Malposition of septum primum in isolated dextrocardia: unique and rare form of anomalous pulmonary venous return in association with partial absence of pericardium-case report

Background Total anomalous pulmonary venous return (TAPVR) refers to an anomaly in which all of the pulmonary veins drain directly or indirectly to the systemic venous circulation. However, unusual types constitute approximately 5% or less of TAPVRs and there may be obstruction or discontinuity of pulmonary vein at various levels. Case presentation A 3-month-old infant was presented to us with history of poor feeding, respiratory distress and desaturations. The routine echocardiographic investigation initially confirmed the diagnosis of an atrial septal defect with dextrocardia. However, due to disproportionate severity of symptoms and congestive heart failure a cardiac computer tomography angiogram was done that revealed a rare finding of connection of pulmonary veins fused with the posterior atrium, but on the rightward side of the deviated atrial septum. Therefore, pulmonary veins entered a sinus that drains directly into the right atrial superior-posterior wall. During surgical repair, we found an area of absent pericardium in the diaphragmatic surface of the heart. The patient underwent total repair of the TAPVR and patch reconstruction of the pericardial defect. The patient is doing well at 6-month follow up. Conclusions The septum primum malposition defect resulting in TAPVR is a very rare congenital anomaly that can be rarely seen without any heterotaxy. The anomalous features including absent pericardium and dextrocardia were present in this patient have not been described previously with TAPVR. Therefore, we have hypothesized the embryological correlation of absent pericardium and cardiac malposition in such case. Transthoracic echocardiography with Doppler interrogation is a reliable method for diagnosing this condition. In case of suboptimal echocardiographic image due to cardiac position, unclear anatomy or unexplained symptoms, advanced imaging such as computer tomographic angiography or cardiac magnetic resonance imaging can be very helpful. Preoperative proper diagnosis of this anomaly facilitates successful surgical management with excellent outcome.

Reliability of left atrial strain reference values: A 3D echocardiographic study

Background Standard apical four-chamber and two-chamber views often maximize the long-axis of the left ventricle, resulting in artifactitious foreshortening of the left atrium (LA), which may overestimate LA longitudinal reservoir strain (LALS). We compared LALS values between 2D echocardiography (2DE) and 3D echocardiography (3DE) in healthy subjects to determine whether 2DE speckle tracking analysis overestimates the reference value of LALS. Methods and results In this study, 4 types of cohorts were included: 1. 105 normal subjects (retrospectively), 2. 53 patients with cardiovascular diseases (retrospectively), 3. 15 patients who received cardiac magnetic resonance (prospectively), and 4. 20 normal subjects (prospectively). LALS and LA length were measured using both 2DE and 3DE in 105 healthy subjects (median age: 42 years). Biplane LALS was measured in apical four- and two-chamber views using 2DE speckle tracking software, and 3DE LALS was measured using new 3DE LA strain software. To determine sensitivity, we also performed the same analysis in 53 patients with cardiovascular disease. The mean value of biplane LALS was 39.6%. LA length at both end-diastole (r = -0.43) and end-systole (r = -0.54) was negatively correlated with biplane LALS. Multivariate regression analysis revealed that both end-diastolic and end-systolic LA length had significant negative relationships with biplane LALS after adjusting for anthropometric and echocardiographic image quality parameters. 3DE LALS (23.7±7.6%) gave significantly lower values than 2DE LALS (39.5±12.0%, p<0.001) with a weak correlation (r = 0.33). LA length measured by 2DE was significantly shorter than that measured by 3DE. The same trend was observed in diseased patients. Conclusions Our results revealed that in 2DE, the LA cavity consistently appears longitudinally foreshortened in apical views, potentially overestimating LALS. 3DE may overcome this limitation.

