CARDIO Flashcards
Most common congenital cardiac anomaly.
VSD
What are the components of the tetralogy of Fallot, and which is the most important determinant for prognosis?
Pulmonary infundibular stenosis * most impt
VSD
RVH
Overriding aorta (overrides VSD.)
How does squatting reduce the symptoms of Tetralogy of Fallot?
Although VSD is normally a left-to-right shunt, in tetralogy there is also pulmonary stenosis present. This actually forces the VSD to be a right-to-left shunt instead, causing cyanosis since blood is bypassing the pulmonary system and entering the systemic circuit too soon. When you squat, you constrict blood flow going to the legs and increase peripheral vascular resistance. This increases the “afterload”, decreasing the right-to-left shunt, and allowing blood to reach the pulmonary circuit to be oxygenated.
What 3 congenital defects can lead to Eisenmenger’s syndrome later on?
Uncorrected VSD, ASD, or PDA. Since this is a left-to-right shunt, eventually the pulmonary vasculature tries to compensate and becomes hypertrophic to accommodate the new blood flow. Eventually, the pressure gets so high in the right side of the heart that it becomes a right-to-left shunt instead. This blood will now bypass the pulmonary circuit and enter the systemic circuit deoxygenated, causing clubbing, cyanosis, and polycythemia.
Explain why a PDA is so detrimental.
A PDA allows a portion of the oxygenated blood from the left heart to flow back to the lungs by flowing from the aorta (which has higher pressure) to the pulmonary artery. If this shunt is substantial, the neonate becomes short of breath: the additional fluid returning to the lungs increases lung pressure to the point that the neonate has greater difficulty inflating the lungs.
In some cases, such as in transposition of the great vessels, a PDA may need to remain open since the PDA is the only way that oxygenated blood can mix with deoxygenated blood. In these cases, prostaglandins are used to keep the DA open.
What is the problem in infantile coarctation of the aorta, and what disease is it associated with?
It is associated with Turner Syndrome.
Coarctation is a narrowing of the aorta that lies after the aortic arch but before the PDA (which is necessary for oxygenated blood to mix with deoxygenated blood to be delivered to the lower extremities). It presents as lower extremity cyanosis, because the left ventricle is generating a ton of pressure in order to force blood through the stenotic valve. However, there will be a deficiency of blood able to reach the lower half of the body, other than the mixed blood (from the PDA), which is why this generally presents with these symptoms.
Where is the coarctation in the adult form of Coarctation of the Aorta and how does this present?
The coarctation lies after the aortic arch but in this case, there is no PDA. There will be hypertension in the upper extremities due to all of the pressure generated by the hard-working left ventricle against the stenotic valve, and hypotension with weak pulses in the lower extremites. Often, rib notching is seen on xrays since collateral circulation develops across the intercostal arteries in order to compensate.
What 2 congenital cardiac defects are associated with DiGeorge syndrome?
Truncus arterosus
Tetralogy of Fallot
What 3 congenital cardiac defects are associated with Congenital Rubella?
Septal defects
PDA
Pulmonary artery steosis
What 2 congenital disorders are associated with Aortic dissection?
Turners and Marfans
What problems are offspring of diabetic mothers at higher risk for?
Transposition of great vessels
Hypoglycemia
Large for gestational age –clavicle fracture, shoulder dystocia, Erb Duchenne palsy, failure to progress during labor and delivery
Describe the murmur of a VSD. How can it be accentuated?
Holosystolic, harsh sounding murmur that is loudest the tricuspid area. Accentuated with the hand grip maneuver due to increased afterload, causing increased L – > R shunting.
What is the MAP equation?
MAP = 1/3 (systolic) + 2/3 (diastolic)
What is the Fick principle?
CO = rate of O2 consumption / (arterial O2-venous O2)
Does decreased extracellular Na+ increase or decrease contractility of the heart?
Increases it. By decreasing extracellular Na+, less Na will want to come into the cell via the Na/Ca2+ exchanger, thus less calcium exits the cardiac myocytes – > increasing contraction.
Name one way to increase afterload and 2 drugs that decrease it.
Increase: Squatting (increases TPR)
Decrease: Ace inhibitors, hydralazine
Acidosis, hypoxia, and hypercapnea all have what effect on the heart’s contractility?
Decrease it.
How does heart failure impact the Starling forces of fluid movement through capillaries?
Increases capillary pressure causing fluid to leave the capillaries.
How does liver failure impact the Starling forces of fluid movement through capillaries?
Decreases oncotic pressure (fluid exits capillaries).
How does renal failure impact the Starling forces of fluid movement through capillaries?
Decreases plasma protein, thus decreasing plasma colloid osmotic pressure.
How does lymphatic blockage impact the Starling forces of fluid movement through capillaries?
Increases osmotic pressure of interstitium.
How does venous insufficiency impact the Starling forces of fluid movement through capillaries?
Increases capillary pressure.
Tree bark appearance of the aorta
This is seen in TERTIARY SYPHILIS.
Tree bark appearance refers to the intimal and sub-intimal plaques that encase the mouth of small aortic branches, due to obliterative endarteritis of vasa vasorum with ischemic destruction of the vascular media causing inflammation, neo-vascularization and fibrous scarring, leading to aneurysms and surface irregularities.
What does S3 correspond with in relation to the cardiac cycle? Name 4 pathological causes and 2 normal physiologic causes.
S3 is in early diastole after mitral valve opens during rapid ventricular filling phase. It is associated with increasing filling pressures (e.g. mitral regurg, CHF, L–>R shunt, dilated cardiomyopathy) as well as dilated ventricles (children, pregnant women).