Search

A cell’s function is defined by its intrinsic characteristics and its niche: the tissue microenvironment in which it dwells. Here, we combine single-cell and spatial transcriptomic data to discover cellular niches within eight regions of the human heart. We map cells to micro-anatomic locations and integrate knowledge-based and unsupervised structural annotations. For the first time, we profile the cells of the human cardiac conduction system, revealing their distinctive repertoire of ion channels, G-protein coupled receptors, and cell interactions using a customCellPhoneDB.orgmodule. We show that the sinoatrial node is compartmentalised, with a core of pacemaker cells, fibroblasts and glial cells supporting paracrine glutamatergic signalling. We introduce a druggable target prediction tool, drug2cell, which leverages single-cell profiles and drug-target interactions, providing unexpected mechanistic insights into the chronotropic effects of drugs, including GLP-1 analogues. In the epicardium, we show enrichment of both IgG+ and IgA+ plasma cells forming immune niches which may contribute to infection defence. We define a ventricular myocardial-stress niche enriched for activated fibroblasts and stressed cardiomyocytes, cell states that are expanded in cardiomyopathies. Overall, we provide new clarity to cardiac electro-anatomy and immunology, and our suite of computational approaches can be deployed to other tissues and organs.

Objectives We sought to identify patients with repaired tetralogy of Fallot (rTOF) at high risk of death and malignant ventricular arrhythmia (VA). Background To date there is no robust ri...

Mitral annular disjunction (MAD) is an abnormal insertion of the hinge line of the posterior mitral leaflet on the atrial wall: the mitral annulus shows a separation or "disjunction" between the leaflet-atrial wall junction and the crest of the left ventricle myocardium. This anomaly is often observed in patients with myxomatous mitral valve prolapse. The anatomical substrate of MAD remains unclear for the following reasons: (1) most studies are focused on the association between MAD and arrhythmias, rather than on pathomorphological aspects of MAD; and (2) the complex anatomic architecture of the posterior mitral annulus is often simply described as the posterior segment of a fibrous ring. The aims of this paper are to review the pertinent normal anatomy of the mitral valve and to propose new hypotheses on the morphological nature of MAD.

Hearts with double outlet ventricles and concordant atrioventricular connections account for about 1%–3% of all cases of congenital heart disease. We review hearts with two ventricles and concordant atrioventricular connections with double outlet right ventricle (DORV), double outlet left ventricle (DOLV) and double outlet both ventricles (DOBV) from the morphological and clinical imaging perspectives. These hearts are a heterogeneous group of congenital cardiac malformations with a wide range of pathophysiologies that require an individualised surgical approach based on a precise understanding of the complex cardiovascular anatomy. Owing to their differing temporal, spatial and contrast resolutions, we propose that multimodality imaging provides optimal characterisation of various intracardiac morphological features of double outlet hearts. This approach aids clinical diagnosis for optimising treatment options across these malformations.

Background: Congenitally corrected transposition of the great arteries (ccTGA) is a rare disease of unknown cause. We aimed to better understand familial recurrence patterns. Methods: An international, multicentre, retrospective cohort study was conducted in 29 tertiary hospitals in 6 countries between 1990 and 2018, entailing investigation of 1043 unrelated ccTGA probands. Results: Laterality defects and atrioventricular block at diagnosis were observed in 29.9% and 9.3%, respectively. ccTGA was associated with primary ciliary dyskinesia in 11 patients. Parental consanguinity was noted in 3.4% cases. A congenital heart defect was diagnosed in 81 relatives from 69 families, 58% of them being first-degree relatives, including 28 siblings. The most prevalent defects in relatives were dextro-transposition of the great arteries (28.4%), laterality defects (13.6%), and ccTGA (11.1%); 36 new familial clusters were described, including 8 pedigrees with concordant familial aggregation of ccTGA, 19 pedigrees with familial co-segregation of ccTGA and dextro-transposition of the great arteries, and 9 familial co-segregation of ccTGA and laterality defects. In one family co-segregation of ccTGA, dextro-transposition of the great arteries and heterotaxy syndrome in 3 distinct relatives was found. In another family, twins both displayed ccTGA and primary ciliary dyskinesia. Conclusions: ccTGA is not always a sporadic congenital heart defect. Familial clusters as well as evidence of an association between ccTGA, dextro-transposition of the great arteries, laterality defects and in some cases primary ciliary dyskinesia, strongly suggest a common pathogenetic pathway involving laterality genes in the pathophysiology of ccTGA.

