Chapter 26 – Cardiac Flashcards
What do right to left shunts cause?
Cyanosis; this can lead to polycythemia, strokes, brain abscess, endocarditis, hypertrophic osteoarthropathy
How do children compensate for right to left shunt?
Squat to increase SVR and decrease right to left shunting
What is Eisenmenger’s syndrome?
Shift from left to right to right to left shunt; sign of increasing pulmonary vascular resistance and pulmonary hypertension, generally irreversible
What do left to right shunts cause?
CHF; can manifest as failure to thrive, tachycardia, tachypnea, hepatomegaly
What is the first sign of left to right shunting in children?
Hepatomegaly
What causes a left to right shunt?
VSD, ASD, PDA
What causes a right to left shunt?
Tetralogy of Fallot, transposition of the great vessels, truncus arteriosus
What is ductus arteriosus?
Connection between descending aorta and left pulmonary artery, blood shunted away from lungs in utero
What is ductus venosum?
Connection between portal vein and IVC, blood shunted away from liver
How many umbilical arteries and veins are there?
Two umbilical arteries, one umbilical vein
What is the most common congenital heart defect?
Ventricular septal defect
VSD causes what type of shunt?
Left to right
What is the pathological timeline of VSDs?
Most close spontaneously by six months.
Large VSD’s cause symptoms after 4 to 6 weeks as pulmonary vascular resistance decreases and shunt increases to the right. Patients get CHF, failure to thrive, tachypnea, and tachycardia (all left to right shunts share these symptoms).
Most common congenital shunt.
Medical treatment for VSD’s?
Diuretics and digoxin
What is the timing of repair of the VSDs?
With CHF: most common reason for repair; before school-age if does not close spontaneously; PVR greater than 4-6 Woods units; PVR greater than 10-12 to Woods units contraindication for repair
What type of shunt does ASD cause?
Left to right
What is ostium secundum?
Most common, centrally located, PFO; can have anomalous pulmonary venous return, IVC can connect the left atrium
What is ostium primum?
Also known as atrioventricular septal defects or endocardial cushion defects; defect more inferior, can get mitral valve and coronary sinus defects, caused by a deficiency in remnants of left horn of sinus venosum?
What are possible complications as an adult with ASD?
Can get paradoxical emboli and arrhythmias
What is the medical treatment of ASD?
Diuretics and digoxin
Timing of repair of ASD?
Volume overload, before school-age if does not close spontaneously, PVR greater than 10 to 12 woods units contraindication for repair; all need repair
What is the Tetralogy of Fallot?
VSD, pulmonic stenosis, overriding aorta, right ventricular hypertrophy
What type of shunt does T of F cause?
Right to left
What is the most common congenital heart defect that results in cyanosis?
T of F
What is the medical treatment for T of F?
Beta blocker
What is the timing of operation for T of F?
Increasing cyanosis; Blalock-Taussig shunt can be used for palliation to delay repair
What is definitive repair for T of F?
RV outflow tract obstruction division, patch enlargement of outflow tract, VSD repair
What is the most common cyanotic disorder presenting in the first week of life?
Transposition of the great vessels
What type of shunt does transposition of the great vessels cause?
Right to left
Where does the mixing usually happen with transposition of the great vessels?
Most often through ASD; VSD or PDA can serve as additional mixing conduit
Medical treatment for transposition of the great vessels?
Atria septostomy, PGE1
When is the optimal time and method of repair for transposition of the great vessels?
Early switch with coronary reimplantation posteriorly in the first 2 to 3 weeks of life while LV is still getting high resistance
What type of shunt does truncus arteriosus cause?
Right to left
How do neonates present with truncus arteriosus?
CHF, 80% die in first year
Medical treatment for truncus arteriosus?
Diuretic, digoxin, fluid restriction, after load reduction
Timing and method of repair of truncus arteriosus?
Onset of tachypnea, sign of decreased PVR; Repair VSD, remove PA from aorta, repair aorta, restore RV outflow tract with Dacron graft to PA
What type of shunt does a PDA cause?
Left to right
What is the treatment for PDA?
Indomethacin causes PDA to close, rarely successful beyond the neonatal period; usually requires surgical repair through left thoracotomy, PGE1 keeps PDA open
Where does coarctation of the aorta occur?
Just distal to the left subclavian artery
What syndrome is coarctation of the aorta associated with?
Turner syndrome
What is rib notching caused by with coarctation of the aorta?
From the IMA and intercostal collaterals
How can coarctation of the aorta present?
Profound CHF
What is the treatment for coarctation of the aorta?
All require treatment, try to perform end to end repair
What is the treatment for univentricular heart?
Fontan procedure to direct all vena cava blood to the PA, best approach is to attach the right atrium and SVC to the PA directly; normal PA pressure and normal PVR’s prerequisite
What is the treatment for hypoplastic left heart?
