The heart exhibits right to left communication between the fibres of the muscular part of the interventricular septum.

1900 years ago Galen stated that blood seeps through the perforations in the interventricular septum. However, William Harvey, working 400 years ago, failed to find any. In this study an aqueous solution of a black dye was gently pumped by hand into the right ventricle of 20 porcine hearts. The area in the middle ofthe left muscular part of the interventricular septum in 13 of the hearts was bloodstained under the endocardium at the time the heart stopped beating. The same area of all 20 hearts eventually became stained black. A small amount of black dye seeped through the endocardium of 18 hearts in the middle of the left muscular part of the interventricular septum. In another 20 porcine hearts theinterventricular septa were dissected after boiling. The deep pit under the anterior interventricular sulcus communicated with the right ventricle and with the middle of the left muscular part of the interventricular septum between the fibres of the muscle. The communication closed tight at the very early systole. The communication resembled that reported by Galen 1900 years ago. The communication may be the real foetal route for diastolic circulation through the muscular part of the interventricular septum from right to left. The results suggested that the anatomy, function and embryology of the African monkey, human and porcine heart are not yet fully understood.

[Left-ventricular surface trabeculae of the interventricular septum in the human fetal heart].

Left-ventricular surface of the interventricular septum (IVS) was studied in the heart of 85 human fetuses (at weeks 17-28 of development) formed without congenital defects and minor abnormalities. Two anatomical types of trabeculae (bridge-like and parietal) and their two topographical groups are described: trabeculae of the anterior corner of the left ventricle (LV) and the septal trabeculae. The prevalence of trabeculae in both groups was found to be equal (81-81.2%). No correlation between the numbers of septal trabeculae and the trabeculae of the anterior LV corner was found. While the parietal trabeculae were detected in both groups, the bridge-like type was found only in the anterior LV corner. The number of the bridge-like trabeculae of the anterior LV corner and the septal trabeculae increased from the base to the apex of the heart; this was accompanied by the decrease in the IVS myocardium compactness. Among the first topographical group, there were trabeculae in the shape of skewed cylinders or truncated cones, flattened perpendicularly to their long axis. As a rule, in cone-shaped trabeculae, their broad base was directed towards the IVS. In the second group, the ribbon-shaped trabeculae were prevalent. The data on trabecular width are presented. The formation of the cardiac LV and IVS trabecular pattern in prenatal period is discussed.

The positional relationship between the coronary sinus musculature and the atrioventricular septal junction.

AIMS: The atrioventricular (AV) septal junction includes the coronary sinus (CS) and the compact part of the AV node and its posterior extensions. It has been recognized as the target site for ablation therapy of the AV nodal reentrant tachycardia and its variant forms. Despite the clinical significance of this region, the arrangement of the musculature in the AV septal junction, including the CS, has not fully been elucidated. We tried to explore the histological muscular diversity within the AV septal junction. METHODS AND RESULTS: Sixteen autopsied human hearts (seven women), mean age 59.8 years, without structural anomalies, were studied. We removed the whole AV septum, including the CS opening after the macroscopic measurements, and prepared serial sections parallel to mitral and tricuspid annuli (short-axis style) to elucidate the positional relationships between the compact AV node and the CS musculature. Out of 16 hearts, the CS musculature extended deeply into the AV septal junction in eight hearts. In the other eight hearts, the CS musculature was located above the AV septal junction. In the former group, we found that the offset of both annuli was wide (mean 3.8 +/- 1.4 vs. 2.4 +/- 1.1 mm), the distance between CS opening and membranous septum was long (mean 14.8 +/- 1.6 vs. 12.3 +/- 2.2 mm), and the CS opening level was lower and closer to the His bundle level (mean 2.8 +/- 1.9 vs. 5.8 +/- 2.9 mm) (P < 0.05). CONCLUSION: The deep extension of CS musculature into the AV septal junction seems to increase the tissue non-uniformity in this area.

Utility of echocardiography in predicting mortality in infants with severe bronchopulmonary dysplasia.

