What is the area on the anterior chest overlying the heart & great vessels called?
Where is the Mediastinum and what does it contain?
Midthroacic cavity in the 2nd to 5th ICS, right sternal border to border to left MCL
Contains the heart & great vessels (aorta, pulmonary artery, inferior / superior vena cava)
Where is the base of the heart located?
Where is the apex located?
Apex is pointed and located at the bottom
5th ICS, 7 - 9 cm left of midsternal line (approximately at MCL)
How is the heart positioned?
Heart is rotated so that the right side is anterior & left side is poterior
What causes the apex shift to the left when the heart is enlarged?
Hypertrophy of heart muscle
What are the structures of the heart?
What is the pericardium and what is it attached to?
Pericardium is the pericardial sac
It is attached to vessels, esophagus, sternum & pleura; anchored to the diaphragm
Where is the epicardial pacemaker placed in case of an emergency?
What does the Myocardium do?
A lot of muscle on the left side pumps blood throughout the body compared to the right side that pumps blood to the lungs.
What is the most inner part of the heart?
What kind of valve pushes the blood through one way?
What kind of valve depends on the pressure gradient of the heart?
Open & close passively hearts
Greater the volume, greater the pressure.
What are the atrioventricular valves?
Left AV = Mitral (Bicuspid)
Right AV = Tricuspid
What is the purpose of the tricuspid (right AV)?
Chordae tendinea attach the AV valves to papillary muscles & provide stability to valves during systole
Rupture of the chordae tendinea may be life threatening. When the chordae tendinea pulls away from the muscle, immediate death occurs.
What are the semilunar valves?
Right = Pulmonic
Left = Aortic
Which semilunar valve mostly pumps unoxygenated blood?
Pulmonic Semilunar Valve (Right)
Which semilunar valve pumps blood from the left ventricle to the aorta into the body?
Aortic Semilunar Valve (Left)
What are the 2 systems in the heart that work together?
Conduction System & Hemodynamic System
Which electrical system initiates & conducts heart beat?
Which system moves blood through the heart & vessels?
What is another word for electrical pathway?
What is the electrical tissue that starts the electrical process?
What is the intrinsic pacemaker?
How does conduction work?
It works like a spark that starts the heart beat & then it is transmitted across atria to the AV node, then to the Bundle of His & finally to the Perkinje fibers in the ventricles.
T/F. Pacemaker can be dormant if normal pacemaker works.
What reflects the electrical conduction through the heart?
Which wave depolarizes the atria?
Which wave spreads stimuli through the atria?
What does it mean when the P wave loos abnormal or absent?
SA node isn't firing properly or doesn't fire at all
At what rate should the SA node fire?
60 - 100 beats per minute (bpm)
What will happen if the heart rate is slower (less than 60)?
As the heartbeat is lower, the lower pacemakers (AV node / junctional node, which is 40 - 60 bpm) take over
What does it mean when the P wave increase?
SA node generates heartbeat.
What happens during the PR interval?
It is the time from stimulation of atria to stimulation of ventricles.
Firing of the SA nodes
The QRS complex is known for what 2 things?
1. Depolarization of ventricles
2. Spread of stimuli through ventricles
What 2 things is the T wave known for?
1. Repolarization of ventricles.
2. Resting phase
The U wave is known for what 2 things?
1. Final ventricular repolarization
2. Not always seen on EKG
What lies at the base of the heart?
- Venous blood
- Arterial blood
Which way does the flow of blood go?
Blood flows from higher to lower pressure gradients
Which way does the blood flow from the lower body?
Lower Body (abdomen, liver) -> Inferior Vena Cava -> Right Atrium
Which way does the blood flow from the head & neck?
Head & neck -> superior vena cava drains venous blood -> Right Atrium
What happens to the blood from the Right Atrium?
Right Atrium carries venous blood -> Tricuspid Valve -> Right Ventricle -> Pulmonary Semilunar Valve -> Pulmonary Arteries (unoxygenated blood) -> lungs / alveoli (oxygenate the blood) -> pulmonary veins (oxygenated blood) -> Left Atrium (arterial blood) -> Mitral Valve -> Left Ventricle -> Aortic Semilunar Valve -> Aorta -> Body
How does the blood move?