Bei haufiger rechtsventrikularer apikaler Schrittmacherstimulation kann eine Einschrankung der linksventrikularen Pumpfunktion mit dem klinischen Bild einer Herzinsuffizienz resultieren, mit zusatzlichen moglichen Konsequenzen bis hin zu erhohter Mortalitat. Dies fuhrte zu dem Bestreben, alternative Stimulationsorte zu identifizieren, die eine physiologischere Stimulation erlauben. Als attraktive Alternative wird heutzutage das His-Bundel(HB)-Pacing diskutiert, bei dem durch direkte Stimulation das physiologische Reizleitungssystem genutzt werden kann und so eine intrinsische Uberleitung mit physiologischer Kammerkontraktion moglich wird. Das Aufsuchen und Identifizieren des His-Bundels stellt fur den Implanteur eine Herausforderung dar. Erforderlich fur das endokardiale Mapping ist eine exakte Kenntnis der anatomischen Orientierungspunkte sowie die Fahigkeit zur Beurteilung lokaler Elektrogramme. Ziel dieses Ubersichtsartikels ist die Beschreibung der anatomischen Landmarken, die helfen sollen, diese wichtigen Zielstrukturen aufzufinden.

Even though the tricuspid valve is no longer “forgotten”, it still remains poorly understood. In this review, we focus on some controversial and still unclear aspects of tricuspid anatomy as illustrated by noninvasive imaging techniques. In particular, we discuss the anatomical architecture of the so-called tricuspid annulus with its two components (i.e., the mural and the septal annulus), emphasizing the absence of any fibrous “ring” around the right atrioventricular junction. Then we discussed the extreme variability in number and size of leaflets (from two to six), highlighting the peculiarities of the septal leaflet as part of the septal atrioventricular junction (crux cordis). Finally, we describe the similarities and differences between the tricuspid and mitral valve, suggesting a novel terminology for tricuspid leaflets.

Aims Supraventricular tachycardia (SVT) is one of the most frequent complications in adult patients with congenital heart disease (CHD). Limited experience exists for successful ablation in complex CHD patients with prior Damus-Kaye-Stansel (DKS) surgery. Methods All patient files of a single-center were screened retrospectively to identify CHD patients with prior DKS surgery throughout a time-interval from 1998 to 2020. These were analysed with focus on SVT, treatment and outcome of catheter ablation (CA). Results Overall, 13 patients with prior DKS surgery were identified (median age 22.0 years (IQR 20.5–25.5 years), 76.9% male, 92.3% NYHA Class I, median systemic ventricular ejection fraction 58.5% (IQR 53.0–65.5), 69.2% extra cardiac tunnel). Seven patients (53.8%) presented with symptomatic SVT (median cycle length 440 ms (IQR 360–517 ms)). Of these, five patients underwent CA using remote magnetic navigation. The majority of procedures were performed through a retrograde access using three-dimensional image integration. Median procedure time was 180.5 min (IQR 160.8–274.5 min), median fluoroscopy time 1.5 min (IQR 0.5–4.7 min) and radiofrequency time 851 s (265–2005 s). No peri- or postinterventional complications were observed. After a mean of 1.5 procedures, all patients were complaint-free without documentation of tachycardia recurrence throughout a median follow-up of 13 months (IQR 5.8–17.5 months). Conclusion In complex univentricular situations after Damus-Kaye-Stansel surgery, ablation for supraventricular tachycardia can be achieved safely and successfully. Techniques such as remote magnetic navigation and three-dimensional image integration may aid for successful procedure results.

For many years, the left atrial appendage (LAA) was considered a dormant embryological remnant; however, it is a structurally complex and functional organ that contributes to cardiac haemodynamic changes and volume homeostasis through both its contractile properties and neurohormonal peptide secretion. When dysfunctional, the LAA contributes to thrombogenesis and subsequent increased predisposition to cardioembolic events. Consequently, the LAA has gained much attention as a therapeutic target to lower this risk. In addition, attention has focused on the LAA in its role as an electrical trigger for atrial tachycardia and atrial fibrillation with ablation of the LAA to achieve electrical isolation showing promising results in the maintenance of sinus rhythm. This in-depth review explores the structure, physiology and pathophysiology of the LAA, as well as LAA intervention and their sequelae.

