Cardiac Flashcards
Functions of the Heart
Heart pump –Oxygen to the body from blood flow through the heart
Functions of the Heart
Electrical activity
Electrical activity starts at the SA node
Functions of the Heart
Coronary flow/Vascular
Arterial vascular problems—Circulation
Oxygen
poor blood returns to the heart through the vena cavae (superior and inferior)
The blood enters
the right atrium
The blood flows through the
the tricuspid valve into the right ventricle
The right ventricle pumps the blood to the lungs
through the pulmonary valve to the pulmonary arteries
In the lungs,
the blood picks up oxygen and gets rid of carbon dioxide
The oxygen-rich blood returns to the heart through
the pulmonary veins and into the left atrium
The blood flows through the mitral/Bicuspid valve into
into the left ventricle
The left ventricle pumps the blood out of the aortic valve
the body through the aorta
Heart Valves
TP My Ass
Automaticity
Ability to initiate an impulse spontaneously and continuously
Excitability
Ability to be electrically stimulated
Conductivity
Ability to transmit an impulse along a membrane in an orderly manner
Blocks affect conductivity
Contractility
Ability to respond mechanically to an impulse
Contraction or relaxation
P wave
atrial contraction
Should always be upright
P-R interval
from beginning of p wave to the end of the r
Should be 0.12-0.20
QRS
ventricular contraction and atrial relaxation
Can be upright or downward
0.06-0.10
QRS
ventricular contraction and atrial relaxation
Can be upright or downward
0.06-0.10
QT Interval
0.4-0.43
Q wave
should be downward (if half the size of S wave it can be a sign of old infarct)
T wave
repolarization of ventricles
ST elevation
STEMI - MI
ST depression
ischemia
U wave
repolarization or perkinges seen in hypokalemia
Lead Placement
White on right
Smoke over fire
Shit in the middle
3 lead—White, black, red leads used
big box
0.2
small box
0.04
artifact
junk
if artifact is present
ask pt to stop moving or move leads around
Normal Sinus Rhythm
SA node fires 60 to100 beats/min
No abnormalities
Follows normal conduction pattern
P wave is normal, upright, and precedes QRS complex
QRS has normal shape and duration
Normal is 0.06–0.10
Sinus Bradycardia
SA nodes fires at less than 60 beats/min
Causes
Can be normal rhythm in:
Aerobically trained athletes
During sleep
Anesthesia
Can occur in response to unopposed PNS stimulation
Brain injury/death
Also associated with some disease states
Hypothermia
Inferior MIs
Medications—Beta blockers (—olol), CA channel blockers (—pine)
Increased ICP, hypothyroidism, hypothermia
Normal P waves and intervals other than QT or QRS
Possible prolonged QT and QRS
Bradycardia Meds
Atropine 0.5-1mg IVP
Dopamine or epinephrine infusion
If atropine is not working
IV continuous infusion
Raise HR and BP
Bradycardia Tx
Pacemaker
Can be outside pacing with pacing pads
Transcutaneous pacing—pads
IV pacemaking
Both temporary
Implanted cardiac pacemaker
Permanent
Sinus Tachycardia
HR between 100-180
Still normal intervals and P waves
Vagal inhibition or sympathetic stimulation
Unopposed sympathetic response
Associated with other physiologic and psychologic stressors/factors—
Tx for tachycardia
Guided by cause
Ie. treat fever or pain
Acetaminophen (Tylenol) (Tylenol) or pain meds
Vagal maneuver—Take a breathe in and bare down like they are having a bowel movements
Adenosine
Stop or pause cardiac cycle and restart it (hopefully in a normal sinus rhythm)
Calcium channel blockers
Diltiazem (Cardizem) drip
Very effective
Synchronized cardioversion
RARE for sinus tachycardia
Only if patient is not responding to any other treatments
Premature Atrial Contraction
Atrial contraction which results from depolarization of an ectopic focus in atria
Discharges before SA node
Early beat but skinny QRS complex
Clinical associations of Premature atrial contraction
Clinical association
Emotional stress
Sepsis
Stimulants
Caffeine
Nicotine
Tobacco
COPD
Valvular disease
Atherosclerosis
Electrolyte disturbances
Paroxysmal Supraventricular Tachycardia (PSVT) (SVT)
“Before the ventricle” (atrial)
Reentrant phenomenon: PAC triggers a run of repeated premature beats
Paroxysmal refers to an abrupt onset and ending
Can have sustained SVT
Paroxysmal
refers to an abrupt onset and ending
SVT Manifestations
HR is 151 to 220 beats/min
Little runs/bursts of severe tachy
HR greater than 180 leads to decreased cardiac output and stroke volume—deteriorate fast
SVT Treatment
IV adenosine—EMERGENCY TX
Give 6mg over 3 seconds with flush for first dose
Rapid IV push
Repeat with 12 mg as needed
Short half life (10s) causes asystole
If PSVT occurs after asystole—
give another dose of adenosine
12 mg IVP fast followed by flush
Ablation for SVT
if patients lives in this rhythm and other treatments have been done many times without helping
Burn area in the heart to scar tissue so ectopic electrical currents don’t occur
May do multiple areas
Atrial Flutter
Non-sinus Rhythm
Stimulus is started in the atrium
Several P-waves
Document the ratio
4:1
REGULAR
Drugs used for a flutter
Digoxin—pretty effective
Epinephrine
Treatment for a flutter
*(a)Diltiazem: IV infusion calcium channel blocker
(b)Digoxin—PO when patient goes home
(c)B-blockers
(d)Antiarrhythmics
Amiodarone—ventricular antidysrhythmic
Sotalol
Electrical cardioversion will be done
Atrial Fibrillation
Paroxysmal or persistent
Can go in and out of AFib (paroxysmal)
Most common dysrhythmia
IRREGULAR
Rate can be normal or RVR
May have no discernible P wave
Afib Tx
1 Diltiazem (Cardizem)
Calcium Channel Blocker as IV infusion
Amiodarone
Can damage lungs as side effect so start with diltiazem
Damage can become permanent
Electrical (synchronized) cardioversion
Anticoagulation
Heparin drip in acute care settings
Pradaxa or warfarin PO at home
NOT for the rhythm but prevents complications associated with AFib
Ie. stroke and PE
if the r is far from the p
then you have a first degree
longer, longer, longer, drop
then you have a Wenkebach
if the Ps dont get through
then you have a mobitz 2
if the Ps & the Qs then you have
a 3rd degree
First-Degree AV Block
AV node PR interval conduction is prolonged (greater than 0.2 sec)Still have a P-wave before all QRS complexes and should have the same P-R interval
Second-Degree AV Block, Type 1 (Mobitz I, Wenckebach)
P—P intervals occur regularly, however the PR interval gets longer and eventually QRS will be missed
Missed QRS (blocked)
PR intervals get bigger until QRS is blocked
PR interval is still prolonged
HR gets lower due to missed QRS complexes
Second-Degree AV Block, Type 2 (Mobitz II)
Impulses are blocked at the AV node on a regular basis
3:1, 2:1 conduction—MISSED QRS ON REGULAR BASIS
In conducted beats, the PR interval is constant
Measure the same
The block is in HIS Purkinje system
QRS wider
Regular atrial rate with irregular ventricular rate
