Aortic root morphometry revisited-Clinical implications for aortic valve interventions.

The complex anatomy of the aortic root is of great importance for many surgical and transcatheter cardiac procedures. Therefore, the aim of this study was to provide a comprehensive morphological description of the nondiseased aortic root. We morphometrically examined 200 autopsied human adult hearts (22.0% females, 47.9 ± 17.7 years). A meticulous macroscopic analysis of aortic root anatomy was performed. The largest cross-section area of the aortic root was observed in coaptation center plane (653.9 ± 196.5 mm2), followed by tubular plane (427.7 ± 168.0 mm2) and basal ring (362.7 ± 159.1 mm2) (p < 0.001). The right coronary sinus was the largest (area: 234.3 ± 85.0 mm2), followed by noncoronary sinus (218.7 ± 74.8 mm2) and left coronary sinus (201.2 ± 78.08 mm2). The noncoronary sinus was the deepest, followed by right and left coronary sinus (16.4 ± 3.2 vs. 15.9 ± 3.1 vs. 14.9 ± 2.9 mm, p < 0.001). In 68.5% of hearts, the coaptation center was located near the aortic geometric center. The left coronary ostium was located 15.6 ± 3.8 mm above sinus bottom (within the sinus in 91.5% and above sinutubular junction in 8.5%), while for right coronary ostium, it was 16.2 ± 3.5 mm above (83.5% within sinus and 16.5% above). In general, males exhibited larger aortic valve dimensions than females. A multiple forward stepwise regression model showed that anthropometric variables might predict the size of coaptation center plane (age, sex, and heart weight; R2 = 31.8%), tubular plane (age and sex; R2 = 25.6%), and basal ring (age and sex; R2 = 16.9%). In conclusion, this study presents a comprehensive analysis of aortic-root morphometry and provides a platform for further research into the intricate interplay between structure and function of the aortic root.

Definition and anatomical description of the left atrial appendage neck.

The left atrial appendage (LAA) is well known as a source of cardiac thrombus formation. Despite its clinical importance, the LAA neck is still anatomically poorly defined. Therefore, this study aimed to define the LAA neck and determine its morphometric characteristics. We performed three-dimensional reconstructions of the heart chambers based on contrast-enhanced electrocardiography-gated computed tomography scans of 200 patients (47% females, 66.5 ± 13.6 years old). The LAA neck was defined as a truncated cone-shaped canal bounded proximally by the LAA orifice and distally by the lobe origin and was present in 98.0% of cases. The central axis of the LAA neck was 14.7 ± 2.3 mm. The mean area of the LAA neck walls was 856.6 ± 316.7 mm2 . The LAA neck can be divided into aortic, arterial (the smallest), venous (the largest), and free surfaces. All areas have a trapezoidal shape with a broader proximal base. There were no statistically significant differences in the morphometric characteristics of the LAA neck between LAA types. Statistically significant differences between the sexes in the main morphometric parameters of the LAA neck were found in the central axis length and the LAA neck wall area. The LAA neck can be evaluated from computed tomography scans and their three-dimensional reconstructions. The current study provides a complex morphometric analysis of the LAA neck. The precise definition and morphometric details of the LAA neck presented in this study may influence the effectiveness and safety of LAA exclusion procedures.

Comparison of the effectiveness of contrast-enhanced mammography in detecting malignant lesions in patients with extremely dense breasts compared to the all-densities population.

Purpose: To assess the effectiveness of contrast-enhanced mammography (CEM) recombinant images in detecting malignant lesions in patients with extremely dense breasts compared to the all-densities population. Material and methods: 792 patients with 808 breast lesions, in whom the final decision on core-needle biopsy was made based on CEM, and who received the result of histopathological examination, were qualified for a single-centre, retrospective study. Patient electronic records and imaging examinations were reviewed to establish demographics, clinical and imaging findings, and histopathology results. The CEM images were reassessed and assigned to the appropriate American College of Radiology (ACR) density categories. Results: Extremely dense breasts were present in 86 (10.9%) patients. Histopathological examination confirmed the presence of malignant lesions in 52.6% of cases in the entire group of patients and 43% in the group of extremely dense breasts. CEM incorrectly classified the lesion as false negative in 16/425 (3.8%) cases for the whole group, and in 1/37 (2.7%) cases for extremely dense breasts. The sensitivity of CEM for the group of all patients was 96.2%, specificity - 60%, positive predictive values (PPV) - 72.8%, and negative predictive values (NPV) - 93.5%. In the group of patients with extremely dense breasts, the sensitivity of the method was 97.3%, specificity - 59.2%, PPV - 64.3%, and NPV - 96.7%. Conclusions: CEM is characterised by high sensitivity and NPV in detecting malignant lesions regardless of the type of breast density. In patients with extremely dense breasts, CEM could serve as a complementary or additional examination in the absence or low availability of MRI.