The mitral annulus (MA) is not a continuous ring of connective tissue from which are suspended mitral leaflets. Instead, it is a much more complex structure made up of a mix of fibrous, muscular, and adipose tissues. MA is a key structure in any type of mitral valve repair and recently it has been targeted for transcutaneous devices. Thus, a deep understanding of MA anatomy has never been more important. Traditionally, cardiac anatomy has been described using anatomic specimens. Currently, sophisticated non-invasive techniques allow imaging of MA with a richness of anatomical details unimaginable only two decades ago. The aim of this review is to provide a better understanding of the peculiar aspects of MA as they are revealed through these imaging techniques and discuss clinical implications related to this complex structure.

Idiopathic ventricular arrhythmias occur in the absence of underlying structural heart disease and less commonly in the presence of coexistent, but mechanistically unrelated, myocardial scar. These arrhythmias originate from several anatomical sites in both ventricles, with a predilection in outflow tract structures. The 12-lead surface ECG is the initial mapping tool, which is widely used to identify their origin. Specific features can predict the site of idiopathic ventricular arrhythmias, thus differentiating right from left ventricular, as well as endocardial from epicardial origins. In this review, we aim to analyse electrocardiographic landmarks for determination of idiopathic ventricular arrhythmia sources, with specific emphasis on pertinent caveats and anatomical relationships.

Interest in the anatomy of the interatrial septum (IAS) and its adjoining atrioventricular (AV) junction has risen enormously in the past two decades with the simultaneous evolution of left-sided percutaneous structural heart disease and complex electrophysiologic procedures. These procedures require, in fact, a direct route to the left atrium through the IAS. Thus, a thorough understanding of the complex anatomy of the IAS and AV junction is essential for performing a safe and effective transseptal puncture. There is a large amount of literature carefully describing the anatomy of the IAS and AV junction. These studies are based almost exclusively on anatomic specimens. Conversely, in this review the authors emphasize the role of noninvasive imaging techniques, in particular cardiac magnetic resonance, two- and three-dimensional transesophageal echocardiography, and computed tomography in visualizing specific aspects of the normal IAS and AV junction. Where appropriate, the authors present images side by side, with corresponding anatomic specimens.

Aims Inadvertent puncture of the aortic root (AR) is a well-known complication of transseptal puncture (TSP). Strategies for handling of this potentially lethal complication have not been identified yet. In this study, we present typical anatomical locations and clinical management of aortic root puncture (ARP) due to TSP. Methods and results All patients with ARP were retrospectively collected from seven hospitals. Aortic root puncture was identified and classified regarding angiographical and intraoperative findings in cardiac surgery: (i) TSP from the right atrium (RA) to the non-coronary sinus (NCS), (ii) TSP from RA to the non-coronary sinutubular junction (STJ), and (iii) TSP from RA to the ascending aorta (AA). A total of 24 patients with inadvertent ARP were identified. In 19 patients, penetration of the aorta was accomplished by the inner dilator, in 5 patients by the complete sheath. Previous cardiac surgery had been performed in six patients. There were 13 RA-to-NCS punctures, 2 RA-to-STJ punctures, and 9 RA-to-AA punctures. No cardiac tamponade (CT) occurred in patients with RA-to-NCS and RA-to-STJ punctures. In 8 of 9 patients with RA-to-AA puncture, CT occurred immediately requiring urgent pericardiocentesis and surgical repair. Two patients died after surgical repair. In the 16 patients without surgical therapy, no shunt from the AR to the RA was observed 3 months after the procedure. Conclusion Aortic root puncture due to mislead TSP via NCS or STJ is usually not associated with a severe clinical course while ARP into the AA via the epicardial space generally leads to CT requiring surgical repair.

