Longitudinal Reference Ranges for Tricuspid Annular Plane Systolic Excursion and Mitral Annular Plane Systolic Excursion in Normally Grown Fetuses.

OBJECTIVES: The aim of this study was to construct reference ranges for fetal tricuspid annular plane systolic excursion (TAPSE) and mitral annular plane systolic excursion (MAPSE) using conventional M-mode ultrasound (US) in the second half of pregnancy. METHODS: Participants underwent US scans every 4 weeks from 18 weeks' gestation until delivery. The TAPSE and MAPSE were measured by conventional M-mode US at each examination. The relationships between TAPSE and MAPSE and gestational age and estimated fetal weight were modeled by Bayesian mixed effects linear regression. RESULTS: Positive linear relationships were observed between both MAPSE and TAPSE and gestational age and estimated fetal weight. Reference centiles for TAPSE and MAPSE were developed. CONCLUSIONS: This simple technique is a useful tool for assessing cardiac function and could be used for quantitative assessments of fetal cardiac function, particularly in high-risk pregnancies such as those complicated by maternal diabetes.

Early bioprosthetic tricuspid valve stenosis due to size mismatch in Ebstein anomaly-Successful transcatheter treatment.

Patients with congenital heart disease are surviving well into adulthood thanks to advances in medical and clinical care. We present a patient with Ebstein anomaly who underwent surgical tricuspid valve replacement and suffered early valve stenosis due to her unique anatomy. This case highlights the importance of the "unnatural" anatomy that can be encounter in this challenging patient population.

Functional Grading of a Transversely Isotropic Hyperelastic Model with Applications in Modeling Tricuspid and Mitral Valve Transition Regions.

Surgical simulators and injury-prediction human models require a combination of representative tissue geometry and accurate tissue material properties to predict realistic tool-tissue interaction forces and injury mechanisms, respectively. While biological tissues have been individually characterized, the transition regions between tissues have received limited research attention, potentially resulting in inaccuracies within simulations. In this work, an approach to characterize the transition regions in transversely isotropic (TI) soft tissues using functionally graded material (FGM) modeling is presented. The effect of nonlinearities and multi-regime nature of the TI model on the functional grading process is discussed. The proposed approach has been implemented to characterize the transition regions in the leaflet (LL), chordae tendinae (CT) and the papillary muscle (PM) of porcine tricuspid valve (TV) and mitral valve (MV). The FGM model is informed using high resolution morphological measurements of the collagen fiber orientation and tissue composition in the transition regions, and deformation characteristics predicted by the FGM model are numerically validated to experimental data using X-ray diffraction imaging. The results indicate feasibility of using the FGM approach in modeling soft-tissue transitions and has implications in improving physical representation of tissue deformation throughout the body using a scalable version of the proposed approach.

Morpho-functional characterization of the heart of Gallus gallus domesticus with special reference to the right muscular atrioventricular valve.

In this work, we studied the structure and function of the adult chicken heart with a focus on the right muscular atrioventricular valve using anatomic and echocardiographic methods. We demonstrated that the free wall thickness of the right and left ventricles changes from the apex to the base of the heart. The right muscular atrioventricular valve (RAVV) is joined directly to both the parietal right ventricle free wall (one attachment) and the interventricular septum (two attachments: ventral and dorsal). This valve does not have chordae tendineae or papillary muscles. The quantitative morphological and functional characterization of the RAVV is given. In color Doppler echo, no regurgitation of blood flow in the RAVV was observed in any of the studied birds. The blood flow velocity in the RAVV is 56.2 ± 9.6 cm s-1 . A contractile function of the RAVV is shown. Based on the findings obtained, we conclude that the RAVV has a sufficient barrier function. In addition, as this valve is an integral part of the right ventricle free wall, it contributes to the right ventricle pump function. An agreed nomenclature of the parts of the RAVV is required.

Intra-procedural evaluation of the cavo-tricuspid isthmus anatomy with different techniques: comparison of angiography and intracardiac echocardiography.

