Card Set Information
A&P Test 4
A&P Chapter 23
What is the first heart sound (S1) associated with?
Closure of the AV valves at the beginning of systole
Mitral and tricuspid
R-wave on EKG
What is the second heart sound (S2) associated with?
Closure of the semilunar valves at the end of systole
Aortic and pulmonic
End of QRS complex
What is the third heart sound (S3) associated with?
Blood entering and distending a relatively noncompliant LV
Ventricular diastolic gallop indicates significant LV dysfunction and may be the first sign of CHF
Weak rumble heard during the second 1/3 of diastole
Corresponds to T-wave
What is the 4th heart sound (S4) associated with?
Late diastolic atrial contraction causes a rushing of blood into ventricles
Almost never heard with stethascope except in hypertensive patients with a thick LV
Corresponds to P-wave
What anitomical location are S3 and S4 heard?
Apex of the heart
What are the 4 main causes of murmurs?
1) Rheumatic fever
2) Bacterial endocarditis
3) Congenital defects
4) Degenerative defects
What leads to the greatest number of valvular lesions?
What is the organism responsible for rheumatic fever?
Group A hemolytic streptococci
What is the mechanism by which group A strep. causes valvular lesions?
Typically initiates an antibody response which can persist up to 1 year. This ultimately leads to autoimmune/immunologic damage
What valves are most frequently affected by rheumatic fever?
MV most frequently
AV second most frequently
What are typical causes of bacterial endocarditis?
1) IV drug abuse
2) Dental decay
What are 2 congenital defects of valves that may cause murmurs?
2) Lack of 1 or more leaflets; congenital bicuspid AV
What type of defect would calcific aortic stenosis be?
What are pressure overload lesions caused by?
What are volume overload lesions caused by?
What type of murmur is produced by AS?
Systolic ejection murmur that may be transmitted into the neck
What is the normal area of the AV?
What are criteria for surgical repair of AS?
1) Pressure gradient >50mmHg or
2) Valve area <1cm2
How high may LV pressure be in severe AS? What about aortic root pressure?
LV pressure may be as high as 300mmHg with normal aortic root pressure
What type of LV changes may be caused by AS?
Concentric LV hypertrophy as sarcomeres are added in parallel
Angina pectoris, DOE, and syncope are the classic triad of what valvular lesion?
What is the life expectancy without surgery of a patient presenting with aortic stenosis?
What type of lesion is AS?
How do you manage hypotension in a patient with aortic stenosis?
Neosynepherine or vasopressin; increasing contractility will not increase BP due to stenotic, small orifice in AS
What happens to SV in AS?
Net SV is reduced
What type of murmur is AR?
"Blowing" murmur of relatively HIGH PITCH with swishing quality
Heard maximally over LV during diastole
What is especially important regarding a short duration blowing murmur over the LV during diastole?
Severe aortic regurgitation - blood is flowing back rapidly into LV
What happens with SV during AR?
Decreased net stroke volume as a large amount of blood immediately rushes back into the LV
What type of LV changes may be caused by AR?
Eccentric hypertrophy (big floppy heart) as sarcomeres are added in series
What type of LV change may lead to some signs and symptoms of IHD? Why?
Eccentric hypertrophy, seen in AR.
s/s of IHD because the thin LV wall allows compression of endocardium/subendocardial arteries during LV filling
What type of lesion is AR?
What type of murmur is MR?
High-pitched blowing murmur heard throughout systole (holosystolic)
Transmitted strongly to the LA, but LA is deep in the chest and difficult to hear the murmur
"Woosh-lub" that is less harsh than AS
Where is MR best heard?
Apex of the heart
What valvular lesion allows blood from LV to be ejected back into the LA during systole?
What is the cause of atrial fibrillation and pulmonary edema due to heart valve problems?
Increased LA pressures
What type of lesion is MR?
What will happen with PA and PCWP during MR?
They will be elevated
What are associated characteristics of acute MR?
1) Papillary muscle rupture/ischemia due to LAD infarction
2) High LA pressure
What are associated characteristics of chronic MR?
1) Rheumatic fever
2) Bacterial endocarditis
3) Increased likelihood of A-fib
4) Dilated LA with normal pressure
What type of murmur is MS?