Aortic valve fenestrations: Macroscopic assessment and functional anatomy study.

Aortic valve fenestrations are defined as a loss of aortic valve leaflet tissue. They are a common but overlooked finding with unclear significance. The aim of this study was to investigate the varied functional anatomies of aortic valve fenestrations. A total of 400 formalin-fixed autopsied human hearts were macroscopically assessed and the function of the aortic valve of 16 reanimated human hearts were imaged using Visible Heart® methodologies. Aortic valve leaflet fenestrations were present in 43.0% of autopsied hearts (in one leaflet in 24.0%, in two leaflets 16.0%, in all leaflets 3.0%). Fenestrations were mostly present in left (25.5%) followed by right (23.3%) and noncoronary leaflet (16.3%). In 93.8% of cases, the fenestrations form clusters and were mainly located at the free edge of the leaflet in the commissural area (95.4%). Hearts with aortic valve fenestrations had significantly larger aortic valve diameters and aortic valve areas (p < 0.001). The average surface area sizes of fenestrations were 23.8 ± 16.6 mm2 , and the areas were largest for left followed by right and noncoronary leaflet fenestrations (p < 0.001). The fenestration areas positively correlated with donor age (r = 0.31; p = 0.02). Significant hypermobility and subjective weakening of the leaflet adhesion levels of the fenestrated regions were observed. In conclusion, fenestrations of the aortic leaflets are frequent, and their sizes may be significant. They occur in all age groups, yet their size increase with aging. Fragments of leaflets with fenestrations show different behaviors during the cardiac cycle versus unchanged areas.

Pulmonary valve morphometry revisited: Clinical implications for valvular and supravalvular interventions.

In this cadaver-based study, we aimed to present a novel approach to pulmonary valve (PV) anatomy, morphometry, and geometry to offer comprehensive information on PV structure. The 182 autopsied human hearts were investigated morphometrically. The largest PV area was seen for the coaptation center plane, followed by basal ring and the tubular plane (626.7 ± 191.7 mm2 vs. 433.9 ± 133.6 mm2 vs. 290.0 ± 110.1 mm2 , p < 0.001). In all leaflets, fenestrations are noted and occur in 12.5% of PVs. Only in 31.3% of PVs, the coaptation center is located in close vicinity of the PV geometric center. Similar-sized sinuses were found in 35.7% of hearts, in the remaining cases, significant heterogeneity was seen in size. The mean sinus depth was: left anterior 15.59 ± 2.91 mm, posterior: 16.04 ± 2.82 mm and right anterior sinus: 16.21 ± 2.81 mm and the mean sinus height: left anterior 15.24 ± 3.10 mm, posterior: 19.12 ± 3.79 mm and right anterior sinus: 18.59 ± 4.03 mm. For males, the mean pulmonary root perimeters and areas were significantly larger than those for females. Multiple forward stepwise regression model showed that anthropometric variables might predict the coaptation center plane (sex, age, and heart weight; R2  = 33.8%), tubular plane (sex, age, and BSA; R2  = 20.5%) and basal ring level area (heart weight and sex; R2  = 17.1%). In conclusion, the largest pulmonary root area is observed at the coaptation center plane, followed by the basal ring and tubular plane. The PV geometric center usually does not overlap valve coaptation center. Significant heterogeneity is observed in the size of sinuses and leaflets within and between valves. Anthropometric variables may be used to predict pulmonary root dimensions.

Thickness of the left atrial wall surrounding the left atrial appendage orifice.

