes in Relation to Myocardial Scar in Patients Undergoing Cardiac Resynchronization Therapy

Background

The efficacy of cardiac resynchronization therapy may be reduced in the event of pacing within myocardial fibrosis. We aimed to develop a method to determine the anatomical relationships between the left ventricular (LV) lead and myocardial fibrosis.

Methods and Results

In consecutive patients indicated for cardiac resynchronization therapy, cardiovascular magnetic resonance imaging with late gadolinium enhancement assessment was performed before implantation. After implantation, an injected computed tomography scanner (CT scan) was performed. The 2 imaging techniques were fused to assess the LV lead position relative to myocardial scar. A total of 68 patients were included. Myocardial scar was found in 29 (43%) and was localized in lateral segments in 14 (21%). Scar was significantly associated with male sex, ischemic cardiomyopathy, a Selvester score adapted to left bundle branch block (LBBB Selvester), and Selvester criteria for localizing lateral fibrosis (V2 S/S′ ratio). Image fusion was feasible in all patients. Position within myocardial scar was confirmed for 6 electrodes in 3 patients. Prolonged QRS duration during LV pacing ≥139% predicted electrode positioning within scar tissue (sensitivity, 83%; specificity, 91%; P=0.002).

Conclusions

In cardiac resynchronization therapy patients, fusion between preimplantation cardiovascular magnetic resonance and a postimplantation injected computed tomography scan is a feasible technique. Prolongation of the QRS duration during LV pacing predicts pacing within myocardial scar. Accurate location of LV lead pacing electrodes on the epicardial surface relative to myocardial scar, either by imaging or ECG analyses, may help improve cardiac resynchronization therapy response in selected patients.

A Route Less Traveled: Anomalous Venous Drainage of the Right Heart

Congenital anomalies of the coronary sinus and veins have been well documented, but only one instance of an anomalous small cardiac vein draining into the superior vena cava (SVC) has been reported. The majority of patients with anomalies of the coronary venous system are asymptomatic, but these variants are important to document as they may have clinically significant implications in the management and possible interventions patients may receive. This report describes an anomalous connection from the coronary venous system to the superior vena cava discovered incidentally in a patient with SVC syndrome and end-stage renal disease (ESRD). This may reflect a congenital variant which accommodated collateral flow to bypass the fully occluded SVC. Alternatively, it may be the result of repeated venoplasty of the stenotic SVC which opened an iatrogenic tract that was maintained and vascularized over time.

Anatomy of the coronary artery and cardiac vein in the quail ventricle: patterns are distinct from those in mouse and human hearts

Coronary vessel development has been investigated in avian and mouse embryonic hearts. Quail embryos are a useful tool to examine vascular development, particularly because the QH1 antibody and transgenic quail line, Tg (tie1:H2B-eYFP), are useful to trace endothelial cells. However, there are only a few descriptions of the quail coronary vessels. Using ink injection coronary angiography, we examined the course of coronary vessels in the fetal quail heart. The major coronary arteries were the right and left septal arteries, which, respectively, branched off from the right and left coronary stems. The right septal artery ran posteriorly (dorsally) and penetrated the ventricular free wall to distribute to the posterior surface of the ventricles. The left septal artery ran anteriorly (ventrally) and penetrated the ventricular free wall to distribute to the anterior surface of the ventricles. The right and left circumflex arteries were directed posteriorly along the atrioventricular sulci. The cardiac veins consisted of three major tributaries: the middle, great, and anterior cardiac veins. The middle cardiac vein ascended along the posterior interventricular sulcus and emptied into the right atrium. The great cardiac vein ran along the anterior interventricular sulcus, entered the space between the left atrium and conus arteriosus and emptied into the right atrium behind the aortic bulb. The anterior cardiac vein drained the anterior surface of the right ventricle and connected to the anterior base of the right atrium. The course of coronary vessels in the quail heart was basically the same as that observed in chick but was different from those of mouse and human.

The Human Left Atrial Venous Circulation as a Vascular Route for Atrial Pharmacological Therapies: Effects of Ethanol Infusion

OBJECTIVES

This study catalogued the human venous left atrium (LA) circulation system and the ablative effects of ethanol in different branches.

