**Introduction/Hypothesis:**
Lipomatous Hypertrophy of the Atrial Septum (LHAS) is a rare condition characterized by fatty thickening of the interatrial septum. Although benign, LHAS can pose diagnostic challenges due to its rarity and similarity to other cardiac masses. We present a case of an atrial mass, emphasizing the significance of multimodal cardiac imaging in establishing an accurate diagnosis and guiding appropriate management.

**Methods**
Case Presentation
A 79-year-old female with a history of asthma, fatty liver disease, and recent COVID-19 infection presented to the emergency department with shortness of breath. A chest CT performed to out rule pulmonary embolism revealed an incidental 4.6 x 4.1cm atrial mass. (Image A, attached PDF file) Subsequent outpatient evaluation with cardiac MRI revealed the atrial mass in the area of the superior limbus of the atrial septum and extending into the crista terminalis with mass effect and a possible obstruction of the superior cavoatrial junction. (Image B, attached PDF file) The patient only reported symptoms of palpitations and had a Holter monitor which revealed premature atrial complexes with a burden of 11%. She did not endorse any symptoms of superior vena cava syndrome. Transthoracic echocardiography demonstrated the right atrial mass and did not result in any extrinsic compression by the mass on hemodynamic assessment. (Image C, Scan QR code for Live Echo images, attached PDF file). On review of historical imaging, a CT coronory calcium study 23 years prior revealed presence at that time of a mass in the atrial septum measuring 2.1 x 1.3 cm (Image D). The density of the atrial mass on CT and MRI, its consistent location, and the gradual slow growth over the interceding years indicated that the mass was a benign cardiac LHAS. A beta blocker was initiated for the patient’s symptoms of palpitations, which subsequently improved. She was advised to return for assessment with repeat echocardiography if any symptoms consistent with superior vena cava syndrome, peripheral edema, or ascites developed.

**Results**
Discussion
Cardiac masses commonly raise concern for malignancy owing to their more common occurrence. The cardiac CT and cardiac MRI were essential for tissue characterization and assessing local tissue invasion, which could indicate malignancy. Echocardiography played a crucial role in assessing the hemodynamic impact of the cardiac tumor, particularly due to concerns about SVC obstruction based on cardiac MRI findings. Patients with cardiac lipomas and LHAS can experience cardiac arrythmias that are primarily atrial in nature. (1) Our patient had palpitations secondary to premature atrial complexes, however it is unclear if this was truly from the LHAS or her recent COVID 19 infection. As demonstrated in this case, multimodal cardiac imaging is essential in evaluating cardiac tumors, providing clinicians with confidence in determining whether further intervention, such as a biopsy, is necessary or if longitudinal follow-up is sufficient.

**Conclusion**
See Results section for Conculsion
Please refer to the attached PDF for the images, Live Echo images and references
(Images are on Page 2 and 3 of attached PDF)



**Introduction/Hypothesis:**
Lipomatous Hypertrophy of the Atrial Septum (LHAS) is a rare condition characterized by fatty thickening of the interatrial septum. Although benign, LHAS can pose diagnostic challenges due to its rarity and similarity to other cardiac masses. We present a case of an atrial mass, emphasizing the significance of multimodal cardiac imaging in establishing an accurate diagnosis and guiding appropriate management.

**Methods**
**Case Presentation**
A 79-year-old female with a history of asthma, fatty liver disease, and recent COVID-19 infection presented to the emergency department with shortness of breath. A chest CT performed to out rule pulmonary embolism revealed an incidental 4.6 x 4.1cm atrial mass. (Image A, attached PDF file) Subsequent outpatient evaluation with cardiac MRI revealed the atrial mass in the area of the superior limbus of the atrial septum and extending into the crista terminalis with mass effect and a possible obstruction of the superior cavoatrial junction. (Image B, attached PDF file) The patient only reported symptoms of palpitations and had a Holter monitor which revealed premature atrial complexes with a burden of 11%. She did not endorse any symptoms of superior vena cava syndrome. Transthoracic echocardiography demonstrated the right atrial mass and did not result in any extrinsic compression by the mass on hemodynamic assessment. (Image C, Scan QR code for Live Echo images, attached PDF file). On review of historical imaging, a CT coronory calcium study 23 years prior revealed presence at that time of a mass in the atrial septum measuring 2.1 x 1.3 cm (Image D). The density of the atrial mass on CT and MRI, its consistent location, and the gradual slow growth over the interceding years indicated that the mass was a benign cardiac LHAS. A beta blocker was initiated for the patient’s symptoms of palpitations, which subsequently improved. She was advised to return for assessment with repeat echocardiography if any symptoms consistent with superior vena cava syndrome, peripheral edema, or ascites developed.

**Results**
**Discussion**
Cardiac masses commonly raise concern for malignancy owing to their more common occurrence. The cardiac CT and cardiac MRI were essential for tissue characterization and assessing local tissue invasion, which could indicate malignancy. Echocardiography played a crucial role in assessing the hemodynamic impact of the cardiac tumor, particularly due to concerns about SVC obstruction based on cardiac MRI findings. Patients with cardiac lipomas and LHAS can experience cardiac arrythmias that are primarily atrial in nature. (1) Our patient had palpitations secondary to premature atrial complexes, however it is unclear if this was truly from the LHAS or her recent COVID 19 infection. As demonstrated in this case, multimodal cardiac imaging is essential in evaluating cardiac tumors, providing clinicians with confidence in determining whether further intervention, such as a biopsy, is necessary or if longitudinal follow-up is sufficient.

**Conclusion**
See Results section for Conculsion
Please refer to the attached PDF for the images, Live Echo images and references
(Images are on Page 2 and 3 of attached PDF)



Total Eclipse of the Heart: A Multimodality Cardiac Imaging Expedition to Unravel Lipomatous Hypertrophy of the Atrial Septum