Caso 6/2008: lactente de 13 meses, do sexo masculino, com vaso colateral sistêmico-pulmonar para o lobo inferior esquerdo, com possível fístula arteriovenosa nesse mesmo lobo, com coração estruturalmente normal

Abstract

A cardiomegaly was discovered during chest x-ray indicated due to pneumonia at 7 months of age. Slight fatigue was noticed since then and the patient was kept without medication. Physical examinationThe patient presented slight tachypnea, was acyanotic (98% capillary saturation) and pulses were normally palpated in the upper and in lower limbs. Weight was 12 kg, height= 78 cm, BP= 90/60 mmHg, HR= 128 bpm. The aorta was not palpated at the suprasternal notch.The precordium showed no deformities or impulsions. The ictus cordis was palpated in the 4th left intercostal space in the hemiclavicular line and was limited by one digital pulp. The second heart sound was slightly hyperphonetic in the pulmonary area and a systolic ejection murmur was ausculted in the mitral area and the dorsum to the left.The lungs were well ventilated and had no adventitious sounds; the liver was palpated at 1.5 cm from the right costal border.The electrocardiogram showed a sinus rhythm and signs of left ventricular overload, considering the presence of accentuated QR waves of V4 to V6, with ÂQRS in +40 o , ÂP:+60 o and ÂT: +10 o . Radiographic imagingThe radiographic imaging showed slightly augmented cardiac area, with elongated and rounded left ventricular arch and normal pulmonary vascular network. The middle arch was concave. It was noteworthy a retrocardiac hypertransparent image in the left lower lobe, which shows the more prominent pulmonary vascular network with indistinct borders (Figure 1). Diagnostic impressionThis radiographic image is compatible with the diagnosis of possible accentuated arteriovenous pulmonary fistulae in the lower left lobe, or systemic-pulmonary vessels, with a consequent left ventricular increase. Differential diagnosisAn increased left ventricle with normal pulmonary vascular network could also suggest a cardiopathy with mitral valve failure or even dilated myocardiopathy. Diagnostic confirmationThe clinical elements were compatible with the initial diagnosis of mitral failure, corroborated by the echocardiogram, which showed a slight increase of the left cavities. However, there were no signs of regurgitation at the level of mitral valve, but a systemic-pulmonary flow in the descending aorta due to possible collateral vessel. An angiotomography showed a largecaliber collateral vessel with 7 mm of diameter in the inferior descending aorta that continued with the left lower lobar artery. From then on, the large-caliber and winding vessels in the left lower lobe were visualized, with rapid drainage through the inferior pulmonary vein to the left atrium ( Figure 2). The cardiac catheterism showed this same angiographic aspect, with a rapid pulmonary venous return flow to the left cavities (Figure 2). The lung scintigraphy with technetium 99m showed the lack of mapping in the left lower lobe, with a right pulmonary flow of 60%, left pulmonary flow of 30.2% and systemic flow of 9.7%. A selective injection of the radionuclide directly into the systemic-pulmonary collateral vessels showed that 30% of this flow ...