BACKGROUND

Vascular routes to target the LA could have significant therapeutic potential. Beyond the vein of Marshall (VOM), the fluoroscopic LA venous anatomy has not been described.

METHODS

Patients undergoing ethanol infusion in the VOM as adjunctive therapy to atrial fibrillation (AF) catheter ablation were included in this study. Balloon occlusion venograms of the VOM and other LA veins were obtained in 218 patients.

RESULTS

Sequentially from the coronary sinus (CS) ostium, LA veins included: 1) proximal septal vein draining the inferior septum; 2) inferior LA vein in the annular inferior LA; 3) VOM; 4) LA appendage vein; and 4) anterior LA vein. Additionally, venous sinuses not connected to the CS included roof veins and posterior wall veins, which drained into the right and left atria, respectively. Venous connections between LA veins through capillaries and with pulmonary veins were abundant. Extracardiac collateral vessels were present in 38 patients (17.4%). Ethanol infusion in LA veins led to tissue ablation in their corresponding regions.

CONCLUSIONS

The atrial venous anatomy is amenable to selective cannulation. Consistent anatomical patterns are present. Targeting atrial tissues through atrial veins can be used for therapeutic purposes.

Flow velocity is relatively uniform in the coronary sinusal venous tree: structure-function relation

The structure and function of coronary venous vessels are different from those of coronary arteries and are much less understood despite the therapeutic significance of coronary sinus interventions. Here we aimed to perform a hemodynamic analysis in the entire coronary sinusal venous tree, which enhances the understanding of coronary venous circulation. A hemodynamic model was developed in the entire coronary sinusal venous tree reconstructed from casts and histological data of five swine hearts. Various morphometric and hemodynamic parameters were determined in each vessel and analyzed in the diameter-defined Strahler system. The findings demonstrate an area preservation between the branches of the coronary venous system that leads to relatively uniform flow velocity in different orders of the venous tree. Pressure and circumferential and wall shear stresses decreased abruptly from the smallest venules toward vessels of order -5 (80.4 ± 39.1 µm) but showed a more modest change toward the coronary sinus. The results suggest that vessels of order -5 denote a hemodynamic transition from the venular bed to the transmural subnetwork. In contrast with the coronary arterial tree, which obeys the minimum energy hypothesis, the coronary sinusal venous system complies with the area-preserving rule for efficient venous return, i.e., da Vinci's rule. The morphometric and hemodynamic model serves as a physiological reference state to test various therapeutic rationales through the venous route.

NEW & NOTEWORTHY

A hemodynamic model is developed in the entire coronary sinusal venous tree of the swine heart. A key finding is that the coronary sinusal venous system complies with the area preservation rule for efficient venous return while the coronary arterial tree obeys the minimum energy hypothesis. This model can also serve as a physiological reference state to test various therapeutic rationales through the venous route.

Coronary vasculature patterning requires a novel endothelial ErbB2 holoreceptor

Organogenesis and regeneration require coordination of cellular proliferation, regulated in part by secreted growth factors and cognate receptors, with tissue nutrient supply provided by expansion and patterning of blood vessels. Here we reveal unexpected combinatorial integration of a growth factor co-receptor with a heterodimeric partner and ligand known to regulate angiogenesis and vascular patterning. We show that ErbB2, which can mediate epidermal growth factor (EGF) and neuregulin signalling in multiple tissues, is unexpectedly expressed by endothelial cells where it partners with neuropilin 1 (Nrp1) to form a functional receptor for the vascular guidance molecule semaphorin 3d (Sema3d). Loss of Sema3d leads to improper patterning of the coronary veins, a phenotype recapitulated by endothelial loss of ErbB2. These findings have implications for possible cardiovascular side-effects of anti-ErbB2 therapies commonly used for cancer, and provide an example of integration at the molecular level of pathways involved in tissue growth and vascular patterning.

Semaphorin ligands and cognate receptors are important in patterning the vasculature. Here, Aghajanian et al. report an unexpected role for ErbB2 in endothelial cells where it partners with Nrp1 to form a novel semaphoring holoreceptor required for embryonic vascular patterning.

