Mystifying Masquerade: Renal Cell Carcinoma Associated Arteriovenous Fistula Presenting as High-Output Heart Failure - A Case Study.

We detail an uncommon presentation of high-output heart failure (HOHF) triggered by an arteriovenous fistula (AVF) associated with renal cell carcinoma (RCC) in a middle-aged woman with widespread anasarca. The rarity of HOHF linked to malignancies posed significant diagnostic challenges. This case emphasizes the intricate and thorough diagnostic process required to elucidate the connection between RCC and HOHF. The utilization of advanced abdominal imaging, right heart catheterization, and precise blood gas analysis from both the inferior vena cava and renal vein was pivotal in establishing the diagnosis. This comprehensive diagnostic regimen was crucial in identifying the RCC-associated AVF as the causative factor for HOHF, highlighting the importance of a detailed investigative approach in cases of unusual cardiac presentations associated with malignancy.