INTRODUCTION: The aim of this study was to investigate the thickness of the left atrial wall surrounding the left atrial appendage (LAA) orifice. METHODS AND RESULTS: The tissue thickness around the LAA orifice was measured at four points (superior, inferior, anterior, and posterior) in 200 randomly selected autopsied human hearts. The thickest tissue was observed at the anterior point (3.17 ± 1.41 mm), followed by the superior (2.47 ± 1.00 mm), inferior (2.22 ± 0.80 mm) and posterior (2.22 ± 0.83 mm). The chicken wing LAA type was associated with the lowest thickness at the superior point compared to the cauliflower and arrowhead shapes (p = .024). In hearts with an oval LAA orifice, the atrial wall was significantly thicker in all points than in specimens with a round LAA orifice (p > .05). Both the LAA orifice anteroposterior diameter and orifice surface area were negatively correlated with the tissue thickness in the anterior (r = -.22, p = .004 and r = -.23, p = .001) and posterior points (r = -.24, p = .001 and r = -.28, p = .005). Endocardial surface roughness was commonly in the inferior pole of the LAA orifice (75.5% of cases), while they are much less prevalent in other sectors around the orifice (anterior: 17.5%), superior: 4.0%, and posterior: 1.5%). CONCLUSIONS: Although a significant heterogeneity in the atrial wall thickness around the LAA orifice was observed, the thickness in the respective points is quite conservative and depends only on LAA orifice size and shape, as well as LAA body shape. Thin atrial wall and endocardial surface roughness might challenge invasive procedures within this region.

Morphology of the Left Atrial Appendage: Introduction of a New Simplified Shape-Based Classification System.

BACKGROUND: The left atrial appendage (LAA) is a heart structure with known prothrombogenic and pro-arrhythmogenic properties. AIM: The aim of this study was to evaluate the specific anatomy of the LAA and to create a simple classification system based on the shape of its body. METHOD AND RESULTS: This study investigated 200 randomly selected autopsied human hearts (25.0% females, 46.6±19.1 years old). Three (3) types of LAAs were distinguished: the cauliflower type (no bend, limited overall length, compact structure [36.5%]); the chicken wing type (substantial bend in the dominant lobe [37.5%]), and the arrowhead type (no bend, one dominant lobe of substantial length [26.0%]). Additional accessory lobes were present in 55.5% of all LAAs. Significant variations between category types were noted in LAA length (chicken wing: 35.7±9.8 mm, arrowhead: 30.8±10.1 mm, cauliflower: 22.3±9.6 mm [p<0.001]) and in the thickness of pectinate muscles located within the LAA apex (arrowhead: 1.2±0.7 mm; cauliflower: 1.1±0.6 mm; chicken wing: 0.9±0.6 mm [p<0.001]). Left atrial appendage volume and orifice size were not affected by the type of LAA shape. The age of the donor was positively correlated with LAA volume (r=0.29, p=0.005), body length (r=0.26, p=0.012), and area of the orifice (r=0.36, p<0.001). Donors with an oval LAA orifice were significantly older than those with round orifices (50.2±16.6 vs 43.7±20.4 years [p=0.014]) and had significantly heavier hearts (458.2±104.8 vs 409.6±114.1g [p=0.002]). CONCLUSIONS: This study delivered a new simple classification system of the LAA based on its body shape. An increase in age and heart weight was associated with LAA enlargement and a more oval-shaped orifice. Results of current study may help to estimate the different thrombogenic properties associated with each LAA type and be an assistance during planning and performing interventions on LAA.

Topographical anatomy of the right atrial appendage vestibule and its isthmuses.