Described as a low rumbling "thrill" heard during last 1/3 of diastole over the apex of the heart
"Kentucky" - "lub-dub-purr"
What is the normal MV orifice area?
At what change of MV opening do patients typically become symptomatic in MS?
50% decreased orifice size
MS causes what change in LVEDP? Why?
Decreased LVEDP because flow from LA to LV is decreased
MS can result in what changes in the pulmonary system? How does this affect the RV?
May result in decreased pulmonary compliance causing increased RV pressures and subsequent RV failure
What physiologic changes occur to the LV as the result of MS?
None, the LV is normal
CO and MAP do not decrease nearly as much as with AS
What type of lesion is MS?
What valvular lesions cause a net reduced movement of blood from LA to LV?
MS and MR
What congenital abnormalities are outflow obstructions?
1) Coarctition of the aorta
2) Pulmonic stenosis
3) Aortic stenosis
What congenital abnormalities cause left-to-right shunting?
TOF and hypoplastic left heart are congenital abnormalities causing what type of shunting?
What are examples of "cyanotic" heart defects?
Any abnormality causing a right-to-left shunt
2) Hypoplastic left heart
3) Tricuspid atresia
4) Transposition of the great vessels
What are examples of "acyanotic" heart defects?
4) Coarctition of the aorta
5) Pulmonic stenosis
What makes a PDA a left-to-right shunt?
Blood flows from left side to right side of heart, bypassing systemic circulation
Will see an increase in PA pressures
What is the murmur of PDA?
Machinery murmur more intense during systole, less intense during diastole. Waxes and wanes with each heartbeat
What congenital heart defect can lead to recirculating of blood through lungs? What can this cause?
PDA; can cause decreased respiratory reserve and pulmonary edema
Increased pulmonary flow can lead to RV hypertrophy
What is the treatment for PDA?
For babies, indomethacin or surgical ligation
What is the frequent cause of ASD?
Failure of the foramen ovale to close
What is the prevalence of ASD?
About 1/3 of the population has ASD, but increased LA pressures force it close and many people are asymptomatic
What is the murmur of ASD?
Systolic murmur over pulmonic valve that is very mild and often not detected
What frequently undiagnosed congenital heart defect can lead to MI or CVA in the event of a venous air embolism (VAE)?
ASD; air can shunt to arterial circulation
What are the 3 variations of ASDs?
1) Ostium secundum
a. About 75% of all ASDs
2) Ostium primum
a. Endocardial cushion defect
3) Sinus venosus
What EKG changes may be seen as the result of ASD?
Right axis deviation and RBBB
What arrhythmias are associated with ASD?
a-fib and SVT
What may be seen on a chest X-ray in a patient with ASD?
Prominent pulmonary arteries due to left-to-right shunting increasing pulmonary flow
What is the most common congenital heart defect?
25-35% of congenital heart disease
What congenital heart defect usually spontaneously closes by the age of 2?
What is the murmur of VSD?
Holosystolic murmur at the left sternal border is heard UNLESS the hole is closed during contraction
Small VSDs may not produce a murmur
How can a VSD go from left-to-right shunting to right-to-left shunting?
Early pathophysiologic changes reflect increased pulmonary flow. With chronic increases of pulmonary flow, PVR may become > SVR reversing the shunt
When a VSD is chronic, it becomes a cyanotic defect due to right-to-left shunting
What is unique of CXR and EKG with small VSD?
They are normal
What physiologic changes are seen with moderate to large VSD?
LA and LV enlargement
What EKG changes are seen with VSD causing pulmonary hypertension?
Right axis deviation
Lead I - Lead aVF +
this indicates RA and RV enlargement
What congenital heart defect is the most common "cyanotic" defect?
What 4 anatomical defects characterize TOF?
1) Aortia originates from RV instead of LV or overrides the septum
2) PA stenosis causes preferential flow from the RV through the path of least resistance which is the VSD to the aorta
4) RV hypertrophy secondary to increased afterload of both pulmonary stenosis and systemic afterload
What is the usual treatment for TOF?
What diagnostic tools are available to identify murmurs?
1) Stethascope or phonocardiogram
2) EKG to identify hypertrophic axis deviation
4) Chest radiography
5) Cardiac catheterization