OBJECTIVE: To determine the relationship between interventricular septal position (SP) and right ventricular systolic pressure (RVSP) and mortality in infants with severe BPD (sBPD). STUDY DESIGN: Infants with sBPD in the Children's Hospitals Neonatal Database who had echocardiograms 34-44 weeks' postmenstrual age (PMA) were included. SP and RVSP were categorized normal, abnormal (flattened/bowed SP or RVSP > 40 mmHg) or missing. RESULTS: Of 1157 infants, 115 infants (10%) died. Abnormal SP or RVSP increased mortality (SP 19% vs. 8% normal/missing, RVSP 20% vs. 9% normal/missing, both p < 0.01) in unadjusted and multivariable models, adjusted for significant covariates (SP OR 1.9, 95% CI 1.2-3.0; RVSP OR 2.2, 95% CI 1.1-4.7). Abnormal parameters had high specificity (SP 82%; RVSP 94%), and negative predictive value (SP 94%, NPV 91%) for mortality. CONCLUSIONS: Abnormal SP or RVSP is independently associated with mortality in sBPD infants. Negative predictive values distinguish infants most likely to survive.

Novel Anatomic Predictors of New Persistent Left Bundle Branch Block After Evolut Transcatheter Aortic Valve Implantation.

New persistent left bundle branch block (NP-LBBB) has been associated with adverse outcomes after TAVI but few predictors thus far reported. We sought to identify predictors of NP-LBBB after TAVI with EvolutR/PRO (ER/EP). From 1/2016 to 4/2019, 544 patients from 2 centers underwent TAVI with Evolut (54% ER, 46% EP) for severe native aortic stenosis. Patients with previous LBBB and pacemaker were excluded. Aortic root analysis was performed using 3Mensio Valves Software and membranous septal length (MSL) was determined using the standard coronal view. Clinical, anatomic and procedural characteristics of 396 Evolut were analyzed and predictors of NP-LBBB were identified. Valve Academic Research Consortium-2 outcomes were reported. At discharge, NP-LBBB was seen in 76(19.2%) patients. NP-LBBB in Evolut was associated with implant depth at left coronary cusp (p = 0.004) and 34 mm ER (p = 0.026). Independent predictors of NP-LBBB in Evolut were shorter MSL (odds ratio [OR] = 0.82 per mm septum, 95% confidence interval [CI] = 0.68 to 0.98,p = 0.030), left ventricular outflow tract (LVOT) eccentricity (OR = 1.04 per %, 95% CI = 1.01 to 1.06,p = 0.002), implant depth at noncoronary cusp (NCC) (OR = 1.28 per mm ventricular, 95% CI = 1.11 to 1.48,p = 0.001) and annular perimeter oversizing ≥20% (OR = 2.38, 95% CI = 1.20 to 4.72, p = 0.013). On ROC curve analysis, MSL ≤6.5 mm, NCC depth ≥3 mm and LVOT eccentricity ≥35% were optimal threshold values to predict NP-LBBB. In Conclusion, shorter MSL, LVOT eccentricity, annular oversizing and deeper implant depth are novel predictors of NP-LBBB in Evolut TAVI. Preprocedural CT assessment of aortic root anatomy may help identify patients at risk for NP-LBBB. In such patients, modifying procedural factors such as higher implant and less annular oversizing may reduce the risk of NP-LBBB. Further evaluation of our hypothesis is warranted.

Multiple ventricular bands and the associated trabecula septomarginalis dextra in the right ventricle of the domestic dog (Canis familiaris).

Ventricular bands are strand-like intraventricular structures extending between adjacent papillary muscles; a papillary muscle and the ventricular wall or the interventricular septum and ventricular wall. Examination of the domestic dog right ventricle documented six ventricular band types. Eighty-five of the 89 examined hearts had at least one right ventricular band. In the current study, the right ventricle of the 85 dog hearts was re-examined for more than one ventricular band type. Seven patterns of multiple different bands were identified in the 24 dog hearts. The patterns (i.e., combinations) of different ventricular bands were grouped into three categories. Category 1 had five different patterns of bands. Each pattern had two different band types. Category 2 had one combination of three different bands. Category 3 had one combination of four different bands. The presence of right ventricular bands around the trabecula septomarginalis dextra was also documented. All 24 dog hearts with multiple ventricular bands had a trabecula septomarginalis dextra. The main goal of this study was documentation of multiple right ventricular band patterns. A secondary goal was documentation of the combined presence of these bands and a trabecula septomarginalis dextra. In the dog, the ventricular bands and trabecula are both thin, strand-like intraventricular structures with variable branching patterns before blending into the ventricular wall. The gross similarity of these structures and lack of information on their combined presence could precipitate their misidentification.

Histological and anatomical variations of septomarginal trabecula in bovine hearts.

