Septomarginal Trabeculation Research Articles

Determinants of the difficulty of leadless pacemaker implantation.

The Micra Transcatheter Pacing System is implanted directly in the right ventricle (RV) through the femoral vein using a steerable transcatheter delivery system. The present study was done to identify determinants of difficult leadless pacemaker implant procedures including operator, patient, and RV anatomical characteristics. All patients who underwent a Micra implant from July 2015 to December 2018 at our center were analyzed. From an RV angiogram acquired during implantation, RV geometry including systolic and diastolic volumes and ejection fraction was characterized. The presence of septomarginal trabeculation was noted. One hundred twenty-six patients (mean age: 79±11years old, mostly male: 77%) were enrolled. Mean Micra RV implant procedure time was 24±23min, with 1.7±1.3 deployments of the device. No significant change in implant procedure time was observed after the first 30 implants. Eleven patients had a prominent septal component of the septomarginal trabeculation in the RV. Univariate analysis showed that the procedure time was positively correlated with the presence of a prominent septal component of the septomarginal trabeculation (P<.001) or an episode of heart failure (P=.02) and negatively correlated with the number of procedures performed by the operator (P<.001). After multivariable analysis, only the presence of a prominent septal component of the septomarginal trabeculation (P<.001) and the number of procedures performed by the operator (P<.001) were associated with the implant procedure time. In our experience, implant procedure time of a Micra leadless pacemaker depended on the presence of a prominent septal component of the septomarginal trabeculation and operator experience.

Visualization and quantification of the atrioventricular conduction axis in hearts with ventricular septal defect using phase contrast computed tomography

ObjectiveTo visualize and quantify the atrioventricular conduction axis in the setting of ventricular septal defect using phase contrast computed tomography. MethodsWe used the SPring-8 synchrotron radiation facility in Hyogo prefecture in Japan, processing and reconstructing the data with 3-dimensional software. ResultsWe studied 8 hearts obtained from patients known to have had ventricular septal defects, aged from 6 to 150 days, with a median of 24.5 days. None of the individuals, however, had undergone corrective surgery. The penetrating bundle was found at a median of 1.43 mm from the septal crest, with a range of 0.99 to 1.54 mm. The distance to the nonbranching bundle to the right ventricular endocardium was 1.10 mm, with a range from 0.49 to 2.49 mm, to the origin of the left bundle branch was 2.46 mm, with a range from 1.7 to 3.18 mm, and to the origin of the right bundle branch was 2.34 mm, with a range from 0.50 to 2.59 mm. The median distance from the edge of the caudal limb of the septomarginal trabeculation to the right bundle branch was 1.04 mm, with a range from 0.81 to 1.16 mm. ConclusionsWe were able to show the precise location of the axis, with our findings suggesting that longitudinal sutures placed along the posteroinferior rim should be effective in avoiding iatrogenic injury, but sutures should not be placed in the valley between the limbs of the septomarginal trabeculation.

Right ventricular septomarginal trabeculation hypertrophy is associated with disease severity in patients with pulmonary arterial hypertension.

To characterize the morphological change in the right ventricle (RV) of patients with pulmonary artery hypertension (PAH) and further explore the correlation between septomarginal trabeculation (SMT) and right ventricular (RV) function, myocardial fibrosis, and exercise capacity in patients with PAH. Sixty untreated PAH patients were prospectively included from May 2016 to April 2017. All patients underwent comprehensive clinical evaluation and cardiac magnetic resonance (CMR). The area and diameter of the basal segment of SMT, and the mass of SMT were measured on cine SSFP images. Relationship between parameters of SMT and RV ejection fraction (RVEF), 6min walking distance (6MWD), myocardial fibrosis and pulmonary vascular resistance (PVR) were evaluated by Pearson's correlation and logistic regression. Predictive performance of SMT parameters for reduced RVEF or impaired 6MWD was evaluated by receiver operating characteristics (ROC) analysis. Compared with SMT diameter index and mass index, SMT area index (SMT Ai) in basal segment was the best parameter to show correlation with RVEF (r = - 0.496, P < 0.001), 6MWD (r = - 0.619, P < 0.001), and inferior insertion point (I IP) extracelluar volume (ECV) (r = 0.365, P = 0.008). ROC showed that SMT Ai had the strongest predictive value for reduced RVEF (AUC = 0.756), and impaired 6MWD (AUC = 0.813). SMT parameters were closely correlated with RV systolic function and 6MWD in patients with PAH. SMT Ai is a simple imaging indicator for the severity of PAH.