Anomalous small cardiac vein draining into the superior vena cava

Coronary venous anatomy is little studied, and an abnormal coronary vein drainage is a rarely reported entity. Few cases about abnormal drainage of the great cardiac vein into the superior vena cava have been reported in literature. Herein we present a case of anomalous small cardiac vein draining into superior vena cava.

Assessment of the coronary venous system using 256-slice computed tomography

Purpose

To investigate the coronary venous system and its relation to adjacent structures using 256-slice computed tomography (CT).

Materials and Methods

The study consisted of 102 patients who underwent coronary CT angiography (CTA) using 256-slice CT. For each patient, the coronary venous system and its relation to adjacent structures were evaluated. The appropriate locations and diameters of the posterior interventricular vein (PIV), posterior vein of the left ventricle (PVLV) and the left marginal vein (LMV) were detected. The paired student's t test was used to evaluate the difference between the diameter of the coronary sinus (CS) ostium in anteroposterior direction and that in superoinferior direction.

Results

The CS, great cardiac vein (GCV), PIV, and anterior interventricular vein (AIV) were visualized in all cases. It was possible to evaluate at least one main vein with adequate caliber and regular course for cardiac resynchronization therapy (CRT) in 96.1% of these cases. The diameter of the CS ostium in superoinferior direction (11.7±2.1 mm) was larger than that in anteroposterior direction (9.0±2.0 mm) (t = 13.511, P<0.05). For the majority of the cases, the CS-GCV was located above the level of the mitral valve annulus (MVA), while the left circumflex coronary artery (LCX) was coursed between the CS-GCV and the MVA. LMV had more intersection with the circumflex or circumflex marginal than PVLV.

Conclusion

256-slice CT provides superior noninvasive evaluation of the coronary venous system which has important clinical implications.

Normal anatomy and variants of the venous cardiac system in MDCT coronary angiography

Three separate venous systems drain the blood returning from the heart walls. These veins are characterised by remarkable variability in terms of frequency, size and course. The knowledge of cardiac venous anatomy is of primary importance during interventional cardiac procedures that require catheterisation of cardiac veins. Some anatomical variants may hinder or contraindicate access to target veins. Coronary angiography (CA) with multidetector computed tomography (MDCT-CA) and multiplanar reformations (MPR), maximum intensity projection (MIP) and 3D reconstructions provides noninvasive visualisation of normal cardiac veins and anatomical variants. The purpose of this pictorial review is to describe by MDCT-CA the anatomy and main variants of the cardiac venous system.

Intrinsic left atrial histoanatomy as the basis for reentrant excitation causing atrial fibrillation/flutter in rats

BACKGROUND

Although the pulmonary veins are accepted as preferential trigger sites for paroxysmal atrial fibrillation/flutter (AF/AFL), the intrinsic basis for reentrant excitation is undetermined in persistent AF/AFL.

OBJECTIVE

To identify histoanatomic substrates for reentrant AF/AFL in rats.

METHODS

Spatiotemporal patterns of impulse propagation were visualized optically on the posterior surface of the atria in di-4-ANEPPS-stained Langendorff-perfused rat heart/lung preparations. The relevant histology was also analyzed.

RESULTS

Burst (S1-S2) pacing at the right atrium provoked AF/AFL in 15 of 19 hearts, and most cases developed by organized reentrant excitation through the coronary sinus (CS) and left atrial (LA) roof, with nonorganized irregular propagation in 3 cases. The reentrant circuit developed along 2 pathways of propagation: a slower pathway at the LA roof (conduction velocity, 42.4 ± 16.6 cm/s) and a faster pathway along the CS (conduction velocity, 53.3 ± 9.2 cm/s). Upon extra stimulus (S2) after consecutive S1 pacing, the impulse at the roof propagated retrogradely from the CS, resulting in reentrant propagation anchored by the atrial septum and posterior LA. Histologic quantification revealed significantly lower myocardial density in the posterior LA and the septum than elsewhere in the atria. Moreover, myocytes in the LA roof, than in the CS, were of lower density, more randomly arranged in the direction of conduction, and characterized by more disorganized distribution of connexin 43 over the entire cell membrane, which is consistent with the slower impulse propagation there.