Cavo-tricuspid isthmus (CTI) anatomies are highly variable, and specific anatomies lead to a difficult CTI ablation. This study aimed to compare the clinical utility of angiography and intracardiac echocardiography (ICE) in evaluating CTI anatomies, and to investigate the impact of the CTI anatomy on the procedure when the ablation tactic was adjusted to the anatomy. This study included 92 consecutive patients who underwent a CTI ablation. The CTI morphology was assessed with both right atrial angiography and ICE before the ablation, and the ablation tactic was adjusted to the anatomy. The mean CTI length was 34 ± 9 mm. On ICE imaging, 21 (23%) patients had a flat CTI, while 41 (45%) had a concave CTI with a mean depth of 5.6 ± 2.7 mm. The remaining 30 (32%) had a distinct pouch with a mean depth of 6.4 ± 2.3 mm, located at the posterior, middle, and anterior isthmus in 15, 14, and 1 patients, respectively. The Eustachian ridge (ER) was visualized in 46 (50%) patients. On angiography, a pouch and ER were detected in 22 and 15 patients, but not in the remaining 8 and 31, respectively. A complete CTI block line was created in all patients without any complications. The CTI anatomy did not significantly impact any procedural parameters. ICE was superior to angiography in evaluating the detailed CTI anatomy, especially pouches and the ER. An adjustment of the ablation tactic to the anatomy could overcome the procedural difficulties of the CTI ablation in cases with specific anatomies.

Specific Anatomic Considerations for Tricuspid Interventions.

PURPOSE OF REVIEW: This review discusses the normal anatomy and pathology of the tricuspid valve (TV) and right side of the heart. Emphasis is on those anatomic and pathologic features relevant to interventions intended to restore normal function to the TV in disease states. RECENT FINDINGS: TV pathology is less common than aortic and mitral valve pathology, and treatment and outcomes for interventions face considerable hurdles. New innovations and early data showing safety and efficacy in transcatheter interventions have transformed TV interventions into the next frontier in cardiac valve disease treatment. Certain features of the TV and right heart have presented themselves as potential targets, as well as impediments, for TV intervention. The causes of TV pathology and the anatomy of the TV and right heart bring unique challenges to intervention. Approaches to intervention will continue to progress and change the way we view and treat TV pathology.

Design and Development of Novel Transcatheter Bicaval Valves in the Interventional Treatment of Tricuspid Regurgitation.

The concept of heterotopic implantation of transcatheter tricuspid valve is new and has shown promising results thus far. While the Reynolds shear stress values measured in the vicinity of this valve are relatively low, the values at some time points are higher than the threshold of platelet activation. Hence, in this study, we aim to reduce these values with an innovative stent design. It was shown that the Reynolds shear stress values measured were lower than those of valves made of generic stent design and the maximum Reynolds shear stress values in the vicinity of the valves was very low (∼10 dynes/cm2 ). The results also depicted the interesting flow phenomenon of this non-physiological treatment approach. Thus, this study has shown that bicaval valves could potentially be considered as a minimally invasive option to treat tricuspid regurgitation and valve design improvements could reduce the flow disturbances that were observed.

Geometry of Koch's triangle.

AIMS: The first aim of this study was to determine the size of the Koch's triangle. The second one was to investigate relation between its dimensions and other individual-specific and heart-specific parameters as well as to create universal formula to estimate triangle dimensions based on these parameters. METHODS AND RESULTS: This study is a prospective one, presenting 120 randomly selected autopsied hearts dissected from adult humans (Caucasian) of both sexes (31.7% females), with mean age of 49.3 ± 17.4 years. The length of triangle sides and angles were measured and the triangle area was calculated as well. Sixteen additional heart parameters were measured in order to analyse potential relationship between the dimensions of Koch's triangle and other dimensions of the heart, using linear regression analysis. The mean (±SD) length of the anterior edge was approximated to 18.0 ± 3.8 mm, the posterior edge to 20.3 ± 4.3 mm, and the basal edge to 18.5 ± 4.0 mm. The average values of the apex angle, the Eustachian angle, and the septal leaflet angle were 58.0 ± 14.4°, 53.8 ± 10.6°, and 67.6 ± 14.4°, respectively. The mean value of the Koch's triangle area was 151.5 ± 55.8 mm2. The 95th percentile of triangle's height (the distance from the apex to the coronary sinus) was 21.8 mm. CONCLUSION: Mean values and proportions of triangle's sides and angles were presented. Koch's triangle showed considerable individual variations in size. The dimensions of the triangle were strongly independent from individual-specific and heart-specific morphometric parameters; however, the maximum triangle's height can be estimated as 22 mm.

Porcine Tricuspid Valve Anatomy and Human Compatibility: Relevance for Preclinical Validation of Novel Valve Interventions.