Blood moves by pressure gradients.
How can you get backward flow of blood?
Backflow of blood is caused when atrial pressure are excessively high.
What happens in the right side of the heart during backward flow?
1. No valves between right atrium & vena cava
2. If pressure in the right atrium is greater than vena cava, then blood back flows to the veins of the neck & PV system & results in distended neck veins & peripheral edema - which can lead to right valve disease, lung disease, etc.
What are some right-side heart failure signs?
Swelling in feet and legs
What happens in the left side of the heart during backward flow?
1. No valves are between the left atrium & pulmonary veins
2. If pressure in the left atrium is greater than the pulmonary veins, then blood back flows to the lungs & results in pulmonary congestions (ex. crackles / rales) - which can lead to right valve disease, Hypertension (HTN), defective aortic valve etc.
What sounds do you hear in fluid-filled lungs?
crackles / rales
How many breaths per hour is of the inspired spirameter?
10 breaths / hour
What consists of dead space?
Does the dead space have any function?
What is the equation for Cardiac Output?
CO = HR x SV
- increase heart rate leads to increase cardiac output
- Stroke Volume = amount of blood ejected w/ one heart beat (70 mL)
What is the normal rage of Cardiac Output?
4 - 6 L / min
What is another word for Preload?
Left Ventricular End Diastolic Volume (LVEDV)
What happens when the left ventricular volume increases? (preload)
- Causes more stretch on the myocardial muscle fibers at the end of diastole
What is the Frank Starling Law? (Preload)
Greater the stretch of muscle fibers, stronger the contraction
More stroke volume, more preload
- Give fluids until Stroke Volume starts to decrease
- If Cardiac Output is too low, give pt. diuretic
What is the goal of preload?
The goal is to maximize preload (volume) in order to maximize left ventricular contraction & cardiac output
What happens when the preload is excessive?
Excessive preload leads to decreased Cardiac Output & heart failure
What is artherosclerosis?
Plaque build-up which leads to not enough oxygen in blood & makes the muscle work harder
What are other words for Afterload?
What does the afterload do?
- Ventricles work harder & use more oxygen to pump but don't want to use more oxygen b/c can lead to myocardial infarction
- The opposing pressure in the ventricle must generate to open the aortic valve during systole, which increases SVR (afterload)
What does increased SVR (afterload) cause?
- Causes increased aortic pressures
What does excessive afterload increase?
Myocardial workload & oxygen consumption
What is the cause of excessive afterload?
May be caused by arteriosclerosis, HTN, sympathetic nervous system stimulation (stress - anything that causes stress on the sympathetic nervous system), excessive alcohol intake
What is arteriosclerosis?
Hardening of plaque in artery
What are heart sounds produced by?
Heart sounds are produced by closure of the valves
Which side are the valve sounds louder?
Louder on the left side (ex. mitral valve closure is louder than tricuspid & aortic valve closure is louder than pulmonic)
What are the 5 Valve Sites and where are they located?
1. Aortic Valve - 2nd ICS, right sternal border
2. Pulmonic Valve - 2nd ICS, left sternal border
3. Erbs Point - 3rd ICS, left sternal border (good location for referred sounds, place where murmurs radiate to)
4. Tricuspid Valve - 4th IC, left sternal border
5. Mitral Valve - 5th ICS, MCL
What do you when you are listening to valve sites?
- Listen to all sites w/ diaphragm & bell of stethoscope
- Listen for aortic murmurs (sitting & leaning forward is best)
- Listen for extra heart sounds (left lateral decubitus position is best)
What happens in S1?
- Mitral / tricuspid valves closes -> creates S1
- Aortic / pulmonic valves open (when ventricular pressure exceeds aortic) -> ventricles contract & blood is ejected from ventricles
- Ends diastole; begins systole
What happens in S2?