CONCLUSION

The intrinsic histoanatomic heterogeneity in the LA would constitute a pro-reentrant substrate responsible for perpetuating AF/AFL.

Finite element analysis of the biomechanical interaction between coronary sinus and proximal anchoring stent in coronary sinus annuloplasty

Recent clinical studies of the percutaneous transvenous mitral annuloplasty (PTMA) devices have shown a short-term reduction of mitral regurgitation after implantation. However, adverse events associated with the devices such as compression and perforation of vessel branches, device migration and fracture were reported. In this study, a finite element analysis was carried out to investigate the biomechanical interaction between the proximal anchor stent of a PTMA device and the coronary sinus (CS) vessel in three steps including: (i) the stent release and contact with the CS wall, (ii) the axial pull t the stent connector and (iii) the pressure inflation of the vessel wall. To investigate the impact of the material properties of tissues and stents on the interactive responses, the CS vessel was modelled with human and porcine material properties, and the proximal stent was modelled with two different Nitinol materials with one being stiffer than the other. The results indicated that the vessel wall stresses and contact forces imposed by the stents were much higher in the human model than the porcine model. However, the mechanical differences induced by the two stent types were relatively small. The softer stent exhibited a better fatigue safety factor when deployed in the human model than in the porcine model. These results underscored the importance of the CS tissue mechanical properties. Vessel wall stress and stent radial force obtained in the human model were higher than those obtained in the porcine model, which also brought up questions as to the validity of using the porcine model to assess device mechanical function. The quantification of these biomechanical interactions can offer scientific insight into the development and optimisation of the PTMA device design.

Human coronary venous anatomy: implications for interventions

The coronary venous system is a highly variable network of veins that drain the deoxygenated blood from the myocardium. The system is made up of the greater cardiac system, which carries the majority of the deoxygenated blood to the right atrium, and the smaller cardiac system, which drains the blood directly into the heart chambers. The coronary veins are currently being used for several biomedical applications, including but not limited to cardiac resynchronization therapy, ablation therapy, defibrillation, perfusion therapy, and annuloplasty. Knowledge of the details of the coronary venous anatomy is essential for optimal development and delivery of treatments using this vasculature. This article is part of a JCTR special issue on Cardiac Anatomy.

Imaging of the coronary sinus: normal anatomy and congenital abnormalities

Knowledge of the anatomy of the coronary sinus (CS) and cardiac venous drainage is important because of its relevance in electrophysiologic procedures and cardiac surgeries. Several procedures make use of the CS, such as left ventricular pacing, mapping and ablation of arrhythmias, retrograde cardioplegia, targeted drug delivery, and stem cell therapy. As a result, it is more important for physicians interpreting the results of computed tomographic (CT) examinations dedicated to the heart or including the heart to be able to identify normal variants and congenital anomalies and to understand their clinical importance. Abnormalities of the CS range from anatomic morphologic variations to hemodynamically significant anomalies such as an unroofed CS, anomalous pulmonary venous connection to the CS, and coronary artery-CS fistula. It can be important to identify some anatomic variations, even though they are clinically occult, to ensure appropriate preprocedural planning. Both CT and magnetic resonance imaging provide excellent noninvasive depiction of the anatomy and anomalies of the CS. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.324105220/-/DC1.

Variance in coronary venous anatomy: a critical determinant in optimal candidate selection for cardiac resynchronization therapy

BACKGROUND

Knowledge of coronary sinus (CS) anatomy and its variations is one of the important factors determining the final position of left ventricle pacing lead during cardiac resynchronization therapy.

METHODS

Coronary venous system anatomy, including number, diameter, and opening angles of tributaries, was studied in 50 normal formalin-fixed adult cadaveric hearts.

