Abstract 12262: Tumor Plop Sound: A Unique Phonographic Finding of a Giant Atrial Myxoma Presenitng as an Acute Decompensated Heart Failure

Introduction: Atrial myxoma (AM) is the most common primary cardiac benign tumor, with the most common location being the left atrium (LA) near the fossa ovalis. As the tumor enlarges, hemodynamic changes similar to mitral valve stenosis can occur.

Case: A 51-year-old female without cardiac history was admitted with an acute onset of shortness of breath, started a few minutes prior to arrival at the emergency department. Her blood pressure was 158/74 mmHg, and her heart rate (HR) was 99 bpm, with other vitals remaining stable. Physical examination revealed a tumor plop murmur in left lateral position (Fig.1). Lab work, including CBC, CMP, and high-sensitivity troponins, was unremarkable except for an elevated D-dimer and BNP. EKG indicated sinus rhythm (80 bpm) without ischemic changes. Chest x-ray revealed bilateral opacities, treated with antibiotics. CTA ruled out pulmonary embolism but detected a large hypodense mass in the LA extending to the mitral valve and partially into the left ventricle. Transthoracic echocardiogram measured the mass at 3.5 x 5.2 x 2.8 cm (Fig. 2). The mean diastolic transmitral gradient was 28 mmHg at a heart rate of 92 bpm. The patient was evaluated by cardiothoracic surgeon and underwent excision of the AM following a negative coronary angiogram. Left ventricular end-diastolic pressure was elevated (24 mmHg). Biopsy confirmed cardiac myxoma. The patient was discharged home in stable condition on postoperative day 5. The tumor plop murmur was absent postoperatively (Fig. 1).

Discussion: AMs are predominantly found in the LA (75%) or the right atrium (25%). Thrombus, vegetation, or malignant tumors can be differential diagnoses. Presentation varies based on mass characteristics, with symptoms like flow obstruction, embolism, arrhythmias, valve dysfunction, heart failure, and syncope. Transthoracic/Transesophageal echocardiogram aids diagnosis, while cardiac MRI is the gold standard. Surgical excision is the primary treatment for AMs.