The independence of the infundibular building blocks in the setting of double-outlet right ventricle.

It has long been contentious as to whether the presence of bilateral infundibulums, or conuses, is a prerequisite for the diagnosis of double-outlet right ventricle. As the use of such a criterion would abrogate the so-called "morphological method", which correctly states that one variable entity should not be defined on the basis of another entity that is itself variable, it is now accepted that double outlet can exist in the setting of fibrous continuity between the leaflets of the atrioventricular and arterial valves. Although this debate has now been resolved, there are other contentious areas still requiring clarification in the setting of hearts unified because of the presence of this particular ventriculo-arterial connection - for example, it is questionable whether the channel between the ventricles should be described as a "ventricular septal defect", whereas it is equally arguable that the mere presence of fibrous continuity between the leaflets of the arterial valves does not necessarily place the channel in a doubly committed location. In this review, we describe a series of autopsied hearts in which the anatomical features serve to illuminate these various topics. We then discuss recent findings regarding cardiac development that point to the individuality of the building blocks of the ventricular outflow tracts, specifically the outlet septum, the inner heart curvature, or ventriculo-infundibular fold, and the septomarginal trabeculation, or septal band.

Easily measurable, noninvasive, and novel finding for pulmonary hypertension: Hypertrophy of the basal segment of septomarginal trabeculation of right ventricle.

Effect of pulmonary hypertension (PH) on right ventricular (RV) geometry constitutes an ideal target to assess both pulmonary artery pressure (PAP) and its physiological importance. In this study, we evaluated the diagnostic power of the basal segment of septomarginal trabeculation (SMT) in predicting the PH and RV hypertrophy by cardiovascular magnetic resonance (CMR) in patients with idiopathic pulmonary arterial hypertension (IPAH) and Eisenmenger's syndrome (ES). Eleven patients with IPAH, seven patients with ES, and 20 healthy controls were enrolled. CMR was used to measure the area and the thickness of the basal segment of SMT and right ventricular free wall (RVFW). Pulmonary artery systolic pressures (PASPs) were estimated by transthoracic echocardiography (TTE) with continuous-wave Doppler analysis measuring maximal tricuspid regurgitation (TR) velocity. Late gadolinium enhancement (LGE) findings of CMR and brain natriuretic peptide (BNP) levels were also obtained in all patients and control group. The area and the thickness of the basal segment of SMT were higher in patients with IPAH and ES than control group (P<.001). Pulmonary artery dimension, end-diastolic diameter of RV, RVFW thickness, and BNP levels were found to be significantly correlated with PAP (P<.001). LGE was present at the insertion point of RV only in patients group (P<.001). Increased area and thickness of the basal segment of SMT are easily measurable noninvasive markers of PH in patients with IPAH and ES.

How should we diagnose and differentiate hearts with double-outlet right ventricle?

