50 years old is brought to emergency department for evaluation of fever, chills, malaise and fatigue. Cardiac examination reveals a new holosystolic murmur that radiates towards the axilla. Blood cultures are obtained. He undergoes a transoesophageal echocardiography. The USG probe is placed in mid oesophagus facing anteriorly and the cardiac chambers are interrogated. The chamber which is anatomically closer to the probe is

Answer: a) Left atriumThis patient's presentation suggests acute endocarditis, with confirmation pending the results of the blood cultures and cardiac imaging.Transesophageal echocardiography (TEE) uses ultrasound waves generated from within the esophagus to produce clear images of the neighboring cardiac structures.The left atrium makes up the majority of the heart's posterior surface, with the esophagus passing immediately posterior tothe heart.Therefore, the esophagus lies within closest proximity to the left atrium.This allows the left atrium, atrial septum, and mitral valve to be particularly well visualized on TEE.Due to its adjacent proximity, conditions that result in left atrial enlargement (eg, atrial fibrillation, mitral stenosis) can cause dysphagia through external compression of the esophagus.