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.

Cardiac ventricular false tendons: A meta-analysis.

Ventricular false tendons are fibromuscular structures that travel across the ventricular cavity. Left ventricular false tendons (LVFTs) have been examined through gross dissection and echocardiography. This study aimed to comprehensively evaluate the prevalence, morphology, and clinical importance of ventricular false tendons using a systematic review. In multiple studies, these structures have had a wide reported prevalence ranging from less than 1% to 100% of cases. This meta-analysis found the overall pooled prevalence of LVFTs to be 30.2%. Subgroup analysis indicated the prevalence to be 55.1% in cadaveric studies and 24.5% in living patients predominantly studied by echocardiography. Morphologically, left and right ventricular false tendons have been classified into several types based on their location and attachments. Studies have demonstrated false tendons have important clinical implications involving innocent murmurs, premature ventricular contractions, early repolarization, and impairment of systolic and diastolic function. Despite these potential complications, there is evidence demonstrating that the presence of false tendons can lead to positive clinical outcomes.

Three-dimensional cardiac computed tomography compared with autopsied material for the assessment of the mitral valve.

To compare the morphometrical features of non-diseased mitral valves imaged in three-dimensional (3D) cardiac computed tomography with those analyzed macroscopically in autopsied healthy human hearts. A total of 51 cardiac computed tomography scans and 120 adult autopsied human hearts without cardiovascular disease were examined. The 3D reconstruction and visualization software (Mimics Innovation Suite 22, Materialise) was used for heart chambers semi-automatic segmentation and myocardial manual segmentation to visualize a 3D structure of the mitral valve complex and to perform all measurements. Direct comparison of corresponding mitral valve parameters revealed significant differences between obtained results. Significantly larger intercommisural diameter, aorto-mural diameter, and perimeter of the mitral annulus were observed in tomographic scans (all p < 0.0001). However, the intercommissural/aorto-mural diameter ratio showed comparable values for both groups. Nevertheless, the size of anterior mitral leaflet was higher in autopsied material. The height of the P2 scallops was the only parameter that show no significant difference between two groups (p = 0.3). The use of 3D postprocessing algorithms provides a very accurate image of the mitral valve structure, which could be useful for the precise non-invasive assessment of mitral valve size and structure. Three-dimensional contrast enhanced cardiac computed tomography significantly overestimates the measurements of the mitral annulus compared to postmortem analysis.

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.

Microanatomy of the myocardial extensions of the pulmonary valve in light of modern catheter ablation methodology.

INTRODUCTION: The muscular sleeves (or myocardial extensions) derived from the right ventricle infundibulum myocardium are considered the true anatomic substrate for right ventricular outflow tract arrhythmias. METHODS: Pulmonary valve specimens obtained from 65 donors (24.6% females, mean age 45.9 ± 15.8 years) were investigated micro-anatomically. Specimens were histologically processed, stained with Masson's Trichrome, and examined under a light microscope. RESULTS: The myocardial extensions were present in the left anterior pulmonary valve sinus in 86.2% of cases, in the right anterior sinus in 89.2% of cases and in 90.7% of cases in the posterior sinus (p = .699). In 69.2% of examined hearts, the myocardial extensions were present in all sinuses. The mean height of the extensions was 4.12 ± 1.76 (left anterior) versus 3.69 ± 1.47 (right anterior) versus 4.28 ± 1.73 mm (posterior) (p = .137). The myocardial extensions occupied an average of 28.9 ± 10.4% of the left anterior sinus, 26.7 ± 11.2% of the right anterior sinus, and 31.9 ± 11.3% of the posterior sinus (p = .044). Sleeves extending beyond the fibro-arterial transition zone were present in at least one sinus in 33.8% of hearts (in 7.7% (5/65) of the left and right anterior sinuses and 21.5% (14/65) of posterior sinus, p = .021). CONCLUSIONS: The myocardial extensions of the pulmonary valve are common anatomical entities. Although the length of the myocardial sleeves is similar in all pulmonary valve sinuses, their relative extent is greatest in the posterior sinus. Long sleeves that spread beyond the fibro-arterial transition zone were observed in one-third of hearts, predominantly in the posterior sinus. Myocardial and fibrous tissue layer thicknesses varied considerably.

