Duval and Andrews lectures Flashcards
What is aortic dissection?
A risk associated with HTN. It’s dissection of blood along laminar planes of media with the formation of a blood-filled channel within the aortic wall, usually leading to aortic rupture.
Who is at risk for aortic dissection?
1) Men btwn 40-60 with HTN (that is 90 percent of cases)
2) Those with connective tissue disorders (eg Marfan’s)
3) Pregnancy (rare)
Where are two places that you are most likely to see aortic dissection?
1) 90 percent of the time in the ascending aorta, in the aortic arch about 10cm of the aortic valve.
2) In the descending thoracic aorta, distal to the left subclavian artery.
A lot of those with aortic dissection also have ______?
Concurrent atherosclerosis.
What are the classifications of aortic dissection?
1) Debakey I - Mostly in ascending aorta, dissection is on both sides but larger area than II. (aka Type A)
2) Debakey II - Mostly in the ascending aorta, dissection is both sides of artery but a small area (aka Type A)
3) Debakey III - Mostly in descending aorta, dissection is mainly on one side (aka Type B)
How the aortic dissection generally presents
A longitudinal or oblique tear about 1-5cm long. The dissection is btwn middle and outer thirds of media. Can happen in a portion or the entire circumference of the arc
What does cystic medial necrosis have to do with aortic dissection?
Happens in about 20 percent of cases. Where muscle wall isn’t normal anymore and has spaces and clefts filled with mucus or basophilic material. Happens many times in connective tissue disorders like Marfan’s
What can be the outcome of aortic dissection?
1) Blood can continue to dissect proximally to involve the coronary arteries or distally to involve the iliac and femoral arteries.
2) It can rupture into the pericardial sac, pleural or peritoneal cavity.
3) It can re-rupture back into the aortic lumen (double barreled aorta (better outcome)
4) Can cause a collapse in the inner layers of small arteries causing obstruction
What is Marfan’s syndrome?
It’s a genetic disorder that involved the fibrilin gene (it encodes a protein in elastic connective tissue… like the aorta). About 70-90 percent have HTN. They are at risk for aortic dissection and generally have a thickening of the arterial wall (cystic medial dissection
What is the outside presentation of Marfan’s syndrome?
They are generally tall and lanky, chest wall deformities an long double jointed fingers
What are the classic clinical symptoms of aortic dissection?
A sudden excruciating pain in the anterior chest, radiating to the back and moving downward (DDX acute MI)
How do you diagnose aortic dissection?
Aortic angiography, 2D cardiac ultrasound, CT or MRI scan.
What is the prognosis of aortic dissection?
If caught in time, its 65-75 percent salvageable. Anti-HTN therapy works as well
What is the definition of Congestive heart failure?
It’s a multisystem derangement when the heart is no longer able to eject blood delivered to it by the venous system.
What are 5 causes of Left Heart failure?
1) HTN
2) Mitral valve disease
3) Aortic valve disease
4) Ischemic heart disease
5) Primary myocardial disease
What are 6 causes of Right heart failure?
1) Left Heart failure (most major cause)
2) Cor pulmonale
3) Pulmonary vascular disease
4) Pulmonic valve disease
5) Tricuspid valve disease
6) Congenital heart disease (left to right shunt)
What are ways that the body compensates for heart failure?
1) It increases sympathetic nervous system activity (catecholamines) (that increase contractility and rate)
2) Hypertrophy, heart muscle can thicken (can contract more forcefully)
What happens after body can no longer properly compensate for heart failure
Forward failure, the CO drops that means an increase in end diastolic volume, EDV (can’t pump out all of the blood. That means a rise in end diastolic pressure ,EDP which increases venous pressures and now you have a backward failure (so you have venous congestion). Also increased EDV will stretch fibers and alter contractility
How do you get RHF from LHF?
Left heart is failing as you’re not ejecting the blood, that increases congestion in pulmonary circulation and increases pulmonary edema that increases pulmonary resistance and that can lead to RHF and systemic venous congestion
What is the morphology (what can you see) in Left Ventricular Failure?