RESULTS

Thebesian valve (TV) and Vieussens valve were present in 64% and 60% cases, respectively. CS ostium coverage of ≥75% by TV was seen in 25% (8/32) cases. Number of prominent tributaries lying between anterior interventricular vein and middle cardiac vein varied from 1-4. In 28% of hearts, only one prominent tributary was present. Midlateral vein (average diameter 1.75 ± 0.66 mm) with an average distance of 43.5 ± 12.2 mm from coronary ostium was present in 58% (29/50) hearts, of which it formed an acute angle with CS axis in four (13.39%) cases. Posterolateral vein (average diameter 1.62 ± 0.45 mm) with an average distance of 33.4 ± 11.7 mm from coronary ostium was found in 72% (36/50) cases and formed an acute angle with CS in three (8.33%) cases.

CONCLUSIONS

Restrictive TV covering ≥75% CS ostium (25% cases), presence of single prominent tributary (28% cases), and formation of acute angle of tributary with CS axis (1/4 cases with anterolateral vein, 4/29 cases with midlateral vein, 3/36 cases with posterolateral vein, and 3/28 cases with posterior veins of the left ventricle) can impede successful cannulation of CS.

Atrial Coronary Arteries: Anatomy And Atrial Perfusion Territories

Coronary anatomy has traditionally focused on ventricular circulation. This is largely due to the extent to which coronary artery disease contributes to ischemic heart disease through ventricular myocardial damage. Atrial fibrillation and other tachyarrhythmias that involve the atria, however, remain a major cause of morbidity and mortality. In order to increase mechanistic research and therapeutic interventional procedures for diseases of the atria, an optimal knowledge of atrial anatomy is necessary. While substantial clarity exists regarding the distribution of nerve terminals and the organization of muscle bundles, the anatomy of coronary atrial circulation remains understudied. Historically, the high anatomical variability of atrial coronary branches led to unstandardized nomenclature in the literature. In this review, we delineate the anatomic courses of key atrial coronary branches and their perfusion territories, clarify their nomenclature, and propose unifying anatomical concepts of atrial circulation that we believe to be critical to the success of modern electrophysiologic and surgical procedures.

Comparison of biaxial mechanical properties of coronary sinus tissues from porcine, ovine and aged human species

Due to its proximity to the mitral valve, the coronary sinus (CS) vessel serves as a conduit for the deployment and implantation of the percutaneous transvenous mitral annuloplasty (PTMA) devices that can potentially reduce the mitral regurgitation. Because CS vessel is a venous tissue and seldom diseased, its mechanical properties have not been well studied. In this study, we performed a multi-axial mechanical test and histological analysis to characterize the mechanical and structural properties of the aged human, porcine and ovine CS tissues. The results showed that the aged human CS tissues exhibited much stiffer and highly anisotropic behaviors compared to the porcine and ovine. Both of the porcine and ovine CS vessel walls were thicker and mainly composed of striated muscle fibers (SMF), whereas the thinner aged human CS had higher collagen, less SMF, and more fragmented elastin fibers, which are possibly due to aging effects. We also observed that the anatomical features of porcine CS vessel might be not suitable for PTMA deployment. These differences between animal and human models raise questions for the validity of using animal models to investigate the biomechanics involved in the PTMA intervention. Therefore, caution must be taken in future studies of PTMA stents using animal models.

The ostial valve of the great saphenous vein

Background

Venous valves have been classified into parietal (PVs) and ostial valves (OVs). PVs are located within the lumen of veins, whereas the OVs are located directly at the confluence of two veins. In the common femoral vein (CFV), the most prominent PVs are the suprasaphenic and infrasaphenic valve. The terminal valve (often designated as ‘valvule ostiale’ in the relevant literature in French) defined as that lying between the orifice of the great saphenous vein (GSV) and the most proximal of the major superficial tributary veins and the preterminal valve represent the most important PVs in the GSV. While PVs are well studied, there is not much literature on the OVs of the superficial venous system, especially of the GSV.

Objective

In order to investigate the presence of OVs (defined strictly as valves located at the entrance of a tributary vein) in the GSV, we carried out studies on specimens obtained from bodies bequested to the Division of Clinical and Functional Anatomy of Innsbruck Medical University.

