B4.048 - Congenital Heart Defects Post Quiz Summary

Question 1

A 15-year-old boy complains of pain in his legs when he runs more than 300 meters. Physical examination shows temperature of 36.8°C, pulse 76/min, respirations 22/min, and blood pressure 165/90 mm Hg. The radial pulses are 4+, and the dorsalis pedis pulses are 1+. Arterial blood gas measurement shows a normal oxygen saturation level. What is the most likely lesion?

Answer 1

Coarctation of the aorta

Question 2

what causes a pulse differential from upper to lower extremities in coarcatation of aorta

Answer 2

In adults, the coarctation is typically postductal, and collateral branches from the proximal aorta supply the lower extremities. Diminished renal blood flow increases renin production and promotes hypertension.

Question 3

A pre-school examination of a 5-year-old boy revealed that he has an atrial septal defect (ASD). The parents were told that there are several forms of ASD, and that the child has the most common form of this anomaly. What is it called?

Answer 3

ASD of the septum secundum type

Question 4

This defect occurs in the lower part of the atrial septum, and may occur with other congenital heart problems.

Answer 4

Primum

Question 5

In this rare defect, part of the wall between the coronary sinus — which is part of the vein system of the heart — and the left atrium is missing.

Answer 5

Coronary sinus

Question 6

A 21-year-old primigravida gives birth at term to a 2800-g infant with no apparent external anomalies. The next day, the infant develops increasing respiratory distress and cyanosis and dies. At autopsy, a slit-like left ventricular chamber, small left atrium, and atretic aortic and mitral valves are seen. Which duct could oxygenated blood be reaching the infants systemic circulation?

Answer 6

Patent ductus arteriosus

Question 7

A 2-year-old child suffers from easy fatigability. A “machinery murmur” was heard over the left chest. Angiography revealed an influx of aortic blood into the pulmonary artery. What is the most likely diagnosis?

Answer 7

PDA

Question 8

what are common symptoms of PDA?

Answer 8

tachycardia

respiratory problems

dyspnea

continuous “machine-like” (also described as “rolling-thunder” and “to-and-fro”) heart murmur (usually from aorta to pulmonary artery, with higher flow during systole and lower flow during diastole)

cardiomegaly (enlarged heart, reflecting ventricular dilation and volume overload)

left subclavicular thrill

bounding pulse

widened pulse pressure

increased cardiac output

increased systolic pressure

poor growth

differential cyanosis, i.e. cyanosis of the lower extremities but not of the upper body.

Question 9

Elevated arterial pressure in the arms and the head arteries, associated with much lower arterial pressure in the lower extremities is typical of which congenital cardiovascular anomaly?

Answer 9

Coarctation of the aorta

Question 10

The following results were obtained in a patient:

Heart rate = 100 beats/min

O2 consumption = 240 ml O2 /min

Blood O2 contents:

Right atrium = 14 ml O2 /100 ml blood

Right ventricle = 14 ml O2 /100 ml blood

Pulmonary artery = 16 ml O2 /100 ml blood

Pulmonary vein = 20 ml O2 /100 ml blood

Left atrium = 20 ml O2 /100 ml blood

Brachial artery = 20 ml O2 /100 ml blood

what condition do they have?

Answer 10

Patent ductus arteriosus

Question 11

describe O2 content in patients with PDA

Answer 11

Blood O2 content in the pulmonary artery is greater than that in the right ventricle due to shunting of oxygenated blood from the aorta into the pulmonary artery across a patent ductus arteriosus.

Question 12

A 7-year old boy tires easily while running. On auscultation, a harsh continuous murmur is heard at the left of the sternum between the first two ribs. Arterial blood oxygen content is slightly higher in the right hand than in the left hand. X-rays of the chest show no abnormalities. What is the most likely diagnosis?

