Exam 1 Lecture 4 (2-6-23) Cardiac Anatomy/Stenosis/Regurgitation (Andy's cards) Flashcards
Where is the mediastinum located?
Between the two lungs.
What are the four parts of the mediastinum?
Superior mediastinum
Inferior mediastinum (3 parts):
- Anterior
- Middle (heart is located here)
- Posterior
What part of the mediastinum is indicated by 1 in the figure below?
2?
3?
5?
- Posterior Mediastinum
- Middle Mediastinum
- Anterior Mediastinum
- Superior Mediastinum
What is the nerve that innervates the diaphragm?
Right and Left phrenic nerves
Parasympathetic tone on the heart is innervated by the _______ nerve.
Vagus
What important structure runs next to the descending aorta?
- Esophagus
What does the right vagus nerve innervate?
What does the left vagus nerve innervate?
Right vagus nerve = SA Node.
Left vagus nerve = AV node.
What would the firing rate of the SA node be without any parasympathetic input?
110 bpm
(19:00)
What structure is denoted by 1 in the figure below?
What should be known about this structure?
- Serous Pericardium (Parietal layer)
- Tightly attached to the fibrous pericardium
What structure is denoted by 5 in the figure below?
What should be known about this layer?
-Serous Pericardium (Visceral layer)
- Thin, stretchy, slippery layer that allows for expansion and is covered in lubricating mucous.
What structure is denoted by 6 in the figure below?
What is special about this layer?
-Fibrous Pericardium (external layer)
- Prevents expansion (responsible for tamponade)
List the layers of the pericardium from innermost to outermost.
- Serous pericardium visceral layer
- Serous pericardium parietal layer
- Fibrous pericardium external layer
Too much fluid in the fibrous pericardium layer will prevent what?
Too much fluid in the fibrous pericardium will prevent the heart from adequately filling. (i.e. tamponade)
What two structures of the pericardium are strongly attached to each other?
Serous parietal and the fibrous pericardium.
What tendon does the heart sit on?
Where is this tendon located?
- Central tendon
- Located in the middle of the diaphragm
What would the MAP be in the vessel indicated by 1 below?
100 mmHg
What would the MAP be in the vessel indicated by 3 below?
16 mmHg
What structure is indicated by 2 on the figure below?
What is this?
- Ligamentum Arteriosus
- Remnant of Ductus arteriosus used for fetal circulation.
What is the orientation of cardiac muscle fibers?
Criss-cross pattern, to provide 2-way straining motion in order to squeeze blood out of the heart.
Like wringing out wet laundry
(25:00)
What are the two structures that anchor the AV valves?
What will these structures prevent?
Papillary muscles and Chordae Tendineae
This will prevent the AV valve from bowing out into the atria when the ventricles contract.
What happens to the mitral valve if the left ventricle gets stretched out?
What disorder can cause this to happen?
The orientation of the papillary muscle will be affected and cause the mitral valve to improperly close. (mitral regurgitation)
What percentage of the heart valves have 3 cusps?
75%
3 out of 4 major heart valves have 3 cusps
(Aortic Valve, Pulmonic Valve, Tricuspid)
What percentage of people have a bicuspid aortic valve?
What is the problem with having two cusps on the aortic valve?
1-2%
The aortic open will not be as large, and will need aortic valve replacement eventually.
Which cusps of the aortic valves will be connected to coronary arteries?
Right and left cusp of the aortic valve will be connected to the coronary arteries.
When the aortic valves are closed, the right and left aortic cusp are shaped like bowls. Why could this be important?
During the cardiac cycle, some blood will move back towards the closed valve where the bowl shape cusp can funnel blood in to the right and left coronary artery for perfusion. (34:00)
What is another name for the Posterior Cusp of the aortic valve?
The Non-coronary cusp (The NCC)
What is an important electrical insulator for the top half and bottom half of the heart?
Cardiac Cartilaginous Rings
When does the cartilaginous ring rattle?
During the 3rd heart sound.
What does a 3rd heart sound usually indicate?
What is the exception?
- Indicates non-compliant ventricle in adults.
- 3rd hearts sounds are common in kids.
Why would there be fewer tricuspid valve problems than bicuspid valve problems?
The right side of the heart deals with less pressure than the left side of the heart.
Name the cusps of the bicuspid valve.
Anterior cusp
Posterior cusp/commissural cusp
Which cusp of the mitral valve has the commissural cusp/scallop?
- Posterior cusp
Identify the right coronary artery, left coronary artery, the LAD, and left circumflex artery.
What is another name for the left anterior descending artery?
Widow Maker
(Provides an enormous amount of perfusion to the left ventricle)
The right coronary artery feeds into the _______________.
