When Two Chambers Collide: A Rare Case of an Acquired Gerbode Defect in Infective Endocarditis.

Introduction: The Gerbode defect is a rare cardiac anomaly characterised by abnormal communication between the left ventricle and right atrium. Although primarily congenital, it can also be acquired, typically as a complication of myocardial infarction or infective endocarditis. This report examines a unique case of multivalvular infective endocarditis caused by group B Streptococcal bacteraemia, which led to the development of an acquired Gerbode defect.

Case description: A 64-year-old male patient presented with symptoms of fever and dyspnoea and was diagnosed with group B Streptococcal bacteraemia. Transoesophageal echocardiography (TOE) and cardiac magnetic resonance were used to assess the extent of valvular involvement and detect any underlying structural abnormalities. Comprehensive clinical, microbiological and imaging evaluations were performed to confirm the diagnosis.

Discussion: A transthoracic echocardiography revealed multivalvular vegetations and a newly detected left ventricle-to-right atrium shunt, consistent with a Gerbode defect. Cardiovascular magnetic resonance imaging confirmed the acquired defect. Surgery was considered but deemed too high a risk due to the likelihood of postoperative dialysis and a greater than 50% morality risk. After discussing these risks, the patient and family opted for conservative management, and palliative care was initiated.

Conclusion: This case highlights the rare development of an acquired Gerbode defect in the context of multivalvular infective endocarditis due to group B Streptococcus. Early diagnosis using advanced imaging techniques is critical for proper management. Surgical intervention remains a key therapeutic option, and a multidisciplinary approach is essential for optimising patient outcomes in such complex cases.

Learning points: An acquired Gerbode defect (left ventricular to right atrial shunt) is a rare but critical complication of infective endocarditis.Infective endocarditis caused by group B Streptococcus in adults, though uncommon, carries a high risk of complications and mortality, especially in prosthetic valve patients.Early transoesophageal echocardiography is essential for identifying structural complications of infective endocarditis.