33 Unexplained right heart dilatation; a clue to sinus venosus-atrial septal defect (SV-ASD) diagnosis

• Published in: Heart (British Cardiac Society) Vol. 110; no. Suppl 3; p. A37
• Main Authors: Aye, Yin Nwe, Razvi, Naveed
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and British Cardiovascular Society 01.06.2024; BMJ Publishing Group LTD
• Subjects: ACHD/Valve disease/Pericardial disease/Cardiomyopathy; ASD; Asymptomatic; Cardiac arrhythmia; echocardiography; Heart; Hypertension; Pacemakers; Pulmonary arteries; sinus venosus; Ultrasonic imaging
• ISSN: 1355-6037; 1468-201X
• DOI: 10.1136/heartjnl-2024-BCS.33

ObjectivesFor clinicians to be aware of different types of atrial septal defect and the rare manifestations of sinus venosus atrial septal defect (SV-ASD).To understand the effectiveness of different diagnostic modalities to reach the diagnosis.To familiarize with possibility of inadvertent right ventricular lead placement in left ventricle in patients with sinus venosus atrial septal defect who requires a permanent pacemaker.IntroductionAtrial Septal Defect (ASD) is one of the commonest types of congenital heart defects. Among its five subtypes which include patent foramen ovale, ostium secundum defect, ostium primum defect, sinus venosus defect, and coronary sinus defect, sinus venosus ASD (SV-ASD) is considered less prevalent and can be a challenge to diagnose in adults.There are two types of sinus venosus defect. The superior defect is when superior vena cava orifice overrides the atrial septum and the inferior defect when inferior vena cava overrides both atria.Whilst these patients can be asymptomatic, they can present with stroke, dysrhythmia, and pulmonary hypertension. In the former group of population, unexplained right ventricular dilatation in transthoracic echocardiogram could be a clue to the diagnosis of SV-ASD. Moreover, there are worldwide reported cases of SV-ASD being an associated cause of pacemaker lead malposition as well as cardioembolic implications. This is a specific case of SV-ASD from our institution, shedding light on the varied clinical presentations and associated challenges in diagnosing and managing this subtype of ASD.Case Presentation79 years old lady was referred from primary care to Cardiology Department to investigate for asymptomatic murmur. She has background of hypertension and atrial fibrillation on apixaban. Transthoracic echocardiogram showed right atrium and ventricular dilatation with raised right ventricular systolic pressure. While being investigated for right heart dilatation, she was admitted with atrial fibrillation with significant pauses for which she underwent a dual-chamber pacemaker implantation.Interestingly, months later, when a transoesophageal echocardiogram was done to further investigate for the right heart dilatation, right ventricular pacemaker lead was found attached to the left ventricular free wall (figure 1). Remarkably, it had passed through the sinus venous defect towards the left atrium then to the left ventricle. (Figure 2)As the patient was on apixaban for atrial fibrillation, she did not have complication with embolic phenomena. Lead revision procedure was done, and a new lead was implanted to the right ventricle. Cardiac MRI later showed preserved LV and RV function with significant Qp:Qs ratio of 4.5 and pulmonary artery dilatation of 4.4 cm.It was discussed at MDT meeting at a tertiary center and percutaneous sinus venous defect closure with pulmonary vein redirection procedure was offered. However, patient declined the procedure as her symptoms were manageable with medical therapy.Discussion and ConclusionThis case represents a challenging diagnosis of SV-ASD, which can be asymptomatic presentation and dilatation of the right heart on the echocardiography may be a clue. However, as stated in Pascoe, R. et al, transthoracic echocardiography may not be an ideal diagnostic tool for SV-ASD due to its far field location and can get conclusive diagnosis from transesophageal echocardiography.This case emphasizes the importance of careful fluoroscopy during the pacemaker implantation because there may be high chances of lead traversing through the sinus venous defect to the left atrium and left ventricle. This inadvertent lead displacement may lead to cardioembolic complications.In conclusion, this case highlights the importance of clinical awareness, comprehensive diagnostic approaches, individualized management strategies when dealing with less common subtype of atrial septal defect, particularly SV-ASD.Abstract 33 Figure 1Mid-oesophageal 2 chamber viewAbstract 33 Figure 2Mid-oesophageal bicaval viewConflict of InterestNone