INTRODUCTION: The right atrial appendage (RAA) vestibule is an area located in the right atrium between the RAA orifice and the right atrioventricular valve annulus and may be a target for invasive transcatheter procedures. METHODS AND RESULTS: We examined 200 autopsied human hearts. Three isthmuses (an inferior, a middle, and a superior isthmus) were detected. The average length of the vestibule was 67.4 ± 10.1 mm. Crevices and diverticula were observed within the vestibule in 15.3% of specimens. The isthmuses had varying heights: superior: 14.0 ± 3.4 mm, middle: 11.2 ± 3.1 mm, and inferior: 10.1 ± 2.7 mm (p < .001). The superior isthmus had the thickest atrial wall (at midlevel: 16.7 ± 5.6 mm), the middle isthmus had the second thickest wall (13.5 ± 4.2 mm), and the inferior isthmus had the thinnest wall (9.3 ± 3.0 mm; p < .001). This same pattern was observed when analyzing the thickness of the adipose layer (superior isthmus had a thickness of 15.4 ± 5.6 mm, middle: 11.7 ± 4.1 mm and inferior: 7.1 ± 3.1 mm; p < .001). The average myocardial thickness did not vary between isthmuses (superior isthmus: 1.3 ± 0.5 mm, middle isthmus: 1.8 ± 0.8 mm, inferior isthmus: 1.6 ± 0.5 mm; p > .05). Within each isthmus, there were variations in the thickness of the entire atrial wall and of the adipose layer. These were thickest near the valve annulus and thinnest near the RAA orifice (p < .001). The thickness of the myocardial layer followed an inverse trend (p < .001). CONCLUSIONS: This study was the first to describe the detailed topographical anatomy of the RAA vestibule and that of its adjoining isthmuses. The substantial variability in the structure and dimensions of the RAA isthmuses may play a role in planning interventions within this anatomic region.

Anatomy of the left atrial ridge (coumadin ridge) and possible clinical implications for cardiovascular imaging and invasive procedures.

BACKGROUND: The left atrial ridge is a structure located in the left atrium between the left-sided pulmonary veins ostia and the orifice of the left atrial appendage. Since it was commonly misdiagnosed as a thrombus, the ridge is also known as the "coumadin" or "warfarin" ridge. The left atrial ridge is a potential source of arrhythmias and can be an obstacle in ablation procedures. This study aimed to provide information about the occurrence and spatial morphometric characteristics of the left atrial ridge. METHODS AND RESULTS: The macroscopic morphology of the left atrial ridge was assessed in 200 autopsied human hearts. The ridge was observed in 59.5% of specimens and was absent in the remaining 40.5% of cases. The mean length of the ridge was 22.4 ± 5.1 mm. It was wider at its inferior sector when compared to its superior sector (9.1 ± 5.0 vs 7.9 ± 3.2 mm; P = .028). The total wall thickness measured at the cross section of the ridge was significantly larger in the inferior than in superior sector (6.2 ± 3.5 vs 4.3 ± 1.8 mm; P < .001), although the myocardial thickness was significantly larger at the superior sector (3.1 ± 1.4 vs 1.9 ± 0.9 mm in inferior sector, P < .001). CONCLUSION: The left atrial ridge is a variable structure, present in 59.5% of humans. The ridge is significantly wider and thicker at its inferior sector, although the actual myocardial layer present within the ridge is thinner at this location. Knowledge about the left atrial ridge morphology is key in avoiding unnecessary interventions or complications during invasive procedures.

The Arteries of the Central Forehead: Implications for Facial Plastic Surgery.

BACKGROUND: The forehead has substantial importance as an aesthetic unit. The central and supraorbital parts of this area are supplied by the supratrochlear (ST) and supraorbital (SO) arteries as well as the recently defined paracentral (PA) and central arteries. OBJECTIVES: The authors aimed to assess the morphometry of the vessels of the forehead in the context of plastic surgery and minimally invasive cosmetic procedures. METHODS: This research included 40 cadavers directed for forensic autopsy and subjected to postmortem computed tomography angiography. In total, 75 hemifaces were examined for the course and location of arteries relative to the bones and surrounding structures. RESULTS: The arteries were observed as follows: ST in 97.3%, SO in 89.3%, and PA in 44.0%. The PA can be expected in the 13-mm-wide zone starting 2 mm laterally from the midline. The ST should be expected in the 10-mm-wide area extended laterally from the tenth millimeter from the midline, and the SO should be expected in the slightly wider (11 mm) area extending laterally from the 20th millimeter from the midline. For the proximal main trunks of the ST and SO arteries, we observed no overlap between the zones of occurrence, whereas the zones for the PA and ST main proximal trunks did overlap. No distinctive central artery was observed in the midline region of the forehead, but instead a network of small vessels in the midline region was visible. CONCLUSIONS: The ST is the main and most conservative artery of this region and the PA is the most variable. A unique and detailed anatomical map was created to better understand the vasculature of the forehead area.