BACKGROUND: Tricuspid regurgitation may be a precursor for heart failure, reduced functional capacity, and poor survival. A human compatible experimental model is required to understand the pathophysiology of the tricuspid valve disease as a basis for validating novel tricuspid valve interventions before clinical use. The study aim was to evaluate and compare the tricuspid valve anatomy of porcine and human hearts. METHODS: The anatomy of the tricuspid valve and the surrounding structures that affect the valve during a cardiac cycle were examined in detail in 100 fresh and 19 formalin-fixed porcine hearts obtained from Danish Landrace pigs (body weight 80 kg). All valvular dimensions were compared with human data acquired from literature sources. RESULTS: No difference was seen in the tricuspid annulus circumference between porcine and human hearts (13.0 ± 1.2 cm versus 13.5 ± 1.5 cm; p = NS), or in valve area (5.7 ± 1.6 cm2 versus 5.6 ± 1.0 cm2; p = NS). The majority of chordae types exhibited a larger chordal length and thickness in human hearts compared to porcine hearts. In both species, the anterior papillary muscle (PM) was larger than other PMs in the right ventricle, but muscle length varied greatly (range: 5.2-40.3 mm) and was significantly different in pigs and in humans (12.2 ± 3.2 mm versus 19.2 mm; p <0.001). CONCLUSIONS: The porcine tricuspid valve was determined to be a valid model for preclinical animal studies, despite various anatomic differences being noted between porcine and human hearts.

Assessment of the anatomical variation to be found in the normal tricuspid valve.

The normal tricuspid valve is tri-leaflet, supported by tendinous cords, which are themselves supported by papillary muscles. There can be marked variation in the anatomy of the normal tricuspid valve, which must be understood to differentiate it from pathological malformations. The tricuspid valve of 100 normal heart specimens was examined. The three leaflets of the tricuspid valve, along with the papillary muscles supporting the zones of apposition were identified, and details of the anatomy recorded and analyzed. All three leaflets were identified in all 100 hearts. The septal leaflet had tendinous cord attachments in 93 specimens to the ventricular septum. The medial papillary muscle had a single head in the majority of specimens, supporting the zone of apposition with the antero-superior leaflet in 97 specimens. The anterior papillary muscle attached to the mid-portion of the antero-superior leaflet in 62 specimens, and supplied the zone of apposition between the antero-superior and inferior leaflets in 81 specimens. There were rough zone cord attachments to the antero-superior leaflets in all specimens. The inferior leaflet had basal cord attachments in 87 specimens, with attachments to multiple small muscular heads in 37 specimens. The inferior papillary muscle was well formed in only 58 specimens. Although certain features are relatively constant, multiple variations in the normal tricuspid valve have been identified. Knowledge of these normal variations is necessary in understanding the function of this complex valve apparatus, along with the potential for pathology.

Pregnancy-induced remodeling of heart valves.

Recent studies have demonstrated remodeling of aortic and mitral valves leaflets under the volume loading and cardiac expansion of pregnancy. Those valves' leaflets enlarge with altered collagen fiber architecture, content, and cross-linking and biphasic changes (decreases, then increases) in extensibility during gestation. This study extends our analyses to right-sided valves, with additional compositional measurements for all valves. Valve leaflets were harvested from nonpregnant heifers and pregnant cows. Leaflet structure was characterized by leaflet dimensions, and ECM composition was determined using standard biochemical assays. Histological studies assessed changes in cellular and ECM components. Leaflet mechanical properties were assessed using equibiaxial mechanical testing. Collagen thermal stability and cross-linking were assessed using denaturation and hydrothermal isometric tension tests. Pulmonary and tricuspid leaflet areas increased during pregnancy by 35 and 55%, respectively. Leaflet thickness increased by 20% only in the pulmonary valve and largely in the fibrosa (30% thickening). Collagen crimp length was reduced in both the tricuspid (61%) and pulmonary (42%) valves, with loss of crimped area in the pulmonary valve. Thermomechanics showed decreased collagen thermal stability with surprisingly maintained cross-link maturity. The pulmonary leaflet exhibited the biphasic change in extensibility seen in left side valves, whereas the tricuspid leaflet mechanics remained largely unchanged throughout pregnancy. The tricuspid valve exhibits a remodeling response during pregnancy that is significantly diminished from the other three valves. All valves of the heart remodel in pregnancy in a manner distinct from cardiac pathology, with much similarity valve to valve, but with interesting valve-specific responses in the aortic and tricuspid valves.

