CHAPTER 26- CARDIAC.txt

  1. What do R--> L shunts cause:
    cyanosis
  2. Why do children squat?
    children squat to increase svr and decrease R --> L shunts
  3. What can cyanosis lead to?
    • 1) polycythemia
    • 2) stroke
    • 3) brain abscess
    • 4) endocarditis
    • 5) hypertrophic osteoarthropathy
  4. Eisenmenger's syndrome:
    • 1) shift from L-->R shunt to R-->L shunt
    • 2) sign of increasing pulmonary vascular resistance and pulmonary HTN
    • 3) this condition is generally irreversible
  5. What do L-->R shunts cause?
    • 1) L-->R shunts cause CHF
    • 2) Can manifest as:
    • 1- failure to thrive
    • 2- tachycardia
    • 3- tachypnea
    • 4- hepatomegaly

    CHF in children- hepatomegaly is 1st sign
  6. L--> R shunts:
    • 1) patients get symptoms of CHF
    • 2) VSD, ASD, PDA
  7. R--> L shunts (patients have cyanosis)
    • patients have cyanosis
    • 1) tetralogy of fallot
    • 2) transposition of great vessels
    • 3) truncus arteriosus
  8. Ductus arteriosus
    connection between descending aorta and left pulmonary artery; blood shunted away from lungs in utero
  9. Ductus venosum
    connection between portal vein and IVC; blood shunted away from liver
  10. 1)
    Fetal circulation to placenta:
    Fetal circulation from placenta:
    • 1) 2 umbilical arteries
    • 2) 1 umbillical vein
  11. Ventricular septal defect (VSD)
    • 1) most common congenital heart defect
    • 2) left --> right shunt- most close spontaneously by age 6 months
    • 3) large VSDs- usually cause symptoms after 4-6 weeks of life, as PVR decreases and shunt increases
    • 4) get CHF, failure to thrive, tachypnea, tachycardia
    • 5) Medical tx: diuresis and digoxin
    • 6) Timing of repair
    • 1- CHF resulting in failure to thrive- most common reason for repair
    • 2- before school age if does not close spontaneously
    • 3- PVR >4-6 woods units also indication for repair
    • 4- PVR >10-2 woods units contraindication for repair --> use vasodilators to see if its reversible, if so, can repair
  12. Atrial Septal Defect
    1) Left --> right shunt

    • 2) Osteum secundum
    • 1- most common; centrally located, patent foramen ovale (80%)
    • 2- can have anomalous pulmonary venous return (to right atrium or IVC)
    • 3- IVC can connect to left atrium

    • 3) Ostium primum (or atrioventricular septal defects of endocardial cushion defects)
    • 1- defect more inferior
    • 2- can get mitral valve and coronary sinus defect
    • 3- caused by deficiency in remnant of left horn of sinus venosus

    • 4) usually symptomatic when Qp/Qs >2 --> CHF (fatigue, SOB, recurrent infections)
    • 5) rare for ASD to cause increase in PVR before adulthood
    • 6) can get paradoxical emboli and arrhythmias in adulthood
    • 7) Medical tx: diuretics and digoxin

    • 8) Timing of repair:
    • 1- volume overload (occurs with Qp/Qs >1.5)
    • 2- before school age if doesn't close spontaneously
    • 3- PVR >10-12 woods units contraindication for repair
    • 4- all ostium primum atrioventricular septal defects (ASDs) need repair
  13. Tetralogy of Fallot
    • 1) VSD, pulmonary stenosis, overriding aorta, RV hypertrophy
    • 2) right --> left shunt
    • 3) most common congenital heart defect that results in cyanosis
    • 4) morphologic abnormality- anterior and superior displacement of the infundibular septum
    • 5) Medical Tx: beta blockers
    • 6) timing of operation- increased cyanosis
    • 7) Repair:
    • 1-Blalock-Taussig (BT) shunt can be used for palliation to delay repair (its when one branch of the subclavian or carotid artery is connected to the pulmonary artery)
    • 2- Definitive repair: RV outflow tract obstruction division, patch enlargement of outflow tract, and VSD repair
  14. Transposition of the great vessels
    • 1) most common cyanotic disorder presenting in the 1st week of life
    • 2) Right --> left
    • 3) mixing most often occurs through ASD; VSD and PDA can serve as additional mixing conduit
    • 4) Medical Tx: atrial septostomy, PGE1
    • 5) In patients with large VSDs, significant CHF and pulmonary hypertension may occur by 3 months of age
    • 6) Repair: optimal- early switch with coronary reimplantation posteriorly (first 2-3 weeks of life) while LV is still getting high resistance
    • 7) patients with LVOT obstruction not candidates for early switch
    • 1- most also have large VSDs
    • 2- palliation with systemic to PA shunting preferred early on (BT shunt)
    • 3- definitive repair at 3-5 years of age
  15. Truncus arteriosus
    • 1) usually has associated VSD
    • 2) Right --> left shunt
    • 3) mixing causes arterial saturation of 85-90%
    • 4) neonates present with CHF; 80% die in 1st year due to CHF
    • 5) CXR shows cardiomegaly
    • 6) Medical tx:
    • 1- diuretics
    • 2- digoxin
    • 3- fluid restriction
    • 4- afterload reduction

