Chapter 26: Cardiac Flashcards
What kind of shunts cause cyanosis?
Right to left shunts
Why do children squat in right to left shunts?
To increase SVR and decrease right to left shunts
R -> L shunts cause cyanosis. What can this lead to?
Polycythemia, strokes, brain abscess, endocarditis
Shift from L -> R shunt to R -> L shunt
Eisenmenger’s syndrome
What causes Eisenmenger’s syndrome?
Increasing pulmonary vascular resistance (PVR) and pulmonary HTN; this condition is generally irreversible
What do left to right shunts cause?
CHF: manifests as failure to thrive, increased HR, tachypnea, hepatomegaly; CHF in children, hepatomegaly
What is the first sign of a left to right shunt?
Hepatomegaly
L -> R shunts (CHF)
VSD, ASD, PDA
R -> L shunts (cyanosis)
tetralogy of Fallot
Connection between descending aorta and left pulmonary artery (PA); blood shunted away from lungs in utero
Ductus arteriosus
Connection between portal vein and IVC; blood shunted away from liver in utero
Ductus venosum
Fetal circulation:
- To placenta
- From placenta
to placenta: 2 umbilical arteries
from placenta: 1 umbilical vein
MC congenital heat defect
VSD (L -> R shunt)
% of VSD that close spontaneously
80% (usually by age 6 months)
Usually cause symptoms after 4-6 weeks of life, as PVR decrease, and shunt increased
Large VSDs (can get CHF - tachypnea, tachycardia - and failure to thrive)
Medical treatment: VSD
Diuretics and digoxin
Usually timing of repair:
- Large VSDs (shunt > 2.5)
- Medium VSDs (shunt 2-2.5)
Large: 1 year of age
Medium: 5 years of age
Most common reason for earlier repair of VSD
Failure to thrive
L->R shunt
- Usually symptomatic when shunt > 2 -> CHF (SOB, recurrent infections)
- Can get paradoxical emboli in adulthood
- Medical tx: diuretics and digoxin
Atrial septal defect
Most common (80%); centrally located ASD
Ostium secundum
Can have mitral valve and tricuspid valve problems; frequent in Down’s syndrome
Ostium primum (or atrioventricular canal defects or endocardial cushion defects)
Usual timing of repair ASD
1-2 years of age (age 3-6 months with canal defects)
VSD
Pulmonic stenosis
Overriding aorta
RVH
Tetralogy of Fallot
MC congenital heart defect that results in cyanosis
Tetralogy of Fallot
Medical treatment: tetralogy of fallot
Beta-blocker
Usual timing of repair: tetralogy of fallot
3-6 months of age
Repair: tetralogy of fallot
RV outflow tract obstruction (RVOT) removal, RVOT enlargement, and VSD repair
L-> R shunt
- Requires surgical repair through left thoracotomy if it persists
Patent ductus arteriosus (PDA)
Causes PDA to close; rarely successful beyond neonatal period
Indomethacin
Most common cause of death in the United States
Coronary artery disease
Risk factors: coronary artery disease
Smoking, HTN, male gender, family history, hyperlipidemia, diabetes
Medical treatment: coronary artery disease
Nitrates, smoking cessation, weight loss, statin drugs, ASA
Branches of left main coronary artery branches
Left anterior descending (LAD) and circumflex (Cx) arteries
Location of most atherosclerotic lesions
Most atherosclerotic lesions are proximal
Complications of myocardial infarction
- VSR (ventricular septal rupture)
- Papillary muscle rupture
Hypotension, pansystolic murmur, usually occurs 3-7 days after MI; have a step-up in oxygen content between right atrium and pulmonary artery secondary to L->R shunt
VSR (ventricular septal rupture)
Why is there a step up in oxygen content in ventricular septal rupture?
Step-up in oxygen content between the right atrium and pulmonary artery secondary to L->R shunt.
Dx / Tx: ventricular septal rupture
Dx: echo
Tx: IABP to temporize, patch over septum
Get severe mitral regurgitation with hypotension and pulmonary edema; usually occurs 3-7 days after MI
Papillary muscle rupture
Dx / Tx: papillary muscle rupture
Dx: echo
Tx: IABP to temporize, replace valve
Restonosis rate in drug-eluting stent
Restenosis in 20% at 1 year
5 year potency of saphenous venous graft
80% 5-year patency
What is the internal mammary artery a branch of?