Morphology of the Vieussens valve and its imaging in cardiac multislice computed tomography.

INTRODUCTION: To deliver accurate morphological descriptions of the Vieussens valve (VV) and to investigate whether this structure could be visualized using standard contrast-enhanced electrocardiogram-gated multislice computed tomography (MSCT). METHODS: A total of 145 human autopsied hearts and 114 cardiac MSCT scans were examined. RESULTS: The VV was observed in both study groups, however, the detection rate was significantly worse in the MSCT examination (18.4% in MSCT vs 62.1% in cadavers, P < .0001). The VV height was larger in MSCT patients (2.8 ± 1.2 vs 5.4 ± 1.7 mm; P < .0001). No significant difference was found in the measured distance between the VV and the coronary sinus ostium between the two separate subgroups (27.3 ± 9.5 vs 24.4 ± 5.8 mm; P = .18). In autopsied material the most frequent valve location was the anterior wall of the coronary sinus (43.3%); the same was observed in MSCT scans (71.4%). CONCLUSION: The VV is a common heart structure, present in over 60% of humans, located mainly on the anterior and superior circuit of the coronary sinus, with relatively high morphological variability. Large VVs, which pose a significant obstacle in catheterization procedures, may be visualized using standard-protocol contrast-enhanced cardiac MSCT.

Topographic characteristics of the left atrial medial isthmus.

BACKGROUND: The purpose of this study was to provide detailed topography of the left atrial medial isthmus (situated between the right inferior pulmonary vein ostium and the medial part of the mitral annulus). METHODS: Two hundred human hearts (Caucasian, 22.5% females, 48.7 ± 4.9 years old) were investigated. RESULTS: The mean length of the medial isthmus was 42.4 ± 8.6 mm. Additionally, the medial isthmus line was divided by the oval fossa into three sections with equal mean lengths (upper: 14.2 ± 7.2 vs middle: 14.1 ± 6.1 vs lower: 14.9 ± 4.6 mm; P > .05). The left upper section of the atrial wall was thinner than the lower section (2.5 ± 1.1 vs 3.4 ± 1.6 mm; P < .0001). This study noted three separate spatial arrangements of the isthmus line. Type I (54.5%) had an oval fossa located outside the isthmus line; type II (32.5%) had an oval fossa crossed by the isthmus line, and type III (13.0%) had an oval fossa rim located tangentially to the isthmus line. In 68.5% of the examined specimens, the isthmus area had a smooth surface. Conversely, the remaining 31.5% had additional structures within its borders such as diverticula, recesses, and tissue bridges. CONCLUSION: This study is the first to describe the morphometric and topographical features of the left atrial medial isthmus. Interventions within the medial isthmus line should be performed cautiously, especially when they are transected by the oval fossa (32.5%). Careful navigation of the area is also recommended due to the possibility of existent additional structures. The latter could lead to catheter entrapment during ablation procedures.

Fixative properties of honey solutions as a formaldehyde substitute in cardiac tissue preservation.

OBJECTIVES: To evaluate the properties of natural sweetener solutions in whole organ preservation and assess their influence on the dimension, weight and shape of cardiac tissue samples in stated time intervals, up to a one-year period of observation. BACKGROUND: Tissue fixation is essential for biological sample examination. Many negative toxic effects of formaldehyde-based fixatives have forced us to seek alternatives for formaldehyde based solutions. It has been demonstrated that natural sweeteners can preserve small tissue samples well and that these solutions can be used in histopathological processes. However, their ability to preserve whole human organs are unknown. METHODS: A total of 30 swine hearts were investigated. Three study groups (n = 10 in each case) were formed and classified on the type of fixative: (1) 10% formaldehyde phosphate-buffered solution (FPBS), (2) 10% alcohol-based honey solution (ABHS), (3) 10% water-based honey solution (WBHS). Samples were measured before fixation and in the following time points: 24 hours, 72 hours, 168 hours, 3 months, 6 months and 12 months. RESULTS: The WBHS failed to preserve heart samples and decomposition of tissues was observed one week after fixation. In half of the studied parameters, the ABHS had similar modifying tendencies as compared to FPBS. e overall condition of preserved tissue, weight, left ventricular wall thickness, right ventricular wall thickness and the diameter of the papillary muscle differed considerably. CONCLUSIONS: The ABHS may be used as an alternative fixative for macroscopic studies of cardiac tissue, whereas the WBHS is not suited for tissue preservation.