Myocardial bridges: A meta-analysis.

Myocardial bridges are anatomical entities characterized by myocardium covering segments of coronary arteries. In some patients, the presence of a myocardial bridge is benign and is only incidentally found on autopsy. In other patients, however, myocardial bridges can lead to compression of the coronary artery during systolic contraction and delayed diastolic relaxation, resulting in myocardial ischemia. This ischemia in turn can lead to myocardial infarction, ventricular arrhythmias and sudden cardiac death. Myocardial bridges have also been linked to an increased incidence of atherosclerosis, which has been attributed to increased shear stress and the presence of vasoactive factors. Other studies however, demonstrated the protective roles of myocardial bridges. In this study, using systematic review and a meta-analytical approach we investigate the prevalence and morphology of myocardial bridges in both clinical imaging and cadaveric dissections. We also discuss the pathophysiology, clinical significance, and management of these anatomical entities.

The persistent median artery and its vascular patterns: A meta-analysis of 10,394 subjects.

The presence of a persistent median artery (PMA) has been implicated in the development of compression neuropathies and surgical complications. Due to the large variability in the prevalence of the PMA and its subtypes in the literature, more awareness of its anatomy is needed. The aim of our meta-analysis was to find the pooled prevalence of the antebrachial and palmar persistent median arteries. An extensive search through the major databases was performed to identify all articles and references matching our inclusion criteria. The extracted data included methods of investigation, prevalence of the PMA, anatomical subtype (antebrachial, palmar), side, sex, laterality, and ethnicity. A total of 64 studies (n = 10,394 hands) were included in this meta-analysis. An antebrachial pattern was revealed to be more prevalent than a palmar pattern (34.0% vs. 8.6%). A palmar PMA was reported in 2.6% of patients undergoing surgery for carpal tunnel syndrome when compared to cadaveric studies of adult patients in which the prevalence was 8.6%. Both patterns of PMA are prevalent in a considerable portion of the general population. As the estimated prevalence of the PMA was found to be significantly lower in patients undergoing surgery for carpal tunnel syndrome than those reported in cadaveric studies, its etiological contribution to carpal tunnel syndrome is questionable. Surgeons operating on the forearm and carpal tunnel should understand the anatomy and surgical implications of the PMA and its anatomical patterns.

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.

Changes in heart morphometric parameters over the course of a monocrotaline-induced pulmonary arterial hypertension rat model.

BACKGROUND: Aim of this study was to assess changes in cardiac morphometric parameters at different stages of pulmonary arterial hypertension (PAH) using a monocrotaline-induced rat model. METHODS: Four groups were distinguished: I-control, non-PAH (n = 18); II-early PAH (n = 12); III-end-stage PAH (n = 23); and IV-end-stage PAH with myocarditis (n = 7). RESULTS: Performed over the course of PAH in vivo echocardiography showed significant thickening of the right ventricle free wall (end-diastolic dimension), tricuspid annular plane systolic excursion reduction and decrease in pulmonary artery acceleration time normalized to cycle length. No differences in end-diastolic left ventricle free wall thickness measured in echocardiography was observed between groups. Significant increase of right ventricle and decrease of left ventricle systolic pressure was observed over the development of PAH. Thickening and weight increase (241.2% increase) of the right ventricle free wall and significant dilatation of the right ventricle was observed over the course of PAH (p < 0.001). Reduction in the left ventricle free wall thickness was also observed in end-stage PAH (p < 0.001). Significant trend in the left ventricle free wall weight decrease was observed over the course of PAH (p < 0.001, 24.3% reduction). Calculated right/left ventricle free wall weight ratio gradually increased over PAH stages (p < 0.001). The reduction of left ventricle diameter was observed in rats with end-stage PAH both with and without myocarditis (p < 0.001). CONCLUSIONS: PAH leads to multidimensional changes in morphometric cardiac parameters. Right ventricle morphological and functional failure develop gradually from early stage of PAH, while left ventricle changes develop at the end stages of PAH.

Morphometric characteristics of myocardial sleeves of the pulmonary veins.