Answer 12

PDA

Question 13

A 6-year old boy is brought to the physician by his parents for a follow up examination because of a heart murmur that has been present since birth. His only symptom is fatigue. His pulse is 110/min, and blood pressure is 80/40 mm Hg. Physical examination shows no cyanosis or clubbing of the fingers. Cardiac examination shows a normal S1and a split S2. A grade 3/6 pansystolic murmur is heard maximally at the lower left to mid left sternal border. He undergoes cardiac catheterization and is found to have a higher than expected oxygen level in the right ventricle. Whats the most likely diagnosis?

Answer 13

VSD

Question 14

when does a VSD usually manifest

Answer 14

a few weeks after birth

Question 15

uncorrected VSD can lead to what

Answer 15

reversal of the shunt to Right to Left which will lead to cyanosis

Question 16

what are the components of TOF

Answer 16

Pulmonary stenosis

Overriding aorta

Ventricular septal defect

Right ventricular Hypertrophy

Question 17

what is a patent foramen ovale

Answer 17

A patent foramen ovale (PFO) means the foramen ovale did not close properly at birth, so there is still an opening in the septum. In most cases, the PFO does not stay open at all times. Instead, it’s more like a flap that opens when there is higher pressure than normal in the chambers on the right side of the heart.

Question 18

what percentage of americans have ASD

Answer 18

25%

Question 19

Situations that can cause greater pressure in ASD

Answer 19

straining during bowel movements, coughing and sneezing.

Question 20

A mother unwittingly exposed her 3-week-old embryo to a teratogen which is known to adversely affect the formation of neural crest cells. Which of the following cardiac structures is likely to be compromised as this embryo develops?

Answer 20

Membranous interventricular septum

Question 21

what are CNCCs

Answer 21

Cardiac neural crest cells (CNCCs) are a type of neural crest cells that migrate to the circumpharyngeal ridge (an arc-shape ridge above the pharyngeal arches) and then into the 3rd, 4th and 6th pharyngeal arches and the cardiac outflow tract (OFT)

Question 22

what do CNCCs do

Answer 22

The cardiac neural crest cells have a number of functions including creation of the muscle and connective tissue walls of large arteries; parts of the cardiac septum; parts of the thyroid, parathyroid and thymus glands. They differentiate into melanocytes and neurons and the cartilage and connective tissue of the pharyngeal arches. They may also contribute to the creation of the carotid body, the organ which monitors oxygen in the blood and regulates breathing.

Question 23

What causes the closure of the valve of the foramen ovale at birth?

Answer 23

Higher pressure in the left atrium compared to the right atrium caused by venous return from the pulmonary veins

At birth, when the lungs become functional, the pulmonary vascular pressure decreases and the left atrial pressure exceeds that of the right. This forces the septum primum against the septum secundum, functionally closing the foramen ovale.

Question 24

A mother takes her newborn infant to the physician because he is “blue”. The baby was born 1 week ago at home without difficulty. This is the infant’s first physician visit. The mother states that the infant has a dusky blue hue on his skin, especially around the face and lips. An MRI of the heart reveals right ventricular hypertrophy and an abnormal appearance of the cardiovascular structures. What is the most likely diagnosis?

Answer 24

TOF

Question 25

what is TOF

Answer 25

etralogy of Fallot results in low oxygenation of blood due to the mixing of oxygenated and deoxygenated blood in the left ventricle via the ventricular septal defect (VSD) and preferential flow of the mixed blood from both ventricles through the aorta because of the obstruction to flow through the pulmonary valve. This is known as a right-to-left shunt. The primary symptom is low blood oxygen saturation with or without cyanosis from birth or developing in the first year of life. If the baby is not cyanotic then it is sometimes referred to as a “pink tet”. Other symptoms include a heart murmur which may range from almost imperceptible to very loud, difficulty in feeding, failure to gain weight, retarded growth and physical development, dyspnea on exertion, clubbing of the fingers and toes, and polycythemia. The baby may turn blue with breast feeding or crying.

Question 26

In the apical four chamber view of the heart in the attached diagram, which chamber is indicated by the arrow?

Answer 26

right ventricle

Question 27

what is echocardiography

Answer 27

Use of ultrasound to define cardiac structure and function

Question 28

what is the arrow pointing to

Answer 28

left atrium