Left Atrial Dissection After Mitral and Aortic Valve Replacement: The Importance of Early Diagnosis of a Rare Entity

<b>Background and Clinical Significance:</b> Left atrial dissection is a rare surgical complication (occurring in 0.16% of cases), which results in the formation of a large cavity between the endocardium and the epicardium. <b>Case Presentation</b>: We report a case of a 78-year-old man who underwent combined aortic and mitral valve replacement. Extensive debridement of the calcified mitral annulus most probably precipitated the formation of a dissection flap detected by transesophageal echocardiography after protamine administration. Profound hypotension and hemodynamic instability were treated with inotropic and vasopressor support and fluid administration without any further surgical intervention. <b>Conclusions</b>: The patient recovered uneventfully under conservative management, highlighting the importance of perioperative echocardiography for prompt diagnosis and tailored intervention.