A dilated hypertrophied heart, boggy lungs with a frothy edema fluid. pulmonary vascular congestion, alveolar hemorrhage, heart failure cells and brown induration of the lung
What is the morphology (what can you see) in Right Ventricular Failure?
Soft tissue edema, abdominal visceral congestion (nutmeg liver), cavity fluid and cardiac cirrhosis (scarring of liver)
What are the clinical features of LHF?
A dyspnea (due to reduced lung compliance) aggravated by lying down, when sleeping and exertion, and enlarged heart, S3, tachy, fine rales in lungs and Afib
What are the clinical features of RHF?
Distended neck veins, an enlarged tender liver, weight gain, dependent edema, cyanosis, acidosis, ventricle arrhythmias and sudden death ( and possibly all of the clinical features of LHF)
What is the morphology of Nonbacterial thrombotic endocarditis
Amalgam of fibrin and platelets at the margins of valve closures.
Where is Nonbacterial thrombotic endocarditis most often found?
Most common on the aortic valve
What is the diagnostic lesion called in ineffective endocarditis.
Vegetation
Where can ineffective endocarditis be found?
In cardiac valves and on the mural surfaces of the endocardium
What is the major cause of ineffective endocarditis?
A bacterial infection
Describe the 2 types of ineffective endocarditis.
1) Acute - caused by highly virulent organisms (like Staph aureus). May infect structurally normal or abnormal valves and progress rapidly. 50% mortality rate
2) Subacute - Caused by less virulent bacteria (a-hemolytic strep). Tends to affect previously abnormal valves. Slow progresssion
What are some of the organisms that can cause ineffective endocarditis?
a-hemolytic strep (50-60% of cases), Staph aureus (10-20%), Enterocci or HACEK group (Haemophilus, Actinobacilli, Cardiobacter, Eikinella, Kingells)
What is the most common organism that an infect prosthetic heart valves
Staph epidermis
What side of the heart is more likely to be affected by ineffective endocarditis?
The left side (if right side you should think IV drug use since that goes into the venous system)
What kind of treatment would you need for ineffective endocarditis
Long term IV Abx.
What are the characteristics of ineffective endocarditis?
Single or multiple vegetations that can be on one or more valves. Vegetation enlarges as organism proliferates
Which tend to cause larger vegetations in ineffective endocarditis… bacterial or fungi?
Fungi
How does the vegetation present itself in acute ineffective endocarditis?
It can obstruct valve orifices and rupture leaflets and chordae/papillary muscle. Can cause ring abscesses in myocardium and pools of microorganism
How does the vegetation present itself in subacute ineffective endocarditis?
More firm and less destructive. Less of a chance of ring abscesses. Hallmark sign is granulations tissue at the base of vegetation. Also fibrosis, calcification and chronic infection
What are the main clinical features of ineffective endocarditis?
Fever and a new murmur (90%)
What are the most common pathogens for myocarditis?
Virus (in the US) Coxsackie A&B and Enterovirial (5% associate w Lyme).. Once in a while parasitic
What will viral myocarditis induce?
1) Direct myocardial injury
2) immune related injury
3) Toxin production
What is the morphology of myocarditis
Sometimes but not always a dilated pale flabby heart
What is the histology of the different forms of myocarditis
1) Viral - lots of mononuclear cells, may/may not see viral inclusions.
2) Parasitic - lots of eosinophils
3) Bacterial - (rare) - systemically septic
What are the 3 broad categories of outcomes for bacterial myocarditis
1) Culminates in rapid death
2) Self-limited to full recovery
3) Progresses to chronic CHF with dilated cardiomyopathy (recovers but needs to be on transplant list)
What are the 3 types of cardiomyopathies?
1) Dilated
2) Hypertrophic
3) Restrictive
Is cardiomyopathy a diagnosis?
