Floppy interatrial septum mimicking an ASD: The role of left atrial pressure

Transesophageal echocardiography examination (TEE) was performed in a 61-year-old male patient who presented to our emergency department with a 3-day history of palpitations, tightness in the chest, and dyspnea on exertion. A remarkable interatrial septum (IAS) was observed, with the anterior/superior aspect pointing towards the right atrium (RA) exposing a substance defect with left-to-right shunting in color Doppler and a washout towards the RA in the intravenous (iv) contrast study with agitated saline (Figure 1, Videos S1-S4). Previous medical history included an addiction to alcohol and chronic obstructive pulmonary disease. Liver function was normal, and there was no history of stroke. The electrocardiogram revealed atrial fibrillation (AF) with a heart rate of 159 bpm, oxygen saturation was normal, and physical examination was unremarkable except tachycardia. The patient received electrical cardioversion. TEE was repeated 8 weeks later in sinus rhythm. This time, the IAS is highly mobile (“floppy”), showing a large patent foramen ovale (PFO) with spontaneous right-to-left shunting in the iv contrast study, and maximal diameter of membrane separation was 5 mm. This clinical image presents the same patient in two diverging hemodynamic situations with significant differences in left atrial (LA) pressure between the two examinations. It demonstrates that a large PFO with spontaneous right-to-left shunting can be concealed or even turned into a left-to-right shunt depending on LA pressure. It illustrates the previously shown correlation of pulmonary capillary wedge pressure and the movement of the IAS.1, 2 The absence of detectable right-to-left shunting can be due to image quality, angulation, and elevated LA pressure.3 Therefore, it is crucial to evaluate the anatomy and the morphology of the IAS in every TEE. In conclusion, elevated LA pressure due to any reason can impede the detection of PFO. Open Access funding enabled and organized by Projekt DEAL. All authors have read and approved the submission of the manuscript and have no conflict of interest to disclose. Conceptualization: Veronika Zach, Matthias Schneider. Supervision: Burkert Pieske, Matthias Schneider. Visualization: Veronika Zach, Matthias Schneider. Writing—Original Draft Preparation: Veronika Zach, Matthias Schneider. Writing—Review and Editing: Elisabeth Pieske-Kraigher, Burkert Pieske. All authors have read and agreed to the published version of the manuscript. The corresponding author confirms that he had full access to all of the data and takes complete responsibility for the integrity of the data and the accuracy of the data analysis. The manuscript is an honest, accurate, and transparent account of the clinical image being reported; no important aspects have been omitted. As this report is a “clinical image,” no formal ethics committee vote is available. This research was carried out in accordance with recognized standards (the Declaration of Helsinki, as revised in 2013). Informed consent was obtained from the patient for publication of the clinical image and related accompanying images. Data sharing not applicable to this article as no datasets were generated or analyzed. Video S1. Transesophageal echocardiography during atrial fibrillation. The interatrial septum points towards the right atrium. Video S2. Transesophageal echocardiography in sinus rhythm. The interatrial septum is “floppy”/highly mobile with a large patent foramen ovale. Video S3. Transesophageal echocardiography in sinus rhythm with agitated saline. Spontaneous right-left shunting through large patent foramen ovale. Video S4. Transesophageal echocardiography during atrial fibrillation. Color Doppler shows left-to-right shunting. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.