Norwood procedure; main PA becomes outlet tract for what is to become single ventricle physiology
What is anomalous pulmonary venous return?
Goes to SVC instead of left atrium; most often seen in patients with ASD’s
What are vascular rings? how do they present? What is the treatment?
Double aortic arch most common, may manifest as recurrent pulmonary infections or dysphagia, trachea most commonly affected; divide smaller arch through left thoracotomy
What is the most common cause of death in the United States?
Coronary artery disease
What are risk factors for coronary artery disease?
Smoking, hypertension, male gender, family history, hyperlipidemia, diabetes
What is medical treatment for coronary artery disease?
Nitrates, smoking cessation, weight-loss, statin drugs, aspirin
What is the most common type of circulation of the heart?
Right dominant – posterior descending artery comes off of right coronary artery
What is left dominant circulation?
Posterior descending artery comes off the circumflex coronary artery
Are most atherosclerotic lesions proximal or distal?
Proximal
What are complications of myocardial infarction?
VSD - 5 to 7 days post MI, papillary muscle rupture, free wall rupture - most likely to occur 3 to 7 days post MI, LV aneurysm – most commonly occurs after large, transmural, interior,
What is the rate of restenosis after PTCA?
20 to 30% in less than one year
What is the patency rate of saphenous vein graft?
80 to 90% at five years
What is the patency of internal mammary artery?
Greater than 90% at 10 years; the best conduit for CABG
What causes arrest of the heart in diastole and keeps the heart protected and still while grafts are placed during CABGs procedure?
Potassium and cold solution cardioplegia
What are high mortality risk factors for CA BG?
1 emergency operations, age, reoperation, low EF
What is the most common valve lesion?
Aortic stenosis
What is the most common cause of valve dysfunction?
Rheumatic heart disease; mitral most commonly involved valve
What are the indications for tissue valves?
Patients who want pregnancy, contraindication to anticoagulation, older and unlikely to require another valve, frequent falls
Contraindications for tissue valves?
Because of rapid calcification in children and young patients use is contraindicated in these populations, chronic renal dialysis
Mitral stenosis causes what symptoms?
Pulmonary congestion, can develop mural thrombi with 50% to cerebral circulation
What is the key index of disease progression in patients with mitral regurgitation?
Ventricular function; in end-stage disease, left atrium becomes less compliant leading to pulmonary congestion and right-sided heart failure
Indications for operation for mitral regurgitation?
Symptoms may not develop until after irreversible heart dysfunction has occurred, repair indicated for any functional class II heart failure
Physiologic effects of aortic stenosis?
Adequate CO and normal systemic pressures maintained until late in disease; LV hypertrophy leads to decreased ventricular compliance and pulmonary congestion, LV failure ultimately develops
Cardinal symptoms of a aortic stenosis?
Angina 65%, syncope 25%, heart failure
Physiologic effects of aortic insufficiency?
Volume loading strain on LV, LV becomes dilated, increased wall tension
Indications for operation for aortic insufficiency?
Functional class II heart failure
What is the most common site of prosthetic valve infections with endocarditis?
Aortic valve
What is the most common site of native valve infections?
Mitral valve
Bacteria responsible for endocarditis?
Most commonly staph aureus 50%
Indications for surgery for endocarditis?
Failure of antimicrobial therapy, valve failure, perivalvular abscess, pericarditis
What patients require periprocedural endocarditis prophylaxis?
Prosthetic valves, rheumatic heart disease, congenital cardiac malformations, mitral valve prolapse with regurgitation, previous history of bacterial endocarditis; first-generation cephalosporin
What is the most common benign tumor of the heart? Malignant? Metastatic?
The nine – myxoma, malignant – angiosarcoma, metastatic – lung
What do you do if a patient coming off of cardiopulmonary bypass with aortic root vent blood that is dark and aortic perfusion cannula blood that is red?
Ventilate the lungs
What veins have the lowest oxygen tension of any tissue in the body?
Coronary veins due to high oxygen extraction by myocardium
What is superior vena cava syndrome? Treatment?
Swelling of the upper extremities and face most commonly secondary to lung cancer invading the SVC tumors unresectable, radiation
What is idiopathic hypertrophic subaortic stenosis?
Too much volume causing pulmonary edema due to stenosis region; not enough afterload will cause the aortic outflow tract to collapse also resulting in pulmonary edema
When do you need to re-explore for mediastinal bleeding?
Greater than 500 mL for first hour or greater than 250 mL/h for four hours
What is postpericardiotomy syndrome? Treatment?
Pericardial friction rub, fever, chest pain, SOB; treatment – NSAIDs, steroids
What is the first sign of cardiac tamponade on echo?
Decreased right atrial diastolic filling
