Lab midterm #2 Flashcards
normal axis deviation
lead 1, lead 2, lead 3 all positive
right axis deviation
lead 1 negative
lead 2 positive
lead 3 positive
left axis deviation
lead 1 positive
lead 2 negative
lead 3 negative
heart rate determination
HR in bpm (beats per minute) = 1500/# of tiny beads
PR interval
the time interval from the beginning of the P wave (the onset of atrial depolarization) until the beginning of the QRS complex (the onset of ventricular depolarization) through the AV junction
normal PR interval range
0.12 sec to 0.2 sec
prolonged
> 0.2 sec, indicates heart block
abnormally short
<0.12 sec, indicates less blood flow and lower cardiac output
SA block
(characteristic and where to look)
look at lead II
absent p wave
first degree AV block
(characteristic and where to look)
look at lead II
long PR interval
second degree AV block (Mobitz I)
(characteristic and where to look)
look at lead II
increasing PR intervals, until QRS is dropped or missing
second degree AV block (Mobitz II)
(characteristic and where to look)
look at lead II
multiple p-waves
can be 2:1 ratio or 3:1 ratio
third degree AV block
(characteristic and where to look)
look at lead II and pattern along entire strip
no association
right bundle branch block “RBBB”
(characteristic and where to look)
look at lead V1 and/or V2 (right side leads)
R is left ventricle and R’ is right ventricle
two peaks, R and R’ where R’ is higher
left bundle branch block “LBBB”
(characteristic and where to look)
look at lead V5 and/or V6 (left side leads)
R is right ventricle and R’ is left ventricle
looks like a plateu
right atrial enlargement (RAE)
(characteristic and where to look)
look at lead II, III, and aVF (inferior leads)
tall p wave
left atrial enlargement (LAE)
(characteristic and where to look)
lead II, III, and avF (inferior leads)
lead I has a wide p wave
lead V1 has a biphasic p wave
right ventrical hypertrophy (RVH)
(characteristic and where to look)
look at leads V1 and V5 and V6
V1 and V2 are positive
V2 and V6 are negative
left ventricle hypertrophy (LVH)
(characteristic and where to look)
look at leads in V1 and V5 or V2 and V6
sum of S wave in V1 and R wave in V5 is greater than or equal to 35nm
PVC criteria
- no p wave
- wide QRS complex
- T wave usually points in the opposite direction of the QRS wave
Unifocal PVC
PVC looks the same in a given lead
Comes from the same source
Multifocal
PVC will look different in a given lead
Comes from different sources
Bigeminy
Every other beat is a PVC
Trigeminy
Every third beat is a PVC
Quadrigeminy
Every fourth beat is a PVC
Ventricular tachycardia (V tachycardia)
3 or more PVCs in a row
R on T PVC
R wave of PVC occurs on T wave of the preceding beat
Ventricular Fibrillation (V Fib)
Rapid, irregular electrical signals cause the heart’s ventricles to quiver uselessly instead of pumping blood
Sudden Cardiac Arrest
Sudden loss of heart activity due to an irregular heart rhythm
Sudden Cardiac Arrest symptoms
- collapse
- no pulse
- no breathing
- loss of consciousness
Symptoms before cardiac arrest
- chest discomfort
- shortness of breath
- weakness
- tachycardia
- palpitations (fluttering or pounding heart)
Causes of sudden cardiac arrest
- coronary artery disease
- heart attack
- cardiomyopathy
- heat valve disease
- congenital heart defect
- long QT syndrome (LQTS)
- atrial flutter and atrial fibrillation
Electrical phase
0-4 mins after cardiac arrest
The heart still has a supply of oxygen and glucose. Conditions are favorable for resuscitation. The heart is prepared to respond to defibrillation.
Circulatory phase
4-10 mins after cardiac arrest
Oxygen stores are exhausted; myocardial cells switch to anaerobic metabolism. CPR is needed to restore a supply of oxygen and glucose to enhance the possibility of successful defibrillation
Metabolic phase
Begins 10 minutes after cardiac arrest
The heart muscle is acidic and ischemic, and begins to die. Changes of resection are unfavorable.
