RESUMEN
We describe a case of a very low birth weight premature female twin with intracardiac thrombosis. Her condition was consistent with neonatal sepsis, and she was treated with advanced life support, antibiotic therapy, parenteral nutrition, blood transfusion, and central venous catheterization. Infective endocarditis was suspected, and a large intracavitary thrombus was detected by two-dimensional Doppler echocardiography. Surgical procedure was not only technically difficult but also highly lethal, being contraindicated in some cases. Consequently, the use of the thrombolytic recombinant tissue-plasminogen activator (rTPA) associated with aspirin was the treatment of choice, and complete dissolution of the thrombus was achieved without adverse effects.