Spatial relationship of blood vessels within the mitral isthmus line.

Aims: The aim of this study was to assess the spatial relationship of blood vessels and the thickness of the atrial wall within the mitral isthmus line. Methods and results: A total of 200 randomly selected autopsied adult human hearts (Caucasian) were examined. The mitral isthmus line was cut longitudinally and the thickness of the left atrial wall was measured. The blood vessels within the isthmus were identified and their relationship with the endocardial surface (ES), mitral annulus (MA), and the left inferior pulmonary vein (LIPV) ostium was assessed. The mean myocardial thickness in the upper, middle, and lower 1/3 of the mitral isthmus section were 1.9 ± 1.0, 3.0 ± 1.5, and 2.7 ± 1.3 mm, respectively. The great cardiac vein (GCV) was present within the isthmus in 98.0%, the left circumflex artery (LCx) in 57.0%, and the Marshall vein in 35.0% of all hearts. The GCV was located 4.5 ± 2.2 mm from the ES, 7.3 ± 5.3 mm from the MA, and 24.3 ± 7.3 mm from the LIPV. The LCx was situated 3.8 ± 2.3 mm from the ES, 7.9 ± 5.1 mm from the MA, and 25.3 ± 8.0 mm from the LIPV. We were able to detect eight different patterns of GCV and LCx mutual arrangement within the mitral isthmus line. Conclusion: The myocardium is the thinnest in the upper 1/3 sector, and the blood vessels are mainly located in the middle and lower 1/3. In 49.1%, the LCx is situated at a distance of less than 3 mm from the ES. In 55.3%, the LCx is located between the GCV and ES of the left atrium.

Mid-esophageal bicaval versus short-axis view of interatrial septum in two-dimensional transesophageal echocardiography for diagnosis and measurement of atrial septal pouches.

BACKGROUND: Recent studies suggest that the left-sided septal pouch (SP) may increase the risk of cryptogenic stroke and act as an arrhythmogenic substrate. The aim of this study was to compare two transesophageal echocardiography (TEE) projections of the interventricular septum: mid-esophageal bicaval and short-axis views toward evaluating their ability to detect SPs. MATERIALS AND METHODS: A total of 146 patients with both bicaval and short-axis TEE views were included in this study. The presence of SPs was determined, and they were evaluated for morphology. RESULTS: Irrespective of TEE projection view, the left SP was detected in 74 cases (50.7%), right SP in 16 cases (11.0%), and double in one case (0.7%). Agreement between both projections occurred in 119 cases (81.5%) with a weighted kappa coefficient of 0.68 (good agreement). We detected more left SPs from the bicaval view compared to the short-axis view; however, the observed difference was statistically insignificant (72 vs 59, P = .13). The detection of right SPs was higher in the short-axis view, but also statistically insignificant (9 vs 13, P = .38). Bland-Altman analysis revealed a significant difference in the left SP depth with higher values in the bicaval than short-axis view (systematic difference = 1.17 mm, LoA: -4.88-7.22 mm, P = .02, ICC = 0.58). CONCLUSIONS: The mid-esophageal bicaval view should be preferable over mid-esophageal short-axis view of interatrial septum for the diagnosis and measurement of the left SP.

Blood Vessels and Myocardial Thickness within the Left Atrial Appendage Isthmus Line.

