Cardiology Flashcards
What is the purpose of the cardiovascular system?
Circulate blood containing oxygen and nutrients, while also providing a means for waste removal
What are the three components of the heart?
Heart
Blood
Vasculature structures (Pipes)
Veins carry blood towards where?
The heart
Arteries carry blood away from where?
Away from the heart
The circulatory system is closely tied to which system?
Pulmonary system, changes in one will quickly result in changes to the other
Almost every cell in the body lies adjacent to what?
A capillary
The entire system of blood vessels including arteries, veins and capillaries totals to about how many miles?
60,000
The main energy source in the body is what?
Oxygen
Oxygenated blood leaves from where in the heart?
Left ventricle
Oxygenated blood travels through where after leaving the left ventricle?
The aorta
After oxygenated blood arrives in the artery where does it go?
Arteriole then the capillary
Oxygen and nutrients are exchanged with what gas along with what other products?
CO2 and waste
If perfusion issues occur above the renal arteries what organs are compromised?
Kidneys, Urine output will be slowed and/or stopped
The apex of the heart is inferior or superior to the base of the heart?
inferior
Where is the tricuspid valve located in the heart?
The right side
Which side of the heart is higher pressure/has more muscle mass and why?
left side because it has to pump blood to the whole of the body while the right side only has to pump blood into the lungs
Where does oxygen poor blood enter the heart?
Through the superior and inferior vena cava into the right atrium
Where does blood go from the right atrium?
The right atrium contracts pushing the blood into the right ventricle through the tricuspid valve
Where does blood go from the right ventricle?
Leaves the right ventricle through the pulmonic valve into the pulmonary artery and then to the lungs where it is oxygenated
Where and how does oxygenated blood enter the heart?
Pulmonary vein empties oxygen rich blood from the lungs into the left atrium
As the left atrium contracts where does the blood go?
the left ventricle through the mitral valve
As the left ventricle pumps the blood where does it go?
Leaves the heart through the aortic valve into the aorta and to the body
If the left ventricle is backed up where does the blood back up in?
The lungs
True or false, blood backed up in the right ventricle backs up into the lungs
False
The heart is comprised of what three layers in order of most superficial to deep?
Epicardium
Myocardium
Endocardium
What is the myocardium?
The middle layer and muscle of the heart
What is the endocardium?
The inner lining of the heart
What is the pericardium?
Fibrous tissue that surrounds the heart which consists of the tough outer layer (Parietal Pericardium) and the inner layer (Visceral Pericardium or Epicardium) which lines the outside of the heart as well as the inner most section of the Parietal Pericardium
What is the space between the visceral pericardium and the epicardium filled with?
pericardial fluid
The pressure required to open the aortic valve is known as what?
afterload
In coronary circulation what two major vessels branch off the aorta
Left main coronary artery
Right coronary artery
The left main coronary artery divides into what two other arteries?
Circumflex
Left Anterior Descending
What is coronary circulation?
Circulation of blood through the heart muscle itself
The left anterior descending supplies blood to what structures?
The septum and the ventricular walls
If the left anterior descending is occluded what will happen?
Majority of the left ventricle will become ischemic
The right coronary artery supplies blood to what structures?
The SA and AV node
The right coronary artery also becomes what artery?
The posterior descending artery
Where do coronary veins deposit their blood?
Right atria
Where do coronary veins collect their blood?
From the capillaries into the coronary sinus
What are the two shockable rhythms?
vfib and pulseless vtach
Heart tissue is specialized and found nowhere else in the body, what are the three unique properties to heart tissue?
Automaticity
Excitability
Contractility
Define inotropy
Inotropy is the strength of the cardiac contraction
Define chronotropy
Influence on the heart rate
Define dromotropy
The excitability or willingness of the heart to conduct an impulse through the cardiac cells
What is the Frank-Starling Mechanism?
Mechanism that states the force of blood ejected by the heart is determined primarily by the length of the fibers of its muscular wall
When does atrial kick occur
Occurs just at the conclusion of the transfer between the atria and the ventricles
How much force is potentially lost without atrial kick?
up to 25%
Cardiac cells are connected end to end by what?
an intercalated disk.
What allows an impulse and blood flow to travel all the way down to the apex of the heart?
A system of conduction fibers
Where do contractions begin in the heart?
Contractions begin at the apex and moves towards the base
Where do impulses first occur in the heart?
In the right atrium within a group of specialized cells called the SA (Sino Atrial) Node
The SA node is innervated by what two nervous systems?