Many, if not most, of the controversies regarding the description of the congenitally malformed heart have been resolved over the turn of the 20th century. A group of lesions that remains contentious is the situation in which both arterial trunks, in their greater part, are supported by the morphologically right ventricle. It was considered, for many years, that presence of bilateral infundibulums, or conuses, was a necessity for such a diagnosis. It has now been appreciated that this suggestion founders on many counts. In the first instance, such bilateral infundibulums are to be found in patients with other ventriculo-arterial connections, including the otherwise normal heart. In the second instance, it is clear that such an approach abrogates the important principle now known as the morphological method. This states that entities should be defined in terms of their intrinsic morphology and not on the basis of other variable features. It is now also clear that, when assessed simply on the basis of the ventricular origin of the arterial trunks, a significant number of patients fulfil the criteria for so-called "200%" origin of the trunks from the right ventricle when there is fibrous continuity between the leaflets of the atrioventricular and arterial valves. In this review, we show how attention to the morphology of the channel between the ventricles now provides the key to accurately diagnose the ventriculo-arterial connection in patients with suspected double-outlet right ventricle. This is because, when both arterial trunks arise exclusively or predominantly from the morphologically right ventricle, the outlet septum, of necessity, is itself a right ventricular structure. The channel between the ventricles, therefore, is roofed by the inner heart curvature, whether that structure is fibrous or muscular. Our observations then confirm that it is the attachment of the outlet septum, which itself can be muscular or fibrous, which determines the commitment of the interventricular communication to the subarterial outlets. The interventricular communication itself, when directly committed to the ventricular outlets, opens between the limbs of the septomarginal trabeculation or septal band. The defect is subaortic when the outlet septum is attached to the cranial limb of the trabeculation, subpulmonary when attached to the caudal limb, and doubly committed when attached to the inner heart curvature in the roof of the defect. Non-committed defects are no longer positioned within the limbs of the septomarginal trabeculation. Although readily demonstrable by a skilled echocardiographer, we show how these anatomical features are more easily demonstrated with added accuracy when using CT data sets.

Correlating the morphological features of tetralogy of Fallot and the Eisenmenger malformation.

We studied a series of 43 autopsied cases of tetralogy of Fallot, assessing the mode of insertion of the outlet septum relative to the limbs of the septomarginal trabeculation, and compared the findings in retrospective fashion with our previous observations of a group of hearts with the so-called Eisenmenger malformation. In the majority of hearts with tetralogy of Fallot, the outlet septum inserted frontally relative to the septomarginal trabeculation, but in a minority of cases the outlet septum inserted in lateral fashion, as had been observed in all our hearts studied with the Eisenmenger malformation. The different modes of insertion were found to correlate, first, with the axis of anatomical aortic rightward rotation, coincident with the commissure between the right coronary and the left coronary leaflets of the aortic valve. The different modes of insertion of the outlet septum also correlated with the level of attachment of the arterial valvar leaflets on its subpulmonary and subaortic surfaces; concomitantly, correlation was found between the length of the subpulmonary infundibulum and the length of the muscular outlet septum itself. In the majority of hearts showing tetralogy of Fallot, the elongated infundibulum was also uniformly narrow, but in a minority the infundibulum was well expanded, obstructed only at its mouth, but widening at the valvar level. In all the hearts with the Eisenmenger malformation, in contrast, the unobstructed infundibulum was well expanded. The morphological findings of the present study show unequivocally that tetralogy of Fallot and Eisenmenger malformation are two phenotypically different congenital cardiac anomalies.

Pulmonary artery to aorta ratio for the detection of pulmonary hypertension: cardiovascular magnetic resonance and invasive hemodynamics in heart failure with preserved ejection fraction.

BackgroundPrevious work indicates that dilatation of the pulmonary artery (PA) itself or in relation to the ascending aorta (PA:Ao ratio) predicts pulmonary hypertension (PH). Whether these results also apply for heart failure with preserved ejection fraction (HFpEF) is unknown.In the present study we evaluated the diagnostic and prognostic power of PA diameter and PA:Ao ratio on top of right ventricular (RV) size, function, and septomarginal trabeculation (SMT) thickness by cardiovascular magnetic resonance (CMR) in HFpEF.Methods and Results159 consecutive HFpEF patients were prospectively enrolled. Of these, 111 underwent CMR and invasive hemodynamic evaluation.By invasive assessment 64 % of patients suffered from moderate/severe PH (mean pulmonary artery pressure (mPAP) ≥30 mmHg). Significant differences between groups with and without moderate/severe PH were observed with respect to PA diameter (30.9 ± 5.1 mm versus 26 ± 5.1 mm, p < 0.001), PA:Ao ratio (0.93 ± 0.16 versus 0.78 ± 0.14, p < 0.001), and SMT diameter (4.6 ± 1.5 mm versus 3.8 ± 1.2 mm; p = 0.008). The strongest correlation with mPAP was found for PA:Ao ratio (r = 0.421, p < 0.001). By ROC analysis the best cut-off for the detection of moderate/severe PH was found for a PA:Ao ratio of 0.83.Patients were followed for 22.0 ± 14.9 months. By Kaplan Meier analysis event-free survival was significantly worse in patients with a PA:Ao ratio ≥0.83 (log rank, p = 0.004). By multivariable Cox-regression analysis PA:Ao ratio was independently associated with event-free survival (p = 0.003).ConclusionPA:Ao ratio is an easily measureable noninvasive indicator for the presence and severity of PH in HFpEF, and it is related with outcome.

