Acquired Budd–Chiari syndrome secondary to radiofrequency catheter ablation for right focal atrial tachycardia in a 6‐month‐old dog

A 6‐month‐old golden retriever was referred for supraventricular tachycardia. Echocardiography showed a dilated cardiomyopathy phenotype of unknown aetiology. A 12‐lead electrocardiogram revealed a non‐sustained focal atrial tachycardia from the floor of the right atrium. Baseline 24‐h Holter monitoring showed frequent supraventricular ectopic beats organised in non‐sustained runs of focal atrial tachycardia. Endocardial mapping and 14 ablations of a wide ectopic focus at the opening of the caudal vena cava were performed. Endomyocardial biopsy findings revealed signs of active advancement of non‐inflammatory necrosis and degeneration. Post‐procedure, 24‐h Holter monitoring showed rare solitary premature ectopic atrial beats. One month after discharge without complications, the dog presented with mild ascites. Echocardiography revealed acquired stenosis of the caudal vena cava secondary to radiofrequency applications; iatrogenic Budd–Chiari syndrome was diagnosed based on computed tomography scans. A cover stent was placed at the caudal vena cava with clinical signs resolved at the 8‐month follow‐up.