Defibrillation for..
V tach and BV fib
Defibrillation for..
V tach and BV fib
Defibrillation not advised for…
Asystole: absence of electrical activity
Pulses less electrical activity
Cardiac management
- activation of emergency response
- high quality CPR
- defibrillation
- advanced resuscitation
- post cardiac arrest care
- recovery
Crash cart
A self contained, mobile unit that contains life saving supplied and equipment that can be used during a cardiac or respiratory emergency within a medical facility
Drawer 1
Medications
Drawer 2
Incubation materials
Drawer 3
Airway suction materials used to clear obstructed airways, and maybe incubation materials
Drawer 4
IV starting equipment
Drawer 5
IV solutions
Drawer 6
Prepackaged kits for various urgent and emergency procedures
Drawer 6
Prepackaged kits for various urgent and emergency procedures
epicardium
outer layer, visceral layer of the pericardium
myocardium
middle layer, the actual muscle that contracts
endocardium
inner layer, the lining of heart chambers and vessels
coronary artery
vessels that deliver oxygen rich blood to the myocardium
direction of blood flow
from the epicardium towards the endocardium
coronary circulation
the circulation of blood in the blood vessels of the heart muscle
prominent plateau phase
long refractory period that prevents summation and tetanus
tetanus
prolonged contraction of muscle caused by rapidly repeated stimuli
muscles cells around the endocardium are the first to __ and last to __
depolarize, repolarize
muscle cells around the epicardium are the last to ___ and the first to ___
depolarize, repolarize
ischemic heart disease
lumen creates myocardial infarction when it gets clogged to a certain degree
decrease blood flow and oxygen supply
ischemic heart disease causes
- smoking
- hypertension
- high blood LDL
- diabetes
endothelial injury hypothesis
When the endothelial lining of blood vessels is injured, collagen in the basement membrane comes in direct contact with blood causing platelet aggregation
platelets secrete platelet derived from growth factor (PDGF) that stimulate smooth muscle growth that narrows the blood vessel and slows blood flow, and initiation of blood clot
non-transmural infarction
a myocardial infarction that does not involve the full thickness of the myocardium
Types of ST segment depression
downsloping
upsloping
horizontal
downsloping depression
St segment going towards peak of T wave
upsloping depression
nondiagnostic for ischemia
horizontal depression
indicates myocardial ischemia
ST segment elevation
myocardial infarction
ST segment above baseline
transmural myocardial infarction
lack of oxygen delivery (via coronary blood vessel) through the entire wall of the heart
not enough ATP for the Na+/K+ ATPase pump to re-establish the concentration gradient
cells generate action potentials of small amplitude
cells in the epicardium are more affected than cells in the endocardium
inferior wall infarction
leads II, II, aVF
anterior wall infarction
leads V1, V2, V3, V4
lateral wall infarction
leads I, aVL, V5, V6
anterolateral wall infarction
anterior and lateral leads
leads V1, V2, V3, V4
leads I, aVL, V5, V6
risk factors of heart disease
family history, smoker, high LDL, ect
sensitivity
the percent of individuals with heart disease that test positive for the disease
specificity
the percent of individuals without heart disease that test negative for the disease
angiography
can be used to confirm the existence and location of coronary artery disease
medical imaging technique where a catheter is directed to a coronary artery and a radiopaque substance is injected in order to visualize the blood vessels
stent
catheder is directed into the occluded coronary artery and there is a balloon stent
stent pushes the plaque outward against the arterial wall and the artery widens, restoring blood flow
stent made of anticoagulant to prevent platete aggregation
coronary artery bypass graft (CABG)
open heart surgery for people with several coronary obstructions
another blood vessel used to direct blood around obstructed area - saphenous vein or left internal mammary artery (LIMA)
blood directed to a heart by bypass machine while blood vessel is attached
higher risk or mortality, higher cost, increased recovery time