Parasympathetic and Sympathetic systems
What is the Atrioventricular Node?
Acts as a gateway, electrically connecting the atria to the ventricles.
Also slows down the conduction to allow for atrial kick
What do the bundle branches do?
Transmit electrical impulses quickly into the apex of the ventricles
Where do impulses terminate in the heart?
In a network of small conduction fibers known as the Purkinje network
How are cardiac cells interconnected?
End to end through an intercalated disk
Does the body always want all electrical forces neutral?
Yes
How does the body attempt to maintain the number of particles in balance?
Diluting an area of higher concentration of particles with an area of lower concentration of particles
Where are Sodium and Potassium particles found in highest concentrations?
Sodium is found in high concentration outside the cell
Potassium is found in high concentration inside the cell
What are the two axis on a cardiac monitor represent?
Y axis: Millivolts
X Axis: Time in seconds
Which wave represents the movement of conduction from the SA node to the AV node
P wave
If the P wave is depressed below the isoelectric line, what does that indicate?
The AV node firing towards the SA node
The section of the wave after the P wave represents what?
The delay in conduction in the AV node to allow atrial kick to occur
A resting cell is polarized or depolarized?
Polarized
What does the QRS wave represent?
Ventricle depolarization
One small box on an ECG grid paper is how many seconds?
0.04 seconds
One large box on ECG grid paper is how many seconds?
0.20 Seconds (One large box is 5 small boxes lengthwise)
What is the PR interval normal duration?
between 0.12 and 0.20 seconds
What can a prolonged PR Interval indicate?
Delay in the AV node
How long does a normal QRS complex take?
between 0.04 and 0.12 seconds
If after the P wave there is only a single negative deflection what is that wave called?
QS Wave
What does the T wave represent and how long is the normal duration?
Represents the repolarization of the ventricles and duration is normally between 0.10 and 0.25 seconds
What is the J point?
The end of depolarization
What speed does ECG paper come out?
25mm per second
What does STEMI stand for?
ST ELEVATION MI
What are the five steps you follow when interpreting EKG strips?
- Rate (Beats per minute)
- Rhythm (including presence of ectopic beats)
- Presence and shape of the P wave, and its relationship to the QRS
- PR Interval
- QRS Complex
How does an EKG count heart rate and what should you be conscious of?
An EKG only detects electrical impulses but DOES NOT notice if a heart beat is actually perfusing
What is a good method for counting beats in an irregular rhythm?
Count the number of R waves in a 6 second strip and multiply by 10
What is a method of estimating heart rate on an EKC strip?
Count the number of large squares between two consecutive R waves and divide into 300
OR
Memorize this scale: 1 large square = 300 bpm 2 large square = 150 bpm 3 large square = 100 bpm 4 large square = 75 bpm 5 large square = 60 bpm 6 large square = 50 bpm
What are the 4 regularities of rhythm?
Regular
Essentially regular
Regularly irregular
Irregularly irregular
If the length of a PR interval is longer than 0.20 seconds what could that potentially be?
Blockage in the AV node or junction
While inspecting the QRS complex you must look at:
The duration
The height
The presence of Q waves and their lengths and size
General configuration of the complex noting any slurring or notching
What is a Q wave?
Initial negative deflection on an EKG, lengthening of the Q wave may indicate myocardial infarction
Define Absolute Refractory period.
Period of time where a second action is unable to be started no matter how large of a stimulus is given.
Define relative refractory period.
Period of time where a second action can be initiated but is inhibited or requires a large amount of stimulus
heart rate is affected by what nervous system?
Autonomic nervous system, (parasympathetic and sympathetic branches)
How many millivolts are one small box equal to on an EKG strip equal to?
1/10th of a millivolt
How many millivolts are large boxes on an EKG strip?
0.5 millivolts
Define wandering pacemaker
Pacemaker site that wanders between the sinus node, the atria and the AV junction. Although each impulse originates from a different focus, the rate usually remains within normal ranges.
What are the rules for a Wandering Pacemaker?
Regularity: slightly irregular Rate: Usually normal, 60-100 P Wave: Morphology changes from one complex to the next PRI:Less than 0.20 QRS: Less than 0.12
Describe one Valsalva maneuver:
Ask the patient to bear down as if to move his/her bowels with his/her nose and mouth closed.
An increase in afterload results in a(n) ________ workload of the heart, especially in the ________ ventricle.
Increased; left
Define Premature Atrial Complex
The pacemaker is an irritable focus within the atrium that fires prematurely and produces a single ectopic beat.