- Aortic / pulmonic valves (semilunar) close -> creates S2
- Mitral / tricuspid valves open
- Rapid filling phase (passive initial filling of ventricles)
- Atrial kick (atrial contraction ejects last 25% of SV into ventricles). AK is normal, but not the S4
- End systole; begins diastole. Diastolic filling
What happens in S3?
S1 ------- S2, S3
"Ken ------- tucky"
- Extra Heart Sounds (Gallops) - diastolic sounds
- Heart Failure
- Non-compliant Ventricle
- Early diastole
- Indicates ventricular resistance to early passive filling
- Occurs in early diastole (immediately after S2)
What are the causes of S3?
- Decreased ventricular compliance (early sign of HF)
- High output conditions such as hyperthyroid, pregnancy, etc.
What happens to compliant ventricles?
Blood flows in freely
What happens in S4?
S4, S1 ------- S2
"Tenness ------- ee"
- Extra Heart Sounds (Gallops) - diastolic sounds
- Heart Failure
- Indicates ventricular resistance to filing during the atrial kick
- Occurs in late diastole (immediately before S1)
What are the causes of S4?
What consists of the Summation Gallop?
S3 & S4
What is Split S1?
- Mitral valve closing before tricuspid valve due to higher pressures on the left
- Uncommon since closure of tricuspid is usually too faint to hear
- May be mistaken for S4
What is Split S2?
- Can be re-created
- Aortic valve closing before pulmonic during deep inspiration
- Changes in intrathoracic pressure w/ deep inspiration causes asynchronous valve closure
- May be mistaken for S3 although S3 isn't affected by breathing patterns
- Most prominent at 2nd ICS, left sternal border at peak inspiration (in contrast to S3 which is best heard at the apex)
What are murmurs?
Blowing / swooshing sound that occurs w/ turbulent flow through valves or great vessels
What causes murmurs?
- Increased velocity (exercise)
- Decreased viscosity (thin)
- Decreased volume (anemia)
- Defective valves (forward or backward flow)
- Septal defects (ABN openings between chambers)
What are the Stenotic Murmurs?
- Stenotic - narrow vessels / narrow valves
- Blood flows through the narrow
- Occurs when a valve is open
- Prevents adequate forward flow through thick, stiff valves
- Causes harsh murmurs
What are the Regurgitant Murmurs?
- Regurgitant - blood goes the wrong way
- Murmurs of insufficiency
- Occurs when a valve is closed or not tightly closed
- Also referred to as insufficiency
- Results in backward flow due to poor valve closure
- Causes turbulent sound
What are the Systolic Murmurs?
- Heard in systole after S1
- Aortic / pulmonic stenosis - when semilunar valves are open
- Mitral / tricuspid insufficiency (regurgitant) - when A/V valves are closed
What are the Diastolic Murmurs?
- Heard in diastole after S2
- Mitral / tricuspid stenosis - when A/V valves are open
- Aortic / pulmonic insufficiency (regurgitant) - when semilunar valves are closed
Determine what type of murmur you are hearing you must:
1. Know if you are in systole or diastole
- One way to tell if you are in systole or diastole is to palpate the carotid pulse while listening to the heart sounds; if you feel the pulse immediately after you hear the heart sound, then you are in systole.
2. Identify at which valve site the murmur is the loudest
3. Know which valves are open & closed to determine if it's stenotic or regurgitant murmur
What are the characteristics of murmurs?
- Systolic vs Diastolic
- Early, mid, or late cycle
- Entire cycle
- Holodiastolic (between S2 & S1)
- Holosystolic (between S1 & S2)
- Intensity (graded 1 [soft] through 6 [loud])
- Location (valve site)
What is an Innocent Murmur?
- Functional murmur
- No valve, cardiac or other pathology
- Common in childhood (usually due to increased blood flow)
What is etiology of chest pain?
- Cardiac (angina, MI, mitral valve prolapse)
- Acute Coronary Syndrom until diagnosis w/ heart attack
- Pulmonary (pneumonia, pleurisy, embolis)
- Pericardial (pericarditis - pain with each heart beat after myocardial infarcation)