Cardiovascular system Flashcards
Fetal circulation
Blood arrives via vena cava
Ductus Venosus shunts blood away from semi functional liver and to the heart via IVC
Blood enter the R atrium
Foramen ovale shunts blood from R to L atrium
Ductus arteriosus connects aorta with pulmonary artery further shunting blood away from lungs to the aorta
Paediatrics BP
Infant 1-12m 72-104/37-56 Toddler 1-2yr: 86-106/42-63 Preschooler 3-5: 89-112/46-72 School age 6-9: 97-115/57-76 Preadolescent 10-11: 102-120/61-80 Adolescent 12-15: 110-131/64-83
Paeds HR
Awake vs Sleeping Neonate (<28 d) 100-205 90-160 Infant (1 mo-1 y) 100-190 90-160 Toddler (1-2 y) 98-140 80-120 Preschool (3-5 y) 80-120 65-100 School-age (6-11 y) 75-118 58-90 Adolescent (12-15 y) 60-100 50-90
Causes of secondary hypertension
Renal Artery stenosis Polycystic kidney disease Neuroblastoma Hyperthyroidism Cushings Pheochromocytoma Chronic renal failure Coarctation of the aorta Hyperaldosteronism Systemic Lupus Erythamtosus
Grading of heart murmur
Grade 1: very soft and heard with difficulty
Grade 2: soft but readily heard
Grade 3: moderately loud, no thrill. Approximately the same intensity as the first and second heart sounds.
Grade 4: Loud with thrill (palpable vibration of the chest wall) present. Louder than the first and second heart sounds.
Grade 5: Thrill, very loud, but not audible without a stethoscope
Grade 6: Thrill, audible without a stethoscope
Types of innocent heart murmur
Still’s murmur: Most common. Heard left sternal border. Likely due to an accessory mitral valve chord attaching to the ventricular septum (termed a “false tendon”)
DDx: subaortic stenosis, small VSD
Pulmonary flow murmur: More common in older children and adolescent. Hear blood flow over the pulmonary valve. More common in kids who have thin chest walls, where the heart may be physically closer to the stethoscope and therefore easier to hear
Cervical Venous Hum: Caused by the sound of blood flow returning normally through the veins above the heart. Specifically, the jugular veins drain blood from the head and neck and connect to larger veins which return to the heart. Commonly heard in young school children when sitting or standing upright
Atrial septal defect
Failure of closure of foramen ovale resulting in shunting of blood from the left side of the heart to the right side.
Types of ASD
Ostium secundum ASD: Middle of atrium in region of fossa ovalis Most common (80%), At least half close on their own.
Ostium Primium: anterior to the fossa ovalis and superior to the atrioventricular valves. Associated with cleft of anterior leaflet of mitral valve. Rare, does not close on it’s own.
Sinus Venosus: Superior and posterior to fossa ovalis. Usually involves flow of IVC and SVC. Commonly associated with drainage of right pulmonary vein to right atrium (rather than left)
Unroofed coronary sinus defects are found near the os of the coronary sinus and are associated with a persistent left superior vena cava.
Signs and Symptoms of ASD
Asymptomatic
If large ASD then the child may experience dyspnoea, fatigue, failure to thrive, or recurrent lower respiratory infections.
May hear an ejection systolic murmur loudest over the left sternal border. With larger defects there may be a mid diastolic murmur along the lower sternal border.
EXTRA NOTES:
When pulmonary hypertension has developed, the volume of the left-to-right shunt decreases and results in loss of fixed splitting of the second heart sound, increased intensity of the pulmonary component of the second heart sound, shortening of the systolic murmur, and disappearance of the diastolic murmur. If the shunt reverses, the patient will appear cyanosed and may develop finger clubbing.
Investigations for ASD
ECHO: Confirms diagnosis and determines the adequacy of tissue rims for defect closure.
ECG: Not needed often normal unless severe shunt i which case taller P waves (>2.5mm) suggesting R atrial enlargement
Management of ASD
Small close spontaneously. All ASD are monitered
LEFT TO RIGHT
Qp:Qs, is <1.5= doesn’t need surgical closure
Qp:Qs ratio is or remains ≥1.5, or there is evidence of right atrial enlargement=Requires surgical intervention
RIGHT TO LEFT
Reversible=operable
Irreversible=Eisenmenger’s syndrome. Avoid avoid pregnancy, dehydration, and high altitudes. Endocardial pacing is contra-indicated
Ventral septal defect
A defect in the interventricular septum that allows shunting of blood between the left and right ventricles.
Usually congenital, but rarely acquired after myocardial infarction or trauma.
May be associated with other congenital defects such as tetralogy of Fallot.
Classification of VSD
Type 1: lies beneath the semilunar valves in the conal or outlet septum
aortic regurgitation produced by prolapse of the anterior aortic valve leaflet
Type 2: confluent with the membranous septum, bordered by an atrioventricular (AV) valve (most common)
Type 3: involves the inlet of the ventricular septum immediately inferior to the AV valve apparatus
Typically occur in patients with Down’s syndrome.
Type 4: completely surrounded by muscle; multiple defects may be present, producing a ‘Swiss cheese’ appearance of the septum.
Investigation of VSD and findings on clinical examination.
Murmur on examination (holosystolic over left sternal edge)
Palpable thrill
Echocardiogram
May be signs of cardiomegaly
Tachypnoea in children with heart failure
Management of VSD
Qp:Qs, is <1.5= doesn’t need surgical closure
Qp:Qs ratio is or remains ≥1.5, or there is evidence of right atrial enlargement=Requires surgical intervention
Severe VSD or Eisenmonger’s syndrome, there is no surgical intervention.
Coarctation of the aorta
Narrowing of aorta. Commonly at the juxtaductal region (
