Case Presentation: A 40-year-old male presented with decompensated heart failure and severe pulmonary hypertension (echo-predicted right ventricular systolic pressure 60 mmHg). Right heart catheterization revealed high output heart failure (cardiac index 7.3 L/min/m 2 ), left to right shunt (Qp:Qs 3.6:1), pulmonary hypertension (mean 38 mmHg), and normal pulmonary resistance (1.53 Wood units). Transesophageal echocardiogram revealed a large non-coronary sinus of Valsalva aneurysm with communication to the right atrium (Figure 1a and b). Percutaneous transcatheter closure of the aneurysm was deferred due to large size (3.3 x 4.3 cm), proximity to the right coronary artery, and risk of aneurysm rupture with catheter manipulation (Figure 1c). The patient underwent surgical aneurysm resection and aortic root replacement and recovered well. Discussion: Sinus of Valsalva aneurysms (SVAs) are rare pathologies characterized by expansion of the aortic root wall between the sinotubular junction and the aortic valve annulus and are often associated with connective tissue disorders. SVAs are often diagnosed incidentally on imaging but can present with symptoms if they rupture into nearby cardiac structures, such as an aorto-atrial fistula with left to right shunting, high output heart failure and hemodynamic compromise, as in this case. While transthoracic echocardiogram is the diagnostic modality of choice for most SVAs, multimodality imaging, catheterization, and advanced imaging may also be needed. Surgical repair remains the gold standard of therapy, however treatment with transcatheter device placement has also been successfully performed.