Posterior descending artery (PAD)
______% of people’s PDA comes from the right coronary artery.
_______% of people’s PDA comes from the left coronary artery.
85% from the right coronary artery
15% from the left coronary artery
When would it be considered a bad thing for someone’s PDA to come from the left coronary artery?
The PDA would then be subjected to much higher left wall pressures.
(41:20)
The vast majority of people are ________ coronary dominant.
Right (85%)
Name all the cusps in the tricuspid valve.
Anterior Cusp
Posterior Cusp
Septal Cusp
Name all the cusps of the pulmonic valve.
Anterior Cusp
Right Cusp
Left Cusp
Coronary blood flow is related to _______.
What two factors will drive coronary pressure?
ΔP
Aortic pressure and Wall Pressure (Ventricular Pressure)
_______ wall pressure will make coronary perfusion more difficult.
High wall pressure (more resistance)
What will the wall pressure of the heart be related to?
Where will the highest wall pressure be found?
Chamber pressure (atrial or ventricular pressure)
The highest wall pressure will be in the LV.
(44:00)
Where will you place your stethoscope to auscultate the aortic valve?
2nd intercostal space right of the sternum
Where will you place your stethoscope to auscultate the pulmonic valve?
2nd intercostal space left of the sternum
Where will you place your stethoscope to auscultate the tricuspid valve?
5th intercostal space left of the sternum.
Where will you place your stethoscope to auscultate the mitral valve?
5th intercostal space left midclavicular line.
Label the valves
In a normal heart, what causes the first heart sound?
What is the duration of the first heart sound?
Closure of the AV valves will produce a low pitch (“Lub”)
0.14 seconds
In a normal heart, what causes the second heart sound?
What is the duration of the second heart sound?
Closure of the Aortic and Pulmonic valves will produce a higher pitch than S1. (“Dub”)
0.11 seconds
The oscillation that occurs over a period of time (1 second) will be measured in __________.
Hertz (Hz)
What is the lowest pitch a human can hear?
What is the highest pitch a human can hear? What causes degradation of this hearing capability?
20 Hz
20 kHz (can be cut in half or lower as you get older)
What equipment is used to hear low-frequency heart sounds and help diagnose a murmur or stenosis?
Phonocardiagram
What is causing the 3rd heart sound?
Heart rattling the ventricular walls and cartilaginous ring during filling toward the end of the rapid filling phase.
What will cause the 4th heart sound?
Atrial kick
What is A?
Normal heart sound
What is B?
Aortic Stenosis
Systolic murmur, excess vibrations d/t narrowed valve that increases blood velocity, small diameter, louder sound, more turbulence
What is C?
Mitral Regurgitation
Blood will move in the wrong direction during systole, resulting in a systolic murmur
What is D?
Aortic Regurgitation (diastolic murmur)
When there is high pressure in the aorta and low pressure and volume in the ventricle, blood will flow back to the LV during diastole. Causing a diastolic murmur
What is E?
Mitral Stenosis
Diastolic murmur, due to blood flow through the narrowed valve, filling issue
What is F?
Patent Ductus Arteriosus
Diastolic and systolic murmur present, there is a bad blood flow going from the aorta (100 mmHg) to the pulmonary artery (16 mmHg)
Of all the heart valve problems, which one will produce the loudest sound?
Aortic Stenosis
(55:00)
What produces the sound toward the end of a diastolic murmur in mitral stenosis?
Atrial contraction, squeezing blood through a narrow valve
(57:00)
Which heart valve issue will produce a systolic murmur?
Aortic Stenosis
Mitral valve regurgitation
Which heart valve issue will produce a diastolic murmur?
Mitral valve stenosis
Aortic regurgitation
What other factors not relating to valve problems can affect heart sounds?
↑CO = loud heart
(Beriberi, hyperthyroidism, pregnancy, anemia, etc)
When will coronary perfusion be the greatest?
When will coronary perfusion be the lowest?
During diastole (↑ΔP = more perfusion)
During systole, aortic pressure almost equals ventricular pressure, small delta P.
When will you see retrograde perfusion in the coronary artery?
At the beginning of systole when ventricular pressure (wall pressure) is greater than aortic pressure. There will be retrograde perfusion.
What are two benefits of a longer time spent in diastole?
- Increased ventricular filling
- Increased coronary perfusion
How will aortic stenosis affect coronary perfusion?
- ↓coronary perfusion from AS.
- ↓SV from ↑ ventricular pressure.
- Lower SV = ↑HR = less time in diastole for coronary filling.
What is the coronary blood flow per 100mg?
70mL/min/100 grams of heart muscle
What is a normal resting coronary blood flow for a young adult?
225 mL/min
If the normal resting coronary blood flow for a young adult is 225 mL/min, what would you expect this young adult’s heart to weigh in grams?
~ 321.43 grams
What will be the resting coronary blood flow for a heart that weighs 300 grams?