Surgery for tetralogy of Fallot has a long history, which may be described as both a success story and a failure story. It is a success story because prognosis without surgery is very poor, but surgery makes it possible for affected babies to reach adulthood and lead productive lives. It is a failure story, however, since we still cannot cure this condition; we can only palliate it as illustrated in the sobering long-term outcome of affected patients. In this review article, we aim to explore the reason for this failure. This may be summed up in terms of the nature of the obstruction to the right ventricular outflow tract, which characterizes this malformation and must be relieved. This obstruction has several possible components, but none may be eliminated without harming the ventricle. There seems to be no 'extra' muscle band in tetralogy of Fallot that may be dispensed with without undermining ventricular function; every muscle band that is there should be there, just like in the normal heart, except that these are thicker than normal and somewhat displaced in tetralogy of Fallot, thus narrowing the right ventricular outflow tract. Consequently, ventricular function deteriorates with every muscle band that is cut, just like in the normal heart. We have to harm the heart in order to repair it. Every repaired Fallot is inevitably a damaged heart. Consequently, repair of this condition cannot be curative at present; it is palliative surgery.

Transcatheter procedures offer an alternative to cardiac surgery in select patients with structural heart disease (SHD). Unfortunately, inadvertent disruption of electrical pathways and subsequent development of new onset conduction disturbances can occur in up to 5–70% of percutaneous interventions, result in pacemaker implantation, and confer a worse prognosis. The physical proximity between the conduction system (atrioventricular node, bundle of His, and bundle branches) and the site of percutaneous repair is increasingly recognized as a key factor influencing new onset conduction disturbance development in procedures located near the conduction system. This review covers the incidence, clinical significance, and mechanisms of new onset conduction disturbances and discusses current and emerging strategies to address this complication in these populations.

Introduction Congenitally corrected transposition of the great arteries (ccTGA) is a rare disease of unknown aetiology. We aimed to better understand familial recurrence pattern. Methods An international, multicentre, retrospective cohort study was conducted in 29 tertiary hospitals in 6 countries between 1990 and 2018, leading to investigate 1043 unrelated ccTGA probands. Results Atrioventricular block at diagnosis and laterality defects were observed in 35.4% and 29.9%, respectively. ccTGA associated with primary ciliary dyskinesia in 10 patients. Parental consanguinity was noted in 3.4% cases. A congenital heart defect was diagnosed in 81 relatives from 69 families, 58% of them being first-degree relatives, including 28 siblings. The most prevalent defects in relatives were dextro-transposition of the great arteries (d-TGA: 28.4%), laterality defects (13.6%) and ccTGA (11.1%); 36 new familial clusters were described, including 8 pedigrees with concordant familial aggregation of ccTGA, 19 pedigrees with familial co-segregation of ccTGA and d-TGA and 9 familial co-segregation of ccTGA and laterality defects. In one family there was co-segregation of ccTGA, d-TGA and heterotaxy syndrome in 3 distinct relatives. Conclusion ccTGA is not always a sporadic congenital heart defect. Familial clusters as well as evidence of an association between ccTGA, d-TGA, laterality defects and in some cases primary ciliary dyskinesia strongly suggest a common pathogenetic pathway involving laterality genes in the pathophysiology of ccTGA.

This study sought to identify patients with repaired tetralogy of Fallot (rTOF) at high risk of death and malignant ventricular arrhythmia (VA).To date there is no robust risk stratification scheme to predict outcomes in adults with rTOF.Consecutive patients were prospectively recruited for late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) to define right and left ventricular (RV, LV) fibrosis in addition to proven risk markers.The primary endpoint was all-cause mortality. Of the 550 patients (median age 32 years, 56% male), 27 died (mean follow-up 6.4 ± 5.8; total 3,512 years). Mortality was independently predicted by RVLGE extent, presence of LVLGE, RV ejection fraction ≤47%, LV ejection fraction ≤55%, B-type natriuretic peptide ≥127 ng/L, peak exercise oxygen uptake (V0We present a score integrating multiple appropriately weighted risk factors to identify the subgroup of patients with rTOF who are at high annual risk of death who may benefit from targeted therapy.

The overall aim of an invasive electrophysiological (EP) evaluation is to accurately diagnose the mechanism and substrate responsible for a documented or suspected arrhythmia to treat the patient’s symptoms or improve his/her prognosis. Significant developments in the understanding of arrhythmias as well as technological advances have allowed electrophysiology studies to be considered as a diagnostic first line option. This chapter discusses the fundamental principles of invasive electrophysiology and provides an essential guide in terms of establishing the correct diagnosis and ablation strategy.

