iarjmcrIARJMCRIARJMCR2709-3220https://doi.org/10.47310/iarjmcr.2021.v02i01.003Cor Triatriatum Sinister in a Seven Months Old GirlFatimaI.BohlokZahraaM. AbouHamdanFatimaA.DiraniAliA.JibbawiImadChamiCor triatriatum sinister is a rare congenital condition characterized by the presence of a membrane within the left atrium dividing it into two chambers the upper one which receives the pulmonary veins and the lower part contains the atrial appendage and empties into the mitral valve. Case Description: A 7 months old baby girl presented to the emergency department for respiratory symptoms including cough and tachypnea. She was initially treated with intravenous antibiotics, bronchodilators and oxygenation. Later with thorough investigations cor triatiatum sinister was diagnosed. Discussion: Cor triatriatum sinister patients usually present during infancy with cyanosis which helps in their early diagnosis. In fewer cases, cor triatriatum is diagnosed later in life due to atypical presentation with respiratory symptoms that may mimic asthma or respiratory infections. Conclusion: Recurrent respiratory complaints that do not respond to the common treatments must raise the suspicion of cardiac anomalies including cor triatriatum sinister. Early surgical treatment can protect the patient from short- and long-term complications.