The use of hearts from different animals as models in the experimental pharmacology and surgical clinic has led, in recent years, to an increase on interest of research with this organ. The heart's conducting system, from the septomarginal trabecula, presents several variations, which generates numerous controversies in the literature. So, the objective of the present study is to analyse the morphology of the septomarginal trabecula of bovine hearts, identifying possible macro- and microscopic variations. Thirty-four bovine hearts were analysed. Each trabecula was analysed macroscopically to obtain an anatomical description and measurements of its length and thickness. For histological and morphometric analysis, the samples were fixed in Bouin's solution and then subjected to histological processing. In all the analysed bovine hearts, the septomarginal trabecula presented itself as a smooth, tubular meaty structure of muscular consistency, with variable length and diameter. The anatomical variations observed included a trabecula with forked marginal fixation, and single septal fixation, in addition to a trabecula with extremely reduced or excessively thick caliber. The septomarginal trabecula consists of cardiac muscle fibres, connective tissue, vascular tissue and conduction myofibrils or Purkinje fibres. In the samples of smaller thicknesses, there was a predominance of connective tissue and scarce cardiac muscle tissue, whereas in the thicker samples the predominance was of cardiac striated muscle tissue. Therefore, there are significant macro- and microscopic differences between the bovine septomarginal trabecula concerning their diameter and constituent tissue, and that can lead to possible changes in cardiac physiology.

An anatomical study on interventricular septum of postmortem hearts of adult Bangladeshi people.

To study the thickness of interventricular septum (both muscular and membranous parts) of adult Bangladeshi people, fifty postmortem hearts were collected, fixed in 10% formol saline and examined. The thickness of both muscular and membranous parts of the septum was measured. Among fifty hearts, thirty-six were collected from male and fourteen from female cadavers. All hearts were collected from medicolegal cases. The findings were compared between male and female cadavers of our country as well as with the findings of the western countries. The findings suggest that in female, the thickness of both muscular and membranous parts of the septum was less than that of male though there was no significant difference statistically (P>0.05). The findings were compared with the findings of other workers and not so much variation was found. There was no available data regarding the thickness of the membranous part of the septum to compare.

Crista Supraventricularis Purkinje Network and Its Relation to Intraseptal Purkinje Network.

Using transparent specimens with a dual color injection, microscopy, and computer tomography, this report shows that the right and left ventricular subendocardial Purkinje networks are connected by an extensive septal network in the bovine heart. The septal network is present along the entire septum except at a free zone below ventricular valves. Being the only communication of the basal right septum with the right free wall, the supraventricular crest is an enigmatic but not, by any means, hidden muscular structure. It is one of the last structures to be activated in human heart. It is shown here that the supraventricular crest Purkinje network connects the anterosuperior right ventricular basal free wall Purkinje network to anterior right ventricular basal septal Purkinje network. It is suggested that the stimulus initiated at middle left ventricular endocardium will activate the supraventricular crest. The intraseptal connection found between the basal left ventricular subendocardial septal Purkinje network and the right ventricular basal septal Purkinje network is, probably, the pathway for the stimulus. An anatomic basis is provided to explain why the inflow tract contracts earlier than the outflow tract in the right ventricle systole. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1793-1801, 2017. © 2017 Wiley Periodicals, Inc.

Morphology and Classification of Right Ventricular Bands in the Domestic Dog (Canis familiaris).

Ventricular bands, also designated as 'false tendons', are described as single or multiple strands that cross the ventricles and have no connection to valvular cusps. Previous work indicates these strands are present in the ventricles of humans and some animal hearts and not always associated with cardiac pathologies. Despite these previous studies, the published literature is limited in documenting the morphology of these strands and incidence in animals. In this study, examination of 89 hearts showed six types of ventricular bands in the right ventricle of the domestic dog. These bands were classified according to their prevalence and points of attachment. Type I extended from the interventricular septum to the ventricular free wall, type II connected a musculus papillaris parvus to the ventricular free wall and type III connected trabeculae carneae on the interventricular septum. Type IV connected the trabeculae carneae on the ventricular free wall, type V interconnected papillary muscles and type VI connected the interventricular septum to a papillary muscle. While the study of these ventricular bands provided additional information on the cardiac anatomy of the domestic dog, it also showed their clinical importance. Several studies have proposed that their position in the ventricle may interfere with cardiac catheterization and pacemaker lead placement or be misinterpreted during echocardiography.

Exercises in anatomy: holes between the ventricles.