Subclavian artery
- Best conduit for CABG (>95% 20 year potency when placed to LAD)
- Collateralizes with superior epigastric artery
Internal mammary artery
For CABG procedure: causes arrest of the heart in diastole; keeps the heart protected and still while grafts are placed
Potassium and cold solution cardioplegia
Best indications for CABG
- > 70% stenosis significant for most areas except left main disease.
- Left main disease (> 50% stenosis considered significant
- 3 vessel disease (LAD, Cx, and right coronary artery)
- 2 vessel disease involving the LAD
- Lesions not amenable to stenting
High mortality risk factors in coronary artery disease
Pre-op cardiogenic shock (#1 risk factor).
Emergency operations.
Age.
Low EF.
Most common valve lesion, calcification produces stenosis
Aortic stenosis
What type of valve does not require anticoagulation?
Bioprosthetic tissue valves
When would you consider bioprosthetic tissue valves?
For patients who want pregnancy, have contraindication to anticoagulation, are older (>65) and unlikely to require another valve in their lifetime, or have frequent falls
How long does bioprosthetic tissue valve last?
Lasts 10-15 years -> not as durable as mechanical valves
Why are bioprosthetic tissue valves contraindicated in children and younger patients?
Because of rapid calcification in children and young patients, use of tissue valves is contraindicated in those populations.
Valvular lesion most from degenerative calcification
Aortic stenosis
Cardinal symptoms of aortic stenosis
- DOE: mean survival 5 years
- Angina: mean survival 4 yrs
- Syncope: mean survival 3 yrs
Worst of the cardinal symptoms of aortic stenosis
Syncope: mean survival is 3 years
Indications for operation in aortic stenosis
When symptomatic (usually have a peak gradient > 50 mmHg and a valve area
Valve disease causing dilation of the left ventricle
Mitral regurgitation (MR)
Key index of disease progression in patients with MR
Ventricular function
Arrhythmia common in mitral regurgitation
Atrial fibrillation: is common, in end-stage disease, pulmonary congestion occurs
Indications for operation in mitral regurgitation
When symptomatic or if severe mitral regurgitation
Rare now, most from rheumatic fever
- Get pulmonary edema and dyspnea
Mitral stenosis
Indication for operation in mitral stenosis
When symptomatic (usually have valve area
Often used as 1st procedure for mitral stenosis
Balloon commissurotomy to open valve often used as 1st procedure (not as invasive)
Symptoms of endocarditis
Fevers, chills, sweats
Most common site of prosthetic valve infections
Aortic valve endocarditis
Most common site of native valve infections
Mitral valve endocarditis
Responsible for 50% of cases of endocarditis
Staphylococcus aureus
Most common organisms causes endocarditis in drug abusers
Pseudomonas
Most common site of endocarditis in drug abusers
Left sided endocarditis
Initial treatment of endocarditis
Medical therapy first: successful in 75%, sterilizes valve in 50%
Indications for surgery in endocarditis
Failure of antimicrobial therapy, severe valve failure, perivalvular abscesses, pericarditis
Most common benign tumor of the heart
Myxoma; 75% in LA
Most common malignant tumor of the heart
Angiosarcoma
Most common metastatic tumor to the heart
Lung cancer
Tx: coming off cardiopulmonary bypass and aortic root vent, blood is dark and aortic perfusion cannula blood is red
Tx: ventilate the lungs
Have the lowest oxygen tension of any tissue in the body
Coronary veins: due to high oxygen extraction by myocardium
Swelling of the upper extremities and face
- Most cases secondary to lung CA invading the SVC
Superior vena cava (SVC) syndrome
Treatment of tumors causing SVC syndrome
These tumors are unresectable since the tumor has invaded the mediastinum.
- Tx: emergent XRT
Mediastinal bleeding: when do you need to re-explore after cardiac procedure?
> 500 cc for 1st hour or > 250cc/hr for 4 hours
Risk factors for mediastinitis
Obesity, used of bilateral internal mammary arteries, diabetes
Tx: mediastinitis
Debridement with pectoralis flaps, can also use omentum
Pericardial friction rub, chest pain, SOB
- EKG: diffuse ST-segment elevation in multiple leads
Treatment?
Post-pericardiotomy syndrome
TX: NSAIDS, steroids