The morphological changes that occur in myxomatous mitral valve disease (MMVD) involve various components, ultimately leading to the impairment of mitral valve (MV) function. In this context, intrinsic mitral annular abnormalities are increasingly recognized, such as a mitral annular disjunction (MAD), a specific anatomical abnormality whereby there is a distinct separation between the mitral annulus and the left atrial wall and the basal portion of the posterolateral left ventricular myocardium. In recent years, several studies have suggested that MAD contributes to myxomatous degeneration of the mitral leaflets, and there is growing evidence that MAD is associated with ventricular arrhythmias and sudden cardiac death. In this review, the morphological characteristics of MAD and imaging tools for diagnosis will be described, and the clinical and functional aspects of the coincidence of MAD and myxomatous MVP will be discussed.

Background: Adults with repaired tetralogy of Fallot die prematurely from ventricular tachycardia (VT) and sudden cardiac death. Inducible VT predicts mortality. Ventricular scar, the key substrate for VT, can be noninvasively defined with late gadolinium enhancement (LGE) cardiovascular magnetic resonance but whether this relates to inducible VT is unknown. Methods: Sixty-nine consecutive repaired tetralogy of Fallot patients (43 male, mean 40±15 years) clinically scheduled for invasive programmed VT-stimulation were prospectively recruited for prior 3-dimensional LGE cardiovascular magnetic resonance. Ventricular LGE was segmented and merged with reconstructed cardiac chambers and LGE volume measured. Results: VT was induced in 22 (31%) patients. Univariable predictors of inducible VT included increased RV LGE (odds ratio [OR], 1.15; P =0.001 per cm 3 ), increased nonapical vent LV LGE (OR, 1.09; P =0.008 per cm 3 ), older age (OR, 1.6; P =0.01 per decile), QRS duration ≥180 ms (OR, 3.5; P =0.02), history of nonsustained VT (OR, 3.5; P =0.02), and previous clinical sustained VT (OR, 12.8; P =0.003); only prior sustained VT (OR, 8.02; P =0.02) remained independent in bivariable analyses after controlling for RV LGE volume (OR, 1.14; P =0.003). An RV LGE volume of 25 cm 3 had 72% sensitivity and 81% specificity for predicting inducible VT (area under the curve, 0.81; P 10 cm 3 was 100% sensitive and >36 cm 3 was 100% specific for predicting inducible VT. Conclusions: Three-dimensional LGE cardiovascular magnetic resonance-defined scar burden is independently associated with inducible VT and may help refine patient selection for programmed VT-stimulation when applied to an at least intermediate clinical risk cohort.

The detailed anatomy of the interatrial septum (IAS) and mitral annulus (MA) as observed on cardiac magnetic resonance, computed tomography and two-dimensional/three-dimensional transthoracic and transesophageal echocardiography is reviewed. The IAS comprises of two components: the septum primum that is membrane-like forming the floor of the fossa ovalis (FO) and the septum secundum that is a muscular rim that surrounds the FO. The latter is an enfolding of atrial wall forming an interatrial groove. Named Waterston’s groove, it is filled with adipose tissue on the epicardial side. Thus, the safest area for transseptal puncture (TSP) is within the limits of the FO floor, which provides direct interatrial access. While crossing an intact septum is a well-established procedure, TSP is a more complex and time-consuming procedure in the presence of patent foramen ovalis, aneurysmal FO or atrial septal defect closure devices. MA comprises two distinctive segments: an anterior-straight and a posterior-curved segment. The posterior MA is a thin, discontinuous fibrous ‘string’, interspersed with adipose tissue, where four components converge: the atrial and ventricular musculature, epicardial adipose tissue and the leaflet’s hinge line. In parts of where this fibrous string is deficient or absent, the posterior leaflet is inserted directly on ventricular and atrial myocardium rendering the MA less robust and producing an ‘asymmetric’ dilation. The marked vulnerability of posterior MA to calcifications might be due to its insertion on the crest of ventricular myocardium being subject to friction injury due to the contraction and relaxation of LV.

