Patent truncus arteriosus leads to –
Correct Answer: Both ventricular hypertrophy
Description: Ans. is 'a' i.e., Both ventricular hypertrophy * In truncus arteriosus, a single arterial trunk (truncus arteriosus) arises from the heart and supplies the systemic, pulmonary, and coronary circulations. A VSD is always present, with the truncus overriding the defect and receiving blood from both the right and left ventricles.* The number of truncal valve cusps varies from 2 to as many as 6 and the valve may be stenotic, regurgitant, or both.* The electrocardiogram shows right, left, or combined ventricular hypertrophy.* Types:-i) Type I:- The pulmonary arteries can arise together from the posterior left side of the persistent truncus arteriosus and then divide into left and right pulmonary arteries.ii) Types II and III - No main pulmonary artery is present, and the right and left pulmonary arteries arise from separate orifices on the posterior (type II) or lateral (type III) aspects of the truncus arteriosus.iii) Type IV - No identifiable connection between the heart and pulmonary arteries, and pulmonary blood flow is derived from major aortopulmonary collateral arteries arising from the transverse or descending aorta; this is essentially a form of pulmonary atresia.* Both ventricles are at systemic pressure and both eject blood into the truncus. When pulmonary vascular resistance is relatively high immediately after birth, pulmonary blood flow may be normal; as pulmonary resistance drops in the 1st mo of life, blood flow to the lungs is greatly increased and heart failure ensues.* Truncus arteriosus is a total mixing lesion with complete admixture of pulmonary and systemic venous return.* Because of the large volume of pulmonary blood flow, clinical cyanosis is usually mild. If the lesion is left untreated, pulmonary resistance eventually increases, pulmonary blood flow decreases, and cyanosis becomes more prominent.* The clinical signs of truncus arteriosus vary with age and depend on the level of pulmonary vascular resistance. In the immediate newborn period, signs of heart failure are usually absent; a murmur and minimal cyanosis may be the only initial findings.* Over the next 1-2 month of life, pulmonary blood flow begins to become torrential and the clinical picture is dominated by heart failure, with still mild cyanosis.
Category:
Pediatrics
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