BACKGROUND: The pulmonary veins are covered by a myocardial layer, which is often an electrical substrate for atrial fibrillation. The aim of this study was to study the morphologic characteristics of the myocardial sleeves of pulmonary veins by examining a large group of freshly autopsied human material. METHODS AND RESULTS: The study macroscopically examined a total of 498 pulmonary veins draining the left atrium (120 unpreserved human hearts). In 75.0% of specimens, a classical pulmonary venous pattern was observed. The remainder of specimens either had an additional middle right pulmonary vein (20.0% of cases) or a common left pulmonary vein (5.0% of cases). Among all the veins seen in the classical pulmonary venous drainage type, the left superior pulmonary vein had the longest myocardial sleeves (9.4 ± 4.6 mm; coverage = 60.1 ± 19.4%), followed by the left inferior pulmonary vein (6.6 ± 3.5 mm; coverage = 47.6 ± 18.3%), the right superior pulmonary vein (6.0 ± 2.7 mm; coverage = 50.5 ± 13.9%) and then the right inferior pulmonary vein (5.0 ± 2.8 mm; coverage = 45.6 ± 16.2%; analysis of variance p < .001). In hearts with an additional right pulmonary vein, this vessel had the shortest myocardial sleeves (2.7 ± 1.1 mm; coverage = 36.0 ± 11.6%). In hearts with a common left pulmonary vein, the myocardial sleeves had the longest course for the common vein (13.7 ± 4.4 mm; coverage = 79.7 ± 4.9%). CONCLUSIONS: Myocardial sleeves of the pulmonary veins were seen in each examined specimen, however, their length varied significantly. In hearts with a classical venous drainage pattern, the left superior pulmonary vein had the longest sleeves. When present, an additional middle right pulmonary vein had the shortest myocardial sleeves, while the left common pulmonary vein had the longest sleeves.

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.

Morphometric Features of Patent Foramen Ovale as a Risk Factor of Cerebrovascular Accidents: A Systematic Review and Meta-Analysis.

INTRODUCTION: It is still disputable whether specific morphometric features of the patent foramen ovale (PFO) may stratify patients by the related probability that a discovered PFO is incidental or stroke related. OBJECTIVE: We aimed to determine whether certain morphometrical characteristics of PFO are associated with an increased risk of cerebrovascular accidents, using a meta-analytical approach. METHODS: We performed a systematic review of electronic databases for studies that compared morphometric parameters of PFO assessed by transesophageal echocardiography (TEE) in subjects with cryptogenic cerebrovascular accidents (Group 1) and control (Group 2). Data were extracted and pooled into a meta-analysis. RESULTS: A total of 895 patients with PFO were reported (Group 1: 493, Group 2: 402). No difference was found in the PFO channel length (Group 1: 10.8 [8.6-12.9] mm vs. Group 2: 10.4 [9.1-11.7] mm), as well as in PFO height measured at rest (Group 1: 2.4 [1.5-3.3] mm vs. Group 2: 1.8 [1.4-2.2] mm). The PFO height measured during a Valsalva maneuver was larger in Group 1 (3.5 [2.8-4.1] mm) than in Group 2 (1.7 [1.2-2.2] mm). Also, the septal excursion distance was found to be larger in Group 1 (6.4 [5.1-7.8] mm) than in Group 2 (3.1 [1.8-4.4] mm). The risk of cerebrovascular accident was higher in patients with PFO and concomitant septal aneurysm (OR 4.00; 95% CI 2.63-6.09; p < 0.001) and with large right-to-left shunt PFO (OR 3.81; 95% CI 2.21-6.55; p < 0.001), no such relationship was found for the presence of a Eustachian valve or Chiari's network (OR 1.90; 95% CI 0.90-4.05; p = 0.094). CONCLUSIONS: The TEE may help in identifying PFO that are of high risk of cerebrovascular accident. Greater PFO height during a Valsalva maneuver, larger septal excursion distance, concomitant atrial septal aneurysm, and large right-to-left shunt are associated with stroke-related PFOs.

Deep septal deployment of a thin, lumenless pacing lead: a translational cadaver simulation study.