No , it’s a description of a diseased heart muscle
What are the array of etiologies for dilated cardiomyopathy?
1) End stage myocarditis
2) ETOH abuse
3) Chemicals (cobolt or chemo agents)
4) 3rd trimester, early post partum
5) Idiopathic - most common
Who is most affected with dilated cardiomyopathy?
20-50 y/o and more males than females
What is the morphology of dilated cardiomyopathy?
4 chamber dilation and hypertrophy and very heavy heart weights (greater than 900 gm … normal 250-300gm)
What are the clinical features of dilated cardiomyopathy
1) Ejection fraction of less than 25%
2) Progressive CHF (due to mitral valve regurg)
What is the outcome of many postpartum dilated cardiomyopathy
50% will self-resolve.
What are characteristics of hypertrophic cardiomyopathy?
Big and stiff
1) LV hypertrophy with a subaortic (large) septum (bend into the left ventricle)
2) abnormal diastolic filling
3) heart weight is greater than 800gm
4) Myofibril disarray
How is hypertrophic cardiomyopathy classified?
As a autosomal dominant disorder with variable penetrance (next generation may have it less/more than parent) and 50% exrpressivity (even if you get gene you have gene 50% you’ll have an OK heart). Its mostly due to a missense point mutation
What are the clinical features of hypertrophic cardiomyopathy?
1) Ejection is forceful by ineffective due to low LV volume
2) Dynamic obstruction to LV outflow (dyspnea and angina)
3) Harsh systolic ejection murmur
4) Ventricular arrhythmia
5) Progressive CHF with increasing fibrosis.
Describe restrictive cardiomyopathy
Heart is normal size but it’s infiltrated with something that restricts contractility of the heart
What are some etiologies of restrictive cardiomyopathy?
1) Endocardial fibrosis
2) Eosinophilic endomyocardial fibrosis (in kids… Loeffler’s syndrome)
3) Amylodosis (deposits of amyloid protein)
4) Hemochromatosis - Iron pigment
5) Radiation from lung cancer
What are the three major types of congenital heart disease?
1) Left to right shunt - Acyanotic at presentation
2) Right to left shunt - Cyanotic at birth (very bad)
3) Coarctation of aorta - both pre-ductal and post-ductal
What are the most common heart defect
Left to right shunts (the less dangerous one) Ventricular most common
When does an atrial septal defect occur
In the fourth to sixth week of fetal life (not to be confused with foramen ovale)
What are the clinical features of atrial septal defects?
1) Left to right shunt post partum
2) Lesions less than 1 cm tolerated well
3) Significant lesions can produce pulmonary HTN that can cause cyanosis and CHF
When and where do ventricular septal defects occur?
Fourth to Eight week of life
90% are located in the basilar or membranous septum (high up in ventricle)
what are some s/s of ventricular septal defect
1) tough breathing
2) failure to thrive
3) lack of appetitie
What is the most common cause of cyanotic heart disease
Tetralogy of Fallot
Tetralogy of Fallot
1) A membranous VSD
2) a displaced (to the right) aortic root
3) RV outflow obstruction w/w-out pulmonary valve stenosis
4) RVH (boot shaped heart)
Why does a child with Tetralogy of Fallot squat?
He is trying to increase his venous return
What are the clinical features of Tetralogy of Fallot?
1) Cyanosis
2) Prostaglandin E2
3) Squatting
4) transposition of great vessels
What must be done for a child with Tetralogy of Fallot
A balloon septostomy (to create an artificial linkage between R and L)
What is coarctation of the aorta
A discrete narrowing in the aorta
What are two types of coarctation of the aorta?
Preductal - (in infants)
Postductal - (in adults)
What might contribute to coarctation of the aorta?
1) An isolated lesion (in 1/2 the cases)
2) Saccular aneurisms of CNS (circle of WIllis)
What are the clinical features of perductal coarctation of the aorta?
1) CHF
2) Cyanosis of lower extremities
3) Differential pulses (femoral pulse weaker)