    • 7)Timing of repair: onset of tachypnea is sign of decreased PVR
    • 8) Treatment: repair of VSD, remove PAs from aorta, and repair aorta; restore RV outflow tract with Dacron graft to PAs.
  16. Patent Ductus arteriosus (PDA)
    • 1) left --> right shunt
    • 2) Indomethacin- causes the PDA to close; rarely successful beyond neonatal period
    • 3) usually requires surgical repair through left thoracotomy if persists
    • 4) PGE1- keeps PDA open
  17. Coarctation of the aorta
    • 1) usually occurs just distal to the left subclavian artery
    • 2) associated with turner's syndrome
    • 3) Rib notching from the IMA and intercostal collaterals
    • 4) can present with profound CHF
    • 5) all patients should undergo repair to prevent heart failure
    • 6) try to perform end-to-end repair
  18. Univentricular heart
    • 1) need Fontan procedure to direct all vena cava blood to PA
    • 2) best approach is to attach the right atrium and SVC to the PA directly
    • 3) Prerequisites- normal PA pressure (<20mmHg) and normal PVR (<2 woods units)
  19. Hypoplastic left heart
    • 1) need norwood procedure
    • 2) main PA becomes outlet tract for aorta for what is to become single-ventricle physiology
    • 3)Treatment: aorta is augmented with large piece of allograft artery and attached to main PA trunk
    • 1- distal PAs are separated and supplied through systemic-PA shunt (BT shunt)
    • 2- many patients eventually need heart TXP
  20. Anomalous pulmonary venous return
    • 1- goes to SVC instead of left atrium
    • 2- most often seen in patients with ASDs
  21. Vascular rings
    • 1) double aortic arch most common
    • 2) may manifest as recurrent pulmonary infections or dysphagia
    • 3) trachea most commonly affected
    • 4) Treatment: divide smaller arch through left thoractomy
  22. Coronary artery disease
    • 1) most common cause of death in the united states
    • 2) Risk factors:
    • 1- smoking
    • 2- HTN
    • 3- male gender
    • 4- family history
    • 5- hyperlipidemia
    • 6- diabetes

    • 3) Medical Treatments:
    • 1- nitrates
    • 2- smoking cessation
    • 3- weight loss
    • 4- statin drugs
    • 5- ASA
  23. Right dominant circulation
    • 1) most common
    • 2) posterior descending artery comes of the right coronary artery
  24. Left dominant circulation
    1) posterior descending artery comes off the circumflex coronary artery
  25. Left main coronary artery:
    Left main coronary artery branches into left anterior descending and circumflex
  26. Where are most atherosclerotic lesions?
    proximal
  27. Complications of myocardial infarction:
    1) VSD (pansystolic murmur), papillary muscle rupture, and free wall rupture. --> most likely to occur 3-7 days post-MI

    • 2) Post-MI VSD (pansystolic murmur) - transesophageal echo best test
    • 1- usually occurs 5-7 days after MI
    • 2- step-up in oxygen content between right atrium and pulmonary artery secondary to L-->R shunt

    • 3) LV aneurysm- most commonly occurs after large, transmural, anterior MI
    • 1- Symptoms: CHF, arrhythmias, angina
    • 2- Indications for surgery: refractory symptoms, arrhythmias
  28. PTCA
    1) restenosis in 20-30% in <1 year
  29. Saphenous vein graft
    80-90% 5 year patency
  30. Internal mammary artery
    • 1) off subclavian arteries
    • 2) best conduit for CABG- >90% 10yr graft patency rate
    • 3) collateralizes with superior epigastric artery
  31. CABG procedure:
    1) potassium and cold solution cardioplegia- causes arrest of the heart in diastole; keeps the heart protected and still while grafts are placed

    • 2) Indications:
    • 1- left main disease
    • 2- left main equivalent disease (LAD>70% and proximal left complications)
    • 3- 3 vessel disease
    • 4- 2 vessel disease with:
    • - proximal LAD stenosis and either LVEF <50% or extensive ischemia on noninvasive imaging study
    • 5- 1 or 2 vessel disease with
    • - stable angina, large area of viable myocardium, and high-risk criteria on noninvasive testing
    • or
    • - disease causing life threatening arrhythmias
    • or
    • - disabling stable angina despite medications when patient has acceptable risk

    3) unstable angina- patients with ongoing ischemia despite maximal nonsurgical therapy

    • 4) High mortality risk factors:
    • 1- emergency operations (#1 risk factor)
    • 2- age
    • 3- reoperation
    • 4- low EF
  32. what is the most common valve lesion
    Aortic stenosis
  33. What produces stenosis?
    calcification
  34. Rheumatic heart disease-
    • - most common cause of valve dysfunction
    • - mitral valve most commonly involved
  35. Stenosis
    stenosis predominates; see regurgitation with progressive valve degeneration (volcano orifice, sticks open)
  36. Degenerative processes
    • 1) 3rd or 4th decade of life
    • 2) mitral most commonly affected
    • 3) insufficiency predominates
  37. Tissue valves
    1) do not require anticoagulation

