Atrial shunts: presentation, investigation, and management, including recent advances in magnetic resonance imaging

Abstract

Atrial shunts are a common finding in both paediatric and adult populations. Recent developments in advanced imaging have widened the options for diagnosis and evaluation of such shunts. This paper reviews the various types of interatrial communications, discusses the features of clinical presentation in adults and children, and provides an overview of the clinical assessment including physical examination, electrocardiography, echocardiography, cardiac catheterisation, computed tomography, and magnetic resonance imaging. Focus will be placed on recent developments in magnetic resonance imaging that may improve the non-invasive evaluation of atrial shunts.

Assessment of long-term cardiac adaptation in adult patients with type II atrial septal defect

“…Atrial septal defect (ASD), the second most common congenital heart defect, is a common cause of right heart dilatation, but as it is often well tolerated, the defect may remain undiagnosed till at a later age [1,2]. As filling pressures in the left atrium exceed right atrial pressures, the shunt direction is typically left to right (LR), causing a right heart volume overload at the expense of left ventricular filling (LV) [3]. Longstanding left-to-right (LR) shunt, however, may lead to shunt reversal, if right heart pressures increase secondary to pulmonary arterial hypertension, leading to the so-called Eisenmenger syndrome [3].…”

“…As filling pressures in the left atrium exceed right atrial pressures, the shunt direction is typically left to right (LR), causing a right heart volume overload at the expense of left ventricular filling (LV) [3]. Longstanding left-to-right (LR) shunt, however, may lead to shunt reversal, if right heart pressures increase secondary to pulmonary arterial hypertension, leading to the so-called Eisenmenger syndrome [3]. Cardiac imaging in ASD patients is important to depict, describe, and size the defect, but also to determine the impact on ventricular volumes, function, and strain, to estimate pulmonary arterial hypertension [4].…”

“…Moreover, imaging in ASD patients is particularly important to exclude additional defects, i.e., abnormal pulmonary venous return, as it has important therapeutic consequences. Transthoracic (TTE) and transesophageal (TEE) echocardiography are first-line imaging modalities in the diagnostic workup of ASD [3][4][5][6][7]. Besides, cardiovascular magnetic resonance imaging (CMR) and cardiac computed tomography (CCT) are increasingly used in the diagnosis of this congenital defect [3,4,8].…”

“…Transthoracic (TTE) and transesophageal (TEE) echocardiography are first-line imaging modalities in the diagnostic workup of ASD [3][4][5][6][7]. Besides, cardiovascular magnetic resonance imaging (CMR) and cardiac computed tomography (CCT) are increasingly used in the diagnosis of this congenital defect [3,4,8]. Although CCT provides excellent anatomic detail, for assessment of ventricular volumes and estimation of intracardiac shunt severity, substantially higher radiation doses are needed [8].…”

“…CMR, in contrast, provides accurate and reproducible data on ventricular volumes and function. It allows measuring flow velocities and volumes, and thus calculating shunt volume either directly through the defect or indirectly by means of the difference between the pulmonary trunk and ascending aorta forward volume (Qp/Qs) [3,4,[9][10][11][12][13][14]. CMR is highly valuable to depict abnormal pulmonary venous return [15,16].…”