Real‐time three‐dimensional (3D) echocardiographic characterisation of an atrial septal defect in a horse

Abstract

Atrial septal defects have been well reported in humans and dogs and the principles of intervention have been well established. In contrast, there is very little information published about these congenital anomalies in horses. True ASDs are regarded as rare and little is known about the clinical significance of these defects in horses. An 11‐year‐old Thoroughbred gelding with a history of poor performance was diagnosed with an atrial septal defect, measuring approximately 2 cm in diameter, on 2D transthoracic echocardiography. Real‐time three‐dimensional (3D) echocardiography was used to map the structure of the defect and was useful in fully characterising the ASD in this case.

Three‐dimensional and catheter‐based intracardiac echocardiographic characterization of the interatrial septum in 2 horses with suspicion of a patent foramen ovale

“…The recent advent of real‐time 3D‐TTE in equine cardiology solves this issue, as instead of a 2D slice, a 3D volume is acquired using a matrix‐array transducer, thus gaining insight into the 3D conformation of cardiac structures. Clinical use of 3D‐TTE has been reported for the evaluation of the aortic valve and an atrial septal defect 7,8 . Left atrial volumetric assessment by 3D‐TTE is also gaining attention for use in horses 9 .…”

“…This way, fetal oxygenated blood is led directly to the fetal tissues, instead of detouring past the nonfunctional lungs. 8 , 28 , 29 , 31 In the different types of atrial septal defects, 1 or more septal components are absent or malformed, recognized by an abrupt interruption in the interatrial septum with evidence of interatrial communication on color flow Doppler. In contrast, all septal components are present in a PFO but anatomical and functional closure does not take place.…”

“…Atrial left‐to‐right shunts cause right‐sided volume overload and lead to increased pulmonary artery flow and therefore increased pulmonary venous return, which can result in left‐sided volume overload. 8 , 25 , 33 Left‐to‐right shunts are regarded as important if the pulmonary‐to‐systemic flow ratio is higher than 1.8 : 1. 25 Therefore, the hemodynamic effect of the shunt was within functional limits in Case 2.…”

“…Pulmonary-to-systemic flow ratio (Qp : Qs), based on pulsed-wave Doppler of the pulmonary 3 and aortic flow, 4 been reported for the evaluation of the aortic valve and an atrial septal defect. 7,8 Left atrial volumetric assessment by 3D-TTE is also gaining attention for use in horses. 9 A disadvantage is that 3D-TTE suffers from the trade-off of spatial and temporal resolution.…”

Science‐in‐brief: Equine Cardiology Virtual Retreat June 2020

“…Three‐dimensional echocardiography in horses is in its infancy and limited by the large dimensions of horses’ hearts, leading to low recording frame rates. Current experience suggests that 3DE might be useful for quantification of chamber dimensions, measurement of the regurgitant orifice of insufficient valves and the size of septal defects, 11 and characterisation of structural valvular abnormalities.…”