AIMS: The recently introduced technique of direct transseptal pacing of the left bundle branch is poorly characterized with many questions with regard to the optimal implantation strategy and safety concerns largely left unanswered. We developed a cadaver model for deep septal lead deployment in order to investigate the depth of penetration in relation to lead behaviour, lead tip position, and the number of rotations. METHODS AND RESULTS: Five fresh human hearts and five lumenless, 4.1-Fr pacing leads were used for deep septal deployment simulations. The leads were positioned with the use of a dedicated delivery sheath and screwed into the interventricular septum at several sites progressively more distal from the atrioventricular ring with a predetermined number of lead rotations. During each lead deployment, the depth of tip penetration was measured and the lead behaviour was noted. Four distinct lead behaviours were observed: (i) helix only penetration, no matter how many rotations were performed, due to the 'endocardial entanglement effect' (43.1% cases) or (ii) 'endocardial barrier effect' (19.6% cases), (iii) shallow/moderate penetration, with ensuing 'drill effect' when more rotations were added (9.8% cases), and (iv) deep progressive penetration with each additional rotation, occurring when the 'screwdriver effect' was present (27.4% cases, including three septal perforations). These different lead behaviours seemed to be determined by the lead position-mainly the strength of the initial endocardial layer-and the number of fully transmitted rotations. CONCLUSION: New insights into deep septal lead deployment technique were gained with regard to safe and successful implantation.

Identification of CD34+/PGDFRα+ Valve Interstitial Cells (VICs) in Human Aortic Valves: Association of Their Abundance, Morphology and Spatial Organization with Early Calcific Remodeling.

Aortic valve interstitial cells (VICs) constitute a heterogeneous population involved in the maintenance of unique valvular architecture, ensuring proper hemodynamic function but also engaged in valve degeneration. Recently, cells similar to telocytes/interstitial Cajal-like cells described in various organs were found in heart valves. The aim of this study was to examine the density, distribution, and spatial organization of a VIC subset co-expressing CD34 and PDGFRα in normal aortic valves and to investigate if these cells are associated with the occurrence of early signs of valve calcific remodeling. We examined 28 human aortic valves obtained upon autopsy. General valve morphology and the early signs of degeneration were assessed histochemically. The studied VICs were identified by immunofluorescence (CD34, PDGFRα, vimentin), and their number in standardized parts and layers of the valves was evaluated. In order to show the complex three-dimensional structure of CD34+/PDGFRα+ VICs, whole-mount specimens were imaged by confocal microscopy, and subsequently rendered using the Imaris (Bitplane AG, Zürich, Switzerland) software. CD34+/PDGFRα+ VICs were found in all examined valves, showing significant differences in the number, distribution within valve tissue, spatial organization, and morphology (spherical/oval without projections; numerous short projections; long, branching, occasionally moniliform projections). Such a complex morphology was associated with the younger age of the subjects, and these VICs were more frequent in the spongiosa layer of the valve. Both the number and percentage of CD34+/PDGFRα+ VICs were inversely correlated with the age of the subjects. Valves with histochemical signs of early calcification contained a lower number of CD34+/PDGFRα+ cells. They were less numerous in proximal parts of the cusps, i.e., areas prone to calcification. The results suggest that normal aortic valves contain a subpopulation of CD34+/PDGFRα+ VICs, which might be involved in the maintenance of local microenvironment resisting to pathologic remodeling. Their reduced number in older age could limit the self-regenerative properties of the valve stroma.

Quadricuspid pulmonary valve: macroscopic and microscopic morphometric examination.

A quadricuspid pulmonary valve obtained upon autopsy of a 26-year-old male was examined. The macroscopic evaluation revealed three normal (posterior, right anterior and left anterior) leaflets and one additional leaflet of the pulmonary valve. Except that, the heart showed neither other anatomical variabilities nor any signs of heart disease. The additional leaflet was located between the left anterior and right anterior leaflets and was significantly smaller in size. Under the microscope, all leaflets showed preservation of the typical, layered structure. The thickness and extracellular matrix composition of the particular layers differed between the leaflets. Right ventricular myocardium (myocardial sleeves) exceeded the level of the hinge line in all three normal leaflets, which was not observed in the additional leaflet. Autonomic nerves and ganglia were not seen in the perivalvular epicardial adipose tissue surrounding the additional leaflet. The sinus wall of all the leaflets revealed typical organization of collagen bundles as well as elastic fibers and showed no signs of disruption. The abnormality seen in the structure of the pulmonary valve is likely to be a result of disturbed embryonic development and may affect the clinical management of patients with such variation.