Echocardiography from a transhepatic approach in left ventricular assist device patients with difficult transthoracic imaging

Background Left ventricular assist devices (LVADs) are increasingly used in the treatment of end-stage heart failure. One important limitation in the follow-up of these patients is the very difficult echocardiographic image, because of the interposition of implanted materials. Case summary We present here a case series of LVAD patients with severely limited transthoracic echocardiographic windows in whom the echocardiographic analysis of the left and right ventricular function could be obtained from a very unusual approach, using a right intercostal transhepatic window, allowing visualization of the heart chambers and quantification of function even in these very challenging cases. In one case, the result was confirmed by computed tomography. In the second case, computed tomography images were unreliable because of strong artefacts from the LVAD system and implantable cardioverter-defibrillator leads, but the transhepatic approach still provided sufficient image quality in order to allow the imaging follow-up of the patient. In the third case, the transhepatic window was the only approach that provided echocardiographic images, and due to the good visualization of the heart cavities, this imaging technique was considered sufficient for follow-up studies in this stable subject with LVAD as destination therapy. Discussion The transhepatic window may represent a good alternative in selected LVAD patients with very difficult acoustic access in traditional transthoracic views. Modified or alternate echocardiographic windows may reduce the need for invasive procedures (transoesophageal echocardiography) or imaging methods using radiations.

A SHORT RECURRENCE TIME OF LEFT ATRIAL MYXOMA: CASE REPORT AND LITERATURE REVIEW

Background: Recurrence of sporadic cardiac myxoma remains unusual but the seriousness of the situation justifies the realization of a surgical resection as complete as possible with post-operative clinical and echocargdiographic monitoring. Case presentation: We recall the case of myxoma of the left atriumin a 64-year-old women complicated by functional mitral stenosis and heart failure. She underwent urgent heart surgery, during which a friable tumor attached by a sessile base to the anterior atrial septum was removed. The postoperative effects were complicated by a pulmonary embolism. Eight months later, the patient consulted for exertional dyspnea with an echocardiographic image in favor of a recurrence of myxoma of the left atrium. Conclusion: Several mechanisms have been proposed to explain such recurrence, the most avoidable remain incomplete surgical resection and Implantation of embolic fragments of the original tumor in the myocardium due to a previous surgery.

Site-specific automated contouring model generalisibiliy enhancement

Funding Acknowledgements Type of funding sources: None. Background Segmentation of cardiac structures in echocardiography is a pre-requisite for accurately assessing cardiac morphology and function. Manual or semi-automated segmentation are both routinely used in clinical practice, although these can be time-consuming, and can introduce high inter- and intra- operator variability resulting in decreased reproducibility. Effective contouring with no manual input has proven to be challenging due to variations in image quality, image noise, motion during the acquisition and the lack of a well-defined geometry. Methods This work proposes a coordinate regression method for automated left ventricle (LV) segmentation, presented in Figure 1 (a). The proposed method is based on a modified U-net architecture that outputs the likelihood of coordinates of landmark points. The obtained likelihood heatmaps are converted to 2D coordinates using a differentiable spatial to numerical transform. The model was trained and validated on UK multisite data (1383 subjects) comprising apical 2 and 4 chamber views for both contrast and non-contrast echocardiographic images. The Cardiac Acquisitions for Multi-structure Ultrasound Segmentation (CAMUS) echocardiographic image segmentation database was used to assess the performance of the proposed method acting as data from a new clinical site. The CAMUS dataset comprises apical 2 and 4 chamber views acquired from 500 patients with manually annotated cardiac structures for end-diastole and end-systole frames. The original CAMUS dataset was split into training (450 patients) and testing (50 patients), with manual contours being available only for the training dataset. Therefore, we used the CAMUS training dataset to both test and improve our model, by using a random sample of 100 studies as an independent testing dataset and the remaining 350 studies were used for retraining the initial model to improve performance for this dataset. Results The results obtained on the testing images are presented in Figure 1 (b). When the model was trained using no CAMUS data for the LV segmentation, a mean Dice coefficient of 0.890 and a median of 0.911 was obtained. Including 350 studies with the original 1383 UK dataset and retraining the same model improved the average Dice coefficient to 0.930 and the median to 0.939. The CAMUS dataset authors reported the best average Dice coefficient of 0.924 on the 50 CAMUS testing images, therefore the proposed points regression method introduces a promising alternative to mask-based segmentation models. Conclusions In conclusion, the auto-contouring framework has proven to be effective in terms of its performance and ability to generalise to new data. Furthermore, this work highlights the importance of both evaluating model performance on data from new clinical sites and also enhancing model performance. Abstract Figure.