Abstract Background Pulmonary arteriovenous malformations (PAVM) are rare, and most cases are congenital. They require prompt recognition and management particularly in patients presenting with hypoxia and haemoptysis. We describe a unique case of recurrent endocarditis causing pulmonary artery aneurysms (PAAs) and formation of PAVM. Case summary A 60-year-old woman presented with dyspnoea, haemoptysis, and severe hypoxia. Her background was significant for previous pacemaker lead infection, refractory heart failure secondary to severe tricuspid valve distortion by her pacemaker lead, tricuspid and mitral valve replacements complicated by recurrent endocarditis over several years. Two years prior to her current presentation computed tomography (CT) scanning revealed new small PAAs thought possibly to be mycotic in origin. After her current presentation, prompt high-resolution CT scanning of her chest with contrast revealed significant pulmonary haemorrhage and new clusters of PAVM. Urgent pulmonary angiography confirmed PAVM and was successfully treated with coil embolization. Her dyspnoea, pulmonary haemorrhage, and hypoxia resolved. Discussion Acquired causes account for a very small percentage of PAVM and the mechanism of their development is unknown. As she had recurrent right-sided endocarditis and her PAAs developed following this, with new PAVM developing 2 years later; we hypothesize that they were causally related. We believe this is the first case of recurrent left- and right-sided endocarditis leading to formation of PAAs and development of PAVM presenting with significant hypoxia and haemoptysis requiring prompt intervention.