Landmarks for diagnosis and surgery in abnormal ventriculo-arterial connections with usual arrangement

Background The term “malposition of great arteries“ is commonly used for diagnosis and surgery in abnormal ventriculoarterial connections with usual arrangement and two well developed ventricles. In these abnormalities the variability of the arterial relationships is considerable and all relationships from normal to side by side to antero posterior have to be expected. Can we find other anatomical landmarks for the diagnosis and the subsequent corrective surgery? Methods We reviewed the specimens previously published and observations collected in three different institutions. Results There is a gradual transition from Tetralogy of Fallot to double outlet right ventricle with subaortic ventricular septal defect to Taussig-Bing hearts to transposition of great arteries. In this transition the normal aortic-mitral continuity is progressively lost with gradual development of pulmonary- mitral continuity. The key features determining the sequence of these abnormalities are the relationships between the outlet septum and the ventricular musculature. We may describe and group these malformations in function of the anticlockwise rotation of the outlet septum and the septomarginal trabeculation. Conclusion The term “malposition of great arteries“ is a generic term which is of little help for diagnosis and surgery, therefore, it should be avoided. We recommend a detailed description of the outlet septum and the septomarginal trabeculation in relation to the VSD. Careful attention to these structures dictates the diagnosis and the best surgical approach.

Hypertrophy of right ventricular septomarginal trabeculation by cardiac magnetic resonance imaging predicts presence and severity of pulmonary hypertension and outcome

Hypertrophy of right ventricular septomarginal trabeculation by cardiac magnetic resonance imaging predicts presence and severity of pulmonary hypertension and outcome

1019Hypertrophy of right ventricular septomarginal trabeculation by CMR imaging predicts presence and severity of pulmonary hypertension and outcome

1019Hypertrophy of right ventricular septomarginal trabeculation by CMR imaging predicts presence and severity of pulmonary hypertension and outcome

Double Outlet Right Ventricle Versus Aortic Dextroposition: Morphologically Distinct Defects

This study concerns the morphological differentiation between double outlet right ventricle (DORV) and aortic dextroposition (AD) defects, namely tetralogy of Fallot and Eisenmenger anomaly. Indeed, despite the similar condition in terms of sequential ventriculo-arterial connections, DORV and AD are two distinct morphological entities. It is proposed that the borderline between these two groups of malformations is represented by the specific insertion of the infundibular septum into the left anterior cranial division of the septomarginal trabeculation (or septal band) occurring in ADs and lacking in DORV. Furthermore, the spiraliform versus straight parallel arrangement of the great arteries in the two groups of anomalies is emphasized as an additional and distinctive morphological feature. Emphasis is also given to the association of straight parallel great arteries conotruncal malformations, DORV and transposition of the great arteries, with the asplenia type of heterotaxy laterality defects. Within this context, the absence of subaortic ventricular septal defect and concomitantly of spiraliform great arteries in the asplenia group of heterotaxy anomalies, as detected by this study, further substantiates our belief of not mixing collectively the ADs with the DORV in clinico-pathological diagnosis.