Evaluation of right ventricular function using single-beat three-dimensional echocardiography in neonate.

Aim of our study was to evaluate right ventricular (RV) systolic function in neonate using newly developed single-beat three-dimensional echocardiography (sb3DE). We enrolled 15 healthy or premature neonates (0-53 days after birth). We scanned one beat full volume using Siemens ACUSON SC2000 (Siemens AG) echocardiography with 4Z1c full-volume transducer without ECG gating. RV end-diastolic volume (RVEDV) and RV end-systolic volume (RVESV) were computed with special software dedicated to analysis for RV volume. RV ejection fraction (RVEF) and RV stroke volume (3D-RVSV) were calculated. And RV stroke volume was also determined from the recordings of ejection blood flow velocity and diameter at the level of the pulmonary orifice in RV outflow tract (Doppler-RVSV). Tricuspid annular plane systolic excursion (TAPSE) was also measured by 2D echocardiography. RVEDV ranged from 5.1 to 10.7 ml (average 7.5 ml), RVESV ranged from 2.3 to 5.8 ml (average 3.9 ml). There was a good correlation between 3D-RVSV and Doppler-RVSV (r = 0.77). Bland-Altman plot revealed that 3D-RVSV became underestimation of an average of 1.78 ml compared to Doppler-RVSV. And TAPSE positively correlated with 3D-RVEF (r = 0.58, P = 0.038). Newly developed sb3DE enables us to perform three-dimensional acquisition of RV volume without ECG gating even in neonate. However, 3D-RVSV currently tends to be underestimated in neonatal measurement.

Differential and linear insertion of atrioventricular valves: a useful tool?

OBJECTIVE: The differential insertion of the atrioventricular valves is the ultrasonographic representation of the more apical attachment of the tricuspid valve to the septum with respect to the mitral valve. A linear insertion is present when both valves form a linear continuum and has been suggested as a marker for atrioventricular septal defects (AVSDs). The objective of this study was to evaluate the anatomical substratum of differential and linear insertions of the atrioventricular valves in normal fetal hearts and fetal hearts with an AVSD. METHODS: The extent and position of the fibrous skeleton and attachment of the atrioventricular valves to the septum were studied in histological sections of 17 normal hearts and four hearts with an AVSD from 10 + 0 weeks' gestation to 3 days postpartum with various immunohistochemical tissue markers. In addition, spatiotemporal image correlation (STIC) volumes of 10 normal hearts and STIC volumes of eight hearts with an AVSD at 13 + 6 to 35 + 5 weeks' gestation were examined. RESULTS: The differential insertion of the atrioventricular valves was visible in normal hearts in the four-chamber plane immediately beneath the aorta, but nearer the diaphragm a linear insertion was found. In hearts with an AVSD, a linear appearance was observed in the four-chamber plane immediately beneath the aorta. Towards the diaphragm, however, first a differential insertion and, more caudally, a linear insertion was found. CONCLUSIONS: Both differential and linear insertions can be found in normal fetal hearts and fetal hearts with AVSD, depending on the plane in which the four-chamber view is visualized. Therefore, measurement of the differential insertion is likely to be useful only in experienced hands.

Relation of cuspal asymmetry to development of aortic stenosis in adults with tricuspid aortic valves.

BACKGROUND AND AIM OF THE STUDY: The contribution of aortic valve (AV) cusp asymmetry to the future development of aortic stenosis (AS) has not been studied. METHODS: Of the 412,458 patients that underwent echocardiography between January 2003 and January 2011 at the Cleveland Clinic, 34,326 with aortic stenosis (AS) were identified from the Echocardiography Database. Among these patients, 5,830 had undergone echocardiography on more than one occasion. The review identified 71 patients who had tricuspid AV without stenosis, sclerosis or calcification, who met the study criteria, and who ultimately developed AS at a mean of 56.5 ± 19.4 months after the initial echocardiogram. Comprehensive echocardiographic AV cusp measurements taken from these echocardiograms were compared to those of 71 age- and gender-matched control subjects without AS. RESULTS: In the AS group, 11 patients (15.4%) had three equal-sized AV cusps, six (8.4%) had two equal-sized cusps, and 54 (76.1%) had three different-sized cusps. In the control group, 70 subjects (98.6%) had three equal-sized AV cusps, none had two equal-sized cusps, and one subject (1.4%) had three different-sized cusps. The average asymmetry index (AIx; %) among all the corresponding cusp measurements was significantly larger in the AS group (p = 0.000). Among the 71 AS patients, 32 developed mild AS, 30 moderate AS, and nine severe AS. The average AIx did not differ significantly based on AS severity. CONCLUSION: The presence of asymmetry among AV cusps is strongly associated with the future development of AS. The present data suggest that a non-laminar flow secondary to an asymmetric valve may predispose the AV to become stenotic.