Methods

Ninety-eight specimens consisting of the CFV and the attached tributary veins including the GSV were investigated.

Results

In five of these (5.1%), a single-cusped OV, in six (6.1%) a two-cusped OV and in 10 (10.2%) remnants of an OV were identified. Thus, OVs do not seem to be primarily present in all GSVs.

Conclusion

The distinction between PVs and OVs is not always clear in literature, and as a consequence misinterpretations may occur. Very often the terminal valve of the GSV, which is in fact a PV, is designated as an ‘ostial valve’. In view of its widespread use, we suggest that the term ‘ostial valve’ together with its clear description be included in the consensus documents of the ‘Union Internationale de Phlébologie’.

Time-resolved analysis of coronary vein motion and cross-sectional area

PURPOSE

To quantify periods of low motion and cross-sectional area changes of the coronary veins during the cardiac cycle for planning magnetic resonance coronary venograms (MRCV).

MATERIALS AND METHODS

Images were acquired from 19 patients with coronary artery disease (CAD) and 13 patients scheduled for cardiac resynchronization therapy (CRT). The displacement and cross-sectional area of the coronary sinus was tracked, and periods of low motion were defined as consecutive time points during which the position of the coronary sinus remained within a 0.67-mm diameter region. Patients were classified as systolic dominant or diastolic dominant based on the relative duration of their low motion periods.

RESULTS

All CRT patients were classified as systolic dominant, and 32% of these had no separate diastolic rest period. All CAD patients with ejection fraction < 35% were classified as systolic dominant, while all CAD patients with ejection fraction > 35%were diastolic dominant. In 77% of all subjects, the cross-sectional area of the coronary sinus was larger in systole than in diastole.

CONCLUSION

The movement of the coronary sinus can be used to classify patients as either having a longer systolic or diastolic rest period. The classification of the CRT patients as systolic dominant suggests that MRCVs be acquired in systole for CRT planning; however, each patient's low motion periods should be categorized to ensure the correct period is being used to minimize motion artifacts.

Theoretical models for coronary vascular biomechanics: progress & challenges

A key aim of the cardiac Physiome Project is to develop theoretical models to simulate the functional behaviour of the heart under physiological and pathophysiological conditions. Heart function is critically dependent on the delivery of an adequate blood supply to the myocardium via the coronary vasculature. Key to this critical function of the coronary vasculature is system dynamics that emerge via the interactions of the numerous constituent components at a range of spatial and temporal scales. Here, we focus on several components for which theoretical approaches can be applied, including vascular structure and mechanics, blood flow and mass transport, flow regulation, angiogenesis and vascular remodelling, and vascular cellular mechanics. For each component, we summarise the current state of the art in model development, and discuss areas requiring further research. We highlight the major challenges associated with integrating the component models to develop a computational tool that can ultimately be used to simulate the responses of the coronary vascular system to changing demands and to diseases and therapies.

Characterization of the mechanical properties of the coronary sinus for percutaneous transvenous mitral annuloplasty

The coronary sinus (CS) vessel serves as a conduit for the deployment of percutaneous transvenous mitral annuloplasty (PTMA) devices for the treatment of functional mitral regurgitation. Characterization of the mechanical response of the CS is an important step towards an understanding of tissue-device interaction in PTMA intervention. The purpose of this study was to investigate the mechanical properties of the porcine CS using the pressure-inflation test and constitutively model the wall behavior using a four fiber family strain energy function (SEF). The results showed that the CS exhibited an S-shaped pressure-radius response and could be dilated up to 88% at a pressure of 80mmHg. Excellent results from model fitting indicated that the four fiber family SEF could capture the experimental data well and could be used in future numerical simulations of tissue-device interaction. In addition, a histological study was performed to identify the micro-structure of the CS wall. We found a high content of striated myocardial fibers (SMFs) surrounding the CS wall, which was also mainly composed of SMFs, while the content of smooth muscle cells was very low. Elastin and collagen fibers were highly concentrated in the luminal and outer layers and sparsely distributed in the medial layer of the CS wall. These structural and mechanical properties of the CS should be taken into consideration in future PTMA device designs.