Increased Right Ventricular Septomarginal Trabeculation Mass is a Novel Marker for Pulmonary Hypertension

: To prospectively evaluate the cardiac magnetic resonance (MR) imaging-derived measurement of right ventricular (RV) septomarginal trabeculation (SMT) mass as a noninvasive marker for pulmonary hypertension (PH), compared with the ventricular mass index (VMI = RV mass/left ventricular mass) and RV mass. : A total of 49 patients (60 ± 12 years; 35 female) with suspected PH underwent cardiac MR and right heart catheterization on the same day. Eighteen normal volunteers were also included. The performance of SMT mass, VMI and RV mass measurement, with regard to PH detection, was analyzed using receiver operating characteristic curves. Logistic regression analysis was used to assess the association between SMT mass, RV mass, VMI, and PH. : The area under the receiver operating characteristic curve for SMT mass/body surface area (BSA), VMI, and RV mass/BSA in diagnosing the presence or absence of PH was 0.88, 0.87, and 0.73 respectively. In multivariable models, both SMT mass/BSA (P = 0.005, odds ratio: 8.6) and VMI (P = 0. 012, odds ratio: 1.1) were found to be significant, independent predictors of PH. : Compared with right heart catheterization measurement, SMT mass and VMI are reproducible and noninvasive MR imaging markers for the diagnosis of PH.

The following comments provide the views of an anatomist working in the clinical arena of Terminologia Anatomica, with specific reference to the cardiovascular system

The following comments provide the views of an anatomist working in the clinical arena of <i> Terminologia Anatomica</i>, with specific reference to the cardiovascular system

The following comments provide the views of an anatomist working in the clinical arena of Terminologia Anatomica, with specific reference to the cardiovascular system.

The following comments provide the views of an anatomist working in the clinical arena of Terminologia Anatomica, with specific reference to the cardiovascular system.

Pulmonary hypertension: role of septomarginal trabeculation and moderator band complex assessed by cardiac magnetic resonance imaging

In the right ventricle (RV), the septomarginal trabecula (SMT) arises as a muscular band originating from the interventricular septum (IVS) at the lower segment of the crista supraventricularis. It forms a functional unit with the moderator band, which attaches to the lateral free wall of the RV [1, 2]. Strategically situated between the RV inflow and outflow tracts, the whole unit serves to help emptying blood into the pulmonary trunk during systole. Thus, it should be anticipated that the SMT may undergo changes in RV hypertrophy secondary to chronic pulmonary hypertension.

Adult Congenital Heart Disease

It has variably been estimated that between 800 000 and 1 million patients with congenital heart disease are now adults and that by 2010 more patients older than 16 years will undergo surgery for congenital heart disease than those younger than 16 years.1 This review will focus on the clinical aspects of identifying and caring for the portion of the unique population that have right ventricular (RV) outflow tract lesions. The left ventricle (LV) and RV both have inlet, apical, and outlet portions, although they differ considerably.2 The inlet of the RV includes the tricuspid valve, and it is separated from the pulmonary valve (PV) by the crista supraventricularis. This structure results in the PV being raised upward. The apical portion of the RV has coarse trabeculations. As shown in Figure 1, the septum is home to a large septomarginal (septal) trabeculation that divides into the anterior and posterior limbs in the outflow tract. A series of septoparietal trabeculations arise along the free wall. The crista supraventricularis inserts between these limbs and is made up of 3 components: the muscular outlet septum, the ventriculoinfundibular fold, and the inner curvature of the RV.3 The small part that separates the RV and LV cavities is the outlet or conal septum. A loop including the septal trabeculation, the moderator band, septoparietal trabeculations, and the outlet septum can be conceptualized as circling the RV outflow tract. The PV is supported by the circular muscular infundibulum rising outside the RV proper. Abnormalities involving the RV outflow tract involve malpositioning of 1 or more of these structures. Figure 1. The anatomy of the RV outflow tract.2 There is a large septomarginal (septal) trabeculation that divides into 2 limbs. The anterior limb supports the leaflets of the PV, and the posterior limb …

An appreciation of the structural variability in the components of the ventricular outlets in congenitally malformed hearts

The morphology of the outlet septum, the ventriculo-infundibular fold, the infundibulum and the septomarginal trabeculation has been well described. These structures are closely interrelated, such that variations in the morphology and orientation of any one of them inevitably affect the morphology and orientation of the others. In this review, we seek to clarify how these normal relationships change within the setting of congenitally malformed hearts. This is of immense surgical significance, since the surgical correction of many congenital cardiac malformations involves procedures on, or in the vicinity of, these structures. We provide an insight into how the appearance of the components of the ventricular outlets can vary with the underlying pathology. We first define the relevant structures and describe how their location can vary in different malformations. We will then describe how the variations in that interrelationship may result in malalignment and deviation of the outlet septum, emphasising the surgical implications of these specific features.

