basic ekg Flashcards
The heart has the innate ability to generate its own spontaneous action potentials without any external stimuli, a phenomenon known
as automaticity.
The rate at which the pacemaker cells fire is
HR
The pacemaker cells do not have a true ___ in their action potential cycle.
The pacemaker cells do not have a true “resting phase” in their action potential cycle.
The contractile cells make up ____ of the myocardium
The contractile cells make up the bulk of the myocardium 99%
what do you give for hyperkalemia
calcium to stabilize the cell membrane
____is the primary pacemaker that produces spontaneous action potentials that will determine the heart rate.
the SA node is the primary pacemaker that produces spontaneous action potentials that will determine the heart rate.
is located at the back of the right atrium near the superior vena cava entry.
SA node
The action potential travels from the SA node through the right atrium via ___, and to the left atrium via ______
The action potential travels from the SA node through the right atrium via the internodal pathway, and to the left atrium via Bachmann’s bundle
the “gatekeeper” that sends the action potential from the atria to the ventricles.
AV node
The other important function of the AV node is that
slows down the conduction velocity of the action potential.
the transition from the end of diastole to the start of systole in the cardiac cycle
, the AV node
can assume what if you have a QRS more than 0.12 sec
ventricular in nature
After the action potential travels through the AV node it will enter___
bundle of His, also known as the atrioventricular bundle.
steps of conduction
- SA node
- internodal pathwya
- AV node
- Bundle of His
- R/L bundle branches
- Purkinje Fibers
SA node speed
60-100
bundle of his speed
40-60
AV node speed
40-60
bundle branch speed
20-40
purkinje fibers speed
20-40
primary cardiac stand still
all you have is P waves
qrs duration
0.08-0.12
P wave positive in what leads
I,
II,
aVF,
V4-V6
AV conduction duration and represented by?
0.10-0.20
PR interval
P wave duration
<0.12sec
ST elevation in all leads
pericarditis
T wave positive in what leads?
I
II
V3-V6
PSVT caused by?
cell doing abhorrent pathway and fires off, then shuts down
Adenosine dosage: for afib
Adenosine dosage: 6mg, 12mg, 12mg
very rare that pt becomes unstable in ?
a flutter
PVC most common cause
hypoxia
what to do with PVC?
Check pulses and see if pt is perfusing with each beat
medication for 2nd degree type 1
isoproteronal, epi, dopa
reversal for TCA antidepressant
sodium bicarb
classic presentation of torsades
taking lots of antacids
excessive hydration
Halothane/enfluranedoes what?
Halothane/enflurane-sensitize myocardium
sevo does what in infants?
brady
bc vagal influence is stronger in kids
desflurane cautious of what?
prolonged QT during induction
MAC is 6, have to dial it slowly
Local anesthetics can cause what? reversal?
severe brady. asystole
lipid rescue
stop brady with what med?
glycopyrullate
most common cause for perioperative dysrhytmias?
intubation
postoperative dysrhytmias causes?
hypoxemia,
cardiac ischemia
catecholamine excess (sometimes we cause)
emd
electrical mechanical dissocition
pea
1 and 2 cause of cardiac arrest
hypoxia and hypovolemia
what kind of MI results in death of pacemaker cells?
right heart
s/s bradycardia hypotension
reversal for lopressor
glucagon
lidocaine contraindicated in heart blocks bc?
lidocaine works primarily in the ventricle, so itll knock out ventricular component
hyperventilation does what to K
hypokalemia
ketamine does what to HR/BP
increase HR/BP
bronchodilator does what to K, albuterol
hypokalemia
during carotid endarectomy, what can you do to stopy brady?
local anesthetitc around vagal area
brady caused how in abdominal surgery?
air is pumped in, IVC compressed with less venous return
atropine vs glycopyrullate
glyco is slow onset and long duration
during cvp cannulation, you see PVCs, what do you do?
pull back, tickling atria
pressure on eyes causes what?
brady
