Abstract 15528: Indeterminate Cardiomyopathy in a Patient With Birt Hogg Dubé Syndrome and a Clinical Diagnosis of Scleroderma and Prior Atrial Tachy Arrhythmias: A Diagnostic and Therapeutic Dilemma

Abstract

Birt Hogg Dubé (BHD) syndrome, tachycardia induced cardiomyopathy and scleroderma are three well defined diagnoses. A link between them has not been reported. We present a diagnostic and treatment challenge, of a patient with BHD, clinical scleroderma and prior tachycardia induced cardiomyopathy with persistent left ventricular dysfunction despite restoration of sinus rhythm. Mr. X medical history includes recurrent bilateral pneumothoraces and bullectomy, with a cystic lung disease. He was diagnosed with BHD syndrome in 2018. He was diagnosed clinically with scleroderma with myositis based on symptoms and clinical signs with paucity of inflammation on muscle biopsy and negative biomarkers. There has been a limited response to immunosuppressants. In 2020 he presented with symptomatic paroxysmal atrial fibrillation. CMRI showed biventricular dilatation with increased volumes with LVEF of 40%, ​RVEF of 25% in sinus bradycardia. LGE showed subendocardial signal in ​​the basal and mid segment of the lateral and posterolateral walls with small foci of myocardial ​​​signal at the basal and mid inferior RV-LV hinge points. A bespoke CRT-D (secondary to cavity size) was inserted following documented broad complex tachycardia, given the history of reduced ejection fraction despite medical therapy. Right and left heart catheterisations were normal. Endomyocardial biopsy showed no pathological features and no fibrosis or evidence of infiltrative disease. Genotype results are pending. BHD is a genetic disorder, affecting folliculin protein, associated with cystic lesions of the lung, kidney, and skin with an increased risk of renal cell carcinoma (1). There is no known link of BHD syndrome with cardiomyopathy. Studies have demonstrated folliculin has a role in cardiomyocyte generation (2). Given the cardiac biopsy result, not in keeping with scleroderma or tachycardia induced cardiomyopathy, he may have an independent cardiomyopathy, or a first case of cardiomyopathy secondary to BHD. Our challenge continues to be optimising available therapies ensuring the best quality of life, whilst balancing the potential need for cardiac transplant with lifelong immunosuppressant therapy in a condition which has a seven-fold increased risk of renal cancer.