Holes between the ventricles are the commonest congenital cardiac malformations. As yet, however, there is no consensus as to how they can best be described and categorized. In this, our third exercise in cardiac anatomy, we address the issue of classification of ventricular septal defects. We begin our demonstration by analysing the normal heart. We show that the larger part of the ventricular septum is made up of its muscular component. The membranous part accounts for only a small portion, which is located centrally within the cardiac base. This small membranous part forms a boundary between the right-sided chambers and the aortic root. Holes at this site, therefore, which account for the commonest defects closed surgically, will open centrally in the cardiac base, being located postero-inferiorly relative to the supraventricular crest. We then show that the larger part of the crest itself is a free-standing muscular sleeve, which lifts the leaflets of the pulmonary valve away from the cardiac base. Only a very small part of the muscle forming the right ventricular outlet is located in the septal position. Turning our attention to malformed hearts, we show how holes between the ventricles can open centrally at the cardiac base, open to the inlet or outlet of the right ventricle or open within the substance of the apical muscular septum. We demonstrate, however, that description of such geographical location of the defects does not paint the full picture, since lesions with markedly different phenotypic features can open in comparable geographic locations. We illustrate how it is the phenotypic features, as seen from the right ventricle, which convey the crucial information for the surgeon with regard to the location of the atrioventricular conduction axis, using hearts with holes opening to the inlet of the right ventricle with muscular as opposed to partially fibrous borders to emphasize this point. We continue by showing how holes with different phenotypes can also open to the outlet of the right ventricle, the key feature in this regard being malalignment between the apical muscular septum relative to the muscular outlet septum or its fibrous remnant. Malalignment can also be found between the apical ventricular septum and the atrial septum, this being shown in a defect opening to the inlet of the right ventricle. We conclude by emphasizing that, so as to bring together all the information of surgical significance, it is necessary to take note of the geographical location of holes between the ventricles, their phenotypic features and the presence or absence of malalignment between the septal components.

Arterial switch for transposed great vessels with intact ventricular septum beyond one month of age.

BACKGROUND: Late referral of patients with transposition of the great arteries (TGA) and intact ventricular septum (IVS) is common in China. This study investigates the impact of later age on the arterial switch operation (ASO) performed for TGA-IVS beyond 1 month of age. METHODS: From 2000 to 2011, a total 109 patients with TGA-IVS were referred over 1 month of age. In group A, 78 patients with satisfactory left ventricular (LV) geometry underwent a one-stage ASO. In group B, 31 patients with LV regression underwent a two-stage ASO with prior LV retraining. RESULTS: The median age at ASO was older in group B (6 months, versus group A 1.9 months; p = 0.01). Group A had more frequent patent ductus arteriosus (70.5%, versus group B 38.7%; p = 0.02). The in-hospital mortality was similar in both groups (group A 2.6%, group B 9.7%; p = 0.14). Late mortality was higher in group B (16%, versus group A 2.7%; p = 0.03), as well as aortic regurgitation rate (group A 9.8% versus group B 33.3%; p = 0.01). The median duration of retraining in group B was 18 days. There were no deaths at retraining, although 2 patients required revision of the pulmonary artery banding. The only significant risk factor for late mortality in group B was age at retraining, as continuous variable (p = 0.04). Age beyond 3 months at LV retraining was associated with late impaired LV ejection fraction (p = 0.01). CONCLUSIONS: The overall outcomes of ASO for TGA-IVS performed beyond 1 month of age are satisfactory. Two-stage ASO has higher late mortality and more neoaortic regurgitation. Later age at retraining is associated with higher late mortality. Age beyond 3 months at retraining is associated with impaired LV function.

Extracorporeal membrane oxygenation as a support for TGA/IVS with low cardiac output syndrome and pulmonary hemorrhage.

A 15-day-old neonate with complete transposition of the great arteries/intact ventricular septum was admitted with life-threatening hypoxemia and heart arrest. After successful resuscitation, heart beat recovered but blood lactate began to arise and maintained above 15 mmol/L 6 hours later. Emergency arterial switch operation was done at 20 hours after resuscitation. Planned extracorporeal membrane oxygenation support was employed postoperatively. The baby experienced severe pulmonary hemorrhage and severe hypoxemia after weaning from cardiopulmonary bypass, which were treated with extracorporeal membrane oxygenation support.

Anatomy and physiology of the right ventricle.