210 mL/min
70ml/min/100grams x 300 grams =
210 mL/min
When will you find the peak flow of coronary perfusion?
At the beginning of diastole where ventricle pressure is the lowest and coronary vessels are wide open.
Which coronary artery will have more consistent perfusion? Why?
Right coronary artery because it feeds the right heart which has lower wall pressures.
Which heart valve problem will have trouble with filling?
Mitral valve stenosis
How does the body compensate for mitral valve stenosis?
What will be the consequence of this?
The body will help out filling by expanding blood volume. Increasing preload in the left heart, by increasing pulmonary venous pressure.
Increasing CVP and afterload in the right heart.
Which cardiac chamber is least affected by mitral valve stenosis?
Left ventricle will not be affected.
Which way will the pressure-volume loop be shifted in mitral valve stenosis?
Shift left (lower intraventricular volume)
What kind of axis deviation would you expect in mitral valve stenosis?
Right axis deviation due to RV hypertrophy.
(90:30)
Mitral valve stenosis will expand out the __________.
Left atrium
A stretched left atria will result in a what EKG change?
prolonged p-wave on the EKG
What will happen if someone with mitral valve stenosis is experiencing atrial fibrillation?
Severe decrease in filling = ↓↓↓ CO
What happens if someone with mitral valve stenosis is experiencing tachycardia?
Decreased period of diastole will shorten the time the heart needs to fill the ventricles.
What can cause mitral stenosis?
Rheumatic Fever
Strep Infection
Where is the blood going during systole in mitral valve regurgitation?
Blood will be pushed into the left atrium.
What is the normal venous return to the heart per beat?
What does that mean for the left atria with mitral valve regurgitation?
What does it mean for LV EDV?
70 cc
The left atria will have more than 70 mL in the chamber d/t to blood being backed up during systole.
This means there will be enhanced filling for the LV EDV.
_______% of people with coronary artery disease will have mitral regurgitation.
10-20%
Less than _______ mL of backward flow will be considered mild mitral regurgitation
less than 30 mL is mild mitral regurgitation.
Between ______ and ______ mL of backward flow will be considered mid-grade mitral regurgitation.
30 to 60 mL is midgrade mitral regurgitation
Greater than _______ mL of backward flow will be considered severe mitral regurgitation
Greater than 60 mL is severe or end-stage mitral regurgitation
What are two ways to reduce mitral valve regurgitant blood flow?
Decrease afterload = decrease ventricular pressure.
Being slightly tachycardiac (80-90bpm) will decrease time in systole thus decreasing the time of high ventricular pressure
What is the consequence of an increased time in systole with mitral valve regurgitation?
Increased regurgitation into the left atrium
What do you want to avoid in mitral valve regurgitation?
Avoid Bradycardia
In mitral valve regurgitation, the left atria is being filled from what two places?
Venous return from the pulmonary veins
Regurgitation from the left ventricle
(This will result in the left atrium being stretched out, increasing risk of atrial fibrillation)
In aortic regurgitation, the left ventricle is being filled from what two places?
Filling from the left atria
Filling from aortic regurgitation
Increases left ventricular volume
What shift will occur in the pressure-volume loop with aortic regurgitation?
Shift right (higher intraventricular volume)
What will be the body’s innate response to aortic regurgitation?
Constrict blood vessels to maintain arterial blood pressure
(This will unfortunately increase the amount of regurgitation d/t to increase afterload. More blood will move in the wrong direction.)
How will a decrease in afterload affect aortic valve regurgitation?
Less regurgitation
How will intraventricular pressure compare to normal in aortic stenosis?
There will be a higher intraventricular pressure in aortic stenosis.
(115:00)
What will happen to pulse pressure with aortic stenosis?
What will happen to BP?
Decrease pulse pressure downstream from the bad valve.
Blood pressure may decrease.
What will happen to stroke volume in aortic stenosis?
↓ SV
What will be the compensatory mechanism for aortic stenosis?
↑HR to compensate for decreased SV to maintain CO.
Aortic stenosis will cause problems with coronary perfusion which will put patients at increased risk for _________.
Myocardial Infarctions
What type of heart wall thickening happens with aortic stenosis?
Concentric Hypertrophy of the LV
Thickening of heart walls via the addition of parallel sarcomeres
What conditions will cause eccentric hypertrophy?
- Aortic valve regurgitation
- Mitral valve regurgitation
Eccentric hypertrophy is the addition of sarcomeres in series, resulting in elongated (dilated) heart walls
How will preload be affected by concentric hypertrophy?
There will need to be a higher preload to fill the blood with a normal amount of volume due to decreased compliance (thick muscles).
Differentiate concentric hypertrophy vs eccentric hypertrophy at the cellular level.
- Concentric Hypertrophy = sarcomeres in parallel.
- Eccentric Hypertrophy = sarcomeres in series.