    • 2) for patients who:
    • 1- want pregnancy
    • 2- have contraindication to anticoagulation
    • 3- are older and unlikely to require another valve in their lifetime
    • 4- because of rapid calcification in children and young patients, use of tissue valves is contraindicated in these populations
    • 5- have frequent falls
    • 6- chronic renal dialysis is also a contraindication

    3) not as durable as mechanical valves
  38. Mitral stenosis
    • 1) leads to signs of pulmonary congestion
    • 2) can develop mural thrombi- 50% go to cerebral circulation
    • 3) indications for operation- when symptomatic (usually have valve area <1cm2)
  39. Mitral regurgitation
    • 1) LV becomes dilated, wall tension increases
    • 2) ventricular function- key index of disease progression in patients with MR
    • 3) in end-stage disease, left atrium becomes less compliant --> pulmonary congestion ensues and can lead to right-sided heart failure. Atrial fibrillation is common
    • 4) Indications for operation- symptoms may not develop until after irreversible heart dysfunction has occured
    • - repair indicated for any functional class II heart failure (SOB on exertion)
  40. Aortic stenosis
    • 1) adequate CO and normal systemic pressures are maintained until late in the disease
    • 2) eventually, LV hypertrophy leads to decreased ventricular compliance and pulmonary congestion. LV failure ultimately develops
    • 3) Cardinal symptoms:
    • Angina- develops in 65%; mean survival is 5 years
    • Syncope- develops in 25%, mean survival is 3 years
    • Heart Failure- mean survival is 2 years (strongest prognostic indicator)
    • 4) Indications for operation- when symptomatic (usually have a peak gradient of 50mmHg and a valve area <1.0 cm2)
  41. Aortic insufficiency
    • 1) produces volume loading strain on the LV
    • 2) LV becomes more dilated, wall tension increases (law of Laplace)
    • 3) cardiac output can increase to 30L/min
    • 4) Indications for operation- symptoms may not develop until after irreversible heart dysfunction has occured
    • - repair indicated for any functional class II heart failure (SOB with exertion)
  42. Endocarditis
    • 1) fever, chills, sweats
    • 2) Aortic valve- most common site of prosthetic valve infections
    • 3) Mitral valve- most common site of native valve infections
    • 4) most commonly left sided except in drug abusers
    • 5) staphylococcus aureus responsible for 50% of cases
    • 6) medical therapy first- successful in 75%; sterilizes valve in 50%
    • 7) indications for surgery:
    • 1- failure of antimicrobial therapy
    • 2- valve failure
    • 3- perivalvular abscess
    • 4- pericarditis
  43. Periprocedural endocarditis prophylaxis indicated for patients
    • 1) prosthetic valves
    • 2) rheumatic heart disease
    • 3) congenital cardic malformations
    • 4) mitral valve prolapse with mitral regurgitation
    • 5) previous history of bacterial endocarditis

    1st generation cephalosporins usually used --> need to start oral antibiotics 1 day prior
  44. Modified duke criteria for diagnosis of infective endocarditis
    pg 174
  45. Most common tumors of heart
    • 1) most common benign tumor- myxoma; 75% in LA, mitral valve stenosis-type symptoms
    • 2) most common malignant tumor- angiosarcoma
    • 3) most common metastatic tumor to the heart- lung Ca
  46. Coming off cardiopulmonary bypass and aortic root vent blood is dark and aortic perfusion cannula blood is red, whats the tx?
    ventilate the lungs
  47. What has the lowest oxygen tension over any tissue in the body and why?
    coronary veins have the lowest oxygen tension of any tissue in the body due to high oxygen extraction by myocardium
  48. Superior vena cava syndrome:
    • 1) swelling of the upper extremities and face
    • 2) most cases secondary to lung Ca invading the SVC
    • 3) these tumors are unresectable since the tumor has invaded the mediastinum
    • 4) Tx: XRT
  49. Idiopathic hypertrophic subaortic stenosis:
    • 1) too much volume can cause pulmonary edema due to stenosis region
    • 2) not enough afterload will cause the aortic outflow tract to collapse, also resulting in pulmonary edema
    • 3) very tricky management
  50. Mediastinal bleeding:
    1) >500 cc for 1st hour or >250cc/h for 4 hrs--> need to reexplore after cardiac procedure
  51. Risk factors for mediastinitis:
    • 1) obesity
    • 2) diabetes
    • 3) use of bilateral internal mammary arteries

    Treatment: debridement with pectoralis flaps; can also use omentum
  52. postpericardiotomy syndrome
    • 1) pericardial friction rub
    • 2) fever, chest pain, SOB
    • 3) EKG- diffuse ST segment elevation in multiple leads
    • 4) NSAIDs and steroids
  53. 1st sign of cardiac tamponade on echocardiogram
    1) decreased right atrial diastolic filling
Author
scottmreis
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CHAPTER 26- CARDIAC.txt
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