Electric isolation of the left atrial appendage (LAA) and linear ablations in the area of the LAA base are gaining popularity. However, very little is known about the myocardial architecture and the presence of epicardial blood vessels within this region, which could significantly influence the course of such procedures. We examined 200 autopsied hearts (22.5% females, 46.7 ± 16.8 years old). The LAA isthmus (i.e., the line between the LAA ostium and the mitral annulus) was cut longitudinally. The myocardium was thickest at the LAA end of the isthmus (2.4 ± 0.7 mm) followed by its middle sector (2.1 ± 0.7 mm) inside the LAA, 5 mm from its ostium (1.9 ± 0.7 mm), and the mitral annulus end of the isthmus (1.8 ± 0.6 mm) (P < 0.0001). At least one artery was found in 96.5% of all samples (89.5% were single branched, 7% had two branches). The great cardiac vein was found in 77.0% and the left marginal vein in 2.5%. The artery was interposed between the endocardium and the great cardiac vein in 31.5% of cases. The smallest distance between the endocardium and the artery was 0.5 mm and between the endocardium and the vein was 0.7 mm. In total, we were able to distinguish fifteen different types of vascular arrangements within the LAA isthmus line in this study. The myocardium within the LAA isthmus is thickest at its LAA end. The left circumflex coronary artery branches are the most frequently-occurring vessels within the isthmus and are present in almost all cases, while the great cardiac vein is present in three quarters of hearts. Clin. Anat. 31:1024-1030, 2018. © 2018 Wiley Periodicals, Inc.

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.

Penetration of formaldehyde based fixatives into heart.

OBJECTIVES: To investigate the penetration depth of formaldehyde-based fixatives into cardiac muscle samples over the course of fixation. BACKGROUND: Fixation is the essential step in anatomical studies. However, very little is known about penetration of most common fixatives into cardiac tissue. METHODS: A total of 40 heart samples were investigated. 4 study groups (n=10 in each case) were formed in such manner they differed only in concentration and type of fixative (1) - 2% formaldehyde phosphate-buffered solution (FPBS); (2) - 4% FPBS (formalin); (3) - 10% FPBS; (4) - alcoholic formalin. Samples were measured before fixation and in the following time points: 24 hours, 72 hours, 168 hours. RESULTS: The penetration depth differed significantly among studied fixatives (p<0.0001). 100% penetration occurred in all samples after 72 hours in alcoholic formalin solution and after 168 hours in 10% FPBS. After alcoholic formalin fixation, the tissue is more brittle and sub-epicardial blisters were observed in some cases. CONCLUSIONS: Alcoholic formalin solution is the fastest fixative among the studied ones, however it has several adverse effects on tissue structure. It was found that 10% FPBS is the best and a relatively fast fixative for cardiac morphometric studies.

Influence of different fixation protocols on the preservation and dimensions of cardiac tissue.

Recent extensive progress in invasive cardiac procedures has triggered a wave of dozens of heart morphometric anatomical studies that are carried out largely using autopsied samples fixed in formaldehyde solution prior to observations and measurements. In reality, very little is known about changes in heart tissue dimensions during fixation. The aim of this study was therefore to investigate how fixation affects the dimensions of cardiac tissue, and if different types and concentrations of reagents affect this phenomenon. A total of 40 pig heart samples were investigated, and seven different measuring sites were permanently marked in every heart prior to fixation. Four study groups (n = 10 each) were assembled that differed only in concentration and the type of fixative: (i) 2% formaldehyde solution; (ii) 4% formaldehyde solution (formalin); (iii) 10% formaldehyde solution; (iv) alcoholic formalin. The samples were measured before and after fixation at the following time points: 24 h, 72 h and 168 h. It was found that different fixatives significantly affected different parameters. Almost all of the heart dimensions that were measured stabilized after 24 h; later changes were statistically insignificant in the point-to-point comparison. Change in the length of the interatrial septum surface was not altered significantly in any of the fixatives after 24 h of preservation. It was found that 10% formaldehyde increased the thickness of muscular tissue only after 24 h; this thickening was reduced after 72 h and was insignificant at 168 h. Other heart parameters in this group do not present significant changes over the entire fixation time duration. In conclusion, the 10% formaldehyde phosphate-buffered solution appeared to be the best fixative among the fixatives that were studied for cardiac morphometric purposes; this solution caused the smallest changes in tissue dimensions. Measurements should be obtained at least after 1 week of preservation when most parameters exhibit the smallest changes compared with the non-preserved samples.