Objectives This study sought to systematically evaluate the ability of a high-resolution mapping system (Rhythmia, Boston Scientific, Marlborough, Massachusetts) to rapidly and accurately localize residual endocardial and epicardial conduction after mitral isthmus (MI) ablation, facilitating MI block. Background Achieving conduction block across the mitral isthmus (MI) is challenging. Methods Fifty consecutive patients undergoing MI ablation after pulmonary vein isolation were enrolled. After initial endocardial radiofrequency (RF) ablation across the lateral MI, high-resolution activation mapping of the MI with simultaneous coronary sinus (CS) mapping was performed to verify block or localize residual conduction across the MI during left atrial (LA) appendage and CS pacing. Propagation maps were used to identify residual conduction across the MI as endocardial, via the CS or Marshall tract. Results In all 50 patients, after the initial endocardial ablation across the MI, repeat high-resolution mapping of the LA and CS was obtained (median: 3,329 mapped points; 4.0 min of mapping time). The initial endocardial MI ablation resulted in block in 9 of 50 patients (18%). In the remaining 41 patients, the propagation map identified residual conduction in 4 patterns: 1) only endocardial gap in 12 patients (29%); 2) only CS connection in 10 patients (24%); 3) both endocardial and CS connections in 14 patients (34%); and 4) Marshall tract connection in 5 patients (12%). In 8 patients, the propagation map revealed residual conduction, despite differential atrial pacing suggesting bidirectional block. Focal ablation at the identified residual conduction site (median: 0.7 min of RF) resulted in block in 49 of 50 (98%) patients. Conclusions High-resolution propagation maps of the LA/CS rapidly and accurately localize residual endocardial and epicardial conduction across the MI. Focal ablation with short RF time at the identified gap(s) achieved complete block across MI in 98% of cases.

Tricuspid regurgitation (TR) is a frequent and complex problem, commonly combined with left-sided heart disease, such as mitral regurgitation. Significant TR is associated with increased mortality if left untreated or recurrent after therapy. Tricuspid regurgitation was historically often disregarded and remained undertreated. Surgery is currently the only Class I Guideline recommended therapy for TR, in the form of annuloplasty, leaflet repair, or valve replacement. As growing experience of transcatheter therapy in structural heart disease, many dedicated transcatheter tricuspid repair or replacement devices, which mimic well-established surgical techniques, are currently under development. Nevertheless, many aspects of TR are little understood, including the disease process, surgical or interventional risk stratification, and predictors of successful therapy. The optimal treatment timing and the choice of proper surgical or interventional technique for significant TR remain to be elucidated. In this context, we aim to highlight the current evidence, underline major controversial issues in this field and present a future roadmap for TR therapy.

Long-term right ventricular apical pacing is known to be deleterious for left ventricular function leading to the clinical picture of heart failure with all the possibly associated complications, ranging up to death of the affected patient. This led to the ambition to find alternative pacing sites such as pacing at the right ventricular outflow tract or septal pacing. An attractive alternative is selective His bundle pacing with the goal to use the physiologic His-Purkinje system in order to enable intrinsic conduction and physiologic myocardial contraction. To find and identify the His bundle poses a challenge for operators. For exact endocardial mapping, knowledge of the anatomic landmarks is as important as the ability to evaluate local electrocardiograms. The goal of this review is to characterize the anatomic landmarks to help physicians to identify these precise targets for His bundle pacing.

For full understanding of the relevance of a deep knowledge of the anatomy of the interatrial septum (IAS), this chapter begins with a brief description of the history of transseptal puncture (TSP) from its origin to the current day. Moreover, a brief clarification of interatrial septation in fetal life will help readers to better understand terms such as septum primum (SP) and septum secundum (SS), as well as adjectives such as “false” and “true” IAS.

As in the previous chapters, the three imaging techniques will be used to illustrate anatomy. In this chapter we describe the anatomy of left ventricle (LV) and right ventricle (RV).

This chapter describes the anatomy of the right and left atria using computed tomography (CT), cardiac magnetic resonance (CMR), and two-dimensional (2D) and three-dimensional (3D) transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE), illustrated side-by-side with anatomic specimens where possible. Because these noninvasive techniques differ in their ability to visualize right atrial structures, however, this chapter begins by describing the advantages and limits of CT, CMR, and 2D/3D TTE and TEE.

