9. cardiovascular: congenital, vascular, degenerative

list the pathologies covered in this section

ASD, VSD, patent ductus arteriosus, tetralogy of fallot, dextrocardia

describe how fetal circulation normally works, starting from oxygenated blood in the placenta

blood from the placenta enters the fetal heart via the umbilical vein. it skips the liver by going through the ductus venosus and joining the IVC = blood into the RA. flows to the LA via the foramen ovale. it then goes to the LV and to the aorta = to the body. the rest of the blood from the RA goes to the RV, but instead of entering the pulmonary artery to the lungs, it goes through the ductus arteriosus to the artery

what is the most common congenital heart defect

atrial septal defect

ASD classification

congenital

ASD etiology

foramen ovale fails to close after birth

ASD pathogenesis

foramen ovale fails to close = allows blood to flow from the LA to the RA (due to pressure differences). hypertrophy of the right side of the heart occurs = pulmonary edema\

ASD signs and symptoms

audible heart murmur, atrial dysrhythmia on ECG

ASD tx

no intervention with small defects, surgery for large defects

ASD modality

sonography; doppler echocardiography

ASD: what does CXR show

enlarged right side of heart (cardiomegaly), may be increased pulmonary markings + potential for pulmonary edema

ASD: what does MRI and CT show

shows the defect, assesses hypertrophy

ventricular septal defect classification

congenital

VSD etiology

abnormal opening between the ventricles

VSD pathogenesis

blood flows from LV to RV (due to pressure differences) = excess blood returns to the lungs. over time the pressure builds = shunt reverses = blood is shunted back and forth between ventricles

VSD signs and symptoms

symptoms more severe than atrial shunts, may close after the first few weeks of life, audible heart murmur

VSD tx

surgery before it switches into a right to left shunt

VSD modality used

sonography: doppler echocardiography

VSD: what does CXR show

large left side of the heart, increased lung markings and possible pulmonary edema

VSD: what does CT and MRI show

the defect, hypertrophy

patent ductus arteriosus classification

congenital

patent ductus arteriosus etiology

failure of the ductus arteriosus to close after birth = normal circulation is not established

patent ductus arteriosus pathogenesis

in utero, the ductus arteriosus allows fetal blood to bypass the lungs and go from RV to aorta. upon birth, it should close and normal circulation starts. here, oxygenated blood doesn’t reach the tissues = pulmonary edema + cardiomegaly

patent ductus arteriosus signs and symptoms

heart murmur, fast breathing, SOB, rapid HR, tiredness

patent ductus arteriosus modality

sonography: echocardiography

patent ductus arteriosus: what does CXR show

enlarged LA and LV, prominent aortic knob, increased pulmonary vascularity, pulmonary edema

patent ductus arteriosus tx

medication to close the defect, interventional endovascular closure device, surgery

list the 4 issues that constitute tetralogy of fallot

ventricular septal defect (rt to lt shunt), aorta overrides the septum (takes blood from the RV due to misplacement of the aorta), stenosis of the pulmonary artery, RV hypertrophy

what is tetralogy of fallot also called (2)

coer de sabot, wooden shoe shaped heart

tetralogy of fallot classification

congenital, hereditary

tetralogy of fallot etiology

the 4 conditions act together to impair oxygenated blood from flowing through the body = cyanosis

tetralogy of fallot pathogenesis

VSD sits high on the wall between the ventricles, pulmonary artery is narrowed, blood from the RV enters the LV, the aorta sits closer to the ventricular wall than normal. these all lead to RV hypertrophy. deoxygenated blood enters the aorta and circulates the body. very little blood goes to the lungs

tetralogy of fallot signs and symptoms

cyanosis, O2 has no effect, tachypnea and tachycardia

tetralogy of fallot modality

sonography: echocardiography

tetralogy of fallot: what does CXR show

enlargement of RV = upward and lateral displacement of the heart. boot shaped heart. increase in pulmonary markings

tetralogy of fallot: what does MRI show

spin echo MRI shows the 4 conditions + shows the pulmonary stenosis better than echocardiogram

tetralogy of fallot: what is CT used for

f/u post surgery

tetralogy of fallot tx

surgical repair of stenosis, VSD, and potentially moving the aorta

tetralogy of fallot: what happens if left untreated

90% of pts die by age 10

what is dextrocardia

apex points to the right (wrong side)

dextrocardia classification

congenital, hereditary

dextrocardia etiology

idiopathic

dextrocardia pathogenesis

in utero, the heart is a tube, where stretching and looping creates the chambers and vessels. improper looping = heart points to the wrong side

dextrocardia pathogenesis

causes a range of heart defects: transposition of the aorta and pulmonary artery, double outlet syndrome (both aorta and pulmonary artery come off the RV), septal defects, pulmonary stenosis

list the two types of dextrocardia

isolated dextrocardia, dextrocardia with situs inversus

what is dextrocardia with situs inversus

both the heart and the great vessels are reversed. more serious; all body organs are reversed

dextrocardia signs and symptoms

can be asymptomatic, ECG is reversed, SOB, fatigue, cyanosis, hypoxia, edema

dextrocardia: what does CXR show

commonly an incidental finding. finding the gas bubble will confirm which type it is

dextrocardia: what does CT show

shows extent, location of heart chambers and great vessels

dextrocardia tx

based on symptoms. usually only situs inversus cases need intervention to correct other cardiac abnormalities