Assessment of functional tricuspid regurgitation.

Functional tricuspid regurgitation (FTR) is characterized by structurally normal leaflets and is due to the deformation of the valvulo-ventricular complex. While mild FTR is frequent and usually benign, patients with severe FTR may develop progressive ventricular dysfunction and incur increased mortality. Therefore, FTR should not be ignored, should be appropriately diagnosed and quantified by Doppler echocardiography, and should be evaluated for corrective surgical procedures. At present, referral for surgical correction of FTR is often delayed until patients develop intractable heart failure. However, this strategy frequently translates in poor clinical outcome characterized by notable operative mortality and reduced long-term survival. Appropriate patient selection and proper timing for tricuspid valve (TV) repair or replacement are crucial for optimal outcome, but objective criteria for clinical decison-making remain poorly defined. In the present paper, we review the anatomy of the normal TV, the pathophysiology of FTR, the assessment of its severity and functional significance, and propose an algorithm for selecting patients for surgical treatment.

Gross morphology and morphometry of native and decellularized heart valves of caprine: A comparative study.

The gross morphological examination of native caprine heart valves revealed distinctive structural characteristics of the caprine's cardiac anatomy. Four primary orifices were identified, each protected by thin, valve-like structures. Atrioventricular orifices featured tricuspid and bicuspid valves, while the aorta and pulmonary arteries were guarded by semilunar valves. Within the atrioventricular apparatus, distinct features were observed including the tricuspid valve's three leaflets and the bicuspid valve's anterior and posterior leaflets. Ultrasonography provided insights into valve thickness and chordae tendineae lengths. Morphometric studies compared leaflets/cusps within individual native valves, showcasing significant variations in dimensions. Comparative analysis between native and decellularized valves highlighted the effects of decellularization on leaflet thickness and chordae tendineae lengths. Decellularized valves exhibited reduced dimensions compared to native valves, indicating successful removal of cellular components. While some dimensions remained unchanged post-decellularization, significant reductions were observed in leaflet thicknesses and chordae tendineae lengths. Notably, semilunar valve cusps displayed varying responses to decellularization, with significant reductions in cusp lengths observed in the aortic valve, while the pulmonary valve exhibited more subtle changes. These findings underscore the importance of understanding structural alterations in heart valves post-decellularization, providing valuable insights for tissue engineering applications and regenerative medicine.

Anatomical evaluation of a novel echocardiography based tricuspid valve classification in 60 hearts from body donors.

OBJECTIVES: This study aimed to provide comprehensive morphological descriptions of the morphology of the tricuspid valve and to evaluate if a novel echocardiography-based tricuspid valve nomenclature can also be understood anatomically. METHODS: Tricuspid valves of 60 non-embalmed human body donors without a medical history of pathologies or macroscopic malformations of the heart were included. Length, height and surface area of leaflets were measured. The valves were morphologically classified according to a novel echocardiography-based classification, in which 6 types are distinguished: classic 3-leaflet configuration, bicuspid valves, valves with 1 leaflet split into 2 scallops or leaflets and valves with 2 leaflets divided into 2 scallops or leaflets. RESULTS: We found a true 3-leaflet configuration in only 19 (31.7%) of valves. Five (8.3%) had a 2-leaflet configuration with a fused anterior and posterior leaflet. Of those, 3 had a divided septal leaflet. Four valves (6.7%) had a divided anterior leaflet, 17 (28.3%) had a divided posterior leaflet, 6 (10%) had a divided septal leaflet and 9 (15.0%) had 2 leaflets divided. Overall, 39 (65%) of valves have at least 1 leaflet that is divided. In 22 (36.7%) specimens, the leaflet was divided into true leaflets, and in 17 (28.3%) specimens, the leaflet was divided into scallops. In addition, we could identify 9 (15%) valves having 1 leaflet divided not only in 2 but 3 scallops or leaflets. CONCLUSIONS: This study provides further anatomical insight for the significant variability in the morphology of the tricuspid valve. By updating the understanding of its morphological characteristics, this study equips clinicians with valuable insights to effectively advance surgical and interventional treatment of tricuspid valves.