A deep understanding of human coronary arteries anatomy and spatial relationships between coronary vessels and surrounding myocardium helps to provide insights for interpreting invasive coronary angiography and recognizing potential ischemic territories. On the other hand, a sustained interest in the anatomy of the coronary veins system is due to the introduction of cardiac resynchronization therapy and to the development of new devices that are implanted in the coronary sinus with the aim to reduce functional mitral regurgitation. These topics will be covered extensively in this chapter. Finally, a brief paragraph on the histology of coronary arteries explains the relevant role of endothelium.

The term aortic root (or arterial root) refers to the entirety of the aortic valve from its position at the left ventricular outlet to its junction with the tubular portion of the ascending aorta. Thus, the functioning valve is much more complex than only leaflets or flaps passively guarding the ventricular exit. The first “scientific” report of the sophisticated architecture of the aortic root dates back to the writings and drawings of Leonardo da Vinci. He drew three small bulges at the base of the aorta and correctly theorized their function, picturing the “eddy currents” or vortexes between leaflets and sinuses. Two hundred years later, these three bulges would be given the name “Valsalva’s sinuses” by Antonio Maria Valsalva, an Italian anatomist. In reality, Valsalva was more interested in the anatomy of the hearing system, and his famous book, De Aure Humana Tractatus (“The Book of the Human Ear”), remained the gold standard on the subject for more than a century. He had also discovered an original method of pressurizing the middle ear, the Valsalva maneuver, which is still widely used. Valsalva performed many dissections of the chest, and described the sinuses of Valsalva as “pouches of the aorta and the pulmonary artery opposite the flaps of the semilunar valves.” He was intrigued by the uniform presence of sinuses in a variety of birds and mammalians and concluded that the sinuses must have a common important function in these living species.

Interest in the anatomy of the tricuspid valve has increased in the past two decades with the awareness that functional tricuspid regurgitation (FTR) is not an innocuous bystander of left-side heart disease but, on the contrary, is an insidious disease progressively leading to untreatable right heart failure and eventually to death. Most cases of severe tricuspid regurgitation are functional, due to right ventricular (RV) enlargement, annular dilatation, and leaflet tethering. Commonly, RV dilatation is secondary to left-side valvular diseases (mainly mitral valve stenosis or regurgitation), heart failure, and RV volume or pressure overload. Less frequently, severe FTR is the consequence of tricuspid annular dilatation due to isolated atrial enlargement caused by atrial fibrillation. Mild tricuspid regurgitation in the setting of a structurally normal tricuspid valve is a normal echocardiographic aspect.

Deficiencies in the septum separating the two atrial chambers are among the most common of congenital heart malformations. This article reviews the developmental aspects of the partitioning of the primitive atrium into right and left atrial chambers, the anatomical components of the atrial septum, and deficiencies that produce the various types of interatrial communications. Knowledge of the components of the true atrial septum in the developed heart clarifies the morphology of various types of interatrial communications. The oval fossa defect (also termed secundum ASD) is located within the true septum. The patent foramen ovale (PFO) is a tunnel-like passageway between the free edge of the overlapping ovale fossa valve and its muscular rim. Other defects such as superior and inferior sinus venosus defects, coronary sinus defects, and ostium primum defects lie outside the area of the true septum.

The mitral valve (MV) is a complex and intricate structure. With the development of transesophageal echocardiography in the 1990s, it became possible to evaluate MV anatomy and function in real time during surgical procedures. Subsequently, new surgical and percutaneous techniques for MV repair as well as replacement have evolved. Development of 3-dimensional and intracardiac echocardiography, as well as computed tomography, cardiac resonance imaging, and most recently fusion imaging, have paved the way for a more comprehensive evaluation of the MV as well as for the planning of percutaneous MV procedures such as balloon valvuloplasty, paravalvular mitral leak closure, percutaneous edge-to-edge repair, transcatheter MV annuloplasty, artificial chord implantation, and transcatheter MV replacement. The applicability and use of the various imaging modalities for the assessment and guidance of therapy for MV disorders is discussed in this paper.