High-output heart failure secondary to iatrogenic arteriovenous fistula: A case report.

Background: Arteriovenous fistula is a rare cause of refractory heart failure, and corrective measures may lead to dramatic improvement; however, the long-term cardiac remodeling outcomes, particularly after delayed closure, remain unclear.

Case summary: A 57-year-old man was admitted to the hospital with complaints of exertional dyspnea for more than 10 years. Physical examination revealed wet crackles in the lungs and a continuous machinery murmur in the left lower back and groin area. Asymmetric edema and varicose veins were observed in the lower limbs. Echocardiography revealed a dilated right ventricle with severe pulmonary hypertension. Computed tomography revealed a left common iliac arteriovenous fistula linked to prior lumbar disc surgery. Surgical repair resolved the symptoms, with echocardiography at 4 months showing a reduced right atrium (RA) and ventricular (RV) diameter and tricuspid regurgitation. However, during the 2-year follow-up, gradual RA and RV re-expansion (from 35 mm to 51 mm and from 26 mm to 46 mm, respectively) was observed, despite sustained clinical stability.

Conclusion: This case highlights that delayed arteriovenous fistula closure may result in incomplete right heart reverse remodeling, even after symptomatic relief. Potential mechanisms include persistent hemodynamic stress from subclinical residual shunting or functional impairment due to chronic volume overload. Early intervention before irreversible right heart damage is critical for optimal outcomes.