ECG Flashcards
Where is the base of the heart located?
Level of the second rib
Where is the apex of the heart located?
Towards the left hip, rest on the diaphragm between the 5th-6th rib
What is the right and left atrias separated by?
Interatrial septum
What blood does the right atrium receive?
It receives deoxygenated blood returning from the systemic circulation
What blood does the left atrium receive?
Receives oxygenated blood returning from the pulmonary circulation
What separates the left and right ventricles?
Interventricular septum
Where does the right ventricle pump blood to?
The lungs
Where does the left ventricle pump blood to?
The rest of the body
What does the superior vena cava do?
Transports blood from parts of the body superior to the diaphragm to the right atrium
What does the inferior vena cava do?
Transports blood from parts of the body below the diaphragm to the right atrium
What does the coronary sinus do?
Transports deoxygenated blood back to the right atrium from coronary circulation
What does the pulmonary artery do?
Transports deoxygenated blood to the lungs
What does the pulmonary vein do?
Returns blood from the lungs to the left atrium
What does the aorta do?
Pumps blood out of the heart, largest artery of the heart
Where is the Atrioventricular (AV) valve located?
Located between the atria and the ventricles
What are the two AV valves?
- Tricuspid
- Mitral (bicuspid)
What does the semi lunar valve do?
Prevents backflow of blood into the ventricles
What are the two semi lunar vlaves?
- Pulmonary valve
- Aortic valve
What is the pericardium?
Surrounds the heart and roots of the great vessels
What are the two layers of the pericardium?
- Parietal layer
- Visceral layer
What is the epicardium?
A serous membrane that forms the innermost layer of the pericardium and the outer surface of the heart
What is the myocardium?
Is the muscular middle layer of the wall of the heart
What is the endocardium?
The thin, smooth membrane which lines the inside of the chambers of the heart and forms the surface of the valves
What is pericarditis?
Inflammation of the pericardium
What is endocarditis?
An inflammation of the inner lining of the heart
What is myocarditis?
An inflammation of heart muscle
what is cardiac tamponade?
Is compression of the heart produced by the accumulation of fluid or blood in the pericardial sac
What is the pulmonary circuit?
- Blood enters the right atrium through (inferior vena cava, superior vena cava, coronary sinus)
- Pass down to the right ventricle
- Than enters the pulmonary arteries
- Go into the left and right lung
- Carbon dioxide is unloaded, and oxygen picked up
- Returns to the left atrium through pulmonary veins
What is the systemic circuit?
- Left atrium to left ventricle to the aorta
- enters the aorta (the right and left coronary)
- Goes to the arteries reaching body tissues, branch into small capillaries
- Oxygen leaves blood to enter body tissue, carbon dioxide from tissue cells is picked up
- Capillaries join to form veins leading back to the heart
What includes the left main coronary artery?
- Left anterior descending (LAD)
- Left circumflex artery
What includes the right coronary artery?
Includes the posterior descending artery
What do both the right and left coronary artery do?
Returns blood back to the right atrium through the coronary sinus
What is the dominant pacemaker of the heart
SA node
What is Polarization?
Depolarization?
Repolarization?
- Polarization=Resting state during which no electrical activity occurs
- Depolarization=When the cardiac cell is stimulated “contraction of the muscle”
- Repolarization=The returning to a resting state
What are the major ions that affect cardiac function?
- Sodium
- Potassium
- Calcium
What is refractory periods?
When the cell cannot be re-stimulated (it is necessary to allow the ventricles sufficient time to empty)
What is automaticity?
Ability to spontaneous initiate an impulse
What is excitability?
Ability to respond to an impulse
What is conductivity?
Ability to receive and transmit an impulse
What is contractility?
Ability to contract in response to an impulse
What is the sinus node?
- The hearts natural pacemaker
- Initiates heart rates between 60-100 bpm at rest
What is the atrioventricular Node (AV node)?
- Receives impulses from SA node
- Delivers impulses to the His-Purknje network
- Delivers heart rates between 40-60bpm (if SA node fails to deliver impulses)
What is the bundle of His?
Begins conduction to the ventricles
What is the Purkinje network?
Moves the impulse through the ventricles for contraction
What is called the escape rhythm?
The Purkinje network that initiate heart rates between 20-40 bpm
What is the automatic nervous system?
Controls of the heart rate and force of contractility
Which leads are the bipolar leads?
I, II, III
Which leads are the augmented unipolar leads?
aVR, aVL, aVF
Which leads are the precordial or chest leads?
V1, V2, V3, V4, V5 and V6
What are the cardiac deflections?
P,Q,R,S,T
What is the purpose of an ECG?
- The amount of voltage generated by the heart
- The time required for the voltage to travel through the heart
What will an ECG not reflect?
- Mechanical function of the heart
- Etiology and pathology of the heart disease
- Structural and functional impairment
- Coronary heart disease when related to silent ischemia
For the triangle in bipolar leads, where is lead I
Left arm and right arm
For the triangle in bipolar leads, where is lead II?
Right arm and left leg
For the triangle in bipolar leads, where is lead III?
Left arm and left leg
What does the a in aVL stand for?
augmented lead
What is the normal paper speed?
25 mm/second
What are three clinically acceptable ECG?
Baseline: must be constant, horizontal or flat and free from artifacts, wherever possible
Leads: must be correctly place connect patient cable
Tracing: properly centered, coded and labelled correct leads, patients name, date and time
What are two technical errors?
- Reversed arm leads
- Chest leads hooked up incorrectly
What is a wandering baseline?
Weaves up and down rhythmically with a “snakelike” motion
this artifacts makes it difficult to evalulate ST segment
How do you fix a wandering baseline artifact?
- Dry electrodes
- Loose connections
- Patient cable swinging or dangling
What is the most common artifact and has no fixed pattern?
Muscle artifact
What does an alternating current (AC) artifact look like?
recognized by its uniform and regular saw-tooth appearance. (60 cycle interference)
What is the cause of alternating current artifacts?
Leakage of 60 cycle electrical current from: nearby electrical equipment which may not be property grounded, such as a ventilator, electric beds, etc
Where are the normal placements for on the arms and legs?
Mid-calf and mid-forearm
Which leads should not be compromised where at all possible?
Precordial leads
What are 6 types of patients that may need modifications?
- Isolation
- Burns
- Geriatric
- Mastectomy and breast implants
- Pediatric
- Psyhiatric
What does the mean QRS axis represent?
The average of instantaneous forces generated during a sequence of ventricular depolarization
What does the normal QRS axis range from?
0 degrees to +90 degrees