Predictors for the development of severe tricuspid regurgitation with anatomically normal valve in patients with atrial fibrillation.

BACKGROUND AND AIMS: Atrial fibrillation (AF) may be a risk factor for severe functional tricuspid valve regurgitation (FTR). We aimed to determine the predictors of severe FTR in patients with AF. METHODS AND RESULTS: From our echocardiographic laboratory database, we searched for and reviewed the medical records of consecutive patients with severe FTR and AF seen at Mayo Clinic in Arizona from 2002 through 2009. Our search identified 42 patients who met all inclusion criteria. These patients (cases) with severe FTR and AF were compared with 38 patients (controls) with AF who had no greater than mild tricuspid regurgitation. Case patients with severe FTR were older than controls (mean, 81 years vs. 76 years; P < 0.001) and more frequently had chronic AF (69% vs 26%; P < 0.001). Mean right atrial volume (86 mL/m(2) vs 46 mL/m(2) ; P < 0.001), right ventricular volume (42 mL ± 33 mL vs 22 mL ±8 mL; P < 0.001) and tricuspid annular diameter (3.6 cm vs 3.0 cm; P < 0.001) were larger in cases than in controls. Patients with severe FTR also had a higher prevalence of right-sided heart failure (69% vs 16%; P < 0.001). After adjusting for age and gender, right atrial and right ventricular volumes were independent predictors for the development of severe FTR in patients with AF (odds ratio, 1.7 [95% CI, 1.3-2.8] for every 10 mL/m(2) increase in right atrial volume; P = 0.0002 and odds ratio, 3.1 [95% CI, 1.5-8.9] for every 10 mL increase in right ventricular volume; P = 0.0002). CONCLUSIONS: Severe FTR occurs in older patients with chronic AF as a result of marked right atrial and right ventricular dilatation; and enlargement of the tricuspid annulus in the absence of pulmonary hypertension. More importantly, severe FTR leads to increased prevalence of right-sided heart failure underscoring the nonbenign nature of chronic AF.

Sex variations in the structure of human atrioventricular annuli.

Atrioventricular annuli are important in haemodynamic flexibility, competence, and support for tricuspid and mitral valves. The anatomical features of the annuli, such as circumference, organisation of connective tissue fibres, myocardium, and cellularity, may predispose to annular insufficiency and valvular incompetence. These pathologies occur more commonly in females, although the anatomical basis for this disparity is unclear. Sex variation in the structure of the annuli is important in providing a morphological basis for the patterns of these diseases. This study therefore aimed to determine the sex variations in the structure of human atrioventricular annuli. One hundred and one hearts (48 males, 53 females) obtained from the Department of Human Anatomy of the University of Nairobi were studied. Annular circumferences were measured using a flexible ruler and corrected for heart weight. Results were analysed using SPSS version 17.0 and sex differences determined using student's t-test. A p-value of less than 0.05 was considered significant. For light microscopy, specimens were harvested within 48 hours post-mortem, processed, sectioned, and stained with Masson's trichrome and Weigert's elastic stain with van Gieson counterstaining. Females had significantly larger annular circumferences than males after correcting for heart weight (p ≤ 0.05). Histologically, myocardium was consistently present in all male annuli while this was absent in females except in one specimen. The annuli were more elastic and cellular in males especially in the annulo-myocardial and annulo-valvular zones, respectively. The corrected larger annular circumference in females may limit heart valve coaptation during cardiac cycle and may be a risk factor for valvular insufficiency. The predominance of myocardium, annular cellularity, and elasticity may be more protective against heart valve incompetence in males than in females.

The heart and pericardium.

This article describes the normal anatomy of the heart and pericardium. Included is a detailed description of the pericardium, mediastinal nerves, cardiac chambers, valves, coronary arteries and veins, and the conduction tissues. As cardiac and thoracic surgery continue to get more specialized and the procedures become less invasive, it is essential for the cardiothoracic surgeon to have a thorough working knowledge of cardiothoracic anatomy.