A3-month-old term infant presents for a wellness exam, and his parents report worsening in his feeding habits and rapid breathing. on exam, there is a grade iii/vi harsh heart murmur heard over the left subclavicular region that starts in early systole, peaks at s2, and decrescendos until the next s1. the infant is tachypneic and has bounding pulses of his upper and lower extremities. all other findings are within normal limits. a chest x-ray shows an enlarged left ventricle and atrium and increased pulmonary vasculature markings. based on the above findings, what is the most likely diagnosis? answer choices: a atrial septal defectb congenital pulmonic valve stenosisc ventricular septal defect d patent ductus arteriosuse congenital aortic valve stenosis

D Patent Ductus Arteriosus

Explanation:

Patent Duct Arteriosus is a congenital heart defect most common in preterm infants and also widely found in animals, especially dogs.

It is caused by a failure to close the canal that connects the pulmonary artery to the aorta at birth. It may be associated with prematurity, low birth weight, prostaglandins, maternal rubella during the first trimester of pregnancy, high altitudes and hypoxia. The truth is that after birth, two ducts found in the circulatory structure of the heart (the foramen ovale and the ductus arteriosus) close so that blood can circulate through the body. When these ducts do not close after birth, part of the blood present in the left side of the heart reaches the lung, and it would be correct to fall into the general circulation. Babies with this problem have symptoms similar to the baby exposed in the question, so we can conclude that this baby has a patent duct arteriosus.

c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.