Clinical, hemodynamic, and intracardiac echocardiographic characteristics of secundum atrial septal defects-related paradoxical embolism in adulthood

Diagnosing Atrial Septal Defect from Electrocardiogram with Deep Learning

The heart murmur associated with atrial septal defects is often faint and can thus only be detected by chance. Although electrocardiogram examination can prompt diagnoses, identification of specific findings remains a major challenge. We demonstrate improved diagnostic accuracy realized by incorporating a proposed deep learning model, comprising a convolutional neural network (CNN) and long short-term memory (LSTM), with electrocardiograms. This retrospective observational study included 1192 electrocardiograms of 728 participants from January 1, 2000, to December 31, 2017, at Tokyo Women's Medical University Hospital. Using echocardiography, we confirmed the status of healthy subjects-no structural heart disease-and the diagnosis of atrial septal defects in patients. We used a deep learning model comprising a CNN and LTSMs. All pediatric cardiologists (n = 12) were blinded to patient groupings when analyzing them by electrocardiogram. Using electrocardiograms, the model's diagnostic ability was compared with that of pediatric cardiologists. We assessed 1192 electrocardiograms (828 normally structured hearts and 364 atrial septal defects) pertaining to 792 participants. The deep learning model results revealed that the accuracy, sensitivity, specificity, positive predictive value, and F1 score were 0.89, 0.76, 0.96, 0.88, and 0.81, respectively. The pediatric cardiologists (n = 12) achieved means of accuracy, sensitivity, specificity, positive predictive value, and F1 score of 0.58 ± 0.06, 0.53 ± 0.04, 0.67 ± 0.10, 0.69 ± 0.18, and 0.58 ± 0.06, respectively. The proposed method is a superior alternative to accurately diagnose atrial septal defects.

Cardiac arrest in a healthy child due to paradoxical embolus across a previously unrecognised sinus venosus defect

A previously healthy, preadolescent female suffered an unwitnessed cardiac arrest with prompt return of circulation following bystander initiated resuscitation. Workup demonstrated the cause of her cardiac arrest to be distal left anterior descending coronary artery occlusion with small apical left ventricular transmural myocardial infarction, from a paradoxical embolus traversing a previously undiagnosed large sinus venous defect. This case demonstrates the value of cardiac magnetic resonance imaging may bring to the diagnosis of the pathophysiology leading to cardiac arrest.

Pregnancy in adults with repaired/unrepaired atrial septal defect

Atrial septal defect (ASD) is the most common form of congenital heart disease. Left-to-right shunting leads to right ventricular (RV) volume overload with excessive pulmonary blood flow. Complications include exercise intolerance, pulmonary vascular disease, RV dysfunction, paradoxical thromboemboli, and atrial arrhythmias. Women with coexisting severe pulmonary hypertension should be counselled against pregnancy due to high incidence of maternal and fetal morbidity and mortality. In the absence of pulmonary hypertension, pregnancy is generally well tolerated in the setting of an ASD. Nevertheless, hemodynamic changes throughout gestation may increase the risk for complications, particularly in those with unrepaired ASDs. Arrhythmias are the most common cardiac event and occur in 4-5%, followed by paradoxical emboli in 2-5%. Obstetrical and neonatal complications include preeclampsia, a higher incidence of infants born small for gestational age, and higher fetal/perinatal mortality. Although there is no definitive evidence demonstrating superiority of an aggressive approach to ASD closure prior to pregnancy, it is currently common practice to electively close asymptomatic but large and/or hemodynamically significant ASDs prior to childbearing. Cardiology follow up during pregnancy should be adapted to clinical circumstances and includes transthoracic echocardiography during the second trimester and arrhythmia monitoring in the event of symptoms.

[Paradoxical embolism: Myth or reality?]

Paradoxical embolism should be suspected in front of a clinical phenomenon of thromboembolism associated with an anatomical right-to-left shunt. Others potential cardiac sources of thromboembolism must be ruled out. Strokes constitute the most frequent clinical manifestations of paradoxical embolism. Right-to-left left shunts are in connection with intracardiac defects (atrial septal defect and patent foramen ovale) or pulmonary arteriovenous malformations. The probability that a discovered PFO is stroke-related can be evaluated by a score. Therapeutic approaches for secondary prevention of recurrent stroke include antithrombotic and/or percutaneous treatments. The choice strategy begins to be clearer with the recent results of randomized controlled studies.

Persistent iatrogenic atrial septal defects after pulmonary vein isolation: long-term follow-up with contrast transesophageal echocardiography

PURPOSE

Pulmonary vein isolation using cryoballoon ablation is an established approach to treating atrial fibrillation. The procedure involves insertion of a 15-Fr sheath into the left atrium across the interatrial septum. This creates an iatrogenic atrial septal defect, which may have important long-term clinical relevance, especially in younger patients. We sought to determine the long-term incidence of these defects and determine the direction of shunt using contrast transesophageal echocardiography.

METHODS

Individuals who had undergone a single pulmonary vein isolation procedure were invited to attend for transesophageal echocardiography (TOE). Patients who had undergone more than one procedure involving puncture of the interatrial septum were excluded. The interatrial septum was interrogated using two-dimensional imaging, color flow Doppler, and microbubble contrast study.

RESULTS

A total of 27 patients were recruited with a median follow-up time of 553 days from pulmonary vein isolation to TOE. Seven patients had persistent iatrogenic atrial septal defects with three demonstrating right to left shunt either at rest or with Valsalva. There were no reported adverse events during the study period.

CONCLUSIONS

Persistent iatrogenic atrial septal defects are relatively common following cryoballoon ablation procedures. Right to left shunting can be observed using microbubble contrast in a subset of patients with iatrogenic atrial septal defect (iASD). Further studies that longitudinally assess shunt fraction, pulmonary artery pressure, and the incidence of paradoxical embolism are needed to better understand the clinical impacts of such defects.