Under normal baseline conditions the unique anatomy, myocardial ultrastructure, and coronary physiology of the right ventricle (RV) reflect a high-volume low-pressure pump. Early work described the RV as a passive conduit with minimal pumping capability. It is now appreciated that through a mechanism of ventricular interdependence, RV systolic function and diastolic load are extremely important in the prognosis and treatment of congestive heart failure, cardiac transplantation, pulmonary hypertension, congenital heart disease, and left ventricle assist devices. Magnetic resonance imaging with three-dimensional analysis has shown the complex geometry of the RV and the interaction of both ventricles within the pericardium.

A septal angle measured on computed tomographic pulmonary angiography can noninvasively estimate pulmonary vascular resistance in patients with chronic thromboembolic pulmonary hypertension.

PURPOSE: To explore the correlation between a septal angle measured on computed tomographic pulmonary angiography (CTPA) and pulmonary vascular resistance (PVR) determined by right heart catheterization in patients with chronic thromboembolic pulmonary hypertension (CTEPH). MATERIALS AND METHODS: Eighty-six patients with CTEPH (54 men, mean age: 53.08±12.43 y) were retrospectively reviewed, and 86 sex-matched and age-matched individuals without pulmonary artery hypertension and pulmonary embolism were used as the control group. All patients with CTEPH underwent CTPA before right heart catheterization. Septal angle was measured on transverse CTPA images as the angle between the interventricular septum and the line joining the midpoint of the sternum to the thoracic vertebral spinous process. Hemodynamic PVR was calculated on the basis of the data from right heart catheterization. RESULTS: Septal angle was 65.27±12.24 degrees and 39.43±9.79 degrees in the CTEPH group and control group, respectively, which was statistically significant (t=18.139, P=0.000). The septal angle correlated positively with PVR (r=0.629, P=0.000). By stepwise linear regression analysis, the septal angle was shown to be the only variable (r=0.578) that was independently associated with PVR levels, leading to the following equation: PVR=21.591×septal angle-374.641. By receiver operating characteristic analysis, septal angle ≥67.55 degrees had a sensitivity of 71.6% and a specificity of 73.4% for predicting PVR≥1000 dyne s/cm with an area under the curve of 0.739±0.055, which was higher than the area under the curve of right ventricular area/left ventricular area (0.627±0.061) and that of transverse diameter of right ventricle/transverse diameter of left ventricle (0.612±0.060). CONCLUSION: The septal angle is a useful tool for estimating PVR in patients with CTEPH.

Color-coded longitudinal interventricular septal tissue velocity imaging, strain and strain rate in healthy Doberman Pinschers.

OBJECTIVE: To determine reference values for septal longitudinal tissue Doppler imaging (TDI) in Doberman Pinschers. BACKGROUND: TDI includes several new techniques, such as tissue velocity imaging (TVI), strain, and strain rate that might be used to detect early myocardial dysfunction. However, before these techniques can be used, breed specific reference ranges need to be established. ANIMALS, MATERIALS AND METHODS: One-hundred healthy Doberman Pinschers ≥ 4 years of age were prospectively evaluated using electrocardiography, Holter recording, and echocardiography. Systolic, early and late diastolic parameters of septal longitudinal color-coded TVI, strain, and strain rate were analyzed in three myocardial segments (basal, middle, and apical). RESULTS: TDI was feasible in all Doberman Pinschers. Reference values were established for every myocardial segment. There was a significant velocity gradient from the basal to the apical segment for all TVI parameters. No differences between the three segments were found for systolic strain and strain rate. Several diastolic strain rate values were significantly different between myocardial segments. Influence of age, weight, and gender was not clinically relevant. CONCLUSIONS: This study provides reference values for TVI, strain, and strain rate in Doberman Pinschers. The parameters established here can be used for a supportive diagnostic approach.

Thrombotic occlusion of a large septal perforator presenting as ST-segment elevation in V1-V2 and treated with aspiration thrombectomy: a brief review of the literature.

The interventricular septum constitutes approximately one-third of the mass of the left ventricle, and the bulk of the anterior septum is supplied by septal branches of the left anterior descending coronary artery. Ischemia of the interventricular septum results in angina, infarction, biventricular failure and ventricular arrhythmias. While the majority of septal infarctions are due to occlusions of the proximal left anterior descending coronary artery, a large first septal branch thrombosis can rarely be the culprit. Given the paucity of data pertaining to septal perforator disease, a thorough discussion on septal perforator coronary artery interventions and an illustrative case will be provided.