The morphologic nature of noncommitted ventricular septal defects in specimens with double-outlet right ventricle

Background: Lev's contribution to the understanding of the morphology of hearts with double-outlet right ventricle and the surgical feasibility for correction is important and remains in current use. However, the term noncommitted ventricular septal defect remains enigmatic. The aim of this study was to elucidate the morphologic nature of the noncommitted ventricular septal defect in view of its surgical implications. Methods: We examined 67 specimens with double-outlet right ventricle, focusing on the relationship of the ventricular septal defect to the semilunar orifices. Results: The defect was subaortic, subpulmonary, or doubly committed in 55 specimens. In a further 8 specimens, the defect opened into the outlet portion of the right ventricle, but the distance between the ventricular septal defect and the semilunar orifice was extensive, either because of extreme dextroposition of the aorta or a broad ventriculoinfundibular fold, which, in some cases, was associated with a long-outlet septum. A truly noncommitted ventricular septal defect was found in the inlet in the remaining 4 specimens. An atrioventricular septal defect without extension to the outlet was present in 3 cases, and a ventricular septal defect limited to the inlet was found in another case. The ventriculoinfundibular fold, part of the outlet septum and septal band or septomarginal trabeculation, had fused to form a crestlike structure. The septomarginal trabeculation is a useful landmark in the right ventricle to differentiate the inlet from the outlet in different forms of double-outlet right ventricle. Conclusion: We do not suggest to discard the Lev terminology but rather to differentiate the noncommitted ventricular septal defect into 2 types: the truly noncommitted defect of the inlet type and the not-directly-committed defect, which does open into the outlet portion of the right ventricle. The implication for the surgeon is 2-fold. The tricuspid valve or right part of the atrioventricular valve is interposed between the noncommitted ventricular septal defect and the semilunar orifice. The not-directly-committed defect opens into the outlet portion of the right ventricle but is not directly subaortic or subpulmonary.J Thorac Cardiovasc Surg 2002;124:984-90

Double-chambered right ventricle or sub-infundibular stenosis assessed by cardiovascular magnetic resonance.

This paper presents magnetic resonance findings in four adults with double-chambered right ventricle or sub-infundibular stenosis, a condition that is treatable by surgery, but which can be difficult to assess echocardiographically. Four patients referred for cardiovascular magnetic resonance in the last 2 years were identified from CMR findings, although not necessarily from previous echocardiography, as having sub-infundibular stenosis. We used multislice spin echo imaging, cine imaging in oblique sagittal planes, and phase velocity mapping. We performed spin echo imaging of a post-mortem heart without known structural abnormality to illustrate right ventricular myocardial morphology. Results in patients showed evidence of sub-infundibular muscular obstruction separating the hypertrophied inlet and apical portions of the right ventricle from a thin-walled, unobstructed infundibular region in each case, with a systolic jet originating at least 15 mm beneath the unstenosed pulmonary valve. In addition to previously described structural components contributing to stenosis--enlargement and/or displacement of the septomarginal trabeculation, septoparietal trabeculations or the moderator band--CMR suggested additional components: a right ventricular papillary muscle in one, an anteriorly bulging aortic sinus in one, and hypertrophied muscular ridges of the parietal wall of the right ventricle. Even in this small group of patients, the causes of sub-infundibular stenosis appeared to be varied and multi-factorial. The abilities of magnetic resonance to give unrestricted, multi-planar views of right ventricular anatomy, movement and flow make it well suited for diagnosis and characterization of sub-infundibular stenosis, especially in adults.