14 EKG Basics
Last updated
Was this helpful?
Last updated
Was this helpful?
_..
SA to LA and RA myocytes
HIS bundles, left and right BBB, purkinje embedded in myocytes
time x axis, electrical activity in y axis
P: atrial depolarization
flat after P: time for electrical activity to go to ventricles
QRS: ventricle depolarize
T: repolarization of ventricle. Atrial repolarization happens during QRS
_..
speed by which electricity moves through heart
most of time between P and QRS is by AV nodal conduction
_..
small box: 40 ms
big box: 200 ms
300 / # of big boxes
_..
some electrical activity to left, right
sum of all activity: arrow
each of 12 EKG leads look at summation from different POV = different QRS shape
AVR: summation away, negative QRS
1, AVL: summation towards, positive
_..
-30 and -90
V tach, activity not from SA node but from ventricle itself
90 and 180
positive lead 1: toward 0
negative lead 1: towards 180
positive lead 2: going down
negative lead 2: going up
added lead 1 and 2 vectors to have summation vector
exception: part up part down, physiologic, slightly to left, nl
_..
PR: shorter than 1 big box
_..
less than 3 small boxes
Inactivated peanut butter jar: TCAs block the cardiac fast Na+ channels, decreased contractility, QRS, QT propagation
Wide QRS crack: TCAs can widen the QRS complex on ECG
Twisted torsades streamer: TCAs can induce torsades
Lightly held peanut butter jar: class IA antiarrhythmics have an intermediate binding affinity for the Na+ channel (intermediate use-dependence, moderate slowing of the phase 0 upstroke)
Pushing away the curtain: class IA antiarrhythmics also block K+ channels, prolonging phase 2 and 3 of the cardiac action potential -> prolonged refractory period
Twisted torsades streamer: class IA antiarrhythmics can cause Q-T interval prolongation (precipitates torsades) (K channel prolongation)
Wide QRS shaped crack: class I antiarrhythmics widen the QRS complex on the ECG (decreased AP conduction velocity) (faster cells bind more and slow down more) (QRS widen as HR increases)
_..
less than half QRS - QRS
left: T begin immediately without flat portion
hypocalcemia: less driving force to move Ca in, longer for Ca to go in, longer for QT interval to occur (myocyte in ventricles to depolarize, repolarize )
Torsades strip: risk of prolonged Q-T interval
Twisted streamer: FGAs can cause torsades de pointes
Lightly held peanut butter jar: class IA antiarrhythmics have an intermediate binding affinity for the Na+ channel (intermediate use-dependence, moderate slowing of the phase 0 upstroke)
Pushing away the curtain: class IA antiarrhythmics also block K+ channels, prolonging phase 2 and 3 of the cardiac action potential -> prolonged refractory period
Twisted torsades streamer: class IA antiarrhythmics can cause Q-T interval prolongation (precipitates torsades) (K channel prolongation)
Wide QRS shaped crack: class I antiarrhythmics widen the QRS complex on the ECG (decreased AP conduction velocity) (faster cells bind more and slow down more) (QRS widen as HR increases)
Pushing away the curtain: class III antiarrhythmics block K+ channels prolonging phase 2 and 3 of the cardiac action potential -> prolonged refractory period
Twisted streamer: sotalol, dofetilide, and ibutilide can induce torsades (although all type III antiarrhythmics can widen the QT interval)
Inactivated peanut butter jar: TCAs block the cardiac fast Na+ channels, decreased contractility, QRS, QT propagation
Wide QRS crack: TCAs can widen the QRS complex on ECG
Twisted torsades streamer: TCAs can induce torsades
_..
Torsades strip: risk of prolonged Q-T interval
Twisted streamer: FGAs can cause torsades de pointes
Lightly held peanut butter jar: class IA antiarrhythmics have an intermediate binding affinity for the Na+ channel (intermediate use-dependence, moderate slowing of the phase 0 upstroke)
Pushing away the curtain: class IA antiarrhythmics also block K+ channels, prolonging phase 2 and 3 of the cardiac action potential -> prolonged refractory period
Twisted torsades streamer: class IA antiarrhythmics can cause Q-T interval prolongation (precipitates torsades) (K channel prolongation)
Pushing away the curtain: class III antiarrhythmics block K+ channels prolonging phase 2 and 3 of the cardiac action potential -> prolonged refractory period
Twisted streamer: sotalol, dofetilide, and ibutilide can induce torsades (although all type III antiarrhythmics can widen the QT interval)
Inactivated peanut butter jar: TCAs block the cardiac fast Na+ channels, decreased contractility, QRS, QT propagation
Wide QRS crack: TCAs can widen the QRS complex on ECG
Twisted torsades streamer: TCAs can induce torsades
_..
longer to depolarize/repolarize, longer QT
not really seizures, passing out from torsades
_..
hyperacute: precede ST elevation in ischemia