Note: this is a single beat and not an entire rhythm, the underlying rhythm must also be identified
The PR interval reflects all _____ activity
Atrial
Define Atrial Tachycardia
The pacemaker is a single irritable site within the atrium that fires repetitively at a very rapid rate.
Define atrial flutter
A single irritable focus within the atria issues an impulse that is conducted in a rapid repetitive fashion. To protect the ventricles form receiving too many impulses from being conducted through to the ventricles.
Looks similar to a saw tooth
Define Atrial Fibrillation
The atria are so irritable that a multitude of foci initiate impulses, causing the atria to depolarize repeatedly in a fibrillary manner. The AV node blocks most of the impulses allowing only a limited number to go through to the ventricles
Define F waves
Fibrillatory waves associated with atrial fibrillation
What are key characteristics of PVC?
QRS complex longer than 0.12 secs
No preceding P wave
Commonly produces T wave that deflects opposite of the QRS
Compensatory pause
During a junctional rhythm the pacemaker site is located where?
At the AV Junction in the middle of the heart
During a junctional rhythm how will the P wave appear?
Inverted and in different locations dependent on if the atria are depolarized before, during or after the ventricles
During a junctional rhythm if the atria are depolarized before the ventricles how long will the PRI be?
less than 0.12 seconds
An inverted P wave may be what two kinds of rhythms?
Atrial or Junctional
When you see an inverted P wave after the QRS complex where is the origin of the rhythm?
AV Junction
If the inverted P wave occurs prior to the QRS complex what is an important clue to determine if the rhythm originates in the AV Junction or the Atria?
PRI for a junctional rhythm should be less than 0.12 while a rhythm occurring in the atria should take the normal length of time
Define Premature Junctional Complex
Irritable focus in the AV Junction that produces a single ectopic beat. P wave will be inverted if visible and if the P wave occurs prior to the QRS complex it will last shorter than 0.12 seconds.
Define junctional escape rhythms
Regular rhythm
Rate of between 40-60
P wave inverted before during or after the QRS complex
Define and differentiate Accelerated Junctional Rhythm and Junctional Tachycardia
Accelerated junctional is a junctional rhythm that has a rate between 60 - 100
Junctional tachycardia is a junctional rhythm that has a rate of between 100 - 180
What rhythms are classified under Supraventricular Tachycardia?
Sinus Tach
Atrial Tach
Junctional Tach
Atrial Flutter
How many degrees of heart blocks are there?
3 degrees
Define 1st degree heart block
AV Node holds each impulse longer than normal before conducting it to the ventricles. Each Impulse is eventually conducted.
How do you define a first degree heart block on an EKG?
Normal sinus rhythm except the PRI is greater than 0.20
Define second degree heart block type 2
The AV Node constantly holds PRI longer than normal and blocks some P waves
Define “wenckebach” type 1 second degree heart block
PR Intervals will get progressively longer until one is blocked and the cycle starts over
What is the difference in QRS between a third degree heart block with ventricular or junctional escape
Junctional escape QRS is under 0.12 while a ventricular escape will have a QRS of greater than 0.12
Define ventricular tachycardia
Irritable focus I the ventricles firing quickly and overriding higher sites In the heart
Regular
No p wave
Define ventricular fibrillation
Multiple focus sites become irritable in the ventricles
Completely chaotic with no patterns
Define idioventricular rhythm
Ventricles initiate a regular impulse at their inherent rate of 20 - 40 bpm
No p wave
Wide QRS
Bpm of 20 - 40
Define asystole
No electrical activity
What does a wide QRS duration indicate?
Ventricular rhythm
What does a narrow QRS duration indicate?
Atrial or junctional rhythm
Define artificial pace maker
Device used to provide artificial electrical stimulus to the myocardial tissue to stimulate depolarization
Every time a pacemaker fires, what is produced in an ekg strip?
Spike
What are two different types of pacemakers
Temporary and permanent
What are the two types of temporary pacemakers
Transcutaneous and Transvenous
Are pace makers able to stimulate different areas of the heart?
Yes
When would you classify a rhythm as SVT?
When a P Wave is not visible and the rate is common among other arrhythmia
Define interpolated PVC
A PVC that occurs and does not interrupt the underlying rhythm
Define unifocal PVC
PVC’s that occur in the same spot, the morphology will be similar
Define R on T phenomenon
PVC that occurs during the preceding t wave
Define PVC Cooley and run
Two PVC’s in a row is a couplet
More than that it’s a run
Define bigeminy, trigeminy, quadrageminy
PVC’s that occur consistantly on the specified beast
